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</span> <a href="/www/command-line-options.html#adaptive-resize">‑adaptive‑resize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#adaptive-sharpen">‑adaptive‑sharpen</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#adjoin">‑adjoin</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#affine">‑affine</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#alpha">‑alpha</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#annotate">‑annotate</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#antialias">‑antialias</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#append">‑append</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#attenuate">‑attenuate</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#authenticate">‑authenticate</a> <span class='bull'> • </span> <a 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href="/www/command-line-options.html#colormap">‑colormap</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#color-matrix">‑color‑matrix</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#colors">‑colors</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#colorspace">‑colorspace</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#combine">‑combine</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#comment">‑comment</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#compose">‑compose</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#composite">‑composite</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#compress">‑compress</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#contrast">‑contrast</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#contrast-stretch">‑contrast‑stretch</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#convolve">‑convolve</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#crop">‑crop</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#cycle">‑cycle</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#debug">‑debug</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#decipher">‑decipher</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#deconstruct">‑deconstruct</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#define">‑define</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#delay">‑delay</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#delete">‑delete</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#density">‑density</a> <span 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href="/www/command-line-options.html#identify">‑identify</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#ift">‑ift</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#immutable">‑immutable</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#implode">‑implode</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#insert">‑insert</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#intent">‑intent</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#interlace">‑interlace</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#interpolate">‑interpolate</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#interline-spacing">‑interline‑spacing</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#interword-spacing">‑interword‑spacing</a> <span class='bull'> • </span> <a 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class='bull'> • </span> <a href="/www/command-line-options.html#log">‑log</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#loop">‑loop</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#lowlight-color">‑lowlight‑color</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#magnify">‑magnify</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#map">‑map</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#map_stream_">‑map[stream]</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#mask">‑mask</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#mattecolor">‑mattecolor</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#median">‑median</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#metric">‑metric</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#mode">‑mode</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#modulate">‑modulate</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#monitor">‑monitor</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#monochrome">‑monochrome</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#morph">‑morph</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#morphology">‑morphology</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#mosaic">‑mosaic</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#motion-blur">‑motion‑blur</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#name">‑name</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#negate">‑negate</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#noise">‑noise</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#normalize">‑normalize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#opaque">‑opaque</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#ordered-dither">‑ordered‑dither</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#orient">‑orient</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#page">‑page</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#paint">‑paint</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#path">‑path</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#pause_animate_">‑pause[animate]</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#pause_import_">‑pause[import]</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#pen">‑pen</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#ping">‑ping</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#pointsize">‑pointsize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#polaroid">‑polaroid</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#posterize">‑posterize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#precision">‑precision</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#preview">‑preview</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#print">‑print</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#process">‑process</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#profile">‑profile</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#quality">‑quality</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#quantize">‑quantize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#quiet">‑quiet</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#radial-blur">‑radial‑blur</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#raise">‑raise</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#random-threshold">‑random‑threshold</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#red-primary">‑red‑primary</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#regard-warnings">‑regard‑warnings</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#region">‑region</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#remap">‑remap</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#remote">‑remote</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#render">‑render</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#repage">‑repage</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#resample">‑resample</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#resize">‑resize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#respect-parentheses">‑respect‑parentheses</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#reverse">‑reverse</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#roll">‑roll</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#rotate">‑rotate</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sample">‑sample</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sampling-factor">‑sampling‑factor</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#scale">‑scale</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#scene">‑scene</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#screen">‑screen</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#seed">‑seed</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#segment">‑segment</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#selective-blur">‑selective‑blur</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#separate">‑separate</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sepia-tone">‑sepia‑tone</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#set">‑set</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#shade">‑shade</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#shadow">‑shadow</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#shared-memory">‑shared‑memory</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sharpen">‑sharpen</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#shave">‑shave</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#shear">‑shear</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sigmoidal-contrast">‑sigmoidal‑contrast</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#silent">‑silent</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#size">‑size</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sketch">‑sketch</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#smush">‑smush</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#snaps">‑snaps</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#solarize">‑solarize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#sparse-color">‑sparse‑color</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#splice">‑splice</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#spread">‑spread</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#statistic">‑statistic</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#stegano">‑stegano</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#stereo">‑stereo</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#stretch">‑stretch</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#strip">‑strip</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#stroke">‑stroke</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#strokewidth">‑strokewidth</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#style">‑style</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#subimage-search">‑subimage‑search</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#swap">‑swap</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#swirl">‑swirl</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#synchronize">‑synchronize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#taint">‑taint</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#text-font">‑text‑font</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#texture">‑texture</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#threshold">‑threshold</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#thumbnail">‑thumbnail</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#tile">‑tile</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#tile-offset">‑tile‑offset</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#tint">‑tint</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#title">‑title</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#transform">‑transform</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#transparent">‑transparent</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#transparent-color">‑transparent‑color</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#transpose">‑transpose</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#transverse">‑transverse</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#treedepth">‑treedepth</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#trim">‑trim</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#type">‑type</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#undercolor">‑undercolor</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#unique-colors">‑unique‑colors</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#units">‑units</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#unsharp">‑unsharp</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#update">‑update</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#verbose">‑verbose</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#version">‑version</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#view">‑view</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#vignette">‑vignette</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#virtual-pixel">‑virtual‑pixel</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#visual">‑visual</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#watermark">‑watermark</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#wave">‑wave</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#weight">‑weight</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#white-point">‑white‑point</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#white-threshold">‑white‑threshold</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#window">‑window</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#window-group">‑window‑group</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#write">‑write</a> ] </p> 222 223<div class="doc-section"> 224 225<p>Below is list of command-line options recognized by the ImageMagick <a 226href="/www/command-line-tools.html">command-line 227tools</a>. If you want a description of a particular option, click on the 228option name in the navigation bar above and you will go right to it. Unless 229otherwise noted, each option is recognized by the commands <a href="/www/convert.html">convert</a>, <a href="/www/mogrify.html">mogrify</a>.</p> 230 231<div style="margin: auto;"> 232 <h4><a id="adaptive-blur"></a>-adaptive-blur <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4> 233</div> 234 235<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Adaptively blur pixels, with decreasing effect near edges.</td><td style='text-align:right;'></td></tr></table> 236<p>A Gaussian operator of the given radius and standard deviation (<em class="arg">sigma</em>) is used. If <em class="arg">sigma</em> is not given it defaults to 1.</p> 237 238<div style="margin: auto;"> 239 <h4><a id="adaptive-resize"></a>-adaptive-resize <em class="arg">geometry</em></h4> 240</div> 241 242<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Resize the image using data-dependent triangulation.</td><td style='text-align:right;'></td></tr></table> 243 244<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <a href="#adaptive-resize">-adaptive-resize</a> option defaults to data-dependent triangulation. Use the <a href="#filter">-filter</a> to choose a different resampling algorithm. Offsets, if present in the geometry string, are ignored, and the <a href="#gravity">-gravity</a> option has no effect.</p> 245 246<div style="margin: auto;"> 247 <h4><a id="adaptive-sharpen"></a>-adaptive-sharpen <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4> 248</div> 249 250<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Adaptively sharpen pixels, with increasing effect near edges.</td><td style='text-align:right;'></td></tr></table> 251 252<p>A Gaussian operator of the given radius and standard deviation (<em class="arg">sigma</em>) is used. If <em class="arg">sigma</em> is not given it defaults to 1.</p> 253 254<div style="margin: auto;"> 255 <h4><a id="adjoin"></a>-adjoin</h4> 256</div> 257 258<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Join images into a single multi-image file.</td><td style='text-align:right;'></td></tr></table> 259 260<p>This option is enabled by default. An attempt is made to save all images of 261an image sequence into the given output file. However, some formats, such as 262JPEG and PNG, do not support more than one image per file, and in that case 263ImageMagick is forced to write each image as a separate file. As such, if 264more than one image needs to be written, the filename given is modified by 265adding a <a href="#scene">-scene</a> number before the suffix, in order to 266make distinct names for each image. </p> 267 268<p>Use <a href="#adjoin">+adjoin</a> to force each image to be written to 269separate files, whether or not the file format allows multiple images per file 270(for example, GIF, MIFF, and TIFF). </p> 271 272<p>Including a C-style integer format string in the output filename will 273automagically enable <a href="#adjoin">+adjoin</a> and are used to specify 274where the <a href="#scene">-scene</a> number is placed in the filenames. These 275strings, such as '<kbd>%d</kbd>' or '<kbd>%03d</kbd>', are familiar to those 276who have used the standard <kbd>printf()</kbd>' C-library function. As an 277example, the command</p> 278 279<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: rose: -morph 15 my%02dmorph.jpg</span></p> 280<p>will create a sequence of 17 images (the two given plus 15 more created by 281<a href="#morph">-morph</a>), named: my00morph.jpg, my01morph.jpg, 282my02morph.jpg, ..., my16morph.jpg. </p> 283 284<p>In summary, ImageMagick tries to write all images to one file, but will 285save to multiple files, if any of the following conditions exist... 286<ol> 287<li>the output image's file format does not allow multi-image files, 288<li>the <a href="#adjoin">+adjoin</a> option is given, or 289<li>a printf() integer format string (eg: "%d") is present in the output 290 filename. 291</ol></p> 292 293 294<div style="margin: auto;"> 295 <h4><a id="affine"></a>-affine 296 <em class="arg">s<sub>x</sub></em>,<em class="arg">r<sub>x</sub></em>,<em 297 class="arg">r<sub>y</sub></em>,<em class="arg">s<sub>y</sub></em>[,<em 298 class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em>]</h4> 299</div> 300 301<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the drawing transformation matrix for combined rotating and scaling.</td><td style='text-align:right;'></td></tr></table> 302 303<p>This option sets a transformation matrix, for use by subsequent <a 304href="#draw">-draw</a> or <a href="#transform">-transform</a> options. </p> 305 306<p>The matrix entries are entered as comma-separated numeric values either in 307quotes or without spaces. </p> 308 309<p>Internally, the transformation matrix has 3x3 elements, but three of them 310are omitted from the input because they are constant. The new (transformed) 311coordinates (<em class="arg">x'</em>, <em class="arg">y'</em>) of a pixel at 312position (<em class="arg">x</em>, <em class="arg">y</em>) in the original 313image are calculated using the following matrix equation.</p> 314 315<div class="eqn"> 316<img alt="affine transformation" src="/images/affine.png"/> 317</div> 318 319<p> The size of the resulting image is that of the smallest rectangle that 320contains the transformed source image. The parameters <em 321class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em> 322subsequently shift the image pixels so that those that are moved out of the 323image area are cut off.</p> 324 325<p>The transformation matrix complies with the left-handed pixel coordinate 326system: positive <em class="arg">x</em> and <em class="arg">y</em> directions 327are rightward and downward, resp.; positive rotation is clockwise.</p> 328 329<p> If the translation coefficients <em class="arg">t<sub>x</sub></em> and <em 330class="arg">t<sub>y</sub></em> are omotted they default to 0,0. Therefore, 331four parameters suffice for rotation and scaling without translation.</p> 332 333<p>Scaling by the factors <em class="arg">s<sub>x</sub></em> and <em 334class="arg">s<sub>y</sub></em> in the <em>x</em> and <em>y</em> directions, 335respectively, is accomplished with the following.</p> 336 337<p>See <a href="#transform">-transform</a>, and the <a 338href="#distort">-distort</a> method '<kbd>Affineprojection</kbd> for more 339information </p> 340 341 342<p class="crtsnip"> 343 -affine <em class="arg">s<sub>x</sub></em>,0,0,<em class="arg">s<sub>y</sub></em> 344</p> 345 346<p>Translation by a displacement (<em class="arg">t<sub>x</sub></em>, <em class="arg">t<sub>y</sub></em>) is accomplished like so:</p> 347 348<p class="crtsnip"> 349 -affine 1,0,0,1,<em class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em> 350</p> 351 352<p>Rotate clockwise about the origin (the upper left-hand corner) by an angle <em>a</em> by letting 353<em>c</em> = cos(<em>a</em>), <em>s</em> = sin(<em>a</em>), and using the following.</p> 354 355<p class="crtsnip"> 356 -affine <em>c</em>,<em>s</em>,-<em>s</em>,<em>c</em> 357</p> 358 359<p>The cumulative effect of a sequence of <a href="#affine" >-affine</a> transformations can be accomplished by instead by a single <a href="#affine" >-affine</a> operation using the matrix equal to the product of the matrices of the individual transformations.</p> 360 361<p>An attempt is made to detect near-singular transformation matrices. If the matrix determinant has a sufficiently small absolute value it is rejected.</p> 362 363<div style="margin: auto;"> 364 <h4><a id="alpha"></a>-alpha <em class="arg">type</em></h4> 365</div> 366 367<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Gives control of the alpha/matte channel of an image.</td><td style='text-align:right;'></td></tr></table> 368 369<p>Used to set a flag on an image indicating whether or not to use existing alpha 370channel data, to create an alpha channel, or to perform other operations on the alpha channel. Choose the argument <em class="arg">type</em> from the list below.</p> 371 372 373<table class="doc"> 374 <tbody> 375 <tr valign="top"> 376 <th align="left" style="width: 8%">type</th> 377 <th align="left">Description</th> 378 </tr> 379 380 <tr valign="top"> 381 <td valign="top"><kbd>Activate</kbd> or <kbd>On</kbd></td> 382 <td valign="top"> 383 Enable the image's transparency channel. Note normally <kbd>Set</kbd> 384 should be used instead of this, unless you specifically need to 385 preserve existing (but specifically turned <kbd>Off</kbd>) transparency 386 channel. </td></tr> 387 388 <tr valign="top"> 389 <td valign="top"><kbd>Deactivate</kbd> or <kbd>Off</kbd></td> 390 <td valign="top"> 391 Disables the image's transparency channel. Does not delete or change the 392 existing data, just turns off the use of that data.</td></tr> 393 394 <tr valign="top"> 395 <td valign="top"><kbd>Set</kbd></td> 396 <td valign="top"> 397 Activates the alpha/matte channel. If it was previously turned off 398 then it also resets the channel to opaque. If the image already had 399 the alpha channel turned on, it will have no effect.</td></tr> 400 401 <tr valign="top"> 402 <td valign="top"><kbd>Opaque</kbd></td> 403 <td valign="top"> 404 Enables the alpha/matte channel and forces it to be fully opaque. 405 </td></tr> 406 407 <tr valign="top"> 408 <td valign="top"><kbd>Transparent</kbd></td> 409 <td valign="top"> 410 Activates the alpha/matte channel and forces it to be fully 411 transparent. This effectively creates a fully transparent image the 412 same size as the original and with all its original RGB data still 413 intact, but fully transparent. </td></tr> 414 415 <tr valign="top"> 416 <td valign="top"><kbd>Extract</kbd></td> 417 <td valign="top"> 418 Copies the alpha channel values into all the color channels and turns 419 '<kbd>Off</kbd>' the the image's transparency, so as to generate 420 a gray-scale mask of the image's shape. The alpha channel data is left 421 intact just deactivated. This is the inverse of '<kbd>Copy</kbd>'. 422 </td></tr> 423 424 <tr valign="top"> 425 <td valign="top"><kbd>Copy</kbd></td> 426 <td valign="top"> 427 Turns '<kbd>On</kbd>' the alpha/matte channel, then copies the 428 gray-scale intensity of the image, into the alpha channel, converting 429 a gray-scale mask into a transparent shaped mask ready to be colored 430 appropriately. The color channels are not modified. </td></tr> 431 432 <tr valign="top"> 433 <td valign="top"><kbd>Shape</kbd></td> 434 <td valign="top"> 435 As per '<kbd>Copy</kbd>' but also colors the resulting shape mask with 436 the current background color. That is the RGB color channels is 437 replaced, with appropriate alpha shape. 438 </td></tr> 439 440 <tr valign="top"> 441 <td valign="top"><kbd>Background</kbd></td> 442 <td valign="top"> 443 Set any fully-transparent pixel to the background color, while leaving 444 it fully-transparent. This can make some image file formats, such as 445 PNG, smaller as the RGB values of transparent pixels are more uniform, 446 and thus can compress better. 447 </td></tr> 448 </tbody> 449</table> 450 451<p>Note that while the <a href="#matte" >+matte</a> operation is the same as 452"<kbd><a href="#alpha" >-alpha</a> Off</kbd>", the <a href="#matte" 453>-matte</a> operation is the same as "<kbd><a href="#alpha" >-alpha</a> 454Set</kbd>" and not "<kbd><a href="#alpha" >-alpha</a> On</kbd>". </p> 455 456 457<div style="margin: auto;"> 458 <h4><a id="annotate"></a> 459 -annotate <em class="arg">degrees</em> <em class="arg">text</em><br /> 460 -annotate <em class="arg">Xdegrees</em>x<em class="arg">Ydegrees</em> <em class="arg">text</em><br /> 461 -annotate <em class="arg">Xdegrees</em>x<em class="arg">Ydegrees</em> {+-}<em class="arg">t<sub>x</sub></em>{+-}<em class="arg">t<sub>y</sub></em> <em class="arg">text</em></h4> 462</div> 463 464<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Annotate an image with text.</td><td style='text-align:right;'></td></tr></table> 465 466<p>This is a convenience for annotating an image with text. For more precise control over text annotations, use <a href="#draw">-draw</a>.</p> 467 468 469<p>The values <em class="arg">Xdegrees</em> and <em class="arg">Ydegrees</em> control the shears with respect to the , respectively, applied to the text, while <em class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em> are offsets that give the location of the text relative to the upper left corner of the image.</p> 470 471<p>Using <a href="#annotate">-annotate</a> <em class="arg">degrees</em> or <a href="#annotate">-annotate</a> <em class="arg">degrees</em>x<em class="arg">degrees</em> produces an unsheared rotation of the text. The direction of the rotation is positive, which means a clockwise rotation if <em class="arg">degrees</em> is positive. (This conforms to the usual mathematical convention once it is realized that the positive <em>y</em>–direction is conventionally considered to be <em>downward</em> for images.)</p> 472 473<p>The new (transformed) coordinates (<em class="arg">x'</em>, <em class="arg">y'</em>) of a pixel at position (<em class="arg">x</em>, <em class="arg">y</em>) in the image are calculated using the following matrix equation.</p> 474<div class="eqn"><img alt="annotate transformation" src="/images/annotate.png"/></div> 475 476<p>If <em class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em> are omitted, they default to 0. This makes the bottom-left of the text becomes the upper-left corner of the image, which is probably undesirable. Adding a <a href="#gravity" >-gravity</a> option in this case leads to nice results.</p> 477 478<p>Text is any UTF-8 encoded character sequence. If <em class="arg">text</em> is of the form '@mytext.txt', the text is read from the file <kbd>mytext.txt</kbd>. Text in a file is taken literally; no embedded formatting characters are recognized.</p> 479 480<div style="margin: auto;"> 481 <h4><a id="antialias"></a>-antialias</h4> 482</div> 483 484<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Enable/Disable of the rendering of anti-aliasing pixels when 485drawing fonts and lines.</td><td style='text-align:right;'></td></tr></table> 486 487<p>By default, objects (e.g. text, lines, polygons, etc.) are antialiased when 488drawn. Use <a href="#antialias">+antialias</a> to disable the addition of 489antialiasing edge pixels. This will then reduce the number of colors added to 490an image to just the colors being directly drawn. That is, no mixed colors 491are added when drawing such objects. </p> 492 493<div style="margin: auto;"> 494 <h4><a id="append"></a>-append</h4> 495</div> 496 497<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Join current images vertically or horizontally.</td><td style='text-align:right;'></td></tr></table> 498 499<p>This option creates a single longer image image, by joining all the current 500images in sequence top-to-bottom. Use <a href="#append">+append</a> to 501stack images left-to-right. </p> 502 503<p>If they are not of the same width, narrower images are padded with the 504current <a href="#background">-background</a> color setting, and their 505position relative to each other can be controlled by the current <a 506href="#gravity">-gravity</a> setting. </p> 507 508 509<div style="margin: auto;"> 510 <h4><a id="attenuate"></a>-attenuate <em class="arg">value</em></h4> 511</div> 512 513<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Lessen (or intensify) when adding noise to an image.</td><td style='text-align:right;'></td></tr></table> 514 515 516<div style="margin: auto;"> 517 <h4><a id="authenticate"></a>-authenticate <em class="arg">password</em></h4> 518</div> 519 520<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Decrypt a PDF with a password.</td><td style='text-align:right;'></td></tr></table> 521 522<p>Use this option to supply a <em class="arg">password</em> for decrypting a PDF that has been encrypted using Microsoft Crypto API (MSC API). The encrypting using the MSC API is not supported.</p> 523 524<p>For a different encryption method, see <a href="#encipher">-encipher</a> and <a href="#decipher">-decipher</a>. </p> 525 526 527 528<div style="margin: auto;"> 529 <h4><a id="auto-gamma"></a>-auto-gamma</h4> 530</div> 531 532<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Automagically adjust gamma level of image.</td><td style='text-align:right;'></td></tr></table> 533 534<p>This calculates the mean values of an image, then applies a calculated <a 535href="#gamma" >-gamma</a> adjustment so that is the mean color exists in the 536image it will get a have a value of 50%. </p> 537 538<p>This means that any solid 'gray' image becomes 50% gray. </p> 539 540<p>This works well for real-life images with little or no extreme dark and 541light areas, but tend to fail for images with large amounts of bright sky or 542dark shadows. It also does not work well for diagrams or cartoon like images. 543</p> 544 545<p>It uses the <a href="#channel" >-channel</a> setting, (including the 546'<em>sync</em>' flag for channel synchronization), to determine which color 547values is used and modified. As the default <a href="#channel" 548>-channel</a> setting is '<em>RGB,sync</em>', channels are modified 549together by the same gamma value, preserving colors. </p> 550 551 552 553<div style="margin: auto;"> 554 <h4><a id="auto-level"></a>-auto-level</h4> 555</div> 556 557<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Automagically adjust color levels of image.</td><td style='text-align:right;'></td></tr></table> 558 559<p>This is a 'perfect' image normalization operator. It finds the exact 560minimum and maximum color values in the image and then applies a <a 561href="#level" >-level</a> operator to stretch the values to the full range of 562values. </p> 563 564<p>The operator is not typically used for real-life images, image scans, or 565JPEG format images, as a single 'out-rider' pixel can set a bad min/max values 566for the <a href="#level" >-level</a> operation. On the other hand it is the 567right operator to use for color stretching gradient images being used to 568generate Color lookup tables, distortion maps, or other 'mathematically' 569defined images. </p> 570 571<p>The operator is very similar to the <a href="#normalize">-normalize</a>, <a 572href="#contrast-stretch" >-contrast-stretch</a>, and <a href="#linear-stretch" 573>-linear-stretch</a> operators, but without 'histogram binning' or 'clipping' 574problems that these operators may have. That is <a href="#auto-level" 575>-auto-level</a> is the perfect or ideal version these operators. </p> 576 577<p>It uses the <a href="#channel" >-channel</a> setting, (including the 578special '<em>sync</em>' flag for channel synchronization), to determine 579which color values are used and modified. As the default <a 580href="#channel" >+channel</a> setting is '<em>RGB,sync</em>', the 581'<em>sync</em>' ensures that the color channels will are modified 582together by the same gamma value, preserving colors, and ignoring 583transparency. </p> 584 585 586<div style="margin: auto;"> 587 <h4><a id="auto-orient"></a>-auto-orient</h4> 588</div> 589 590<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Automagically orient (rotate) an image created by a digital camera.</td><td style='text-align:right;'></td></tr></table> 591 592<p>This operator reads and resets the EXIF image profile setting 'Orientation' 593and then performs the appropriate 90 degree rotation on the image to orient 594the image, for correct viewing. </p> 595 596<p>This EXIF profile setting is usually set using a gravity sensor in digital 597camara, however photos taken directly downward or upward may not have an 598appropriate value. Also images that have been orientation 'corrected' without 599reseting this setting, may be 'corrected' again resulting in a incorrect 600result. If the he EXIF profile was previously stripped, the <a 601href="#auto-orient" >-auto-orient</a> operator will do nothing. </p> 602 603 604<div style="margin: auto;"> 605 <h4><a id="average"></a>-average</h4> 606</div> 607 608<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Average a set of images.</td><td style='text-align:right;'></td></tr></table> 609 610<p>An error results if the images are not identically sized.</p> 611 612 613<div style="margin: auto;"> 614 <h4><a id="backdrop"></a>-backdrop</h4> 615</div> 616 617<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Display the image centered on a backdrop.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>, <a href="/www/display.html">display</a>]</td></tr></table> 618 619<p>This backdrop covers the entire workstation screen and is useful for hiding other X window activity while viewing the image. The color of the backdrop is specified as the background color. The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 620 621<div style="margin: auto;"> 622 <h4><a id="background"></a>-background <em class="arg">color</em></h4> 623</div> 624 625<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the background color.</td><td style='text-align:right;'></td></tr></table> 626 627<p>The color is specified using the format described under the <a href="#fill">-fill</a> option. The default background color (if none is specified or found in the image) is white.</p> 628 629<div style="margin: auto;"> 630 <h4><a id="bench"></a>-bench <em class="arg">iterations</em></h4> 631</div> 632 633<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Measure performance.</td><td style='text-align:right;'></td></tr></table> 634 635<p>Repeat the entire command for the given number of <em class="arg">iterations</em> and report the user-time and elapsed time. For instance, consider the following command and its output. Modify the benchmark with the -duration to run the benchmark for a fixed number of seconds and -concurrent to run the benchmark in parallel (requires the OpenMP feature).</p> 636 637<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: -resize 1000% -bench 5 logo.png</span><span class='crtout'>Performance: 5i 0.875657ips 6.880u 0:05.710</span></p> 638<p>In this example, 5 iterations were completed at 0.875657 iterations per second, using 6.88 seconds of the user's allotted time, for a total elapsed time of 5.71 seconds.</p> 639 640<div style="margin: auto;"> 641 <h4><a id="bias"></a>-bias <em class="arg">value</em>{<em class="arg">%</em>}</h4> 642</div> 643 644<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Add bias when convolving an image.</td><td style='text-align:right;'></td></tr></table> 645 646<p>This option shifts the output of <a href="/www/command-line-options.html#convolve">‑convolve</a> so that positive and negative results are relative to the specified bias value. </p> 647 648<p>This is important for non-HDRI compilations of ImageMagick when dealing with convolutions that contain negative as well as positive values. This is especially the case with convolutions involving high pass filters or edge detection. Without an output bias, the negative values are clipped at zero.</p> 649 650<p>When using an ImageMagick with the HDRI compile-time setting, <a href="/www/command-line-options.html#bias">‑bias</a> is not needed, as ImageMagick is able to store/handle any 651negative results without clipping to the color value range 652(0..QuantumRange).</p> 653 654<p>See the discussion on HDRI implementations of ImageMagick on the page 655<a href="/www/high-dynamic-range.html">High Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this <a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> entry. 656</p> 657 658<div style="margin: auto;"> 659 <h4><a id="black-point-compensation"></a>-black-point-compensation</h4> 660</div> 661 662<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Use black point compensation.</td><td style='text-align:right;'></td></tr></table> 663 664<div style="margin: auto;"> 665 <h4><a id="black-threshold"></a>-black-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 666</div> 667 668<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Force to black all pixels below the threshold while leaving all pixels at or above the threshold unchanged.</td><td style='text-align:right;'></td></tr></table> 669 670<p> The threshold value can be given as a percentage or as an absolute integer value within [0, <em class="QR">QuantumRange</em>] corresponding to the desired <a href="/www/command-line-options.html#channel">‑channel</a> value. See <a href="/www/command-line-options.html#threshold">‑threshold</a> for more details on thresholds and resulting values. 671</p> 672 673 674<div style="margin: auto;"> 675 <h4><a id="blend"></a>-blend <em class="arg">geometry</em></h4> 676</div> 677 678<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>blend an image into another by the given absolute value or percent.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 679 680<p>Blend will average the images together ('plus') according to the 681percentages given and each pixels transparency. If only a single percentage 682value is given it sets the weight of the composite or 'source' image, while 683the background image is weighted by the exact opposite amount. That is a 684<kbd>-blend 30%</kbd> merges 30% of the 'source' image with 70% of the 685'destination' image. Thus it is equivalent to <kbd>-blend 30x70%</kbd>.</p> 686 687 688<div style="margin: auto;"> 689 <h4><a id="blue-primary"></a>-blue-primary <em class="arg">x</em>,<em class="arg">y</em></h4> 690</div> 691 692<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the blue chromaticity primary point.</td><td style='text-align:right;'></td></tr></table> 693 694<div style="margin: auto;"> 695 <h4><a id="blue-shift"></a>-blue-shift <em class="arg">factor</em></h4> 696</div> 697 698<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate a scene at nighttime in the moonlight. Start with a factor of 1.5</td><td style='text-align:right;'></td></tr></table> 699 700<div style="margin: auto;"> 701 702<div style="margin: auto;"> 703 <h4><a id="blur"></a>-blur <em class="arg">radius</em><br />-blur <em class="arg">radius</em>x<em class="arg">sigma</em></h4> 704</div> 705 706<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Reduce image noise and reduce detail levels.</td><td style='text-align:right;'></td></tr></table> 707 708<p>Convolve the image with a Gaussian or normal distribution using the given 709<em class="arg" >Sigma</em> value. The formula is:</p> 710 711<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 712</div> 713 714<p>The <em class="arg" >Sigma</em> value is the important argument, and 715determines the actual amount of blurring that will take place. </p> 716 717<p>The <em class="arg" >Radius</em> is only used to determine the size of the 718array which will hold the calculated Gaussian distribution. It should be an 719integer. If not given, or set to zero, IM will calculate the largest possible 720radius that will provide meaningful results for the Gaussian distribution. 721</p> 722 723<p>The larger the <em class="arg" >Radius</em> the radius the slower the 724operation is. However too small a <em class="arg" >Radius</em>, and sever 725aliasing effects may result. As a guideline, <em class="arg" >Radius</em> 726should be at least twice the <em class="arg" >Sigma</em> value, though three 727times will produce a more accurite result. </p> 728 729<p>This option differs from <a href="#gaussian-blur">-gaussian-blur</a> simply 730by taking advantage of the separability properties of the distribution. Here 731we apply a single-dimensional Gaussian matrix in the horizontal direction, 732then repeat the process in the vertical direction.</p> 733 734<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 735pixels which are outside the image proper are blurred into the final result. 736</p> 737 738 739<div style="margin: auto;"> 740 <h4>-blur <em class="arg">Width</em>[x<em class="arg">Height</em>[+<em class="arg">Angle</em>]]</h4> 741</div> 742 743<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Variably blur and image according to the overlay mapping.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 744 745<p>Each pixel in the overlaid region is replaced with an Elliptical Weighted 746Average (EWA) of the source image, scaled according to the grayscale 747mapping. </p> 748 749<p>The ellipse is weighted with sigma set to the given <em class="arg" 750>Width</em> and <em class="arg" >Height</em>. The <em class="arg" >Height</em> 751defaults to the <em class="arg" >Width</em> for a normal circular Guassian 752weighting. The <em class="arg" >Angle</em> will rotate the ellipse from 753horizontal clock-wise. </p> 754 755<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 756pixels which are outside the image proper are blurred into the final result. 757</p> 758 759 760<div style="margin: auto;"> 761 <h4><a id="border"></a>-border <em class="arg">geometry</em></h4> 762</div> 763 764<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Surround the image with a border of color. </td><td style='text-align:right;'></td></tr></table> 765 766<p>Set the width and height using the <em class="arg">size</em> portion of the 767<em class="arg">gravity</em> argument. See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets are 768ignored. </p> 769 770<p>Set the border color by preceding with the <a 771href="#bordercolor">-bordercolor</a> setting.</p> 772 773<p>The <a href="#border">-border</a> operation is affected by the current <a 774href="#compose">-compose</a> setting and assumes that this is using the default 775'<kbd>Over</kbd>' composition method. It generates a image of the appropriate 776size colors by the current <a href="#bordercolor">-bordercolor</a> before 777overlaying the original image in the center of this net image. This means that 778with the default compose method of '<kbd>Over</kbd>' any transparent parts may 779be replaced by the current <a href="#bordercolor">-bordercolor</a> setting.</p> 780<p>See also the <a href="#frame">-frame</a> option, which has more 781functionality.</p> 782 783<div style="margin: auto;"> 784 <h4><a id="bordercolor"></a>-bordercolor <em class="arg">color</em></h4> 785</div> 786 787<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the border color.</td><td style='text-align:right;'></td></tr></table> 788 789<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 790 791<p>The default border color is <kbd>#DFDFDF</kbd>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p> 792 793<div style="margin: auto;"> 794 <h4><a id="borderwidth"></a>-borderwidth <em class="arg">geometry</em> </h4> 795</div> 796 797<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the border width.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>, <a href="/www/display.html">display</a>]</td></tr></table> 798 799<div style="margin: auto;"> 800 <h4><a id="brightness-contrast"></a>-brightness-contrast <em class="arg">brightness</em><br />-brightness-contrast <em class="arg">brightness</em>{x<em class="arg">contrast</em>}{<em class="arg">%</em>}}</h4> 801</div> 802 803<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Adjust the brightness and/or contrast of the image.</td><td style='text-align:right;'></td></tr></table> 804 805<p>Brightness and Contrast values apply changes to the input image. They are 806not absolute settings. A brightness or contrast value of zero means no change. 807The range of values is -100 to +100 on each. Positive values increase the 808brightness or contrast and negative values decrease the brightness or contrast. 809To control only contrast, set the brightness=0. To control only brightness, 810set contrast=0 or just leave it off.</p> 811 812<p>You may also use <a href="#fill">-channel</a> to control which channels to 813apply the brightness and/or contrast change. The default is to apply the same 814transformation to all channels.</p> 815 816<p>Brightness and Contrast arguments are converted to offset and slope of a 817linear transform and applied 818using <a href="#fill">-function polynomial "slope,offset"</a>.</p> 819 820<p>The slope varies from 0 at contrast=-100 to almost vertical at 821contrast=+100. For brightness=0 and contrast=-100, the result are totally 822midgray. For brightness=0 and contrast=+100, the result will approach but 823not quite reach a threshold at midgray; that is the linear transformation 824is a very steep vertical line at mid gray.</p> 825 826<p>Negative slopes, i.e. negating the image, are not possible with this 827function. All achievable slopes are zero or positive.</p> 828 829<p>The offset varies from -0.5 at brightness=-100 to 0 at brightness=0 to +0.5 830at brightness=+100. Thus, when contrast=0 and brightness=100, the result is 831totally white. Similarly, when contrast=0 and brightness=-100, the result is 832totally black.</p> 833 834<p>As the range of values for the arguments are -100 to +100, adding the '%' 835symbol is no different than leaving it off.</p> 836 837<div style="margin: auto;"> 838 <h4><a id="cache"></a>-cache <em class="arg">threshold</em></h4> 839</div> 840 841<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>(This option has been replaced by the <a href='#limit'>-limit</a> option.)</td><td style='text-align:right;'></td></tr></table> 842 843<div style="margin: auto;"> 844 <h4><a id="caption"></a>-caption <em class="arg">string</em></h4> 845</div> 846 847<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Assign a caption to an image.</td><td style='text-align:right;'></td></tr></table> 848 849<p>This option sets the caption meta-data of an image read in after this 850option has been given. To modify a caption of images already in memory use 851"<kbd><a href="#set">-set</a> caption</kbd>". </p> 852 853<p>The caption can contain special format characters listed in the <a 854href="/www/escape.html">Format and 855Print Image Properties</a>. These attributes are expanded when the caption 856is finally assigned to the individual images. </p> 857 858<p>If the first character of <em class="arg">string</em> is <em 859class="arg">@</em>, the image caption is read from a file titled by the 860remaining characters in the string. Comments read in from a file are literal; 861no embedded formatting characters are recognized.</p> 862 863<p>Caption meta-data ais not visible on the image itself. To do that use the 864<a href="#annotate">-annotate</a> or <a href="#draw">-draw</a> options 865instead.</p> 866 867<p>For example,</p> 868 869<p class="crtsnip"> 870 -caption "%m:%f %wx%h" bird.miff 871</p> 872 873<p>produces an image caption of <kbd>MIFF:bird.miff 512x480</kbd> (assuming 874that the image <kbd>bird.miff</kbd> has a width of 512 and a height of 875480.</p> 876 877 878<div style="margin: auto;"> 879 <h4><a id="cdl"></a>-cdl <em class="arg">filename</em></h4> 880</div> 881 882<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>color correct with a color decision list.</td><td style='text-align:right;'></td></tr></table> 883 884<p>Here is an example color correction collection:</p> 885 886<pre class="text"> 887<?xml version="1.0" encoding="UTF-8"?> 888<ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2"> 889 <ColorCorrection id="cc06668"> 890 <SOPNode> 891 <Slope> 0.9 1.2 0.5 </Slope> 892 <Offset> 0.4 -0.5 0.6 </Offset> 893 <Power> 1.0 0.8 1.5 </Power> 894 </SOPNode> 895 <SATNode> 896 <Saturation> 0.85 </Saturation> 897 </SATNode> 898 </ColorCorrection> 899</ColorCorrectionCollection> 900</pre> 901 902<div style="margin: auto;"> 903 <h4><a id="channel"></a>-channel <em class="arg">type</em></h4> 904</div> 905 906<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify those image color channels to which subsequent operators are limited.</td><td style='text-align:right;'></td></tr></table> 907 908<p>Choose from: <kbd>Red</kbd>, <kbd>Green</kbd>, <kbd>Blue</kbd>, 909<kbd>Alpha</kbd>, <kbd>Cyan</kbd>, <kbd>Magenta</kbd>, <kbd>Yellow</kbd>, 910<kbd>Black</kbd>, <kbd>Opacity</kbd>, <kbd>Index</kbd>, <kbd>RGB</kbd>, 911<kbd>RGBA</kbd>, <kbd>CMYK</kbd>, or <kbd>CMYKA</kbd>.</p> 912 913<p>The channels above can also be specified as a comma-separated list or can be 914abbreviated as a concatenation of the letters '<kbd>R</kbd>', '<kbd>G</kbd>', 915'<kbd>B</kbd>', '<kbd>A</kbd>', '<kbd>O</kbd>', '<kbd>C</kbd>', 916'<kbd>M</kbd>', '<kbd>Y</kbd>', '<kbd>K</kbd>'. 917 918For example, to only select the <kbd>Red</kbd> and <kbd>Blue</kbd> channels 919you can either use </p> 920<p class="crtsnip"> 921 -channel Red,Blue 922</p> 923<p>or you can use the short hand form</p> 924<p class="crtsnip"> 925 -channel RB 926</p> 927 928<p>All the channels that are present in an image can be specified using the 929special channel type <kbd>All</kbd>. Not all operators are 'channel capable', 930but generally any operators that are generally 'grey-scale' image operators, 931will understand this setting. See individual operator documentation. </p> 932 933<br /> 934 935<p>On top of the normal channel selection an extra flag can be specified, 936'<kbd>Sync</kbd>'. This is turned on by default and if set means that 937operators that understand this flag should perform: cross-channel 938synchronization of the channels. If not specified, then most grey-scale 939operators will apply their image processing operations to each individual 940channel (as specified by the rest of the <a href="#channel">-channel</a> 941setting) completely independently from each other. </p> 942 943<p>For example for operators such as <a href="#auto-level">-auto-level</a> and 944<a href="#auto-gamma">-auto-gamma</a> the color channels are modified 945together in exactly the same way so that colors will remain in-sync. Without 946it being set, then each channel is modified separately and 947independently, which may produce color distortion. </p> 948 949<p>The <a href="#morphology">-morphology</a> '<kbd>Convolve</kbd>' method 950and the <a href="#compose">-compose</a> mathematical methods, also understands 951the '<kbd>Sync</kbd>' flag to modify the behaviour of pixel colors according 952to the alpha channel (if present). That is to say it will modify the image 953processing with the understanding that fully-transparent colors should not 954contribute to the final result. </p> 955 956<p>Basically, by default, operators work with color channels in synchronous, and 957treats transparency as special, unless the <a href="#channel">-channel</a> 958setting is modified so as to remove the effect of the '<kbd>Sync</kbd>' flag. 959How each operator does this depends on that operators current implementation. 960Not all operators understands this flag at this time, but that is changing. 961</p> 962 963<p>To print a complete list of channel types, use <a href="#list">-list 964channel</a>.</p> 965 966<br /> 967 968<p>By default, ImageMagick sets <a href="#channel">-channel</a> to the value 969'<kbd>RGBK,sync</kbd>', which specifies that operators act on all color 970channels except the transparency channel, and that all the color channels are 971to be modified in exactly the same way, with a understanding of transprancy 972(depending on the operation being applied). The 'plus' form <a 973href="#channel" >+channel</a> will reset the value back to this default. </p> 974 975<p>Options that are affected by the <a href="#channel" >-channel</a> setting 976include the following. 977 978<a href="#auto-gamma">-auto-gamma</a>, 979<a href="#auto-level">-auto-level</a>, 980<a href="#black-threshold">-black-threshold</a>, 981<a href="#blur">-blur</a>, 982<a href="#clamp">-clamp</a>, 983<a href="#clut">-clut</a>, 984<a href="#combine">-combine</a>, 985<a href="#composite">-composite</a> (Mathematical compose methods only), 986<a href="#convolve">-convolve</a>, 987<a href="#contrast-stretch">-contrast-stretch</a>, 988<a href="#evaluate">-evaluate</a>, 989<a href="#function">-function</a>, 990<a href="#fx">-fx</a>, 991<a href="#gaussian-blur">-gaussian-blur</a>, 992<a href="#hald-clut">-hald-clut</a>, 993<a href="#motion-blur">-motion-blur</a>, 994<a href="#morphology">-morphology</a>, 995<a href="#negate">-negate</a>, 996<a href="#normalize">-normalize</a>, 997<a href="#ordered-dither">-ordered-dither</a>, 998<a href="#radial-blur">-radial-blur</a>, 999<a href="#random-threshold">-random-threshold</a>, 1000<a href="#separate">-separate</a>, 1001<a href="#threshold">-threshold</a>, and 1002<a href="#white-threshold">-white-threshold</a>. 1003</p> 1004 1005<p>Warning, some operators behave differently when the <a href="#channel" 1006>+channel</a> default setting is in effect, verses ANY user defined <a 1007href="#channel" >-channel</a> setting (including the equivalent of the 1008default). These operators have yet to be made to understand the newer 'Sync' 1009flag. </p> 1010 1011<p>For example <a href="#threshold">-threshold</a> will by default gray-scale 1012the image before thresholding, if no <a href="#channel" >-channel</a> setting 1013has been defined. This is not 'Sync flag controlled, yet. </p> 1014 1015<p>Also some operators such as <a href="#blur">-blur</a>, <a 1016href="#gaussian-blur">-gaussian-blur</a>, will modify their handling of the 1017color channels if the '<kbd>alpha</kbd>' channel is also enabled by <a 1018href="#channel" >-channel</a>. Generally this done to ensure that 1019fully-transparent colors are treated as being fully-transparent, and thus any 1020underlying 'hidden' color has no effect on the final results. Typically 1021resulting in 'halo' effects. The newer <a href="#morphology">-morphology</a> 1022convolution equivalents however does have a understanding of the 'Sync' flag 1023and will thus handle transparency correctly by default. </p> 1024 1025<p>As a alpha channel is optional within images, some operators will read the 1026color channels of an image as a greyscale alpha mask, when the image has no 1027alpha channel present, and the <a href="#channel" >-channel</a> setting tells 1028the operator to apply the operation using alpha channels. The <a 1029href="#clut">-clut</a> operator is a good example of this. </p> 1030 1031 1032<div style="margin: auto;"> 1033 <h4><a id="clamp"></a>-clamp</h4> 1034</div> 1035 1036<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Restrict image colors from 0 to the quantum depth.</td><td style='text-align:right;'></td></tr></table> 1037 1038<div style="margin: auto;"> 1039 <h4><a id="charcoal"></a>-charcoal <em class="arg">factor</em></h4> 1040</div> 1041 1042<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Simulate a charcoal drawing.</td><td style='text-align:right;'></td></tr></table> 1043 1044<div style="margin: auto;"> 1045 <h4><a id="chop"></a>-chop <em class="arg">geometry</em></h4> 1046</div> 1047 1048<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Remove pixels from the interior of an image.</td><td style='text-align:right;'></td></tr></table> 1049 1050<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <em class="arg">width</em> 1051and <em class="arg">height</em> given in the of the <em class="arg">size</em> 1052portion of the <em class="arg">geometry</em> argument give the number of 1053columns and rows to remove. The <em class="arg">offset</em> portion of 1054the <em class="arg">geometry</em> argument is influenced by 1055a <a href="#gravity">-gravity</a> setting, if present.</p> 1056 1057<p>The <a href="#chop">-chop</a> option removes entire rows and columns, 1058and moves the remaining corner blocks leftward and upward to close the gaps.</p> 1059 1060<p>While it can remove internal rows and columns of pixels, it is more 1061typically used with as <a href="#gravity">-gravity</a> setting and zero 1062offsets so as to remove a single edge from an image. Compare this to <a 1063href="#shave" >-shave</a> which removes equal numbers of pixels from oppisite 1064sides of the image. </p> 1065 1066<p>Using <a href="#chop">-chop</a> will effectivally undo the results of a <a 1067href="#splice">-splice</a> that was given the same <em 1068class="arg">geometry</em> and <a href="#gravity">-gravity</a> settings. </p> 1069 1070 1071<div style="margin: auto;"> 1072 <h4><a id="clip"></a>-clip</h4> 1073</div> 1074 1075<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply the clipping path if one is present.</td><td style='text-align:right;'></td></tr></table> 1076 1077<p>If a clipping path is present, it is applied to subsequent operations.</p> 1078 1079<p>For example, in the command</p> 1080 1081<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -clip -negate cockatoo.tif negated.tif</span></p> 1082<p>only the pixels within the clipping path are negated.</p> 1083 1084<p>The <a href="#clip">-clip</a> feature requires the XML library. If the XML library is not present, the option is ignored.</p> 1085 1086<div style="margin: auto;"> 1087 <h4><a id="clip-mask"></a>-clip-mask</h4> 1088</div> 1089 1090<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Clip the image as defined by this mask.</td><td style='text-align:right;'></td></tr></table> 1091 1092<p>Use the given image as a 'do-not-modify' mask of the current images in the 1093current image sequence. Assuming the clipmask is a greyscale image the same 1094size at the one already in memory, any areas that is white will not be 1095modified by any of the 'image processing operators' that follow, until the 1096mask is removed. Pixels in the black areas of the clip mask will be modified 1097as normal. </p> 1098 1099<p>In some ways this is similar to (though not the same) as defining 1100a rectangular <a href="#region" >-region</a>, or using the negative of the 1101mask (thrid) image in a three image <a href="#composite" >-composite</a>, 1102operation. </p> 1103 1104 1105<div style="margin: auto;"> 1106 <h4><a id="clip-path"></a>-clip-path <em class="arg">id</em></h4> 1107</div> 1108 1109<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Clip along a named path from the 8BImageMagick profile.</td><td style='text-align:right;'></td></tr></table> 1110 1111<p>This is almost identical to <a href="#clip">-clip</a>. </p> 1112 1113 1114<div style="margin: auto;"> 1115 <h4><a id="clone"></a>-clone <em class="arg">index(s)</em></h4> 1116</div> 1117 1118<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>make a clone of an image (or images).</td><td style='text-align:right;'></td></tr></table> 1119 1120<p>Inside parenthesis (where the operator is normally used) it will make a 1121clone of the images from the last 'pushed' image sequence, and adds them to 1122the end of the current image sequence. Outside parenthesis 1123(not recommended) it clones the images from the current image sequence. </p> 1124 1125<p>Specify the image by its index in the sequence. The first image is index 11260. Negative indexes are relative to the end of the sequence; for 1127example, <kbd>−1</kbd> 1128represents the last image of the sequence. Specify a range of images with a 1129dash (e.g. <kbd>0−4</kbd>). Separate multiple indexes with commas but no 1130spaces (e.g. <kbd>0,2,5</kbd>). A value of '<kbd>0−−1</kbd> will 1131effectively clone all the images. </p> 1132 1133<p>The <a href="#clone">+clone</a> will simply make a copy of the last image 1134in the image sequence, and is thus equivalent to using a argument of 1135'<kbd>−1</kbd>'. </p> 1136 1137<div style="margin: auto;"> 1138 <h4><a id="clut"></a>-clut</h4> 1139</div> 1140 1141<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Replace the channel values in the first image using each 1142corresponding channel in the second image as a <b>c</b>olor 1143<b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style='text-align:right;'></td></tr></table> 1144 1145<p>The second (LUT) image is ordinarily a gradient image containing the 1146histogram mapping of how each channel should be modified. Typically it is a 1147either a single row or column image of replacement color values. If larger 1148than a single row or column, values are taken from a diagonal line from 1149top-left to bottom-right corners.</p> 1150 1151<p>The lookup is further controlled by the <a 1152href="#interpolate">-interpolate</a> setting, which is especially handy for an 1153LUT which is not the full length needed by the ImageMagick installed Quality 1154(Q) level. Good settings for this are the '<kbd>bilinear</kbd>' and 1155'<kbd>bicubic</kbd>' interpolation settings, which give smooth color 1156gradients, and the '<kbd>integer</kbd>' setting for a direct, unsmoothed 1157lookup of color values. </p> 1158 1159<p>This operator is especially suited to replacing a grayscale image with a 1160specific color gradient from the CLUT image. </p> 1161 1162<p>Only the channel values defined by the <a href="#channel">-channel</a> 1163setting will have their values replaced. In particular, since the default <a 1164href="#channel">-channel</a> setting is <kbd>RGB</kbd>, this means that 1165transparency (alpha/matte channel) is not affected, unless the <a 1166href="#channel">-channel</a> setting is modified. When the alpha channel is 1167set, it is treated by the <a href="#clut" >-clut</a> operator in the same way 1168as the other channels, implying that alpha/matte values are replaced using the 1169alpha/matte values of the original image. </p> 1170 1171<p>If either the image being modified, or the lookup image, contains no 1172transparency (i.e. <a href="#alpha" >-alpha</a> is turned 'off') but the <a 1173href="#channel">-channel</a> setting includes alpha replacement, then it is 1174assumed that image represents a gray-scale gradient which is used for the 1175replacement alpha values. That is you can use a gray-scale CLUT image to 1176adjust a existing images alpha channel, or you can color a gray-scale image 1177using colors form CLUT containing the desired colors, including transparency. 1178</p> 1179 1180<p>See also <a href="#hald-clut" >-hald-clut</a> which replaces colors 1181according to the lookup of the full color RGB value from a 2D representation 1182of a 3D color cube. </p> 1183 1184 1185<div style="margin: auto;"> 1186 <h4><a id="coalesce"></a>-coalesce</h4> 1187</div> 1188 1189<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Fully define the look of each frame of an GIF animation sequence, to form a 'film strip' animation.</td><td style='text-align:right;'></td></tr></table> 1190 1191<p>Overlay each image in an image sequence according to 1192its <a href="#dispose">-dispose</a> meta-data, to reproduce the look of 1193an animation at each point in the animation sequence. All images should be 1194the same size, and are assigned appropriate GIF disposal settings for the 1195animation to continue working as expected as a GIF animation. Such frames 1196are more easily viewed and processed than the highly optimized GIF overlay 1197images. </p> 1198 1199<p>The animation can be re-optimized after processing using 1200the <a href="#layers">-layers</a> method '<kbd>optimize</kbd>', although 1201there is no guarantee that the restored GIF animation optimization is 1202better than the original. </p> 1203 1204 1205<div style="margin: auto;"> 1206 <h4><a id="colorize"></a>-colorize <em class="arg">value</em></h4> 1207</div> 1208 1209<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Colorize the image by an amount specified by <em class="arg">value</em> using the color specified by the most recent <a href="#fill" >-fill</a> setting.</td><td style='text-align:right;'></td></tr></table> 1210 1211<p>Specify the amount of colorization as a percentage. Separate colorization 1212values can be applied to the red, green, and blue channels of the image with 1213a comma-delimited list of colorization 1214values (e.g., <kbd>-colorize 0,0,50</kbd>).</p> 1215 1216<div style="margin: auto;"> 1217 <h4><a id="colormap"></a>-colormap <em class="arg">type</em></h4> 1218</div> 1219 1220<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Define the colormap type.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>, <a href="/www/display.html">display</a>]</td></tr></table> 1221 1222<p>The <em class="arg">type</em> can be <kbd>shared</kbd> or <kbd>private</kbd>.</p> 1223 1224<p>This option only applies when the default X server visual 1225is <kbd>PseudoColor</kbd> or <kbd>GrayScale</kbd>. Refer 1226to <a href="#visual">-visual</a> for more details. By default, 1227a shared colormap is allocated. The image shares colors with 1228other X clients. Some image colors could be approximated, 1229therefore your image may look very different than intended. 1230If <kbd>private</kbd> is chosen, the image colors appear exactly 1231as they are defined. However, other clients may go <em>technicolor</em> 1232when the image colormap is installed.</p> 1233 1234<div style="margin: auto;"> 1235 <h4><a id="colors"></a>-colors <em class="arg">value</em></h4> 1236</div> 1237 1238<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the preferred number of colors in the image.</td><td style='text-align:right;'></td></tr></table> 1239 1240<p>The actual number of colors in the image may be less than your request, 1241but never more. Note that this a color reduction option. Images with fewer 1242unique colors than specified by <em class="arg">value</em> will have any 1243duplicate or unused colors removed. The ordering of an existing color 1244palette may be altered. When converting an image from color to grayscale, 1245it is more efficient to convert the image to the gray colorspace before 1246reducing the number of colors. Refer to 1247the <a href="/www/quantize.html"> 1248color reduction algorithm</a> for more details.</p> 1249 1250<div style="margin: auto;"> 1251 <h4><a id="color-matrix"></a>-color-matrix <em class="arg">matrix</em></h4> 1252</div> 1253 1254<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>apply color correction to the image.</td><td style='text-align:right;'></td></tr></table> 1255 1256<p>This option permits saturation changes, hue rotation, luminance to alpha, 1257and various other effects. Although variable-sized transformation matrices 1258can be used, typically one uses a 5x5 matrix for an RGBA image and a 6x6 1259for CMYKA (or RGBA with offsets). The matrix is similar to those used by 1260Adobe Flash except offsets are in column 6 rather than 5 (in support of 1261CMYKA images) and offsets are normalized (divide Flash offset by 255).</p> 1262 1263<p>As an example, to add contrast to an image with offsets, try this command:</p> 1264 1265<pre class="text"> 1266 convert kittens.jpg -color-matrix \ 1267 " 1.5 0.0 0.0 0.0, 0.0, -0.157 \ 1268 0.0 1.5 0.0 0.0, 0.0, -0.157 \ 1269 0.0 0.0 1.5 0.0, 0.0, -0.157 \ 1270 0.0 0.0 0.0 1.0, 0.0, 0.0 \ 1271 0.0 0.0 0.0 0.0, 1.0, 0.0 \ 1272 0.0 0.0 0.0 0.0, 0.0, 1.0" kittens.png 1273</pre> 1274<div style="margin: auto;"> 1275 <h4><a id="colorspace"></a>-colorspace <em class="arg">value</em></h4> 1276</div> 1277 1278<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the image colorspace.</td><td style='text-align:right;'></td></tr></table> 1279 1280<p>Choices are:</p> 1281 1282<pre class="text"> 1283 CMY CMYK Gray HSB 1284 HSL HWB Lab Log 1285 OHTA Rec601Luma Rec601YCbCr Rec709Luma 1286 Rec709YCbCr RGB sRGB Transparent 1287 XYZ YCbCr YCC YIQ 1288 YPbPr YUV 1289</pre> 1290 1291<p>To print a complete list of colorspaces, use <a href="#list">-list colorspace</a>.</p> 1292 1293<p>For a more accurate color conversion to or from the RGB, CMYK, or grayscale colorspaces, use the <a href="#profile">-profile</a> option.</p> 1294 1295<table class="doc"> 1296 <caption>Conversion Of RGB To Other Color Spaces</caption> 1297 <tr><th align="left" valign="middle">CMY</th></tr> 1298 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>−R</td></tr> 1299 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>−G</td></tr> 1300 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>−B</td></tr> 1301 <tr><th align="left" valign="middle">CMYK — starts with CMY from above</th></tr> 1302 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr> 1303 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1304 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1305 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1306 1307 <tr><th align="left" valign="middle">Gray</th></tr> 1308 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 1309 1310 <tr><th align="left" valign="middle">HSB — Hue, Saturation, Brightness; like a cone peak downward</th></tr> 1311 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1312 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1313 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr> 1314 1315 <tr><th align="left" valign="middle">HSL — Hue, Saturation, Lightness; like a double cone end-to-end with peaks at very top and bottom</th></tr> 1316 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1317 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1318 <tr><td align="left" valign="middle">L=distance along axis from bottom upward; L=0.5*max(R,G,B) + 0.5*min(R,G,B); <em>intensity-like</em></td></tr> 1319 1320 <tr><th align="left" valign="middle">HWB — Hue, Whiteness, Blackness</th></tr> 1321 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr> 1322 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr> 1323 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr> 1324 1325 <tr><th align="left" valign="middle">LAB</th></tr> 1326 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr> 1327 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr> 1328 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr> 1329 1330 <tr><th align="left" valign="middle">LOG</th></tr> 1331 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr> 1332 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr> 1333 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr> 1334 1335 <tr><th align="left" valign="middle">OHTA — approximates principal components transformation</th></tr> 1336 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr> 1337 <tr><td align="left" valign="middle">I2=(0.50000*R+0.00000*G−0.50000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1338 <tr><td align="left" valign="middle">I3=(−0.25000*R+0.50000*G−0.25000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1339 1340 <tr><th align="left" valign="middle">Rec601Luma</th></tr> 1341 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 1342 1343 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr> 1344 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1345 <tr><td align="left" valign="middle">Cb=(−0.168736*R-0.331264*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1346 <tr><td align="left" valign="middle">Cr=(0.500000*R−0.418688*G−0.081312*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1347 1348 <tr><th align="left" valign="middle">Rec709Luma</th></tr> 1349 <tr><td align="left" valign="middle">Gray=0.21260*R+0.71520*G+0.07220*B</td></tr> 1350 1351 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr> 1352 <tr><td align="left" valign="middle">Y=0.212600*R+0.715200*G+0.072200*B; <em>intensity-like</em></td></tr> 1353 <tr><td align="left" valign="middle">Cb=(−0.114572*R−0.385428*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1354 <tr><td align="left" valign="middle">Cr=(0.500000*R−0.454153*G−0.045847*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1355 1356 <tr><th align="left" valign="middle">sRGB</th></tr> 1357 <tr><td align="left" valign="middle">if Rs ≤ .04045 then Rs=R/12.92 else Rs=((R+.055)/1.055)^2.4</td></tr> 1358 <tr><td align="left" valign="middle">if Gs ≤ .04045 then Gs=B/12.92 else Gs=((G+.055)/1.055)^2.4</td></tr> 1359 <tr><td align="left" valign="middle">if Bs ≤ .04045 then Bs=B/12.92 else Bs=((B+.055)/1.055)^2.4</td></tr> 1360 1361 <tr><th align="left" valign="middle">XYZ</th></tr> 1362 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr> 1363 <tr><td align="left" valign="middle">Y=0.2126560*R+0.7151580*G+0.0721856*B</td></tr> 1364 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr> 1365 1366 <tr><th align="left" valign="middle">YCC</th></tr> 1367 <tr><td align="left" valign="middle">Y=(0.29900*R+0.58700*G+0.11400*B) (with complicated scaling); <em>intensity-like</em></td></tr> 1368 <tr><td align="left" valign="middle">C1=(−0.29900*R−0.58700*G+0.88600*B) (with complicated scaling)</td></tr> 1369 <tr><td align="left" valign="middle">C2=(0.70100*R−0.58700*G−0.11400*B) (with complicated scaling)</td></tr> 1370 1371 <tr><th align="left" valign="middle">YCbCr</th></tr> 1372 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1373 <tr><td align="left" valign="middle">Cb=(−0.168736*R−0.331264*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1374 <tr><td align="left" valign="middle">Cr=(0.500000*R−0.418688*G−0.081312*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1375 1376 <tr><th align="left" valign="middle">YIQ</th></tr> 1377 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1378 <tr><td align="left" valign="middle">I=(0.59600*R−0.27400*G−0.32200*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1379 <tr><td align="left" valign="middle">Q=(0.21100*R−0.52300*G+0.31200*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1380 1381 <tr><th align="left" valign="middle">YPbPr</th></tr> 1382 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1383 <tr><td align="left" valign="middle">Pb=(−0.168736*R−0.331264*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1384 <tr><td align="left" valign="middle">Pr=(0.500000*R−0.418688*G−0.081312*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1385 1386 <tr><th align="left" valign="middle">YUV</th></tr> 1387 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1388 <tr><td align="left" valign="middle">U=(−0.14740*R−0.28950*G+0.43690*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1389 <tr><td align="left" valign="middle">V=(0.61500*R−0.51500*G−0.10000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr> 1390</table> 1391 1392<div style="margin: auto;"> 1393 <h4><a id="combine"></a>-combine</h4> 1394</div> 1395 1396<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Combine one or more images into a single image.</td><td style='text-align:right;'></td></tr></table> 1397 1398<p>The channels (previously set by <a href="#channel">-channel</a>) of the combined image are taken from the grayscale values of each image in the sequence, in order. For the default -channel setting of <kbd>RGB</kbd>, this means the first image is assigned to the <kbd>Red</kbd> channel, the second to the <kbd>Green</kbd> channel, the third to the <kbd>Blue</kbd>.</p> 1399 1400<p>This option can be thought of as the inverse to <a href="#separate">-separate</a>, so long as the channel settings are the same. Thus, in the following example, the final image should be a copy of the original. 1401</p> 1402 1403<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert original.png -channel RGB -separate sepimage.png</span><span class='crtout'></span><span class="crtprompt"> $magick> </span><span class='crtin'>convert sepimage-0.png sepimage-1.png sepimage-2.png -channel RGB \ <br/> -combine imagecopy.png</span></p> 1404<div style="margin: auto;"> 1405 <h4><a id="comment"></a>-comment <em class="arg">string</em></h4> 1406</div> 1407 1408<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Embed a comment in an image.</td><td style='text-align:right;'></td></tr></table> 1409 1410<p>This option sets the comment meta-data of an image read in after this 1411option has been given. To modify a comment of images already in memory use 1412"<kbd><a href="#set">-set</a> comment</kbd>". </p> 1413 1414<p>The comment can contain special format characters listed in the <a 1415href="/www/escape.html">Format and 1416Print Image Properties</a>. These attributes are expanded when the comment 1417is finally assigned to the individual images. </p> 1418 1419<p>If the first character of <em class="arg">string</em> is <em 1420class="arg">@</em>, the image comment is read from a file titled by the 1421remaining characters in the string. Comments read in from a file are literal; 1422no embedded formatting characters are recognized.</p> 1423 1424<p>Comment meta-data are not visible on the image itself. To do that use the 1425<a href="#annotate">-annotate</a> or <a href="#draw">-draw</a> options 1426instead.</p> 1427 1428<p>For example,</p> 1429 1430<p class="crtsnip"> 1431 -comment "%m:%f %wx%h" bird.miff 1432</p> 1433 1434<p>produces an image comment of <kbd>MIFF:bird.miff 512x480</kbd> (assuming 1435that the image <kbd>bird.miff</kbd> has a width of 512 and a height of 1436480.</p> 1437 1438<div style="margin: auto;"> 1439 <h4><a id="compose"></a>-compose <em class="arg">operator</em></h4> 1440</div> 1441 1442<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the type of image composition.</td><td style='text-align:right;'></td></tr></table> 1443 1444<p>See <a href="/www/compose.html">Alpha Compositing</a> for 1445a detailed discussion of alpha compositing.</p> 1446 1447<p>This setting effects image processing operators that merge two (or more) 1448images together in some way. This includes the operators, 1449<a href="#composite">-composite</a>, 1450<a href="#layers">-layers</a> composite, 1451<a href="#flatten">-flatten</a>, 1452<a href="#mosaic">-mosaic</a>, 1453<a href="#layers">-layers</a> merge, 1454<a href="#border">-border</a>, 1455<a href="#frame">-frame</a>, 1456and <a href="#extent">-extent</a>. </p> 1457 1458<p>It is also one of the primary options for the "<kbd>composite</kbd>" 1459command. </p> 1460 1461 1462<div style="margin: auto;"> 1463 <h4><a id="composite"></a>-composite</h4> 1464</div> 1465 1466<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Perform alpha composition on two images and an optional mask</td><td style='text-align:right;'></td></tr></table> 1467 1468<p>Take the first image 'destination' and overlay the second 'source' image 1469according to the current <a href="#compose">-compose</a> setting. The location 1470of the 'source' or 'overlay' image is controlled according to <a 1471href="#geometry" >-geometry</a>, and <a href="#geometry" >-geometry</a> 1472settings. </p> 1473 1474<p>If a third image is given this is treated as a gray-scale 'mask' image 1475relative to the first 'destination' image. This mask will limit what parts of 1476the destination can be modified by the image composition. However for the 1477'<kbd>displace</kbd>' compose method, the mask is used to provide a separate 1478Y-displacement image instead. </p> 1479 1480<p>If a <a href="#compose">-compose</a> method requires extra numerical 1481arguments or flags these can be provided by setting the <a 1482href="#set">-set</a> '<kbd class="arg">option:compose:args</kbd>' 1483appropriately for the compose method. </p> 1484 1485<p>Some <a href="#compose">-compose</a> methods can modify the 'destination' 1486image outside the overlay area. You can disable this by setting the special <a 1487href="#set">-set</a> '<kbd class="arg">option:compose:outside-overlay</kbd>' 1488to '<kbd>false</kbd>'. </p> 1489 1490 1491<div style="margin: auto;"> 1492 <h4><a id="compress"></a>-compress <em class="arg">type</em></h4> 1493</div> 1494 1495<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Use pixel compression specified by <em class="arg">type</em> when writing the image.</td><td style='text-align:right;'></td></tr></table> 1496 1497<p>Choices are: <kbd class="arg">None</kbd>, <kbd class="arg">BZip</kbd>, <kbd class="arg">Fax</kbd>, <kbd class="arg">Group4</kbd>, <kbd class="arg">JPEG</kbd>, <kbd class="arg">JPEG2000</kbd>, <kbd class="arg">Lossless</kbd>, <kbd class="arg">LZW</kbd>, <kbd class="arg">RLE</kbd> or <kbd class="arg">Zip</kbd>.</p> 1498 1499<p>To print a complete list of compression types, use <a href="#list">-list compress</a>.</p> 1500 1501<p>Specify <a href="#compress">+compress</a> to store the binary image in an uncompressed format. The default is the compression type of the specified image file.</p> 1502 1503<p>If <kbd>LZW</kbd> compression is specified but LZW compression has not been enabled, the image data is written in an uncompressed LZW format that can be read by LZW decoders. This may result in larger-than-expected GIF files.</p> 1504 1505<p><kbd>Lossless</kbd> refers to lossless JPEG, which is only available if the JPEG library has been patched to support it. Use of lossless JPEG is generally not recommended.</p> 1506 1507<p>Use the <a href="#quality">-quality</a> option to set the compression level to be used by JPEG, PNG, MIFF, and MPEG encoders. Use the <a href="#sampling-factor">-sampling-factor</a> option to set the sampling factor to be used by JPEG, MPEG, and YUV encoders for down-sampling the chroma channels.</p> 1508 1509<div style="margin: auto;"> 1510 <h4><a id="contrast"></a>-contrast</h4> 1511</div> 1512 1513<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Enhance or reduce the image contrast.</td><td style='text-align:right;'></td></tr></table> 1514 1515<p>This option enhances the intensity differences between the lighter and darker elements of the image. Use <a href="#contrast">-contrast</a> to enhance the image or <a href="#contrast">+contrast</a> to reduce the image contrast.</p> 1516 1517<p>For a more pronounced effect you can repeat the option:</p> 1518 1519<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -contrast -contrast rose_c2.png</span></p> 1520<div style="margin: auto;"> 1521 <h4><a id="contrast-stretch"></a>-contrast-stretch <em class="arg">black-point</em><br />-contrast-stretch <em class="arg">black-point</em>{x<em class="arg">white-point</em>}{<em class="arg">%</em>}}</h4> 1522</div> 1523 1524<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Increase the contrast in an image by <em>stretching</em> the range of intensity values.</td><td style='text-align:right;'></td></tr></table> 1525 1526<p>While performing the stretch, black-out at most <em 1527class="arg" >black-point</em> pixels and white-out at most <em 1528class="arg" >white-point</em> pixels. Or, if percent is used, black-out at most 1529<em class="arg" >black-point %</em> pixels and white-out at most <em 1530class="arg" >white-point %</em> pixels.</p> 1531 1532<p>Prior to ImageMagick 6.4.7-0, <a href="#contrast-stretch" 1533>-contrast-stretch</a> will black-out at most <em class="arg" 1534>black-point</em> pixels and white-out at most <em class="arg" >total pixels 1535minus white-point</em> pixels. Or, if percent is used, black-out at most <em 1536class="arg">black-point %</em> pixels and white-out at most <em class="arg" 1537>100% minus white-point %</em> pixels.</p> 1538 1539<p>Note that <kbd>-contrast-stretch 0</kbd> will modify the image such that 1540the image's min and max values are stretched to 0 and <em class="QR" 1541>QuantumRange</em>, respectively, without any loss of data due to burn-out or 1542clipping at either end. This is not the same as <a href="#normalize" 1543>-normalize</a>, which is equivalent to <kbd>-contrast-stretch 0.15x0.05%</kbd> (or 1544prior to ImageMagick 6.4.7-0, <kbd>-contrast-stretch 2%x99%</kbd>).</p> 1545 1546<p>Internally operator works by creating a histogram bin, and then uses that 1547bin to modify the image. As such some colors may be merged together when they 1548originally fell into the same 'bin'. </p> 1549 1550<p>All the channels are normalized in concert by the came amount so as to 1551preserve color integrity, when the default <a href="#channel" >+channel</a> 1552setting is in use. Specifying any other <a href="#channel" >-channel</a> 1553setting will normalize the RGB channels independently.</p> 1554 1555<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 1556normalization of mathematical images. </p> 1557 1558<p>This operator is under review for re-development. </p> 1559 1560 1561<div style="margin: auto;"> 1562 <h4><a id="convolve"></a>-convolve <em class="arg">kernel</em></h4> 1563</div> 1564 1565<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Convolve an image with a user-supplied convolution kernel.</td><td style='text-align:right;'></td></tr></table> 1566 1567<p>The <em class="arg">kernel</em> is a matrix specified as 1568a comma-separated list of integers (with no spaces), ordered left-to right, 1569starting with the top row. Presently, only odd-dimensioned kernels are 1570supported, and therefore the number of entries in the specified <em 1571class="arg">kernel</em> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25, 15727<sup>2</sup>=49, etc. </p> 1573 1574<p>Note that the <a href="/www/command-line-options.html#convolve">‑convolve</a> operator supports the <a href="/www/command-line-options.html#bias">‑bias</a> setting. This option shifts the convolution so that 1575positive and negative results are relative to a user-specified bias value. 1576This is important for non-HDRI compilations of ImageMagick when dealing with 1577convolutions that contain negative as well as positive values. This is 1578especially the case with convolutions involving high pass filters or edge 1579detection. Without an output bias, the negative values is clipped at zero. 1580</p> 1581 1582<p>When using an ImageMagick with the HDRI compile-time setting, <a href="/www/command-line-options.html#bias">‑bias</a> is not needed, as ImageMagick is able to store/handle any 1583negative results without clipping to the color value range (0..QuantumRange). 1584See the discussion on HDRI implementations of ImageMagick on the page <a 1585href="/www/high-dynamic-range.html">High 1586Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a 1587href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this 1588<a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> 1589entry. </p> 1590 1591 1592<div style="margin: auto;"> 1593 <h4><a id="crop"></a>-crop <em class="arg">geometry</em></h4> 1594</div> 1595 1596<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Cut out one or more rectangular regions of the image.</td><td style='text-align:right;'></td></tr></table> 1597 1598<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 1599 1600<p>The <em class="arg">width</em> and <em class="arg">height</em> of the <em class="arg">geometry</em> argument give the size of the image that remains after cropping, and <em class="arg">x</em> and <em class="arg">y</em> in the <em class="arg">offset</em> (if present) gives the location of the top left corner of the cropped image with respect to the original image. To specify the amount to be removed, use <a href="#shave">-shave</a> instead.</p> 1601 1602<p>If the <em class="arg">x</em> and <em class="arg">y</em> offsets are present, a single image is generated, consisting of the pixels from the cropping region. The offsets specify the location of the upper left corner of the cropping region measured downward and rightward with respect to the upper left corner of the image. If the <a href="#gravity">-gravity</a> option is present with <kbd>NorthEast</kbd>, <kbd>East</kbd>, or <kbd>SouthEast</kbd> gravity, it gives the distance leftward from the right edge of the image to the right edge of the cropping region. Similarly, if the <a href="#gravity">-gravity</a> option is present with <kbd>SouthWest</kbd>, <kbd>South</kbd>, or <kbd>SouthEast</kbd> gravity, the distance is measured upward between the bottom edges.</p> 1603 1604<p>If the <em class="arg">x</em> and <em class="arg">y</em> offsets are omitted, a set of tiles of the specified geometry, covering the entire input image, is generated. The rightmost tiles and the bottom tiles are smaller if the specified geometry extends beyond the dimensions of the input image.</p> 1605 1606<p>By adding a exclamation character flag to the geometry argument, the 1607cropped images virtual canvas page size and offset is set as if the 1608geometry argument was a viewport or window. This means the canvas page size 1609is set to exactly the same size you specified, the image offset set 1610relative top left corner of the region cropped. </p> 1611 1612<p>If the cropped image 'missed' the actual image on its virtual canvas, a 1613special single pixel transparent 'missed' image is returned, and a 'crop 1614missed' warning given. </p> 1615 1616<p>It might be necessary to <a href="#repage" >+repage</a> the image prior to cropping the image to ensure the crop coordinate frame is relocated to the upper-left corner of the visible image.</p> 1617 1618<div style="margin: auto;"> 1619 <h4><a id="cycle"></a>-cycle <em class="arg">amount</em></h4> 1620</div> 1621 1622<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>displace image colormap by amount.</td><td style='text-align:right;'></td></tr></table> 1623 1624<p><em class="arg">Amount</em> defines the number of positions each 1625colormap entry is shifted.</p> 1626 1627 1628<div style="margin: auto;"> 1629 <h4><a id="debug"></a>-debug <em class="arg">events</em></h4> 1630</div> 1631 1632<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>enable debug printout.</td><td style='text-align:right;'></td></tr></table> 1633 1634<p>The <kbd>events</kbd> parameter specifies which events are to be logged. It can be either <kbd>None</kbd>, <kbd>All</kbd>, <kbd>Trace</kbd>, or a comma-separated list consisting of one or more of the following domains: <kbd>Annotate</kbd>, <kbd>Blob</kbd>, <kbd>Cache</kbd>, <kbd>Coder</kbd>, <kbd>Configure</kbd>, <kbd>Deprecate</kbd>, <kbd>Exception</kbd>, <kbd>Locale</kbd>, <kbd>Render</kbd>, <kbd>Resource</kbd>, <kbd>Security</kbd>, <kbd>TemporaryFile</kbd>, <kbd>Transform</kbd>, <kbd>X11</kbd>, or <kbd>User</kbd>. </p> 1635 1636 1637<p>For example, to log cache and blob events, use.</p> 1638 1639<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p> 1640<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p> 1641 1642<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p> 1643 1644<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p> 1645 1646<p>Use <a href="#debug">+debug</a> to turn off all logging.</p> 1647 1648<p>Debugging may also be set using the <kbd>MAGICK_DEBUG</kbd> <a href="/www/resources.html#environment">environment variable</a>. The allowed values for the <kbd>MAGICK_DEBUG</kbd> environment variable are the same as for the <a href="#debug">-debug</a> option.</p> 1649 1650 1651<div style="margin: auto;"> 1652 <h4><a id="decipher"></a>-decipher <em class="arg">filename</em></h4> 1653</div> 1654 1655<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Decipher and restore pixels that were previously transformed by <a href="#encipher">-encipher</a>.</td><td style='text-align:right;'></td></tr></table> 1656 1657<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 1658 1659<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 1660 1661 1662<div style="margin: auto;"> 1663 <h4><a id="deconstruct"></a>-deconstruct</h4> 1664</div> 1665 1666<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>find areas that has changed between images </td><td style='text-align:right;'></td></tr></table> 1667 1668<p>Given a sequence of images all the same size, such as produced by <a href="#coalesce">-coalesce</a>, replace the second and later images, with a smaller image of just the area that changed relative to the previous image. </p> 1669 1670<p>The resulting sequence of images can be used to optimize an animation sequence, though will not work correctly for GIF animations when parts of the animation can go from opaque to transparent. </p> 1671 1672<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p> 1673 1674 1675<div style="margin: auto;"> 1676 <h4><a id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4> 1677</div> 1678 1679<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>add specific global settings generally used to control 1680coders and image processing operations.</td><td style='text-align:right;'></td></tr></table> 1681 1682<p>This option creates one or more definitions for coders and decoders to use 1683while reading and writing image data. Definitions are generally used to 1684control image file format coder modules, and image processing operations, 1685beyond what is provided by normal means. Defined settings are listed in <a 1686href="#verbose" >-verbose</a> information ("<kbd>info:</kbd>" output format) 1687as "Artifacts". </p> 1688 1689<p>If <em class="arg">value</em> is missing for a definition, an empty-valued 1690definition of a flag is created with that name. This used to control on/off 1691options. Use <a href="#define">+define key</a> to remove definitions 1692previously created. Use <a href="#define">+define "*"</a> to remove all 1693existing definitions.</p> 1694 1695<p>The same 'artifact' settings can also be defined using the <a 1696href="#set" >-set "option:<em class="arg">key</em>" "<em class="arg" 1697>value</em>"</a> option, which also allows the use of <a href="/www/escape.html" >Format and Print Image 1698Properties</a> in the defined value. </p> 1699 1700<p>The <em>option</em> and <em>key</em> are case-independent (they are 1701converted to lowercase for use within the decoders) while the <em>value</em> 1702is case-dependent.</p> 1703 1704<p>Such settings are global in scope, and effect all images and operations. </p> 1705 1706<p>The following definitions are just some of the artifacts that are 1707available:</p> 1708 1709<dl> 1710<dt>dcm:display-range=reset</dt> 1711<dd>Set the display range to the minimum and maximum pixel values for the 1712 DCM image format.</dd> 1713 1714<dt>dot:layout-engine=<em class="arg">value</em></dt> 1715<dd>Set the specify the layout engine for the DOT image format (e.g. 1716 <kbd>neato</kbd>).</dd> 1717 1718<dt>jpeg:extent=<em class="arg">value</em></dt> 1719<dd>Restrict the maximum JPEG file size, for example <kbd>-define 1720 jpeg:extent=400kb</kbd>.</dd> 1721 1722<dt>jpeg:size=<em class="arg">geometry</em></dt> 1723<dd>Set the size hint of a JPEG image, for example, -define jpeg:size=128x128. 1724 It is most useful for increasing performance and reducing the memory 1725 requirements when reducing the size of a large JPEG image.</dd> 1726 1727<dt>jp2:rate=<em class="arg">value</em></dt> 1728<dd>Specify the compression factor to use while writing JPEG-2000 files. The 1729 compression factor is the reciprocal of the compression ratio. The valid 1730 range is 0.0 to 1.0, with 1.0 indicating lossless compression. If defined, 1731 this value overrides the -quality setting. A quality setting of 75 1732 results in a rate value of 0.06641.</dd> 1733 1734<dt>mng:need-cacheoff</dt> 1735 <dd>turn playback caching off for streaming MNG.</dd> 1736 1737<dt>png:bit-depth=<em class="arg">value</em></dt> 1738<dt>png:color-type=<em class="arg">value</em></dt> 1739<dd>desired bit-depth and color-type for PNG output. You can force the PNG 1740 encoder to use a different bit-depth and color-type than it would have 1741 normally selected, but only if this does not cause any loss of image 1742 quality. Any attempt to reduce image quality is treated as an error and no 1743 PNG file is written. E.g., if you have a 1-bit black-and-white image, you 1744 can use these "defines" to cause it to be written as an 8-bit grayscale, 1745 indexed, or even a 64-bit RGBA. But if you have a 16-million color image, 1746 you cannot force it to be written as a grayscale or indexed PNG. If you 1747 wish to do this, you must use the appropriate <a href="#depth">-depth</a>, 1748 <a href="#colors">-colors</a>, or <a href="#type">-type</a> directives to 1749 reduce the image quality prior to using the PNG encoder. Note that in 1750 indexed PNG files, "bit-depth" refers to the number of bits per index, 1751 which can be 1, 2, 4, or 8. In such files, the color samples always have 1752 8-bit depth.</dd> 1753 1754<dt>png:compression-filter=<em class="arg">value</em></dt> 1755 <dd> valid values are 0 through 7. 0-4 are the corresponding PNG filters, 1756 5 means adaptive filtering except for images with a colormap, 6 means 1757 adaptive filtering for all images, 7 means MNG "loco" compression.</dd> 1758 1759<dt>png:compression-level=<em class="arg">value</em></dt> 1760 <dd> valid values are 0 through 9, with 0 providing the least but fastest 1761 compression and 9 usually providing the best and always the slowest.</dd> 1762 1763<dt>png:compression-strategy=<em class="arg">value</em></dt> 1764 <dd> valid values are 0 through 4, meaning default, filtered, huffman_only, 1765 rle, and fixed ZLIB compression strategy. If you are using an old zlib 1766 that does not support Z_RLE (before 1.2.0) or Z_FIXED (before 1.2.2.2), 1767 values 3 and 4, respectively, will use the zlib default strategy 1768 instead.</dd> 1769 1770<dt>png:exclude-chunk=<em class="arg">value</em></dt> 1771<dt>png:include-chunk=<em class="arg">value</em></dt> 1772<dd>ancillary chunks to be excluded from or included in PNG output. 1773 1774 <p>The<em class="arg">value</em> can be the name of a PNG chunk-type such 1775 as <em class="arg">bKGD</em>, a comma-separated list of chunk-types, 1776 or the word <em class="arg">all</em> or 1777 the word <em class="arg">none</em>. There must be no spaces in the 1778 list. Although PNG chunk-names are case-dependent, you can use 1779 all lowercase names if you prefer.</p> 1780 1781 <p>The "include-chunk" and "exclude-chunk" lists only affect the behavior 1782 of the PNG encoder and have no effect on the PNG decoder.</p> 1783 1784 <p>As a special case, if the <kbd>sRGB</kbd> chunk is excluded and 1785 the <kbd>gAMA</kbd> chunk is included, the <kbd>gAMA</kbd> chunk will 1786 only be written if gamma is not 1/2.2, since most decoders assume 1787 sRGB and gamma=1/2.2 when no colorspace information is included in 1788 the PNG file. Because the list is processed from left to right, you 1789 can achieve this with a single define:</p> 1790 1791<pre class="text"> 1792 -define png:include-chunk=none,gAMA 1793</pre> 1794 1795 <p>The critical PNG chunks <kbd>IHDR</kbd>, <kbd>PLTE</kbd>, 1796 <kbd>IDAT</kbd>, and <kbd>IEND</kbd> cannot be excluded. Any such 1797 entries appearing in the list will be ignored.</p> 1798 1799 <p>If the ancillary PNG <kbd>tRNS</kbd> chunk is excluded and the 1800 image has transparency, the PNG colortype is forced to be 4 or 6 1801 (GRAY_ALPHA or RGBA). If the image is not transparent, then the 1802 <kbd>tRNS</kbd> chunk isn't written anyhow, and there is no effect 1803 on the PNG colortype of the output image.</p> 1804 1805 <p>The <a href="#strip">-strip</a> option does the equivalent of the 1806 following for PNG output:</p> 1807 1808<pre class="text"> 1809 -define png:include-chunk=none,gama 1810</pre> 1811 1812 <p>The default behavior is to include all known PNG ancillary chunks 1813 plus ImageMagick's private <kbd>vpAg</kbd> ("virtual page") chunk, 1814 and to exclude all PNG chunks that are unknown to ImageMagick, 1815 regardless of their PNG "copy-safe" status as described in the 1816 PNG specification.</p> 1817 1818 <p>Any chunk names that are not known to ImageMagick are ignored 1819 if they appear in either the "include-chunk" or "exclude-chunk" list. 1820 The ancillary chunks currently known to ImageMagick are 1821 <kbd>bKGD</kbd>, <kbd>cHRM</kbd>, <kbd>gAMA</kbd>, <kbd>iCCP</kbd>, 1822 <kbd>oFFs</kbd>, <kbd>pHYs</kbd>, <kbd>sRGB</kbd>, <kbd>tEXt</kbd>, 1823 <kbd>tRNS</kbd>, <kbd>vpAg</kbd>, and <kbd>zTXt</kbd>.</p> 1824 1825 <p>You can also put <kbd>date</kbd> in the list to include or exclude 1826 the "Date:create" and "Date:modify" text chunks that ImageMagick normally 1827 inserts in the output PNG.</p> 1828 1829</dd> 1830 1831<dt>png:preserve-colormap</dt> 1832 <dd>Use the existing image->colormap. Normally the PNG encoder will 1833 try to optimize the palette, eliminating unused entries and putting 1834 the transparent colors first. If this flag is set, that behavior 1835 is suppressed.</dd> 1836 1837<dt>ps:imagemask</dt> 1838<dd>If the ps:imagemask flag is defined, the PS3 and EPS3 coders will create 1839 Postscript files that render bilevel images with the Postscript imagemask 1840 operator instead of the image operator.</dd> 1841 1842<dt>quantum:format=<em class="arg">type</em></dt> 1843<dd>Set the type to <kbd>floating-point</kbd> to specify a floating-point 1844 format for raw files (e.g. GRAY:) or for MIFF and TIFF images in HDRI mode 1845 to preserve negative values. If <a href="#depth">-depth</a> 16 is 1846 included, the result is a single precision floating point format. 1847 If <a href="#depth">-depth</a> 32 is included, the result is 1848 double precision floating point format.</dd> 1849 1850</dl> 1851 1852<p>For example, to create a postscript file that will render only the black 1853pixels of a bilevel image, use:</p> 1854 1855<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p> 1856<p>Set attributes of the image registry by prefixing the value with 1857<kbd>registry:</kbd>. For example, to set a temporary path to put work files, 1858use:</p> 1859 1860<p class="crtsnip"> 1861-define registry:temporary-path=/data/tmp 1862</p> 1863 1864 1865 1866<div style="margin: auto;"> 1867 <h4><a id="delay"></a>-delay <em class="arg">ticks</em> <br />-delay <em class="arg">ticks</em>x<em class="arg">ticks-per-second</em> {<em class="arg"><</em>} {<em class="arg">></em>}</h4> 1868</div> 1869 1870<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>display the next image after pausing.</td><td style='text-align:right;'></td></tr></table> 1871 1872<p>This option is useful for regulating the animation of image sequences <em>ticks/ticks-per-second</em> seconds must expire before the display of the next image. The default is no delay between each showing of the image sequence. The default ticks-per-second is 100.</p> 1873 1874<p>Use <kbd>></kbd> to change the image delay <em>only</em> if its current value exceeds the given delay. <kbd><</kbd> changes the image delay <em>only</em> if current value is less than the given delay. For example, if you specify <kbd>30></kbd> and the image delay is 20, the image delay does not change. However, if the image delay is 40 or 50, the delay it is changed to 30. Enclose the given delay in quotation marks to prevent the <kbd><</kbd> or <kbd>></kbd> from being interpreted by your shell as a file redirection.</p> 1875 1876 1877<div style="margin: auto;"> 1878 <h4><a id="delete"></a>-delete <em class="arg">indexes</em></h4> 1879</div> 1880 1881<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>delete the image, specified by its index, from the image sequence.</td><td style='text-align:right;'></td></tr></table> 1882 1883<p>Specify the image by its index in the sequence. The first image is index 0. Negative indexes are relative to the end of the sequence, for example, -1 represents the last image of the sequence. Specify a range of images with a dash (e.g. 0-4). Separate indexes with a comma (e.g. 0,2). Use <kbd>+delete</kbd> to delete the last image in the current image sequence.</p> 1884 1885 1886<div style="margin: auto;"> 1887 <h4><a id="density"></a>-density <em class="arg">width</em><br />-density <em class="arg">width</em>x<em class="arg">height</em></h4> 1888</div> 1889 1890<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the horizontal and vertical resolution of an image for rendering to devices.</td><td style='text-align:right;'></td></tr></table> 1891 1892<p>This option specifies the image resolution to store while encoding a raster image or the canvas resolution while rendering (reading) vector formats such as Postscript, PDF, WMF, and SVG into a raster image. Image resolution provides the unit of measure to apply when rendering to an output device or raster image. The default unit of measure is in dots per inch (DPI). The <a href="#units">-units</a> option may be used to select dots per centimeter instead.</p> 1893 1894<p>The default resolution is 72 dots per inch, which is equivalent to one point per pixel (Macintosh and Postscript standard). Computer screens are normally 72 or 96 dots per inch, while printers typically support 150, 300, 600, or 1200 dots per inch. To determine the resolution of your display, use a ruler to measure the width of your screen in inches, and divide by the number of horizontal pixels (1024 on a 1024x768 display).</p> 1895 1896<p>If the file format supports it, this option may be used to update the stored image resolution. Note that Photoshop stores and obtains image resolution from a proprietary embedded profile. If this profile is not stripped from the image, then Photoshop will continue to treat the image using its former resolution, ignoring the image resolution specified in the standard file header.</p> 1897 1898<p>The <a href="#density">-density</a> option sets an <em>attribute</em> and does not alter the underlying raster image. It may be used to adjust the rendered size for desktop publishing purposes by adjusting the scale applied to the pixels. To resize the image so that it is the same size at a different resolution, use the <a href="#resample">-resample</a> option.</p> 1899 1900<div style="margin: auto;"> 1901 <h4><a id="depth"></a>-depth <em class="arg">value</em></h4> 1902</div> 1903 1904<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>depth of the image.</td><td style='text-align:right;'></td></tr></table> 1905 1906<p>This the number of bits in a color sample within a pixel. Use this option to specify the depth of raw images whose depth is unknown such as GRAY, RGB, or CMYK, or to change the depth of any image after it has been read.</p> 1907 1908<div style="margin: auto;"> 1909 <h4><a id="descend"></a>-descend</h4> 1910</div> 1911 1912<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>obtain image by descending window hierarchy.</td><td style='text-align:right;'></td></tr></table> 1913 1914<div style="margin: auto;"> 1915 <h4><a id="deskew"></a>-deskew <em class="arg">threshold</em></h4> 1916</div> 1917 1918<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>straighten an image. A threshold of 40% works for most images.</td><td style='text-align:right;'></td></tr></table> 1919 1920<p>Use <a href="#set">-set</a> <kbd>option:deskew:auto-crop <em>width</em></kbd> to auto crop the image. The set argument is the pixel width of the image background (e.g 40).</p> 1921 1922<div style="margin: auto;"> 1923 <h4><a id="despeckle"></a>-despeckle</h4> 1924</div> 1925 1926<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>reduce the speckles within an image.</td><td style='text-align:right;'></td></tr></table> 1927 1928<div style="margin: auto;"> 1929 <h4><a id="direction"></a>-direction <em class="arg">type</em></h4> 1930</div> 1931 1932<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>render text right-to-left or left-to-right.</td><td style='text-align:right;'></td></tr></table> 1933 1934<div style="margin: auto;"> 1935 <h4><a id="displace"></a>-displace <em class="arg">horizontal-scale</em><br />-displace <em class="arg">horizontal-scale</em>x<em class="arg">vertical-scale</em></h4> 1936</div> 1937 1938<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>shift image pixels as defined by a displacement map.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 1939 1940<p>With this option, the 'overlay' image, and optionally the 'mask' image, 1941is used as a displacement map, which is used to displace the lookup of 1942what part of the 'background' image is seen at each point of the overlaid 1943area. Much like the displacement map is a 'lens' that redirects light shining 1944through it so as to present a distorted view the original 'background' image 1945behind it. </p> 1946 1947<p>Any perfect grey areas of the displacement map produce a zero 1948displacement of the image. Black areas produce the given maximum negative 1949displacement of the lookup point, while white produce a maximum positive 1950displacement of the lookup. </p> 1951 1952<p>Note that it is the lookup of the 'background' that is displaced, not a 1953displacement of the image itself. As such an area of the displacement map 1954containing 'white' will have the lookup point 'shifted' by a positive amount, 1955and thus generating a copy of the destination image to the right/downward from 1956the correct position. That is the image will look like it may have been 1957'shifted' in a negative left/upward direction. Understanding this is a very 1958important in understanding how displacement maps work. </p> 1959 1960<p>The given arguments define the maximum amount of displacement in pixels 1961that a particular map can produce. If the displacement scale is large enough 1962it is also possible to lookup parts of the 'background' image that lie well 1963outside the bounds of the displacement map itself. That is you could very 1964easily copy a section of the original image from outside the overlay area 1965into the overlay area. </p> 1966 1967<p>The '%' flag makes the displacement scale relative to the size of the 1968overlay image (100% = half width/height of image). Using '!' switches 1969percentage arguments to refer to the destination image size instead. 1970these flags were added as of IM v6.5.3-5.</p> 1971 1972<p>Normally a single grayscale displacement map is provided, which with the 1973given scaling values will determine a single direction (vector) in which 1974displacements can occur (positively or negatively). However, if you also 1975specify a third image which is normally used as a <em class="arg">mask</em>, 1976the <em class="arg">composite image</em> is used for horizontal X 1977displacement, while the <em class="arg">mask image</em> is used for vertical Y 1978displacement. This allows you to define completely different displacement 1979values for the X and Y directions, and allowing you to lookup any point within 1980the <em class="arg">scale</em> bounds. In other words each pixel can lookup 1981any other nearby pixel, producing complex 2 dimensional displacements, rather 1982than a simple 1 dimensional vector displacements. </p> 1983 1984<p>Alteratively rather than supplying two separate images, as of IM v6.4.4-0, 1985you can use the 'red' channel of the overlay image to specify the horizontal 1986or X displacement, and the 'green' channel for the vertical or Y displacement. 1987</p> 1988 1989<p>As of IM v6.5.3-5 any alpha channel in the overlay image is used as a 1990mask the transparency of the destination image. However areas outside the 1991overlaid areas will not be effected. </p> 1992 1993 1994<div style="margin: auto;"> 1995 <h4><a id="display"></a>-display <em class="arg">host:display[.screen]</em></h4> 1996</div> 1997 1998<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specifies the X server to contact.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>, <a href="/www/display.html">display</a>]</td></tr></table> 1999 2000<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p> 2001 2002<div style="margin: auto;"> 2003 <h4><a id="dispose"></a>-dispose <em class="arg">method</em></h4> 2004</div> 2005 2006<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>define the GIF disposal image setting for images that are being created or read in. </td><td style='text-align:right;'></td></tr></table> 2007 2008<p>The layer disposal method defines the way each the displayed image is to be 2009modified after the current 'frame' of an animation has finished being 2010displayed (after its 'delay' period), but before the next frame on an 2011animation is to be overlaid onto the display. </p> 2012 2013<p>Here are the valid methods:</p> 2014 2015<pre class="text"> 2016 Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>'). 2017 None 1 Do not dispose, just overlay next frame image. 2018 Background 2 Clear the frame area with the background color. 2019 Previous 3 Clear to the image prior to this frames overlay. 2020</pre> 2021 2022<p>You can also use the numbers given above, which is what the GIF format 2023uses internally to represent the above settings. </p> 2024 2025<p>To print a complete list of dispose methods, use <a href="#list">-list dispose</a>.</p> 2026 2027<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent 2028resetting the layer disposal methods of images being read in. </p> 2029 2030<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image 2031disposal method for images already in memory.</p> 2032 2033<div style="margin: auto;"> 2034 <h4><a id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4> 2035</div> 2036 2037<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>maximum RMSE for subimage match (default 0.2).</td><td style='text-align:right;'>[<a href="/www/compare.html">compare</a>]</td></tr></table> 2038 2039 2040<div style="margin: auto;"> 2041 <h4><a id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4> 2042</div> 2043 2044<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>dissolve an image into another by the given percent.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 2045 2046<p>The opacity of the composite image is multiplied by the given percent, then 2047it is composited 'over' the main image. If <em class="arg">src_percent</em> 2048is greater than 100, start dissolving the main image so it becomes 2049transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages 2050are given, each image are dissolved to the percentages given. </p> 2051 2052<p>Note that dissolve percentages do not add, two opaque images dissolved 2053'50,50', produce a 75% transparency. For a 50% + 50% blending of the two 2054images, you would need to use dissolve values of '50,100'. </p> 2055 2056<div style="margin: auto;"> 2057 <h4><a id="distort"></a>-distort <em class="arg">method arguments</em></h4> 2058</div> 2059 2060<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>distort an image, using the given <em class="arg">method</em> and its required <em class="arg">arguments</em>.</td><td style='text-align:right;'></td></tr></table> 2061 2062<p>The <em class="arg">arguments</em> is a single string containing a list 2063of floating point numbers separated by commas or spaces. The number of 2064and meaning of the floating point values depends on the distortion <em 2065class="arg">method</em> being used. </p> 2066 2067<p>Choose from these distortion types:</p> 2068 2069<table class="doc"> 2070 <tr valign="top"> 2071 <th align="left" style="width: 8%">Method</th> 2072 <th align="left">Description</th> 2073 </tr> 2074 2075 <tr valign="top"> 2076 <td valign="top"><kbd>ScaleRotateTranslate</kbd> 2077 <br/>or <kbd>SRT</kbd></td> 2078 <td valign="top"> 2079 Distort image by first scaling and rotating about a given 'center', 2080 before translating that 'center' to the new location, in that order. It 2081 is an alternative method of specifying a '<kbd>Affine</kbd>' type of 2082 distortion, but without shearing effects. It also provides a good way 2083 of rotating and displacing a smaller image for tiling onto a larger 2084 background (IE 2-dimensional animations). <br/> 2085 2086 The number of arguments determine the specific meaning of each 2087 argument for the scales, rotation, and translation operations. <br/> 2088 2089 <table style="margin-left:auto; margin-right:auto;"> 2090 <tr><td># </td><td>arguments meaning</td></tr> 2091 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr> 2092 <tr><td>2:</td><td><em>Scale Angle</em></td></tr> 2093 <tr><td>3:</td><td><em>X,Y Angle</em></td></tr> 2094 <tr><td>4:</td><td><em>X,Y Scale Angle</em></td></tr> 2095 <tr><td>5:</td> 2096 <td><em>X,Y ScaleX,ScaleY Angle</em></td></tr> 2097 <tr><td>6:</td> 2098 <td><em>X,Y Scale Angle NewX,NewY</em></td></tr> 2099 <tr><td>7:</td> 2100 <td><em>X,Y ScaleX,ScaleY Angle 2101 NewX,NewY</em></td></tr> 2102 </table> 2103 2104 This is actually an alternative way of specifying a 2 dimensional linear 2105 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr> 2106 2107 <tr valign="top"> 2108 <td valign="top"><kbd>Affine</kbd></td> 2109 <td valign="top"> 2110 Distort the image linearly by moving a list of at least 3 or more sets 2111 of control points (as defined below). Ideally 3 sets or 12 floating 2112 point values are given allowing the image to be linearly scaled, 2113 rotated, sheared, and translated, according to those three points. See 2114 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>' 2115 distortions. <br/> 2116 2117 More than 3 sets given control point pairs (12 numbers) is least 2118 squares fitted to best match a lineary affine distortion. If only 2 2119 control point pairs (8 numbers) are given a two point image translation 2120 rotation and scaling is performed, without any possible shearing, 2121 flipping or changes in aspect ratio to the resulting image. If only one 2122 control point pair is provides the image is only translated, (which may 2123 be a floating point non-integer translation). <br/> 2124 2125 This distortion does not include any form of perspective distortion. 2126 </td> 2127 2128 </tr> 2129 2130 <tr valign="top"> 2131 <td valign="top"><kbd>AffineProjection</kbd></td> 2132 <td valign="top"> 2133 Linearly distort an image using the given Affine Matrix of 6 2134 pre-calculated coefficients forming a set of Affine Equations to map 2135 the source image to the destination image. 2136 2137 <div style="text-align: center"><em> 2138 s<sub>x</sub>, r<sub>x</sub>, 2139 r<sub>y</sub>, s<sub>y</sub>, 2140 t<sub>x</sub>, t<sub>y</sub> 2141 </em></div> 2142 2143 See <a href="#affine" >-affine</a> setting for more detail, and 2144 meanings of these coefficients. <br/> 2145 2146 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide 2147 alternative methods of defining this distortion, with ImageMagick doing 2148 the calculations needed to generate the required coefficients. You can 2149 see the internally generated coefficients, by using a <a 2150 href="#verbose" >-verbose</a> setting with those other varients. </td> 2151 2152 </tr> 2153 2154 <tr valign="top"> 2155 <td valign="top"><kbd>BilinearForward</kbd><br/> 2156 <kbd>BilinearReverse</kbd></td> 2157 <td valign="top"> 2158 Bilinear Distortion, given a minimum of 4 sets of coordinate pairs, or 2159 16 values (see below). Not that lines may not appear straight after 2160 distortion, though the distance between coordinates will remain 2161 consistent. <br/> 2162 2163 The '<kbd>BilinearForward</kbd>' is used to map rectangles to any 2164 quadrilateral, while the '<kbd>BilinearReverse</kbd>' form maps any 2165 quadrilateral to a rectangle, while preserving the straigth line edges 2166 in each case. <br/> 2167 2168 Note that '<kbd>BilinearForward</kbd>' can generate invalid pixels 2169 which will be colored using the <a href="#mattecolor" >-mattecolor</a> 2170 color setting. Also if the quadraterial becomes 'flipped' the image 2171 may dissappear. <br/> 2172 2173 There are future plans to produce a true Bilinear distortion that will 2174 attempt to map any quadrilateral to any other quadrilateral, while 2175 preserving edges (and edge distance ratios). 2176 2177 </td> 2178 </tr> 2179 2180 <tr valign="top"> 2181 <td valign="top"><kbd>Perspective</kbd></td> 2182 <td valign="top"> 2183 Perspective distort the images, using a list of 4 or more sets of 2184 control points (as defined below). More that 4 sets (16 numbers) of 2185 control points provide least squares fitting for more accurate 2186 distortions (for the purposes of image registration and panarama 2187 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>' 2188 linear distortion. <br/> 2189 2190 Perspective Distorted images ensures that straight lines remain 2191 straight, but the scale of the distorted image will vary. The horizon 2192 is anti-aliased, and the 'sky' color may be set using the 2193 <a href="#mattecolor" >-mattecolor</a> setting. </td> 2194 </tr> 2195 2196 <tr valign="top"> 2197 <td valign="top"><kbd>PerspectiveProjection</kbd> </td> 2198 <td valign="top"> 2199 Do a '<kbd>Perspective</kbd>' distortion biased on a set of 8 2200 pre-calculated coefficients. You can get these coefficients by looking 2201 at the <a href="#verbose" >-verbose</a> output of a 2202 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself. 2203 If the last two perspective scaling coefficients are zero, the 2204 remaining 6 represents a transposed 'Affine Matrix'. </td> 2205 2206 </tr> 2207 2208 <tr valign="top"> 2209 <td valign="top"><kbd>Arc</kbd></td> 2210 <td valign="top"> 2211 Arc the image (variation of polar mapping) over the angle given around 2212 a circle. <br/> 2213 <table width="90%" style = "margin-left: auto; margin-right: auto;"> 2214 <tr valign="top"><td>Argument</td> 2215 <td>Meaning</td></tr> 2216 <tr valign="top"><td><em>arc_angle</em></td> 2217 <td>The angle over which to arc the image side-to-side</td></tr> 2218 <tr valign="top"><td><em>rotate_angle</em></td> 2219 <td>Angle to rotate resulting image from vertical center</td></tr> 2220 <tr valign="top"><td><em>top_radius</em></td> 2221 <td>Set top edge of source image at this radius</td></tr> 2222 <tr valign="top"><td><em>bottom_radius</em> </td> 2223 <td>Set bottom edge to this radius (radial scaling)</td></tr> 2224 </table> 2225 2226 The resulting image is always resized to best fit the resulting image, 2227 (as if using <a href="#distort" >+distort</a>) while attempting to 2228 preserve scale and aspect ratio of the original image as much as 2229 possible with the arguments given by the user. All four arguments will 2230 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/> 2231 2232 This a variation of a polar distortion designed to try to preserve the 2233 aspect ratio of the image rather than direct Cartesian to Polar 2234 conversion. </td> 2235 </tr> 2236 2237 <tr valign="top"> 2238 <td valign="top"><kbd>Polar</kbd></td> 2239 <td valign="top"> 2240 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of 2241 the image. that is the height of the input image is mapped to the 2242 radius limits, while the width is wrapped around between the 2243 angle limits. <br/> 2244 2245 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/> 2246 2247 All arguments are optional. With <em>Rmin</em> defaulting to zero, the 2248 center to the center of the image, and the angles going from -180 (top) 2249 to +180 (top). If <em>Rmax</em> is given the special value of 2250 '<code>0</code>', the the distance from the center to the nearest edge 2251 is used for the radius of the output image, which will ensure the whole 2252 image is visible (though scaled smaller). However a special value of 2253 '<code>-1</code>' will use the distance from the center to the furthest 2254 corner, This may 'clip' the corners from the input rectangular image, 2255 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with 2256 the same arguments. <br/> 2257 2258 If the plus form of distort (<a href="#distort" >+distort</a>) is used 2259 output image center will default to <code>0,0</code> of the virtual 2260 canvas, and the image size adjusted to ensure the whole input image is 2261 made visible in the output image on the virtual canvas. </td> 2262 2263 </tr> 2264 2265 <tr valign="top"> 2266 <td valign="top"><kbd>DePolar</kbd></td> 2267 <td valign="top"> 2268 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion 2269 but generates the reverse Polar to Cartesian distortion. <br/> 2270 2271 The special <em>Rmax</em> setting of '<code>0</code>' may however clip 2272 the corners of the input image. However using the special 2273 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner 2274 distance) will ensure the whole distorted image is preserved in the 2275 generated result, so that the same argument to '<kbd>Polar</kbd>' will 2276 reverse the distortion re-producing the original. 2277 2278 Note that as this distortion requires the area resampling of a circular 2279 arc, which can not be handled by the builtin EWA resampling function. 2280 As such the normal EWA filters are turned off. It is recommended some 2281 form of 'super-sampling' image processing technique be used to produce 2282 a high quality result. </td> 2283 2284 </tr> 2285 2286 <tr valign="top"> 2287 <td valign="top"><kbd>Barrel</kbd></td> 2288 <td valign="top"> 2289 Given the four coefficients (A,B,C,D) as defined by <a 2290 href="http://wiki.panotools.org/Lens_correction_model" >Helmut 2291 Dersch</a>, perform a barrell or pin-cushion distortion appropriate to 2292 correct radial lens distortions. That is in photographs, make straight 2293 lines straight again. <br/> 2294 2295 Arguments: <em>A B C</em> [ <em>D</em> [ 2296 <em>X</em> , <em>Y</em> ] ] <br/> 2297 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> 2298 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> 2299 [ <em>X</em> , <em>Y</em> ] <br/> 2300 So that it forms the function <br/> 2301 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2302 <em>C</em>*r + <em>D</em> )<br/> 2303 2304 Where <em>X</em>,<em>Y</em> is the optional center of the distortion 2305 (defaulting to the center of the image). <br/> 2306 The second form is typically used to distort images, rather than 2307 correct lens distortions. <br/> 2308 </td> 2309 2310 </tr> 2311 2312 <tr valign="top"> 2313 <td valign="top"><kbd>BarrelInverse</kbd></td> 2314 <td valign="top"> 2315 This is very simular to '<kbd>Barrel</kbd>' with the same set of 2316 arguments, and argument handling. However it uses the inverse 2317 of the radial polynomial, 2318 so that it forms the function <br/> 2319 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2320 <em>C</em>*r + <em>D</em> )<br/> 2321 Note that this is not the reverse of the '<kbd>Barrel</kbd>' 2322 distortion, just a different barrel-like radial distortion method. 2323 2324 </td> 2325 </tr> 2326 2327 <tr valign="top"> 2328 <td valign="top"><kbd>Shepards</kbd></td> 2329 <td valign="top"> 2330 Distort the given list control points (any number) using an Inverse 2331 Squared Distance Interpolation Method (<a 2332 href="http://en.wikipedia.org/wiki/Shepard%27s_method" >Shepards 2333 Method</a>). The control points in effect do 'localized' displacement 2334 of the image around the given control point (preserving the look and 2335 the rotation of the area near the control points. For best results 2336 extra control points should be added to 'lock' the positions of the 2337 corners, edges and other unchanging parts of the image, to prevent 2338 their movement. <br/> 2339 2340 The distortion has been likened to 'taffy pulling' using nails, or 2341 pins' stuck in a block of 'jelly' which is then moved to the new 2342 position, distorting te surface of the jelly. <br/> 2343 2344 Internally it is equivalent to generating a displacement map (see <a 2345 href="#displace" >-displace</a>) for source image color look-up using 2346 the <a href="#sparse-color" >-sparse-color</a> method of the same name. 2347 2348 </td> 2349 </tr> 2350 2351</table> 2352 2353<p>To print a complete list of distortion methods, use <a href="#list">-list 2354distort</a>.</p> 2355 2356<p>Many of the above distortion methods such as '<kbd>Affine</kbd>', 2357'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points 2358defining how these points in the given image should be distorted in the 2359destination image. Each set of four floating point values represent a source 2360image coordinate, followed immediately by the destination image coordinate. 2361This produces a list of values such as...</p> 2362<div style="text-align: center"><em> 2363 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> 2364 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> 2365 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> 2366 ... 2367 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> 2368</em></div> 2369<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the 2370destination image. </p> 2371 2372<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion, 2373needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the 2374perspective distortion of the built-in "rose:" image. Note how spaces were 2375used to group the 4 sets of coordinate pairs, to make it easier to read and 2376understand.</p> 2377 2378<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'> 2379convert rose: -virtual-pixel black \<br/> 2380 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \<br/> 2381 rose_3d_rotated.gif</span></p> 2382<p>If more that the required number of coordinate pairs are given for 2383a distortion, the distortion method is 'least squares' fitted to produce the 2384best result for all the coordinate pairs given. If less than the ideal number 2385of points are given, the distort will generally fall back to a simpler form of 2386distortion that can handles the smaller number of coordinates (usally a linear 2387'<kbd>Affine</kbd>' distortion). </p> 2388 2389<p>By using more coordinates you can make use of image registration tool to 2390find matching coordinate pairs in overlapping images, so as to improve the 2391'fit' of the distortion. Of course a bad coordinate pair can also make the 2392'fit' worse. Caution is always advised. </p> 2393 2394<p>Colors are acquired from the source image according to the <a 2395href="#interpolate" >-interpolate</a> color lookup setting, when the image is 2396magnified. However if the viewed image is minified (image becomes smaller), 2397a special area resampling function (added ImageMagick v6.3.5-9), is used to 2398produce a higher quality image. For example you can use 2399a '<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all 2400the way to the horizon. </p> 2401 2402<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'> 2403convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \<br/> 2404 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \<br/> 2405 checks_tiled.jpg</span></p> 2406<p>Note that a infinitely tiled perspective images involving the horizon can 2407be very slow to generate due to the use of the high quality 'area resampling' 2408function (added ImageMagick v6.3.5-9). You can turn off 'area resampling' 2409using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>' 2410(recommended if you plan to use super-sampling instead). </p> 2411 2412<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last 2413'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a> 2414will use the current <a href="#mattecolor" >-mattecolor</a> setting for these 2415pixels. If you do not what these pixels to be visible, set the color to match 2416the rest of the ground. </p> 2417 2418<p>The output image size will by default be the same as the input image. This 2419means that if the part of the distorted image falls outside the viewed area of 2420the 'distorted space', those parts is clipped and lost. However if you use 2421the plus form of the operator (<a href="#distort" >+distort</a>) the operator 2422will attempt (if possible) to show the whole of the distorted image, while 2423retaining a correct 'virtual canvas' offset, for image layering. This offset 2424may need to be removed using <a href="#repage" >+repage</a>, to remove if it 2425is unwanted. </p> 2426 2427<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a> 2428option:distort:viewport {geometry_string}</kbd>" setting which will specify 2429the size and the offset of the generated 'viewport' image of the distorted 2430image space.</p> 2431 2432<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale 2433{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by 2434that factor without changing the viewed contents of the distorted image. This 2435can be used either for 'super-sampling' the image for a higher quality result, 2436or for panning and zooming around the image (with appropriate viewport 2437changes, or post-distort cropping and resizing). </p> 2438 2439<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a 2440href="#distort" >-distort</a> to attempt to output the internal coefficients, 2441and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study, 2442and debugging purposes. This many not be available for all distorts. </p> 2443 2444<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to 2445produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a> 2446and/or <a href="#shear" >-shear</a> operation, with more control of due to the 2447above settings. It is algorithmically slower however, though that may not be 2448the case in ImageMagick's implementation. </p> 2449 2450 2451<div style="margin: auto;"> 2452 <h4><a id="dither"></a>-dither <em class="arg">method</em></h4> 2453</div> 2454 2455<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply a Riemersma or Floyd-Steinberg error diffusion dither to images when general color reduction is applied via an option, or automagically when saving to specific formats. This enabled by default. </td><td style='text-align:right;'></td></tr></table> 2456 2457<p>Dithering places two or more colors in neighboring pixels so that to the eye a closer approximation of the images original color is reproduced. This reduces the number of colors needed to reproduce the image but at the cost of a lower level pattern of colors. Error diffusion dithers can use any set of colors (generated or user defined) to an image. </p> 2458 2459<p>Dithering is turned on by default, to turn it off use the plus form of the 2460setting, <a href="#dither">+dither</a>. This will also also render PostScript 2461without text or graphic aliasing. Disabling dithering often (but not always) 2462leads to faster process, a smaller number of colors, but more cartoon like 2463image coloring. Generally resulting in 'color banding' effects in areas with 2464color gradients. </p> 2465 2466<p>The color reduction operators <a href="#colors">-colors</a>, <a 2467href="#monochrome">-monochrome</a>, <a href="#remap ">-remap</a>, and <a href="#posterize">-posterize</a>, apply dithering to images using the reduced color set they created. These operators are also used as part of automatic color reduction when saving images to formats with limited color support, such as <kbd>GIF:</kbd>, <kbd>XBM:</kbd>, and others, so dithering may also be used in these cases. </p> 2468 2469<p>Alternatively you can use <a href="#random-threshold">-random-threshold</a> to generate purely random dither. Or use <a href="#ordered-dither">-ordered-dither</a> to apply threshold mapped dither patterns, using uniform color maps, rather than specific color maps. </p> 2470 2471 2472<div style="margin: auto;"> 2473 <h4><a id="draw"></a>-draw <em class="arg">string</em></h4> 2474</div> 2475 2476<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Annotate an image with one or more graphic primitives.</td><td style='text-align:right;'></td></tr></table> 2477 2478<p>Use this option to annotate or decorate an image with one or more graphic primitives. The primitives include shapes, text, transformations, and pixel operations.</p> 2479 2480<p>The shape primitives:</p> 2481 2482<pre class="text"> 2483 point x,y 2484 line x0,y0 x1,y1 2485 rectangle x0,y0 x1,y1 2486 roundRectangle x0,y0 x1,y1 wc,hc 2487 arc x0,y0 x1,y1 a0,a1 2488 ellipse x0,y0 rx,ry a0,a1 2489 circle x0,y0 x1,y1 2490 polyline x0,y0 ... xn,yn 2491 polygon x0,y0 ... xn,yn 2492 bezier x0,y0 ... xn,yn 2493 path path specification 2494 image operator x0,y0 w,h filename 2495</pre> 2496 2497<p>The text primitive:</p> 2498 2499<pre class="text"> 2500 text x0,y0 string 2501</pre> 2502<p>The text gravity primitive:</p> 2503 2504<pre class="text"> 2505 gravity NorthWest, North, NorthEast, West, Center, 2506 East, SouthWest, South, or SouthEast 2507</pre> 2508 2509<p>The text gravity primitive only affects the placement of text and does not interact with the other primitives. It is equivalent to using the <a href="#gravity">-gravity</a> command-line option, except that it is limited in scope to the <a href="#draw">-draw</a> option in which it appears.</p> 2510 2511<p>The transformation primitives:</p> 2512 2513<pre class="text"> 2514 rotate degrees 2515 translate dx,dy 2516 scale sx,sy 2517 skewX degrees 2518 skewY degrees 2519</pre> 2520 2521<p>The pixel operation primitives:</p> 2522 2523<pre class="text"> 2524 color x0,y0 method 2525 matte x0,y0 method 2526</pre> 2527 2528<p>The shape primitives are drawn in the color specified by the preceding <a href="#fill">-fill</a> setting. For unfilled shapes, use <a href="#fill">-fill none</a>. You can optionally control the stroke (the "outline" of a shape) with the <a href="#stroke">-stroke</a> and <a href="#strokewidth">-strokewidth</a> settings.</p> 2529 2530<p>A <kbd>point</kbd> primitive is specified by a single <em>point</em> in the pixel plane, that is, by an ordered pair of integer coordinates, <em>x</em>,<em>y</em>. (As it involves only a single pixel, a <kbd>point</kbd> primitive is not affected by <a href="#stroke">-stroke</a> or <a href="#strokewidth">-strokewidth</a>.)</p> 2531 2532<p>A <kbd>line</kbd> primitive requires a start point and end point.</p> 2533 2534<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p> 2535 2536<p>A <kbd>roundRectangle</kbd> primitive takes the same corner points as a <kbd>rectangle</kbd> followed by the width and height of the rounded corners to be removed.</p> 2537 2538<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p> 2539 2540<p>The <kbd>arc</kbd> primitive is used to inscribe an elliptical segment in to a given rectangle. An <kbd>arc</kbd> requires the two corners used for <kbd>rectangle</kbd> (see above) followed by the start and end angles of the arc of the segment segment (e.g. 130,30 200,100 45,90). The start and end points produced are then joined with a line segment and the resulting segment of an ellipse is filled.</p> 2541 2542<p>Use <kbd>ellipse</kbd> to draw a partial (or whole) ellipse. Give the center point, the horizontal and vertical "radii" (the <em>semi-axes</em> of the ellipse) and start and end angles in degrees (e.g. 100,100 100,150 0,360).</p> 2543 2544<p>The <kbd>polyline</kbd> and <kbd>polygon</kbd> primitives require three or more points to define their perimeters. A <kbd>polyline</kbd> is simply a <kbd>polygon</kbd> in which the final point is not stroked to the start point. When unfilled, this is a <em>polygonal line</em>. If the <a href="#stroke">-stroke</a> setting is <kbd>none</kbd> (the default), then a <kbd>polyline</kbd> is identical to a <kbd>polygon</kbd>. 2545</p> 2546 2547<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p> 2548 2549<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p> 2550 2551<p class="crtsnip"> 2552 -draw 'circle 100,100 150,150' 2553</p> 2554 2555<p>The <kbd>Bezier</kbd> primitive creates a spline curve and requires three or points to define its shape. The first and last points are the <em>knots</em> and these points are attained by the curve, while any intermediate coordinates are <em>control points</em>. If two control points are specified, the line between each end knot and its sequentially respective control point determines the tangent direction of the curve at that end. If one control point is specified, the lines from the end knots to the one control point determines the tangent directions of the curve at each end. If more than two control points are specified, then the additional control points act in combination to determine the intermediate shape of the curve. In order to 2556draw complex curves, it is highly recommended either to use the <kbd>path</kbd> primitive or to draw multiple four-point bezier segments with the start and end knots of each successive segment repeated. For example:</p> 2557 2558<p class="crtsnip"> 2559 -draw 'bezier 20,50 45,100 45,0 70,50' 2560</p> 2561<p class="crtsnip"> 2562 -draw 'bezier 70,50 95,100 95,0 120,50' 2563</p> 2564 2565 2566<p>A <kbd>path</kbd> represents an outline of an object, defined in terms of moveto (set a new current point), lineto (draw a straight line), curveto (draw a Bezier curve), arc (elliptical or circular arc) and closepath (close the current shape by drawing a line to the last moveto) elements. Compound paths (i.e., a path with subpaths, each consisting of a single moveto followed by one or more line or curve operations) are possible to allow effects such as <em>donut holes</em> in objects. (See <a href="http://www.w3.org/TR/SVG/paths.html">Paths</a>.)</p> 2567 2568<p>Use <kbd>image</kbd> to composite an image with another image. Follow the image keyword with the composite operator, image location, image size, and filename:</p> 2569 2570<p class="crtsnip"> 2571 -draw 'image SrcOver 100,100 225,225 image.jpg' 2572</p> 2573 2574<p>You can use 0,0 for the image size, which means to use the actual 2575dimensions found in the image header. Otherwise, it is scaled to the given 2576dimensions. See <a href="/www/compose.html">Alpha Compositing</a> for 2577a detailed discussion of alpha composition methods that are available. 2578The "special augmented compose operators" such as "dissolve" that require 2579arguments cannot be used at present with the <kbd>-draw image</kbd> option. 2580 </p> 2581<p>Use <kbd>text</kbd> to annotate an image with text. Follow the text coordinates with a string. If the string has embedded spaces, enclose it in single or double quotes.</p> 2582 2583<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p> 2584 2585<p class="crtsnip"> 2586 -draw "text 100,100 'Works like magick!' " 2587</p> 2588 2589<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p> 2590 2591<p>The <kbd>rotate</kbd> primitive rotates subsequent shape primitives and text primitives about the origin of the main image. If the <a href="#region">-region</a> option precedes the <a href="#draw">-draw</a> option, the origin for transformations is the upper left corner of the region.</p> 2592 2593<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p> 2594 2595<p>The <kbd>scale</kbd> primitive scales them.</p> 2596 2597<p>The <kbd>skewX</kbd> and <kbd>skewY</kbd> primitives skew them with respect to the origin of the main image or the region.</p> 2598 2599<p>The transformations modify the current affine matrix, which is initialized from the initial affine matrix defined by the <a href="#affine">-affine</a> option. Transformations are cumulative within the <a href="#draw">-draw</a> option. The initial affine matrix is not affected; that matrix is only changed by the appearance of another <a href="#affine">-affine</a> option. If another <a href="#draw">-draw</a> option appears, the current affine matrix is reinitialized from the initial affine 2600matrix.</p> 2601 2602<p>Use the <kbd>color</kbd> primitive to change the color of a pixel to the fill color (see <a href="#fill">-fill</a>). Follow the pixel coordinate with a method:</p> 2603 2604<pre class="text"> 2605 point 2606 replace 2607 floodfill 2608 filltoborder 2609 reset 2610</pre> 2611 2612<p>Consider the target pixel as that specified by your coordinate. The <kbd>point</kbd> method recolors the target pixel. The <kbd>replace</kbd> method recolors any pixel that matches the color of the target pixel. <kbd>Floodfill</kbd> recolors any pixel that matches the color of the target pixel and is a neighbor, whereas <kbd>filltoborder</kbd> recolors any neighbor pixel that is not the border color. Finally, <kbd>reset</kbd> recolors all pixels.</p> 2613 2614<p>Use <kbd>matte</kbd> to the change the pixel matte value to transparent. Follow the pixel coordinate with a method (see the <kbd>color</kbd> primitive for a description of methods). The <kbd>point</kbd> method changes the matte value of the target pixel. The <kbd>replace</kbd> method changes the matte value of any pixel that matches the color of the target pixel. <kbd>Floodfill</kbd> changes the matte value of any pixel that matches the color of the target pixel and is a neighbor, whereas <kbd>filltoborder</kbd> changes the matte value of any neighbor pixel that is not the border color (<a href="#bordercolor">-bordercolor</a>). Finally <kbd>reset</kbd> changes the matte value of all pixels.</p> 2615 2616<p>You can set the primitive color, font, and font bounding box color with <a href="#fill">-fill</a>, <a href="#font">-font</a>, and <a href="#box">-box</a> respectively. Options are processed in command line order so be sure to use these options <em>before</em> the <a href="#draw">-draw</a> option.</p> 2617 2618<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p> 2619 2620<p>Drawing primitives conform to the <a href="/www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p> 2621 2622 2623<div style="margin: auto;"> 2624 <h4><a id="duplicate"></a>-duplicate <em class="arg">count,indexes</em></h4> 2625</div> 2626 2627<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>duplicate an image one or more times.</td><td style='text-align:right;'></td></tr></table> 2628 2629<p>Specify the count and the image to duplicate by its index in the sequence. The first image is index 0. Negative indexes are relative to the end of the sequence, for example, -1 represents the last image of the sequence. Specify a range of images with a dash (e.g. 0-4). Separate indexes with a comma (e.g. 0,2). Use <kbd>+duplicate</kbd> to duplicate the last image in the current image sequence.</p> 2630 2631<div style="margin: auto;"> 2632 <h4><a id="edge"></a>-edge <em class="arg">radius</em></h4> 2633</div> 2634 2635<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>detect edges within an image.</td><td style='text-align:right;'></td></tr></table> 2636 2637<div style="margin: auto;"> 2638 <h4><a id="emboss"></a>-emboss <em class="arg">radius</em></h4> 2639</div> 2640 2641<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>emboss an image.</td><td style='text-align:right;'></td></tr></table> 2642 2643<div style="margin: auto;"> 2644 <h4><a id="encipher"></a>-encipher <em class="arg">filename</em></h4> 2645</div> 2646 2647<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Encipher pixels for later deciphering by <a href="#decipher">-decipher</a>.</td><td style='text-align:right;'></td></tr></table> 2648 2649<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 2650 2651<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 2652 2653 2654 2655<div style="margin: auto;"> 2656 <h4><a id="encoding"></a>-encoding <em class="arg">type</em></h4> 2657</div> 2658 2659<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>specify the text encoding.</td><td style='text-align:right;'></td></tr></table> 2660 2661<p>Choose from <kbd>AdobeCustom</kbd>, <kbd>AdobeExpert</kbd>, <kbd>AdobeStandard</kbd>, <kbd>AppleRoman</kbd>, <kbd>BIG5</kbd>, <kbd>GB2312</kbd>, <kbd>Latin 2</kbd>, <kbd>None</kbd>, <kbd>SJIScode</kbd>, <kbd>Symbol</kbd>, <kbd>Unicode</kbd>, <kbd>Wansung</kbd>.</p> 2662 2663<div style="margin: auto;"> 2664 <h4><a id="endian"></a>-endian <em class="arg">type</em></h4> 2665</div> 2666 2667<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify endianness (<kbd>MSB</kbd> or <kbd>LSB</kbd>) of the image.</td><td style='text-align:right;'></td></tr></table> 2668 2669<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p> 2670 2671<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p> 2672 2673 2674<div style="margin: auto;"> 2675 <h4><a id="enhance"></a>-enhance</h4> 2676</div> 2677 2678<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply a digital filter to enhance a noisy image.</td><td style='text-align:right;'></td></tr></table> 2679 2680 2681<div style="margin: auto;"> 2682 <h4><a id="equalize"></a>-equalize</h4> 2683</div> 2684 2685<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>perform histogram equalization on the image channel-by-channel.</td><td style='text-align:right;'></td></tr></table> 2686 2687<p>To perform histogram equalization on all channels in concert, transform the image into some other color space, such as HSL, OHTA, YIQ or YUV, then equalize the appropriate intensity-like channel, then convert back to RGB.</p> 2688 2689<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p> 2690 2691<p>For YIQ, YUV and OHTA use the red channel. For example, OHTA is a principal components transformation that puts most of the information in the first channel. Here we have ... <kbd>-colorspace OHTA -channel red -equalize -colorspace RGB</kbd> ...</p> 2692 2693<div style="margin: auto;"> 2694 <h4><a id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4> 2695</div> 2696 2697<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Alter channel pixels by evaluating an arithmetic, relational, or logical expression.</td><td style='text-align:right;'></td></tr></table> 2698 2699<p>(See the <a href="#function" >-function</a> operator for some multi-parameter functions. See the <a href="#fx" >-fx</a> operator if more elaborate calculations are needed.)</p> 2700 2701<p>The behaviors of each <em class="arg">operator</em> are summarized in the following list. For brevity, the numerical value of a "pixel" referred to below is the value of the corresponding channel of that pixel, while a "normalized pixel" is that number divided by the maximum (installation-dependent) value <em class="QR">QuantumRange</em>. (If normalized pixels are used, they are restored, following the other calculations, to the full range by multiplying by <em class="QR">QuantumRange</em>.)</p> 2702 2703<table class="doc"> 2704 <col width="25%" /> 2705 <col width="75%" /> 2706 <thead> 2707 <tr> 2708 <th><em class="arg">operator</em></th> 2709 <th>Summary (see further below for details)</th> 2710 </tr> 2711 </thead> 2712 <tbody> 2713 2714 <tr><td>Abs </td> <td>Add <em class="arg">value</em> to pixels and return absolute value. </td></tr> 2715 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr> 2716 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr> 2717 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr> 2718 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2719 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr> 2720 <tr><td>Exp </td> <td>base-e exponential function</td></tr> 2721 <tr><td>Exponential </td> <td>base-e exponential function</td></tr> 2722 <tr><td>LeftShift </td> <td>Shift the pixel values left by <em class="arg">value</em> bits (i.e., multiply pixels by 2<sup><em class="arg">value</em></sup>).</td></tr> 2723 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr> 2724 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr> 2725 <tr><td>Mean </td> <td>Add the <em class="arg">value</em> and divide by 2.</td></tr> 2726 <tr><td>Median </td> <td>Choose the median value from an image sequence.</td></tr> 2727 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr> 2728 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr> 2729 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr> 2730 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr> 2731 <tr><td>RightShift </td> <td>Shift the pixel values right by <em class="arg">value</em> bits (i.e., divide pixels by 2<sup><em class="arg">value</em></sup>).</td></tr> 2732 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr> 2733 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2734 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr> 2735 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr> 2736 2737 <tr><td> </td></tr> 2738 2739 <tr><td>Gaussian-noise</td></tr> 2740 <tr><td>Impulse-noise</td></tr> 2741 <tr><td>Laplacian-noise</td></tr> 2742 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr> 2743 <tr><td>PoissonNoise</td></tr> 2744 <tr><td>Uniform-noise</td></tr> 2745 2746 <tr><td> </td></tr> 2747 2748 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr> 2749 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr> 2750 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr> 2751 </tbody> 2752 </table> 2753 2754<p>The specified functions are applied only to each previously set <a 2755href="#channel" >-channel</a> in the image. If necessary, the results of the 2756calculations are truncated (clipped) to fit in the interval [0, <em 2757class="QR">QuantumRange</em>]. The transparency channel of the image is 2758represented as a 'alpha' values (0 = fully transparent), so, for example, a 2759<kbd>Divide</kbd> by 2 of the alpha channel will make the image 2760semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value 2761as a percentage of the <em class="QR">QuantumRange</em>.</p> 2762 2763<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use 2764<a href="#list">-list evaluate</a>.</p> 2765 2766<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and 2767<kbd>Multiply</kbd> methods can also be achieved using either the <a 2768href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with 2769appropriate argument, to linearly modify the overall range of color values. 2770Please note, however, that <a href="#level" >-level</a> treats transparency as 2771'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with 2772'alpha' values.</p> 2773 2774<p><kbd>AddModulus</kbd> has been added as of ImageMagick 6.4.8-4 and provides addition modulo the <em class="QR">QuantumRange</em>. It is therefore equivalent to <kbd>Add</kbd> unless the resulting pixel value is outside the interval [0, <em class="QR">QuantumRange</em>]. </p> 2775 2776<p><kbd>Exp or Exponential</kbd> has been added as of ImageMagick 6.6.5-1 and works on normalized pixel values. The <em class="arg">value</em> used with <kbd>Exp</kbd> should be negative so as to produce a decaying exponential function. Non-negative values will always produce results larger unity and thus outside the interval [0, <em class="QR">QuantumRange</em>]. The formula is expressed below. </p> 2777 2778 <div style="text-align:center;"> 2779 exp(<em class="arg">value</em> × <b><em>u</em></b>) 2780 </div> 2781 2782<p> If the input image is squared, for example, using <a 2783href="#-function" >-function polynomial "2 0 0"</a>, then a decaying Gaussian function will be the result.</p> 2784 2785<p><kbd>Log</kbd> has been added as of ImageMagick 6.4.2-1 and works on normalized pixel values. This a <em>scaled</em> log function. The <em class="arg">value</em> used with <kbd>Log</kbd> provides a <em>scaling factor</em> that adjusts the curvature in the graph of the log function. The formula applied to a normalized value <b><em>u</em></b> is below. </p> 2786 2787 <div style="text-align:center;"> 2788 log(<em class="arg">value</em> × <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1) 2789 </div> 2790 2791<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on 2792normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a 2793href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent 2794to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used 2795with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used 2796with <kbd>Pow</kbd>.</p> 2797 2798<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and 2799converts the image values into a value according to a (co)sine wave function. 2800The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output 2801is biased 50% and normalized by 50% so as to fit in the respective color value 2802range. The <em class="arg">value</em> scaling of the <em>period</em> of the 2803function (its frequency), and thus determines the number of 'waves' that will 2804be generated over the input color range. For example, if the <em 2805class="arg">value</em> is 1, the effective period is simply the <em 2806class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is 2, 2807then the effective period is the <em>half</em> the <em 2808class="QR">QuantumRange</em>.</p> 2809 2810 <div style="text-align:center;"> 2811 0.5 + 0.5 × cos(2 π <b><em>u</em></b> × <em class="arg">value</em>). 2812 </div> 2813 2814<p>See also the <a href="#function" >-function</a> operator, which is a 2815multi-value version of evaluate. </p> 2816 2817<div style="margin: auto;"> 2818 <h4><a id="evaluate-sequence"></a>-evaluate-sequence <em class="arg">operator</em></h4> 2819</div> 2820 2821<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Alter channel pixels by evaluating an arithmetic, relational, or logical expression over a sequence of images.</td><td style='text-align:right;'></td></tr></table> 2822 2823<div style="margin: auto;"> 2824 <h4><a id="extent"></a>-extent <em class="arg">geometry</em></h4> 2825</div> 2826 2827<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the image size and offset.</td><td style='text-align:right;'></td></tr></table> 2828 2829<p>If the image is enlarged, unfilled areas are set to the background color. To position the image, use offsets in the <em class="arg">geometry</em> specification or precede with a <a href="#gravity">-gravity</a> setting. To specify how to compose the image with the background, use <a href="#compose" >-compose</a>.</p> 2830<p>This command reduces or expands a JPEG image to fit on an 800x600 2831display. If the aspect ratio of the input image isn't exactly 4:3, then the 2832image is centered on an 800x600 black canvas: </p> 2833 2834<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert input.jpg -resize 800x600 -background black -compose Copy \ <br /> -gravity center -extent 800x600 -quality 92 output.jpg</span></p> 2835 2836 2837<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 2838 2839<div style="margin: auto;"> 2840 <h4><a id="extract"></a>-extract <em class="arg">geometry</em></h4> 2841</div> 2842 2843<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Extract the specified area from image.</td><td style='text-align:right;'></td></tr></table> 2844 2845<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p> 2846 2847<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480+1280+960 \ <br/> image.rgb image.png</span><span class='crtout'></span><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 'image.rgb[640x480+1280+960]' \ <br/> image.rgb image.png</span></p><p>If you omit the offsets, as in</p> 2848 2849<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480 \ <br/> image.rgb image.png</span></p> 2850<p>the image is <em>resized</em> to the specified dimensions instead, 2851equivalent to:</p> 2852 2853<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -resize 640x480 image.rgb image.png</span></p> 2854<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 2855 2856<div style="margin: auto;"> 2857 <h4><a id="family"></a>-family <em class="arg">fontFamily</em></h4> 2858</div> 2859 2860<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set a font family for text.</td><td style='text-align:right;'></td></tr></table> 2861 2862<p>This setting suggests a font family that ImageMagick should try to use for rendering text. If the family can be found it is used; if not, a default font (e.g., "Arial") or a family known to be similar is substituted (e.g., "Courier" might be used if "System" is requested but not found). 2863</p> 2864 2865<p>For other settings that affect fonts, see the options <a href="#font">-font</a>, <a href="#stretch">-stretch</a>, <a href="#style">-style</a>, and <a href="#weight">-weight</a>. 2866</p> 2867 2868<div style="margin: auto;"> 2869 <h4><a id="features"></a>-features <em class="arg">distance</em></h4> 2870</div> 2871 2872<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>display features for each channel in the image in each of four directions (horizontal, vertical, left and right diagonals) for the specified distance.</td><td style='text-align:right;'></td></tr></table> 2873 2874<div style="margin: auto;"> 2875 <h4><a id="fft"></a>-fft</h4> 2876</div> 2877 2878<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>implements the forward discrete Fourier transform (DFT).</td><td style='text-align:right;'></td></tr></table> 2879 2880<p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows users in ImageMagick 6.6.0-9). It transforms an image from the normal (spatial) domain to the frequency domain. In the frequency domain, an image is represented as a superposition of complex sinusoidal waves of varying amplitudes. The image x and y coordinates are the possible frequencies along the x and y directions, respectively, and the pixel intensity values are complex numbers that correspond to the sinusoidal wave amplitudes. See for example, <a href="http://en.wikipedia.org/wiki/Fourier_transform">Fourier Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT">Discrete Fourier Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT">Fast Fourier Transform</a>.</p> 2881 2882<p>A single image name is provided as output for this option. However, the output result will have two components. It is either a two-frame image or two separate images, depending upon whether the image format specified supports multi-frame images. The reason that we get a dual output result is because the frequency domain represents an image using complex numbers, which cannot be visualized directly. Therefore, the complex values are automagically separated into a two-component image representation. The first component is the magnitude of the complex number and the second is the phase of the complex number. See for example, <a href="http://en.wikipedia.org/wiki/Complex_numbers">Complex Numbers</a>.</p> 2883 2884<p>The magnitude and phase component images must be specified using image formats that do not limit the color or compress the image. Thus, MIFF, TIF, PFM, EXR and PNG are the recommended image formats to use. All of these formats, except PNG support multi-frame images. So for example,</p> 2885 2886<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p> 2887<p>generates a magnitude image as <kbd>fft_image.miff[0]</kbd> and a phase image as <kbd>fft_image.miff[1]</kbd>. Similarly,</p> 2888 2889<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.png</span></p> 2890<p>generates a magnitude image as <kbd>fft_image-0.png</kbd> and a phase image as <kbd>fft_image-1.png</kbd>. If you prefer this representation, then you can force any of the other formats to produce two output images by including <a href="#adjoin">+adjoin</a> following -fft in the command line.</p> 2891 2892<p>The input image can be any size, but if not square and even-dimensioned, it is padded automagically to the larger of the width or height of the input image and to an even number of pixels. The padding will occur at the bottom and/or right sides of the input image. The resulting output magnitude and phase images is square at this size. The kind of padding relies on the <a href="#virtual-pixel">-virtual-pixel</a> setting.</p> 2893 2894<p>Both output components will have dynamic ranges that fit within [0, <em class="QR">QuantumRange</em>], so that HDRI need not be enabled. Phase values nominally range from 0 to 2*π, but for non-HDRI compilations of ImageMagick, the phase image is scaled to span the full dynamic range. The magnitude image is not scaled and thus generally will contain very small values. As such, the image normally will appear totally black. In order to view any detail, the magnitude image typically is enhanced with a log function into what is usually called the spectrum. A log function is used to enhance the darker values more in comparison to the lighter values. This can be done, for example, as follows:</p> 2895 2896<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br /> 2897 -evaluate log 1000 fft_image_spectrum.png</span></p> 2898<p>where the <a href="#contrast-stretch">-contrast-stretch</a> 0 is used to scale the image to full dynamic range, first. The argument to the <a href="#evaluate">-evaluate</a> log typically is specified between 100 and 10,000, depending upon the amount of detail that one wants to bring out in the spectrum. Larger values produce more visible detail. Too much detail, however, may hide the important features.</p> 2899 2900<p>The <a href="http://www.fftw.org/">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>.</p> 2901 2902<p>Use <a href="#fft">+fft</a> to produce two output images that are the real and imaginary components of the complex valued Fourier transform.</p> 2903 2904<p>However, as the real and imaginary components can contain negative values, this requires that IM be configured with HDRI enabled. In this case, you must use either MIFF, TIF or PFM formats for the real and imaginary component results, since they are formats that preserve both negative and fractional values without clipping them or truncating the fractional part.</p> 2905 2906<p>The real and imaginary component images resulting from <a href="#fft">+fft</a> is also square, even dimensioned images due to the same padding that was discussed above for the magnitude and phase component images.</p> 2907 2908<p>See the discussion on HDRI implementations of ImageMagick on the page 2909<a href="/www/high-dynamic-range.html">High Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this <a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> entry. 2910</p> 2911 2912 2913<div style="margin: auto;"> 2914 <h4><a id="fill"></a>-fill <em class="arg">color</em></h4> 2915</div> 2916 2917<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>color to use when filling a graphic primitive.</td><td style='text-align:right;'></td></tr></table> 2918 2919<p>This option accepts a color name, a hex color, or a numerical RGB, RGBA, HSL, HSLA, CMYK, or CMYKA specification. See <a href="/www/color.html">Color Names</a> for a description of how to properly specify the color argument.</p> 2920 2921<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p> 2922 2923<p>For example,</p> 2924 2925<p class="crtsnip"> 2926 -fill blue 2927</p> 2928<p class="crtsnip"> 2929 -fill "#ddddff" 2930</p> 2931<p class="crtsnip"> 2932 -fill "rgb(255,255,255)" 2933</p> 2934 2935<p>See <a href="#draw">-draw</a> for further details.</p> 2936 2937<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p> 2938 2939<div style="margin: auto;"> 2940 <h4><a id="filter"></a>-filter <em class="arg">type</em></h4> 2941</div> 2942 2943<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Use this <em class="arg">type</em> of filter when resizing or 2944distorting an image.</td><td style='text-align:right;'></td></tr></table> 2945 2946<p>Use this option to affect the resizing operation of an image during 2947operations such as <a href="#resize">-resize</a> and <a href="#distort" 2948>-distort</a>. For example you can use a simple resize filter such as:</p> 2949 2950<pre class="text"> 2951 Point Hermite Cubic 2952 Box Gaussian Catrom 2953 Triangle Quadratic Mitchell 2954</pre> 2955 2956<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided (as well 2957as a faster <kbd>SincFast</kbd> equivalent form). However these filters are 2958generally useless on their own as they are infinite filters that are being 2959clipped to the filters support size. Their direct use is not recommended 2960except via expert settings (see below). </p> 2961 2962<p>Instead these special filter functions are typically windowed by a windowing 2963function that the <a href="#filter" >-filter</a> setting defines. That is 2964using these functions will define a 'Windowed' filter, appropriate to the 2965operator involved. Windowed filters include: </p> 2966 2967<pre class="text"> 2968 Lanczos Hamming Parzen 2969 Blackman Kaiser Welsh 2970 Hanning Bartlett Bohman 2971</pre> 2972 2973<p>Also one special self-windowing filter is also provided 2974<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending 2975on the current 'support' or 'lobes' expert settings (see below).</p> 2976 2977<p>If you do not select a filter with this option, the filter defaults to 2978<kbd>Mitchell</kbd> for a colormapped image, a image with a matte channel, or 2979if the image is enlarged. Otherwise the filter default to 2980<kbd>Lanczos</kbd>.</p> 2981 2982<p>To print a complete list of resize filters, use the <a href="#list">-list 2983filter</a> option.</p> 2984 2985<p>You can modify how the filter behaves as it scales your image through the 2986use of these expert settings (see also <a href="#define" >-define</a> and <a 2987href="#set" >-set</a>):-</p> 2988 2989<dl class="doc"> 2990<dt>-define filter:blur=<em>factor</em></dt> 2991<dd>Scale the X axis of the filter (and its window). Use > 1.0 for 2992 blurry or < 1.0 for sharp. This should only be used with Gaussian and 2993 Gaussian-like filters simple filters, or you may not get the expected 2994 results. </dd> 2995 2996<dt>-define filter:support=<em>radius</em></dt> 2997<dd>Set the filter support radius. Defines how large the filter should be and 2998 thus directly defines how slow the filtered resampling process is. All 2999 filters have a default 'prefered' support size. Some filters like 3000 <kbd>Lagrange</kbd> and windowed filters adjust themselves depending on 3001 this value. With simple filters this value either does nothing (but slow 3002 the resampling), or will clip the filter function in a detrimental way. 3003 </dd> 3004 3005<dt>-define filter:lobes=<em>count</em></dt> 3006<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an 3007 alternative way of specifying the 'support' range of the filter, that is 3008 designed to be more suited to windowed filters, especially when used for 3009 image distorts.</dd> 3010 3011<dt>-define filter:b=<em>b-spline_factor</em></dt> 3012<dt>-define filter:c=<em>keys_alpha_factor</em></dt> 3013<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>, 3014 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as 3015 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values 3016 are defined, the other is set so as to generate a 'Keys' type cubic 3017 filter. Values meaning was defined by a research paper by 3018 Mitchell-Netravali.</dd> 3019 3020<dt>-define filter:filter=<em>filter_function</em></dt> 3021<dd>Use this function directly as the scaling filter. This will allow 3022 you to directly use a windowing filter such as <kbd>Blackman</kbd>, 3023 rather than as its normal usage as a windowing function for 'Sinc' or 3024 'Bessel' functions. If defined, no windowing function is used, unless the 3025 following expert setting is also defined.</dd> 3026 3027<dt>-define filter:window=<em>filter_function</em></dt> 3028<dd>The IIR (infinite impulse response) filters <kbd>Bessel</kbd> and 3029 <kbd>Sinc</kbd> are windowed (brought down to zero over the defined 3030 support range) with the given filter. This allows you to specify a filter 3031 function that is not normally used as a windowing function, such as 3032 <kbd>Box</kbd>, (which effectively turns off the windowing function), 3033 to window a <kbd>Sinc</kbd>, or the function the previous setting defined. 3034 </dd> 3035 3036<dt>-define filter:verbose=<em>1</em></dt> 3037<dd>This causes IM to print information on the final internal filter 3038 selection to standard output. This includes a commented header on the 3039 filter settings being used, and data allowing the filter weights to be 3040 easily graphed. </dd> 3041 3042<dd>Note however that some filters are internally defined in terms of other 3043 filters. The <kbd>Lanczos</kbd> filter for example is defined in terms of 3044 a <kbd>SincFast</kbd> windowed <kbd>SincFast</kbd> filter, while 3045 <kbd>Mitchell</kbd> is defined as a <kbd>Cubic</kbd> filter with specific 3046 'B' and 'C' settings. </dd> 3047 3048</dl> 3049 3050<p>For example, to get a 8 lobe Bessel windowed Bessel filter:</p> 3051 3052<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -filter bessel \ <br/> 3053 -set filter:window=bessel -set filter:lobes=8 \ <br/> 3054 -resize 150% image.jpg</span></p> 3055<p>Or a raw un-windowed Sinc filter with 4 lobes:</p> 3056 3057<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/> 3058 -resize 150% image.jpg</span></p> 3059<p>Note that the use of expert options (except for 'blur' with simple resize 3060filters, and 'verbose' for viewing the internal filter selection), are 3061provided for image processing experts who have studied and understood how 3062resize filters work. Without this knowledge, and an understanding of the 3063definition of the actual filters involved, using expert settings are more 3064likely to be detrimental to your image resizing.</p> 3065 3066 3067<div style="margin: auto;"> 3068 <h4><a id="flatten"></a>-flatten</h4> 3069</div> 3070 3071<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>This is a simple alias for the <a href="#layers" >-layers</a> method "flatten".</td><td style='text-align:right;'></td></tr></table> 3072 3073 3074<div style="margin: auto;"> 3075 <h4><a id="flip"></a>-flip</h4> 3076</div> 3077 3078<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>create a <em>mirror image</em>.</td><td style='text-align:right;'></td></tr></table> 3079 3080<p>reflect the scanlines in the vertical direction. The image will be mirrored 3081upside-down. </p> 3082 3083 3084<div style="margin: auto;"> 3085 <h4><a id="floodfill"></a>-floodfill {<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em> <em class="arg">color</em></h4> 3086</div> 3087 3088<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>floodfill the image with color at the specified offset.</td><td style='text-align:right;'></td></tr></table> 3089 3090<p>Flood fill starts from the given 'seed point' which is not gravity effected. 3091Any color that matches within <a href="#fuzz" >-fuzz</a> color distance of the 3092given <em class="arg">color</em> argument, connected to that 'seed point' 3093will be replaced with the current <a href="#fill" >-fill</a> color. </p> 3094 3095<p>Note that if the pixel at the 'seed point' does not itself match the given 3096<em class="arg">color</em> (according to <a href="#fuzz" >-fuzz</a>), then no 3097action will be taken. </p> 3098 3099<p>This operator works more like the <a href="#opaque" >-opaque</A> option, than 3100a more general flood fill that reads the matching color directly at the 'seed point'. For this form of flood fill, look at <a href="#draw" >-draw</a> and its 'color floodfill' drawing method. </p> 3101 3102 3103<div style="margin: auto;"> 3104 <h4><a id="flop"></a>-flop</h4> 3105</div> 3106 3107<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>create a <em>mirror image</em>.</td><td style='text-align:right;'></td></tr></table> 3108 3109<p>Reflect the scanlines in the horizontal direction, just like the image in 3110a vertical mirror. </p> 3111 3112 3113<div style="margin: auto;"> 3114 <h4><a id="font"></a>-font <em class="arg">name</em></h4> 3115</div> 3116 3117<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the font to use when annotating images with text, or creating labels.</td><td style='text-align:right;'></td></tr></table> 3118 3119<p>To print a complete list of fonts, use the <a href="#list">-list font</a> option (for versions prior to 6.3.6, use 'type' instead of 'font').</p> 3120 3121<p>In addition to the fonts specified by the above pre-defined list, you can 3122also specify a font from a specific source. For example <kbd>Arial.ttf</kbd> 3123is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and 3124<kbd>x:fixed</kbd> is X11 font.</p> 3125 3126<p>For other settings that affect fonts, see the options <a href="#family">-family</a>, <a href="#stretch">-stretch</a>, <a href="#style">-style</a>, and <a href="#weight">-weight</a>. </p> 3127 3128 3129<div style="margin: auto;"> 3130 <h4><a id="foreground"></a>-foreground <em class="arg">color</em></h4> 3131</div> 3132 3133<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Define the foreground color.</td><td style='text-align:right;'></td></tr></table> 3134 3135<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 3136 3137<p>The default foreground color is black.</p> 3138 3139<div style="margin: auto;"> 3140 <h4><a id="format"></a>-format <em class="arg">type</em></h4> 3141</div> 3142 3143<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the image format type.</td><td style='text-align:right;'></td></tr></table> 3144 3145<p>When used with the <kbd>mogrify</kbd> utility, this option converts any image to the image <a href="/www/formats.html">format</a> you specify. For a list of image format types supported by ImageMagick, use <a href="#list">-list format</a>.</p> 3146 3147<p>By default the file is written to its original name. However, if the filename extension matches a supported format, the extension is replaced with the image format type specified with <a href="#format">-format</a>. For example, if you specify <em class="arg">tiff</em> as the format type and the input image filename is <em class="arg">image.gif</em>, the output image filename becomes <em class="arg">image.tiff</em>.</p> 3148 3149<div style="margin: auto;"> 3150 <h4><a id="format_identify_"></a>-format <em class="arg">string</em></h4> 3151</div> 3152 3153<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>output formatted image characteristics.</td><td style='text-align:right;'>[<a href="/www/identify.html">identify</a>]</td></tr></table> 3154 3155<p>See <a href="/www/escape.html">Format and Print Image Properties</a> for an explanation on how to specify the argument to this option.</p> 3156 3157<div style="margin: auto;"> 3158 <h4><a id="frame"></a>-frame <em class="arg">geometry</em></h4> 3159</div> 3160 3161<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Surround the image with a border or beveled frame.</td><td style='text-align:right;'></td></tr></table> 3162 3163<p>The color of the border is specified with the <a href="#mattecolor" 3164>-mattecolor</a> command line option. </p> 3165 3166<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. The <em class="arg">size</em> portion of the <em 3167class="arg">geometry</em> argument indicates the amount of extra width and 3168height that is added to the dimensions of the image. If no offsets are given 3169in the <em class="arg">geometry</em> argument, then the border added is 3170a solid color. Offsets <em>x</em> and <em>y</em>, if present, specify that 3171the width and height of the border is partitioned to form an outer bevel of 3172thickness <em>x</em> pixels and an inner bevel of thickness 3173<em>y</em> pixels. Negative offsets make no sense as frame arguments. 3174</p> 3175 3176<p>The <a href="#frame">-frame</a> option is affected by the current <a 3177href="#compose">-compose</a> setting and assumes that this is using the default 3178'<kbd>Over</kbd>' composition method. It generates a image of the appropriate 3179size with the current <a href="#bordercolor">-bordercolor</a> setting, and then 3180draws the frame of four distinct colors close to the current <a 3181href="#mattecolor">-mattecolor</a>. The original image is then overlaid onto 3182center of this image. This means that with the default compose method of 3183'<kbd>Over</kbd>' any transparent parts may be replaced by the current <a 3184href="#bordercolor">-bordercolor</a> setting.</p> 3185 3186<p>The image composition is not 3187affected by the <a href="#gravity">-gravity</a> option.</p> 3188 3189 3190<div style="margin: auto;"> 3191 <h4><a id="frame_import_"></a>-frame</h4> 3192</div> 3193 3194<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>include the X window frame in the imported image.</td><td style='text-align:right;'>[<a href="/www/import.html">import</a>]</td></tr></table> 3195 3196<div style="margin: auto;"> 3197 <h4><a id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4> 3198</div> 3199 3200<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply a function to channel values.</td><td style='text-align:right;'></td></tr></table> 3201 3202<p>This operator performs calculations based on the given arguments to modify each of the color values for each previously set <a href="#channel">-channel</a> in the image. See <a href="#evaluate">-evaluate</a> for details concerning how the results of the calculations are handled.</p> 3203 3204<p>This is can be considered a multi-argument version of the <a href="#evaluate">-evaluate</a> operator. (Added in ImageMagick 6.4.8−8.)</p> 3205 3206<p>Here, <em class="arg">parameters</em> is a comma-separated list of numerical values. The number of values varies depending on which <em class="arg">function</em> is selected. Choose the <em class="arg">function</em> from:</p> 3207 3208<pre class="text"> 3209 Polynomial 3210 Sinusoid 3211 Arcsin 3212 Arctan 3213</pre> 3214 3215<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p> 3216 3217<dl class="doc"> 3218<dt><kbd>Polynomial</kbd></dt> 3219<dd> 3220<p>The <kbd>Polynomial</kbd> function takes an arbitrary number of parameters, these being the coefficients of a polynomial, in decreasing order of degree. That is, entering</p> 3221 3222<div style="text-align: center"> 3223 -function Polynomial <em>a</em><sub><em>n</em></sub>,<em>a</em><sub><em>n</em>-1</sub>,...<em>a</em><sub>1</sub>,<em>a</em><sub>0</sub> 3224</div> 3225 3226<p>will invoke a polynomial function given by</p> 3227 3228<div style="text-align: center"> 3229 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> + 3230 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> + 3231 ··· <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>, 3232</div> 3233 3234<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p> 3235 3236<p>The <kbd>Polynomial</kbd> function can be used in place of <kbd>Set</kbd> (the <em>constant</em> polynomial) and <kbd>Add</kbd>, <kbd>Divide</kbd>, <kbd>Multiply</kbd>, and <kbd>Subtract</kbd> (some <em>linear</em> polynomials) of the <a href="#evaluate">-evaluate</a> operator. The <a href="#level">-level</a> operator also affects channels linearly. Some correspondences follow.</p> 3237 3238<table class="doc"> 3239 <col width="35%" /> 3240 <col width="35%" /> 3241 <col width="30%" /> 3242 <tr> 3243 <td>-evaluate Set <em class="arg">value</em> </td> 3244 <td>-function Polynomial <em class="arg">value</em></td> 3245 <td>(Constant functions; set <em class="arg">value</em>×100% gray when channels are RGB.)</td> 3246 </tr> 3247 <tr> 3248 <td>-evaluate Add <em class="arg">value</em> </td> 3249 <td>-function Polynomial 1,<em class="arg">value</em></td> 3250 </tr> 3251 <tr> 3252 <td>-evaluate Subtract <em class="arg">value</em> </td> 3253 <td>-function Polynomial 1,−<em class="arg">value</em></td> 3254 </tr> 3255 <tr> 3256 <td>-evaluate Multiply <em class="arg">value</em> </td> 3257 <td>-function Polynomial <em class="arg">value</em>,0</td> 3258 </tr> 3259 <tr> 3260 <td>+level black% x white%</td> 3261 <td>-function Polynomial A,B</td> 3262 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td> 3263 </tr> 3264</table> 3265 3266<p>The <kbd>Polynomial</kbd> function gives great versatility, since polynomials can be used to fit any continuous curve to any degree of accuracy desired.</p> 3267</dd> 3268 3269<dt><kbd>Sinusoid</kbd></dt> 3270<dd> 3271<p>The <kbd>Sinusoid</kbd> function can be used to vary the channel values sinusoidally by setting frequency, phase shift, amplitude, and a bias. These values are given as one to four parameters, as follows,</p> 3272 3273<div style="text-align: center"> 3274 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]] 3275</div> 3276 3277<p>where <em>phase</em> is in degrees. (The domain [0,1] of the function corresponds to 0 through <em class="arg">freq</em>×360 degrees.) The result is that if a pixel's normalized channel value is originally <b><em>u</em></b>, its resulting normalized value is given by </p> 3278 3279<div style="text-align: center"> 3280<em class="arg">amp</em> * sin(2*π* (<em class="arg">freq</em> * <b><em>u</em></b> + <em class="arg">phase</em> / 360)) + <em class="arg">bias</em> 3281</div> 3282 3283<p> For example, the following generates a curve that starts and ends at 0.9 (when <b><em>u</em></b>=0 and 1, resp.), oscillating three times between .7−.2=.5 and .7+.2=.9. </p> 3284 3285<p class="crtsnip"> 3286 -function Sinusoid 3,-90,.2,.7 3287</p> 3288 3289<p>The default values of <em class="arg">amp</em> and <em class="arg">bias</em> are both .5. The default for <em class="arg">phase</em> is 0.</p> 3290 3291<p>The <kbd>Sinusoid</kbd> function generalizes <kbd>Sin</kbd> and <kbd>Cos</kbd> of the <a href="#evaluate">-evaluate</a> operator by allowing varying amplitude, phase and bias. The correspondence is as follows.</p> 3292 3293<table class="doc"> 3294 <tr> 3295 <td>-evaluate Sin <em class="arg">freq</em> </td> 3296 <td>-function Sinusoid <em class="arg">freq</em>,0 </td> 3297 </tr> 3298 <tr> 3299 <td>-evaluate Cos <em class="arg">freq</em> </td> 3300 <td>-function Sinusoid <em class="arg">freq</em>,90 </td> 3301 </tr> 3302</table> 3303</dd> 3304 3305<dt><kbd>ArcSin</kbd></dt> 3306<dd> 3307<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid, 3308and can be used to generate cylindrical distortion and displacement maps. 3309The curve can be adjusted relative to both the input values and output range 3310of values.</p> 3311 3312<p style="text-align: center"> 3313 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3314</p> 3315 3316<p>with all values given in terms of noramlize color values (0.0 for black, 33171.0 for white). Defaulting to values covering the full range from 0.0 to 1.0 3318for bout input (<em class="arg">width</em>), and output (<em 3319class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p> 3320 3321<p style="text-align: center"> 3322<em class="arg">range</em>/π * asin( 2/<em class="arg">width</em> * ( <b><em>u</em></b> - <em class="arg">center</em> ) ) + <em class="arg">bias</em> 3323</p> 3324 3325</dd> 3326 3327<dt><kbd>ArcTan</kbd></dt> 3328<dd> 3329<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from 3330limit values at infinities, though a center using the given slope value. 3331All these values can be adjusted via the arguments.</p> 3332 3333<p style="text-align: center"> 3334 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3335</p> 3336 3337<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'. 3338</p> 3339 3340<p style="text-align: center"> 3341<em class="arg">range</em>/π * atan( <em class="arg">slope</em>*π * ( <b><em>u</em></b> - <em class="arg">center</em> ) ) + <em class="arg">bias</em> 3342</p> 3343 3344</dd> 3345 3346</dl> 3347 3348 3349<div style="margin: auto;"> 3350 <h4><a id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4> 3351</div> 3352 3353<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Colors within this <em class="arg">distance</em> are considered equal.</td><td style='text-align:right;'></td></tr></table> 3354 3355<p>A number of algorithms search for a target color. By default the color must be exact. Use this option to match colors that are close to the target color in RGB space. For example, if you want to automagically trim the edges of an image with <a href="#trim">-trim</a> but the image was scanned and the target background color may differ by a small amount. This option can account for these differences.</p> 3356 3357<p>The <em class="arg">distance</em> can be in absolute intensity units or, by appending <kbd>%</kbd> as a percentage of the maximum possible intensity (255, 65535, or 4294967295).</p> 3358 3359 3360<div style="margin: auto;"> 3361 <h4><a id="fx"></a>-fx <em class="arg">expression</em></h4> 3362</div> 3363 3364<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>apply a mathematical expression to an image or image channels.</td><td style='text-align:right;'></td></tr></table> 3365 3366<p>If the first character of <em class="arg">expression</em> is <kbd>@</kbd>, the expression is read from a file titled by the remaining characters in the string.</p> 3367 3368<p>See <a href="/www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p> 3369 3370 3371<div style="margin: auto;"> 3372 <h4><a id="gamma"></a>-gamma <em class="arg">value</em></h4> 3373</div> 3374 3375<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>level of gamma correction.</td><td style='text-align:right;'></td></tr></table> 3376 3377<p>The same color image displayed on two different workstations may look different due to differences in the display monitor. Use gamma correction to adjust for this color difference. Reasonable values extend from <kbd>0.8</kbd> to <kbd>2.3</kbd>. Gamma less than 1.0 darkens the image and gamma greater than 1.0 lightens it. Large adjustments to image gamma may result in the loss of some image information if the pixel quantum size is only eight bits (quantum range 0 to 255).</p> 3378 3379<p>Gamma adjusts the image's channel values pixel-by-pixel according to a power law, namely, pow(pixel,1/gamma) or pixel^(1/gamma), where pixel is the normalized or 0 to 1 color value. For example, using a value of gamma=2 is the same as taking the square root of the image.</p> 3380 3381<p>You can apply separate gamma values to the red, green, and blue channels of the image with a gamma value list delimited with commas (e.g., <kbd>1.7,2.3,1.2</kbd>).</p> 3382 3383<p>Use <a href="#gamma">+gamma <em class="arg">value</em></a> to set the image gamma level without actually adjusting the image pixels. This option is useful if the image is of a known gamma but not set as an image attribute (e.g. PNG images).</p> 3384 3385<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p> 3386 3387<div style="margin: auto;"> 3388 <h4><a id="gaussian-blur"></a>-gaussian-blur <em class="arg">radius</em><br />-gaussian-blur <em class="arg">radius</em>x<em class="arg">sigma</em></h4> 3389</div> 3390 3391<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Blur the image with a Gaussian operator.</td><td style='text-align:right;'></td></tr></table> 3392 3393<p>Convolve the image with a Gaussian or normal distribution using the given 3394<em class="arg" >Sigma</em> value. The formula is:</p> 3395 3396<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 3397</div> 3398 3399<p>The <em class="arg" >Sigma</em> value is the important argument, and 3400determines the actual amount of blurring that will take place. </p> 3401 3402<p>The <em class="arg" >Radius</em> is only used to determine the size of the 3403array which will hold the calculated Gaussian distribution. It should be an 3404integer. If not given, or set to zero, IM will calculate the largest possible 3405radius that will provide meaningful results for the Gaussian distribution. 3406</p> 3407 3408<p>The larger the <em class="arg" >Radius</em> the radius the slower the 3409operation is. However too small a <em class="arg" >Radius</em>, and sever 3410aliasing effects may result. As a guideline, <em class="arg" >Radius</em> 3411should be at least twice the <em class="arg" >Sigma</em> value, though three 3412times will produce a more accurite result. </p> 3413 3414<p>This differs from the faster <a href="#blur">-blur</a> operator in that a 3415full 2-dimensional convolution is used to generate the weighted average of the 3416neighboring pixels. </p> 3417 3418<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 3419pixels which are outside the image proper are blurred into the final result. 3420</p> 3421 3422 3423<div style="margin: auto;"> 3424 <h4><a id="geometry"></a>-geometry <em class="arg">geometry</em></h4> 3425</div> 3426 3427<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the preferred size and location of the image.</td><td style='text-align:right;'></td></tr></table> 3428 3429<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 3430 3431<div style="margin: auto;"> 3432 <h4><a id="gravity"></a>-gravity <em class="arg">type</em></h4> 3433</div> 3434 3435<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Sets the current gravity suggestion for various other settings and options.</td><td style='text-align:right;'></td></tr></table> 3436 3437<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>, 3438<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>, 3439<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete 3440list of <a href="#gravity">-gravity</a> settings available in your ImageMagick 3441installation.</p> 3442 3443<p>The direction you choose specifies where to position text or subimages. For example, a gravity of <kbd>Center</kbd> forces the text to be centered within the image. By default, the image gravity is <kbd>NorthWest</kbd>. See <a href="#draw">-draw</a> for more details about graphic primitives. Only the text primitive of <a href="#draw">-draw</a> affected by the <a href="#gravity">-gravity</a> option.</p> 3444 3445<p>The <a href="#gravity">-gravity</a> option is also used in concert with the <a href="#geometry">-geometry</a> setting and other settings or options that take <em class="arg">geometry</em> as an argument, such as the <a href="#crop">-crop</a> option. </p> 3446 3447<p>If a <a href="#gravity">-gravity</a> setting occurs before another option or setting having a <em class="arg">geometry</em> argument that specifies an offset, the offset is usually applied to the point within the image suggested by the <a href="#gravity">-gravity</a> argument. Thus, in the following command, for example, suppose the file <kbd>image.png</kbd> has dimensions 200x100. The offset specified by the argument to <a href="#region">-region</a> is (−40,+20). The argument to <a href="#gravity">-gravity</a> is <kbd>Center</kbd>, which suggests the midpoint of the image, at the point (100,50). The offset (−40,20) is applied to that point, giving (100−40,50+20)=(60,70), so the specified 10x10 region is located at that point. (In addition, the <a href="#gravity">-gravity</a> affects the region itself, which is <em>centered</em> at the pixel coordinate (60,70). (See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.)</p> 3448 3449<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -gravity Center -region 10x10-40+20 \ <br/> -negate output.png</span></p> 3450<p>When used as an option to <a href="/www/composite.html">composite</a>, <a href="#gravity">-gravity</a> gives the direction that the image gravitates within the composite.</p> 3451 3452<p>When used as an option to <a href="/www/montage.html">montage</a>, <a href="#gravity">-gravity</a> gives the direction that an image gravitates within a tile. The default gravity is <kbd>Center</kbd> for this purpose.</p> 3453 3454 3455<div style="margin: auto;"> 3456 <h4><a id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4> 3457</div> 3458 3459<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>green chromaticity primary point.</td><td style='text-align:right;'></td></tr></table> 3460 3461 3462<div style="margin: auto;"> 3463 <h4><a id="hald-clut"></a>-hald-clut</h4> 3464</div> 3465 3466<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>apply a Hald color lookup table to the image.</td><td style='text-align:right;'></td></tr></table> 3467 3468<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2 3469dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You 3470can apply any color transformation to the Hald image and then use this option 3471to apply the transform to the image. </p> 3472 3473<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p> 3474<p>This option provides a convenient method for you to use Gimp or Photoshop 3475to make color corrections to the Hald CLUT image and subsequently apply them 3476to multiple images using an ImageMagick script. </p> 3477 3478<p>Note that the representation is only of the normal RGB color space and that 3479the whole color value triplet is used for the interpolated lookup of the 3480represented Hald color cube image. Because of this the operation is not <a 3481href="#channel" >-channel</a> setting effected, nor can it adjust or modify an 3482images transparency or alpha/matte channel.</p> 3483 3484<p>See also <a href="#clut" >-clut</a> which provides color value replacement 3485of the individual color channels, usally involving a simplier gray-scale 3486image. E.g: gray-scale to color replacement, or modification by a histogram 3487mapping. </p> 3488 3489 3490<div style="margin: auto;"> 3491 <h4><a id="help"></a>-help</h4> 3492</div> 3493 3494<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>print usage instructions.</td><td style='text-align:right;'></td></tr></table> 3495 3496<div style="margin: auto;"> 3497 <h4><a id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4> 3498</div> 3499 3500<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>when comparing images, emphasize pixel differences with this color.</td><td style='text-align:right;'></td></tr></table> 3501 3502<div style="margin: auto;"> 3503 <h4><a id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4> 3504</div> 3505 3506<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>specify the icon geometry.</td><td style='text-align:right;'></td></tr></table> 3507 3508<p>Offsets, if present in the geometry specification, are handled in the same manner as the <a href="#geometry">-geometry</a> option, using X11 style to handle negative offsets.</p> 3509 3510<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 3511 3512<div style="margin: auto;"> 3513 <h4><a id="iconic"></a>-iconic</h4> 3514</div> 3515 3516<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>iconic animation.</td><td style='text-align:right;'></td></tr></table> 3517 3518<div style="margin: auto;"> 3519 <h4><a id="identify"></a>-identify</h4> 3520</div> 3521 3522<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>identify the format and characteristics of the image.</td><td style='text-align:right;'></td></tr></table> 3523 3524<p>This information is printed: image scene number; image name; image size; the image class (<em class="arg">DirectClass</em> or <em class="arg">PseudoClass</em>); the total number of unique colors; and the number of seconds to read and transform the image. Refer to <a href="/www/miff.html">MIFF</a> for a description of the image class.</p> 3525 3526<p>If <a href="#colors">-colors</a> is also specified, the total unique colors in the image and color reduction error values are printed. Refer to <a href="/www/quantize.html">color reduction algorithm</a> for a description of these values.</p> 3527 3528<p>If <a href="#verbose">-verbose</a> precedes this option, copious 3529amounts of image properties are displayed including image statistics, profiles, 3530image histogram, and others.</p> 3531 3532<div style="margin: auto;"> 3533 <h4><a id="ift"></a>-ift</h4> 3534</div> 3535 3536<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>implements the inverse discrete Fourier transform (DFT).</td><td style='text-align:right;'></td></tr></table> 3537 3538<p>This option is new as of ImageMagick 6.5.4-3 (and now working for Windows users in ImageMagick 6.6.0-9). It transforms a pair of magnitude and phase images from the frequency domain to a single image in the normal or spatial domain. See for example, <a href="http://en.wikipedia.org/wiki/Fourier_transform">Fourier Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT">Discrete Fourier Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT">Fast Fourier Transform</a>.</p> 3539 3540<p>For example, depending upon the image format used to store the result of the <a href="#fft">-fft</a>, one would use either</p> 3541 3542<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p> 3543<p>or</p> 3544 3545<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image-0.png fft_image-1.png -ift fft_image_ift.png</span></p> 3546 3547<p>The resulting image may need to be cropped due to padding introduced when the original image, prior to the <a href="#fft">-fft</a> or <a href="#fft">+fft</a>, was not square or even dimensioned. Any padding is at the right and/or bottom sides of the image.</p> 3548 3549<p>The <a href="http://www.fftw.org/">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>.</p> 3550 3551<p>Use <a href="#ift">+ift</a> (with HDRI enabled) to transform a pair of real and imaginary images from the frequency domain to a single image in the normal (spatial) domain.</p> 3552 3553<div style="margin: auto;"> 3554 <h4><a id="immutable"></a>-immutable</h4> 3555</div> 3556 3557<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>make image immutable.</td><td style='text-align:right;'></td></tr></table> 3558 3559<div style="margin: auto;"> 3560 <h4><a id="implode"></a>-implode <em class="arg">factor</em></h4> 3561</div> 3562 3563<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>implode image pixels about the center.</td><td style='text-align:right;'></td></tr></table> 3564 3565<div style="margin: auto;"> 3566 <h4><a id="insert"></a>-insert <em class="arg">index</em></h4> 3567</div> 3568 3569<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>insert the last image into the image sequence.</td><td style='text-align:right;'></td></tr></table> 3570 3571<p>This option takes last image in the current image sequence and inserts it at the given index. If a negative index is used, the insert position is calculated before the last image is removed from the sequence. As such <kbd>-insert -1</kbd> will result in no change to the image sequence.</p> 3572 3573<p>The <kbd>+insert</kbd> option is equivalent to <kbd>-insert -1</kbd>. In other words, insert the last image, at the end of the current image sequence. Consequently this has no effect on the image sequence order.</p> 3574 3575<div style="margin: auto;"> 3576 <h4><a id="intent"></a>-intent <em class="arg">type</em></h4> 3577</div> 3578 3579<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>use this type of rendering intent when managing the image color.</td><td style='text-align:right;'></td></tr></table> 3580 3581<p>Use this option to affect the color management operation of an image (see <a href="#profile">-profile</a>). Choose from these intents: <kbd>Absolute, Perceptual, Relative, Saturation</kbd>.</p> 3582 3583<p>The default intent is undefined.</p> 3584 3585<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p> 3586 3587<div style="margin: auto;"> 3588 <h4><a id="interlace"></a>-interlace <em class="arg">type</em></h4> 3589</div> 3590 3591<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the type of interlacing scheme.</td><td style='text-align:right;'></td></tr></table> 3592 3593<p>Choose from:</p> 3594 3595<pre class="text"> 3596 none 3597 line 3598 plane 3599 partition 3600 JPEG 3601 GIF 3602 PNG 3603</pre> 3604 3605<p>This option is used to specify the type of interlacing scheme for raw image formats such as <kbd>RGB</kbd> or <kbd>YUV</kbd>.</p> 3606 3607<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p> 3608 3609<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p> 3610 3611<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p> 3612 3613<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R, 3614image.G, and image.B).</p> 3615 3616<p>Use <kbd>Line</kbd> or <kbd>Plane</kbd> to create an <kbd>interlaced PNG</kbd> or <kbd>GIF</kbd> or <kbd>progressive JPEG</kbd> 3617image.</p> 3618 3619<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p> 3620 3621<div style="margin: auto;"> 3622 <h4><a id="interpolate"></a>-interpolate <em class="arg">type</em></h4> 3623</div> 3624 3625<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the pixel color interpolation method to use when looking up a color based on a floating point or real value.</td><td style='text-align:right;'></td></tr></table> 3626 3627<p>When looking up the color of a pixel using a non-integer floating point 3628value, you typically fall in between the pixel colors defined by the source 3629image. This setting determines how the color is determined from the colors of 3630the pixels surrounding that point. That is how to determine the color of a 3631point that falls between two, or even four different colored pixels. </p> 3632 3633<pre class="text"> 3634 integer The color of the top-left pixel (floor function) 3635 nearest-neighbor The nearest pixel to the lookup point (rounded function) 3636 average The average color of the surrounding four pixels 3637 bilinear A double linear interpolation of pixels (the default) 3638 mesh Divide area into two flat triangular interpolations 3639 bicubic Fitted bicubic-spines of surrounding 16 pixels 3640 spline Direct spline curves (colors are blurred) 3641 filter Use resize <a href="#filter">-filter</a> settings 3642</pre> 3643 3644<p>This most important for distortion operators such as <a href="#distort" 3645>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform" 3646>-transform</a> and <a href="#fx" >-fx</a>. </p> 3647 3648<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p> 3649 3650<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the 3651lookup for positions outside the boundaries of the image. </p> 3652 3653 3654<div style="margin: auto;"> 3655 <h4><a id="interline-spacing"></a>-interline-spacing <em class="arg">value</em></h4> 3656</div> 3657 3658<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the space between two text lines.</td><td style='text-align:right;'></td></tr></table> 3659 3660<div style="margin: auto;"> 3661 <h4><a id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4> 3662</div> 3663 3664<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the space between two words.</td><td style='text-align:right;'></td></tr></table> 3665 3666<div style="margin: auto;"> 3667 <h4><a id="kerning"></a>-kerning <em class="arg">value</em></h4> 3668</div> 3669 3670<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the space between two letters.</td><td style='text-align:right;'></td></tr></table> 3671 3672<div style="margin: auto;"> 3673 <h4><a id="label"></a>-label <em class="arg">name</em></h4> 3674</div> 3675 3676<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>assign a label to an image.</td><td style='text-align:right;'></td></tr></table> 3677 3678<p>Use this option to assign a specific label to the image, as it is read in 3679or created. You can use the <a href="#set" >-set</a> operation to re-assign 3680a the labels of images already read in. Image formats such as TIFF, PNG, 3681MIFF, supports saving the label information with the image.</p> 3682 3683<p>When saving an image to a <em class="arg">PostScript</em> file, any label 3684assigned to an image is used as a header string to print above the postscript 3685image. </p> 3686 3687<p>You can include the image filename, type, width, height, or other image 3688attribute by embedding special format character. See <a href="/www/escape.html">Format and Print Image 3689Properties</a> for details of the percent escape codes.</p> 3690 3691<p>For example,</p> 3692 3693<p class="crtsnip"> 3694 -label "%m:%f %wx%h" bird.miff 3695</p> 3696 3697<p>assigns an image label of <kbd>MIFF:bird.miff 512x480</kbd> to the 3698"<kbd>bird.miff</kbd>" image and whose width is 512 and height is 480, as it 3699is read in. If a <a href="#label">+label</a> option was used instead, any 3700existing label present in the image would be used. You can remove all labels 3701from an image by assigning the empty string. </p> 3702 3703<p>A label is not drawn on the image, but is embedded in the image datastream 3704via <em>Label</em> tag or similar mechanism. If you want the label to be 3705visible on the image itself, use the <a href="#draw">-draw</a> option, or 3706during the final processing in the creation of a image montage.</p> 3707 3708<p>If the first character of <em class="arg">string</em> is <em 3709class="arg">@</em>, the image label is read from a file titled by the 3710remaining characters in the string. Labels in a file are literal, no embedded 3711formatting characters are recognized.</p> 3712 3713 3714<div style="margin: auto;"> 3715 <h4><a id="lat"></a>-lat <em class="arg">width</em><br />-lat <em class="arg">width</em>x<em class="arg">height</em>{<em class="arg">+-</em>}<em class="arg">offset</em>{<em class="arg">%</em>}</h4> 3716</div> 3717 3718<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>perform local adaptive threshold.</td><td style='text-align:right;'></td></tr></table> 3719 3720<p>Adaptively threshold each pixel based on the value of pixels in a 3721surrounding window. If the current pixel is lighter than this average plus 3722the optional <kbd>offset</kbd>, then it is made white, otherwise it is made 3723black. Small variations in pixel values such as found in scanned documents 3724can be ignored if offset is positive. A negative offset will make it more 3725sensitive to those small variations. </p> 3726 3727<p>This is commonly used to threshold images with an uneven background. It is 3728based on the assumption that average color of the small window is the 3729the local background color, from which to separate the forground color. </p> 3730 3731 3732<div style="margin: auto;"> 3733 <h4><a id="layers"></a>-layers <em class="arg">method</em></h4> 3734</div> 3735 3736<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>handle multiple images forming a set of image layers or animation frames.</td><td style='text-align:right;'></td></tr></table> 3737 3738<p>Perform various image operation methods to a ordered sequence of images 3739which may represent either a set of overlaid 'image layers', a GIF disposal 3740animation, or a fully-'coalesced' animation sequence. </p> 3741 3742<table class="doc"> 3743 <tbody> 3744 <tr valign="top"> 3745 <th align="left" style="width: 8%">Method</th> 3746 <th align="left">Description</th> 3747 </tr> 3748 3749 <tr valign="top"> 3750 <td valign="top">compare-any</td> 3751 <td valign="top">Crop the second and later frames to the smallest rectangle 3752 that contains all the differences between the two images. No GIF <a 3753 href="#dispose" >-dispose</a> methods are taken into account. </td> 3754 </tr> 3755 3756 <tr><td></td><td>This exactly the same as the <a href="#deconstruct" 3757 >-deconstruct</a> operator, and does not preserve animations normal 3758 working, especially when animation used layer disposal methods such as 3759 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td> 3760 </tr> 3761 3762 <tr valign="top"> 3763 <td valign="top">compare-clear</td> 3764 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any 3765 opaque pixels which become transparent in the second frame. That is the 3766 smallest image needed to mask or erase pixels for the next frame. </td> 3767 </tr> 3768 3769 <tr valign="top"> 3770 <td valign="top">compare-overlay</td> 3771 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add 3772 extra color to the next image, as a result of overlaying color pixels. 3773 That is the smallest single overlaid image to add or change colors. </td> 3774 </tr> 3775 3776 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha 3777 composition method '<kbd>change-mask</kbd>', to reduce the image to 3778 just the pixels that need to be overlaid. </td> 3779 </tr> 3780 3781 <tr valign="top"> 3782 <td valign="top">coalesce</td> 3783 <td valign="top">Equivalent to a call to the <a href="#coalesce" 3784 >-coalesce</a> operator. Apply the layer disposal methods set in the 3785 current image sequence to form a fully defined animation sequence, as 3786 it should be displayed. Effectively converting a GIF animation into a 3787 'film strip'-like animation. </td> 3788 </tr> 3789 3790 <tr valign="top"> 3791 <td valign="top">composite</td> 3792 <td valign="top">Alpha Composition of two image lists, separated by a 3793 "<kbd>null:</kbd>" image, with the destination image list first, and 3794 the source images last. An image from each list are composited 3795 together until one list is finished. The separator image and source 3796 image lists are removed. </td> 3797 </tr> 3798 3799 3800 <tr><td></td> 3801 <td>The <a href="#geometry" >-geometry</a> offset is adjusted according 3802 to <a href="#gravity" >-gravity</a> in accordance of the virtual 3803 canvas size of the first image in each list. Unlike a normal <a 3804 href="#composite" >-composite</a> operation, the canvas offset is also 3805 added to the final composite positioning of each image. </td> </tr> 3806 3807 <tr><td></td> 3808 <td>If one of the image lists only contains one image, that image is 3809 applied to all the images in the other image list, regardless of which 3810 list it is. In this case it is the image meta-data of the list which 3811 preserved. </td> 3812 </tr> 3813 3814 3815 <tr valign="top"> 3816 <td valign="top">dispose</td> 3817 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of 3818 the animation after the layer disposal method has been applied, before 3819 the next sub-frame image is overlaid. That is the 'dispose' image that 3820 results from the application of the GIF <a href="#dispose" 3821 >-dispose</a> method. This allows you to check what 3822 is going wrong with a particular animation you may be developing. 3823 </td> 3824 </tr> 3825 3826 <tr valign="top"> 3827 <td valign="top">flatten</td> 3828 <td valign="top">Create a canvas the size of the first images virtual 3829 canvas using the current <a href="#background" >-background</a> color, 3830 and <a href="#compose" >-compose</a> each image in turn onto that 3831 canvas. Images falling outside that canvas is clipped. Final 3832 image will have a zero virtual canvas offset. </td> 3833 </tr> 3834 3835 <tr><td></td> 3836 <td>This usally used as one of the final 'image layering' operations 3837 overlaying all the prepared image layers into a final image. </td> 3838 </tr> 3839 3840 <tr><td></td> 3841 <td>For a single image this method can also be used to fillout a virtual 3842 canvas with real pixels, or to underlay a opaque color to remove 3843 transparency from an image.</td> 3844 </tr> 3845 3846 3847 <tr valign="top"> 3848 <td valign="top">merge</td> 3849 <td valign="top">As 'flatten' method but merging all the given image 3850 layers to create a new layer image just large enough to hold all the 3851 image without clipping or extra space. The new images virtual offset 3852 will preserve the position of the new layer, even if this offset is 3853 negative. The virtual canvas size of the first image is preserved. 3854 </td> 3855 </tr> 3856 3857 <tr><td></td><td>Caution is advised when handling image layers with 3858 negative offsets as few image file formats handle them correctly. 3859 Following this operation methd with <a href="#repage" >+repage</a> 3860 will remove the layer offset, and create a image in which all the 3861 overlaid image positions relative to each other is preserved, though 3862 not nessaraily exactly where you specified them. 3863 </td> 3864 </tr> 3865 3866 <tr><td></td><td>See also 'trim-bounds' below whcih is closely related but 3867 without doing the'flatten' to merge the images together. </td> 3868 </tr> 3869 3870 <tr valign="top"> 3871 <td valign="top">mosaic</td> 3872 <td valign="top">As 'flatten' method but expanding the initial canvas size 3873 of the first image in a positive direction only so as to hold all the 3874 image layers. However as a virtual canvas is 'locked' to the origin, 3875 by its own definition, image layers with a negative offsets will still 3876 become clipped by the top and left edges. See 'merge' or 'trim-bounds' 3877 if this could be a problem. </td> 3878 3879 </tr> 3880 3881 <tr><td></td><td>This method is commonly used to layout individual image 3882 using various offset but without knowing the final canvas size. The 3883 resulting image will, like 'flatten' not have any virtual offset, so 3884 can be saved to any image file format. </td> 3885 </tr> 3886 3887 3888 <tr valign="top"> 3889 <td valign="top">optimize</td> 3890 <td valign="top">Optimize a coalesced animation, into GIF animation using 3891 a number of general techniques. This currently a short cut to 3892 apply both the '<kbd>optimize-frame</kbd>', and 3893 '<kbd>optimize-transparency</kbd>' methods but may be expanded to 3894 include other optimization methods as they are developed. </td> 3895 </tr> 3896 3897 <tr valign="top"> 3898 <td valign="top">optimize-frame</td> 3899 <td valign="top">Optimize a coalesced animation, into GIF animation by 3900 reducing the number of pixels per frame as much as possible by 3901 attempting to pick the best layer disposal method to use, while ensuring 3902 the result will continue to animate properly. </td> 3903 </tr> 3904 3905 <tr><td></td><td> There is no guarantee that the best optimization is found. 3906 But then no reasonably fast GIF optimization algorithm can do this. 3907 However this does seem to do better than most other GIF frame 3908 optimizers seen. </td> 3909 </tr> 3910 3911 <tr valign="top"> 3912 <td valign="top">optimize-plus</td> 3913 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the 3914 overall optimization by adding extra frames to the animation, without 3915 changing the final look or timing of the animation. The frames are 3916 added to attempt to separate the clearing of pixels from the 3917 overlaying of new additional pixels from one animation frame to the 3918 next. If this does not improve the optimization (for the next frame 3919 only), it will fall back to the results of the previous normal 3920 '<kbd>optimize-frame</kbd>' technique. </td> 3921 </tr> 3922 3923 <tr><td></td><td>There is the possibility that the change in the disposal 3924 style will result in a worsening in the optimization of later frames, 3925 though this is unlikely. In other words there no guarantee that it is 3926 better than the normal '<kbd>optimize-frame</kbd>' technique. For some 3927 animations however you can get a vast improvement in the final 3928 animation size. </td> 3929 </tr> 3930 3931 <tr valign="top"> 3932 <td valign="top">optimize-transparency</td> 3933 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame 3934 overlay images with transparency, if it does not change the resulting 3935 animation by more than the current <a href="#fuzz" >-fuzz</a> factor. 3936 </td> 3937 </tr> 3938 3939 <tr><td></td><td>This should allow a existing frame optimized GIF animation 3940 to compress into a smaller file size due to larger areas of one 3941 (transparent) color rather than a pattern of multiple colors repeating 3942 the current disposed image of the last frame. </td> 3943 </tr> 3944 3945 <tr valign="top"> 3946 <td valign="top">remove-dups</td> 3947 <td valign="top">Remove (and merge time delays) of duplicate consecutive 3948 images, so as to simplify layer overlays of coalesced animations. 3949 </td> 3950 </tr> 3951 3952 <tr><td></td><td>Usually this a result of using a constant time delay 3953 across the whole animation, or after a larger animation was split into 3954 smaller sub-animations. The duplicate frames could also have been 3955 used as part of some frame optimization methods. </td> 3956 </tr> 3957 3958 <tr valign="top"> 3959 <td valign="top">remove-zero</td> 3960 <td valign="top">Remove any image with a zero time delay, unless ALL the 3961 images have a zero time delay (and is not a proper timed animation, a 3962 warning is then issued). </td> 3963 </tr> 3964 3965 <tr><td></td><td>In a GIF animation, such images are usually frames which 3966 provide partial intermediary updates between the frames that are 3967 actually displayed to users. These frames are usally added for 3968 improved frame optimization in GIF animations. </td> 3969 </tr> 3970 3971 <tr valign="top"> 3972 <td valign="top">trim-bounds</td> 3973 <td valign="top">Find the bounds of all the images in the current 3974 image sequence, then adjust the offsets so all images are contained on 3975 a minimal positive canvas. None of the image data is modified or 3976 merged, only the individual image virtual canvas size and offset. 3977 All the images is given the same canvas size, and and will have 3978 a positive offset, but will remain in the same position relative to 3979 each other. As a result of the minimal canvas size at least one image 3980 will touch every edge of that canvas. The image data touching those 3981 edges however may be transparent. </td> 3982 </tr> 3983 3984 <tr><td></td><td>The result is much like if you used 'merge' followed by a 3985 <a href="#repage" >+repage</a> option, except that all the images 3986 have been kept separate. If 'flatten' is used after using 3987 'trim-bounds' you will get the same result. </td> 3988 </tr> 3989 3990 </tbody> 3991</table> 3992 3993<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p> 3994 3995<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct" 3996>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic" 3997>-mosaic</a> are only aliases for the above methods and may be depreciated in 3998the future. Also see <a href="#page" >-page</a>, <a href="#repage" 3999>-repage</a> operators, the <a href="#compose" >-compose</a> setting, and the 4000GIF <a href="#dispose" >-dispose</a> and <a href="#delay" >-delay</a> 4001settings. </p> 4002 4003 4004<div style="margin: auto;"> 4005 <h4><a id="level"></a>-level <em class="arg">black_point</em>{,<em class="arg">white_point</em>}{<em class="arg">%</em>}{,<em class="arg">gamma</em>}</h4> 4006</div> 4007 4008<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>adjust the level of image channels.</td><td style='text-align:right;'></td></tr></table> 4009 4010<p>Given one, two or three values delimited with commas: black-point, 4011white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and 4012white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white 4013point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center 4014contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string, 4015both black and white points are percentages of the full color range. Gamma 4016will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is 4017omitted, the default of 1.0 (no gamma correction) is assumed.</p> 4018 4019<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that 4020the given '<kbd>black_point</kbd>' value in the original image is set to 4021zero (or black), while the given '<kbd>white_point</kbd>' value is set to 4022<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments 4023to the image. The '<kbd>gamma</kbd>' of the resulting image will then be 4024adjusted. </p> 4025 4026<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or 4027adding the special '!' flag anywhere in the argument list, will cause the 4028operator to do the reverse of the level adjustment. That is a zero, or 4029<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is 4030adjusted to the given level values, allowing you to de-contrast, or compress 4031the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p> 4032 4033<p>Only the channels defined by the current <a href="#channel">-channel</a> 4034setting are adjusted (defaults to RGB color channels only), allowing you to 4035limit the effect of this operator. </p> 4036 4037<p>Please note that the transparency channel is treated as 'matte' 4038values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 4039 4040 4041<div style="margin: auto;"> 4042 <h4><a id="level-colors"></a>-level-colors {<em 4043 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4> 4044</div> 4045 4046<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>adjust the level of an image using the provided dash separated colors.</td><td style='text-align:right;'></td></tr></table> 4047 4048<p>This function is exactly like <a href="#level">-level</a>, except that the 4049value value for each color channel is determined by the 4050'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as 4051described under the <a href="#fill">-fill</a> option). </p> 4052 4053<p>This effectually means the colors provided to <kbd>-level-colors</kbd> 4054is mapped to become 'black' and 'white' respectively, with all the other 4055colors linearly adjusted (or clipped) to match that change. Each channel is 4056adjusted separately using the channel values of the colors specified. </p> 4057 4058<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>) 4059will map the image color 'black' and 'white' to the given colors 4060respectively, resulting in a gradient (de-contrasting) tint of the image to 4061those colors. This can also be used to convert a plain gray-scale image into a 4062one using the gradient of colors specified. </p> 4063 4064<p>By supplying a single color with a comma separator either before or after 4065that color, will just replace the respective 'black' or 'white' point 4066respectively. But if no comma separator is provided, the given color is 4067used for both the black and white color points, making the operator either 4068threshold the images around that color (- form) or set all colors to that 4069color (+ form). </p> 4070 4071 4072<div style="margin: auto;"> 4073 <h4><a id="limit"></a>-limit <em class="arg">type value</em></h4> 4074</div> 4075 4076<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the pixel cache resource limit.</td><td style='text-align:right;'></td></tr></table> 4077 4078<p>Choose from: <kbd>area</kbd>, <kbd>disk</kbd>, <kbd>file</kbd>, <kbd>map</kbd>, <kbd>memory</kbd>, <kbd>threads</kbd>, or <kbd>time</kbd>.</p> 4079 4080<p>The value for <kbd>file</kbd> is in number of files. The other limits are in bytes. By default the limits are 768 files, 2GB of image area, 1.5GiB memory, 8GiB memory map, and 18.45EB of disk. These limits are adjusted relative to the available resources on your computer if this information is available. When any limit is reached, ImageMagick fails in some fashion but attempts to take compensating actions, if possible. For example, the following limits memory:</p> 4081 4082<p class="crtsnip"> 4083 -limit memory 32MiB -limit map 64MiB 4084</p> 4085 4086<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p> 4087 4088<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>identify -list resource</span><span class='crtout'></span></p><pre class="text"> 4089 File Area Memory Map Disk Thread Time 4090 ------------------------------------------------------------------------------ 4091 768 12.404GB 8.6642GiB 23.104GiB 18.446744EB 8 unlimited 4092</pre> 4093 4094<p>Requests for pixel storage to keep intermediate images are satisfied by one of three resource categories: in-memory pool, memory-mapped files pool, and disk pool (in that order) depending on the <a href="/www/command-line-options.html#limit">‑limit</a> settings and whether the system honors a resource request. If the total size of allocated pixel storage in the given pool reaches the corresponding limit, the request is passed to the next pool. Additionally, requests that exceed the <kbd>area</kbd> limit automagically are allocated on disk.</p> 4095 4096<p>To illustrate how ImageMagick utilizes resource limits, consider a typical image resource request. First, ImageMagick tries to allocate the pixels in memory. The request might be denied if the resource request exceeds the <kbd>memory</kbd> limit or if the system does not honor the request. If a memory request is not honored, the pixels are allocated to disk and the file is memory-mapped. However, if the allocation request exceeds the <kbd>map</kbd> limit, the resource allocation goes to disk. In all cases, if the resource request exceeds the <kbd>area</kbd> limit, the pixels are automagically cached to disk. If the disk has a hard limit, the program fails.</p> 4097 4098<p>In most cases you simply do not need to concern yourself with resource limits. ImageMagick chooses reasonable defaults and most images do not tax your computer resources. Where limits do come in handy is when you process images that are large or on shared systems where ImageMagick can consume all or most of the available memory. In this case, the ImageMagick workflow slows other processes or, in extreme cases, brings the system to a halt. Under these circumstances, setting limits give some assurances that the ImageMagick workflow will not interfere with other concurrent uses of the computer. For example, assume you have a web interface that processes images uploaded from the Internet. To assure ImageMagick does not exceed 10mb of memory you can simply set the area limit to 10mb:</p> 4099 4100<p class="crtsnip"> 4101-limit area 10mb 4102</p> 4103 4104<p>Now whenever a large image is processed, the pixels are automagically cached to disk instead of memory. This of course implies that large images typically process very slowly, simply because pixel processing in memory can be an order of magnitude faster than on disk. Because your web site users might inadvertently upload a huge image to process, you should set a disk limit as well:</p> 4105 4106<p class="crtsnip"> 4107-limit area 10mb -limit disk 500mb 4108</p> 4109 4110<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p> 4111 4112<p>In addition to command-line resource limit option, resources can be set with <a href="/www/resources.html#environment">environment variables</a>. Set the environment variables <kbd>MAGICK_AREA_LIMIT</kbd>, <kbd>MAGICK_DISK_LIMIT</kbd>, <kbd>MAGICK_FILE_LIMIT</kbd>, <kbd>MAGICK_MEMORY_LIMIT</kbd>, <kbd>MAGICK_MAP_LIMIT</kbd>, <kbd>MAGICK_THREAD_LIMIT</kbd>, <kbd>MAGICK_TIME_LIMIT</kbd> for limits of image area, disk space, open files, heap memory, memory map, number of threads of execution, and maximum elapsed time in seconds respectively.</p> 4113 4114<p> Inquisitive users can try adding <a href="#debug">-debug cache</a> to their commands and then scouring the generated output for references to the pixel cache, in order to determine how the pixel cache was allocated and how resources were consumed. Advanced Unix/Linux users can pipe that output through <kbd>grep memory|open|destroy|disk</kbd> for more readable sifting. 4115</p> 4116 4117<p>For more about ImageMagick's use of resources, see the section <b>Cache Storage and Resource Requirements</b> on the <a href="/www/architecture.html#cache">Architecture</a> page. 4118</p> 4119 4120<div style="margin: auto;"> 4121 <h4><a id="linear-stretch"></a>-linear-stretch <em class="arg">black-point</em><br />-linear-stretch <em class="arg">black-point</em>{x<em class="arg">white-point</em>}{<em class="arg">%</em>}}</h4> 4122</div> 4123 4124<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Linear with saturation stretch.</td><td style='text-align:right;'></td></tr></table> 4125 4126<p>This is very similar to <a href="#contrast-stretch" >-contrast-stretch</a>, 4127and uses a 'histogram bin' to determine the range of color values that needs to 4128be stretched. However it then stretchs those colors using the <a 4129href="#level" >-level</a> operator.</p> 4130 4131<p>As such while the initial determination may have 'binning' round off 4132effects, the image colors are stretched mathematically, rather than using the 4133histogram bins. This makes the operator more accurate. </p> 4134 4135<p>note however that a <a href="#linear-stretch" >-linear-stretch</a> of 4136'<kbd>0</kbd>' does nothing, while a value of '<kbd>1</kbd>' does a near 4137perfect stretch of the color range. </p> 4138 4139<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 4140normalization of mathematical images. </p> 4141 4142<p>This operator is under review for re-development. </p> 4143 4144 4145<div style="margin: auto;"> 4146 <h4><a id="linewidth"></a>-linewidth</h4> 4147</div> 4148 4149<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the line width for subsequent draw operations.</td><td style='text-align:right;'></td></tr></table> 4150 4151<div style="margin: auto;"> 4152 <h4><a id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4> 4153</div> 4154 4155<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>rescale image with seam-carving.</td><td style='text-align:right;'></td></tr></table> 4156 4157<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 4158 4159<div style="margin: auto;"> 4160 <h4><a id="list"></a>-list <em class="arg">type</em></h4> 4161</div> 4162 4163<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Print a list of supported arguments for various options or settings. Choose from these list types:</td><td style='text-align:right;'></td></tr></table> 4164 4165<pre class="text"> 4166 Align Alpha Boolean Channel 4167 Class ClipPath Coder Color 4168 Colorspace Command Compose Compress 4169 Configure DataType Debug Decoration 4170 Delegate Direction Dispose Distort 4171 Dither Endian Evaluate FillRule 4172 Filter Font Format Function 4173 Gravity ImageList Intent Interlace 4174 Interpolate Kernel Layers LineCap 4175 LineJoin List Locale LogEvent 4176 Log Magic Method Metric 4177 Mime Mode Morphology Module 4178 Noise Orientation Policy PolicyDomain 4179 PolicyRights Preview Primitive QuantumFormat 4180 Resource SparseColor Storage Stretch 4181 Style Threshold Type Units 4182 Validate VirtualPixel 4183</pre> 4184 4185<p>These lists vary depending on your version of ImageMagick. Use "<kbd>-list 4186list</kbd>" to get a complete listing of all the "<kbd>-list</kbd>" arguments 4187available:</p> 4188 4189<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>identify -list list</span></p> 4190<div style="margin: auto;"> 4191 <h4><a id="log"></a>-log <em class="arg">string</em></h4> 4192</div> 4193 4194<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify format for debug log.</td><td style='text-align:right;'></td></tr></table> 4195 4196<p>This option specifies the format for the log printed when the <a 4197href="#debug">-debug</a> option is active.</p> 4198 4199<p>You can display the following components by embedding special format 4200characters:</p> 4201 4202<pre class="text"> 4203 %d domain 4204 %e event 4205 %f function 4206 %l line 4207 %m module 4208 %p process ID 4209 %r real CPU time 4210 %t wall clock time 4211 %u user CPU time 4212 %% percent sign 4213 \n newline 4214 \r carriage return 4215</pre> 4216 4217<p>For example:</p> 4218 4219<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -debug coders -log "%u %m:%l %e" in.gif out.png</span></p> 4220<p>The default behavior is to print all of the components.</p> 4221 4222<div style="margin: auto;"> 4223 <h4><a id="loop"></a>-loop <em class="arg">iterations</em></h4> 4224</div> 4225 4226<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>add Netscape loop extension to your GIF animation.</td><td style='text-align:right;'></td></tr></table> 4227 4228<p>Set iterations to zero to repeat the animation an infinite number of times, 4229otherwise the animation repeats itself up to <em class="arg">iterations</em> 4230times.</p> 4231 4232<div style="margin: auto;"> 4233 <h4><a id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4> 4234</div> 4235 4236<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>when comparing images, de-emphasize pixel differences with this color.</td><td style='text-align:right;'></td></tr></table> 4237 4238<div style="margin: auto;"> 4239 <h4><a id="magnify"></a>-magnify <em class="arg">factor</em></h4> 4240</div> 4241 4242<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>magnify the image.</td><td style='text-align:right;'></td></tr></table> 4243 4244 4245<div style="margin: auto;"> 4246 <h4><a id="map"></a>-map <em class="arg">type</em></h4> 4247</div> 4248 4249<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Display image using this <em class="arg">type</em>.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>, <a href="/www/display.html">display</a>]</td></tr></table> 4250 4251<p>Choose from these <em class="arg">Standard Colormap</em> types:</p> 4252 4253<pre class="text"> 4254 best 4255 default 4256 gray 4257 red 4258 green 4259 blue 4260</pre> 4261 4262<p>The <em class="arg">X server</em> must support the <em class="arg">Standard 4263Colormap</em> you choose, otherwise an error occurs. Use <kbd>list</kbd> as 4264the type and <kbd>display</kbd> searches the list of colormap types in 4265<kbd>top-to-bottom</kbd> order until one is located. See <em 4266class="arg">xstdcmap(1)</em> for one way of creating Standard Colormaps.</p> 4267 4268 4269<div style="margin: auto;"> 4270 <h4><a id="map_stream_"></a>-map <em class="arg">components</em></h4> 4271</div> 4272 4273<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>pixel map.</td><td style='text-align:right;'>[<a href="/www/stream.html">stream</a>]</td></tr></table> 4274 4275<p>Here are the valid components of a map:</p> 4276 4277<pre class="text"> 4278 r red pixel component 4279 g green pixel component 4280 b blue pixel component 4281 a alpha pixel component (0 is transparent) 4282 o opacity pixel component (0 is opaque) 4283 i grayscale intensity pixel component 4284 c cyan pixel component 4285 m magenta pixel component 4286 y yellow pixel component 4287 k black pixel component 4288 p pad component (always 0) 4289</pre> 4290 4291<p>You can specify as many of these components as needed in any order (e.g. 4292bgr). The components can repeat as well (e.g. rgbr).</p> 4293 4294 4295<div style="margin: auto;"> 4296 <h4><a id="mask"></a>-mask 4297<em class="arg">filename</em></h4> 4298</div> 4299 4300<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Prevent updates to image pixels specified by the mask.</td><td style='text-align:right;'></td></tr></table> 4301 4302<p>This the same as using a mask used for composite masking operations, with 4303grayscale values causing blended updates of the image the mask is attached to. 4304</P> 4305 4306<p>Use <a href="#mask">+mask</a> to remove the mask from images.</p> 4307 4308<p>Also see <a href="#clip-mask">-clip-mask</a> which work in the same way, 4309but with strict boolean masking. </p> 4310 4311<div style="margin: auto;"> 4312 <h4><a id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4> 4313</div> 4314 4315<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify the color to be used with the <a href="#frame">-frame</a> option.</td><td style='text-align:right;'></td></tr></table> 4316 4317<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 4318 4319<p>The default matte color is <kbd>#BDBDBD</kbd>, <span 4320style="background-color: #bdbdbd;">this shade of gray</span>.</p> 4321 4322<div style="margin: auto;"> 4323 <h4><a id="maximum"></a>-maximum</h4> 4324</div> 4325 4326<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>return the maximum intensity of an image sequence.</td><td style='text-align:right;'></td></tr></table> 4327 4328<p>Select the 'maximum' value from all the surrounding pixels. </p> 4329 4330<p>This is legacy option from the <a href="#statistic" >method</A> of the same 4331name. </p> 4332 4333<div style="margin: auto;"> 4334 <h4><a id="median"></a>-median <em class="arg">geometry</em></h4> 4335</div> 4336 4337<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>apply a median filter to the image.</td><td style='text-align:right;'></td></tr></table> 4338 4339<p>Select the 'middle' value from all the surrounding pixels. </p> 4340 4341<p>This is legacy option from the <a href="#statistic" >method</A> of the same 4342name. </p> 4343 4344<div style="margin: auto;"> 4345 <h4><a id="metric"></a>-metric <em class="arg">type</em></h4> 4346</div> 4347 4348<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Output to STDERR a measure of the differences between images according to the <em class="arg">type</em> given metric.</td><td style='text-align:right;'></td></tr></table> 4349 4350<p>Choose from:</p> 4351 4352<pre class="text"> 4353 AE absolute error count, number of different pixels (-fuzz effected) 4354 FUZZ mean color distance 4355 MAE mean absolute error (normalized), average channel error distance 4356 MEPP mean error per pixel (normalized mean error, normalized peak error) 4357 MSE mean error squared, average of the channel error squared 4358 NCC normalized cross correlation 4359 PAE peak absolute (normalize peak absolute) 4360 PSNR peak signal to noise ratio 4361 RMSE root mean squared (normalized root mean squared) 4362</pre> 4363 4364<p>Control the '<kbd>AE</kbd>', or absolute count of pixels that are different, 4365with the <a href="#fuzz" >-fuzz</a> factor (ignore pixels which 4366only changed by a small amount). Use '<kbd>PAE</kbd>' to find the 4367size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels 4368'similar', while '<kbd>MAE</kbd>' dtermines the factor needed 4369for about half the pixels to be similar. </p> 4370 4371<p>The '<kbd>MEPP</kbd>' metric returns three different metrics 4372('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>' 4373normalized) from a single comparison run. </p> 4374 4375<p>To print a complete list of metrics, use the <a href="#list">-list 4376metrics</a> option.</p> 4377 4378 4379<div style="margin: auto;"> 4380 <h4><a id="minimum"></a>-minimum</h4> 4381</div> 4382 4383<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>return the minimum intensity of an image sequence.</td><td style='text-align:right;'></td></tr></table> 4384 4385<p>Select the 'minimal' value from all the surrounding pixels. </p> 4386 4387<p>This is legacy option from the <a href="#statistic" >method</A> of the same 4388name. </p> 4389 4390 4391 4392<div style="margin: auto;"> 4393 <h4><a id="mode"></a>-mode <em class="arg">geometry</em></h4> 4394</div> 4395 4396<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>make each pixel the 'predominant color' of the neighborhood.</td><td style='text-align:right;'>[<a href="/www/convert.html">convert</a>, <a href="/www/mogrify.html">mogrify</a>]</td></tr></table> 4397 4398<div style="margin: auto;"> 4399 <h4>-mode <em class="arg">value</em></h4> 4400</div> 4401 4402<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mode of operation.</td><td style='text-align:right;'>[<a href="/www/montage.html">montage</a>]</td></tr></table> 4403 4404<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame, 4405Unframe, or Concatenate</kbd></p> 4406 4407<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>' argument 4408for a list of <a href="#mode" >-mode</a> arguments available in your 4409ImageMagick installation.</p> 4410 4411 4412<div style="margin: auto;"> 4413 <h4><a id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4> 4414</div> 4415 4416<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Vary the <em class="arg">brightness</em>, <em 4417class="arg">saturation</em>, and <em class="arg">hue</em> of an image.</td><td style='text-align:right;'></td></tr></table> 4418 4419<p>The arguments are given as a percentages of variation. A value of 100 means 4420no change, and any missing values are taken to mean 100.</p> 4421 4422<p>The <em class="arg">brightness</em> is a multiplier of the overall 4423brightness of the image, so 0 means pure black, 50 is half as bright, 200 is 4424twice as bright. To invert its meaning <a href="#negate">-negate</a> the image 4425before and after. </p> 4426 4427<p>The <em class="arg">saturation</em> controls the amount of color in an 4428image. For example, 0 produce a grayscale image, while a large value such as 4429200 produce a very colorful, 'cartoonish' color.</p> 4430 4431<p>The <em class="arg">hue</em> argument causes a "rotation" of the colors 4432within the image by the amount specified. For example, 50 results in 4433a counter-clockwise rotation of 90, mapping red shades to purple, and so on. 4434A value of either 0 or 200 results in a complete 180 degree rotation of the 4435image. Using a value of 300 is a 360 degree rotation resulting in no change to 4436the original image. </p> 4437 4438<p>For example, to increase the color brightness by 20% and decrease the color 4439saturation by 10% and leave the hue unchanged, use <a 4440href="#modulate">-modulate 120,90</a>.</p> 4441 4442<p>Use <a href="#set">-set</a> attribute of '<kbd 4443class="arg">option:modulate:colorspace</kbd>' to specify which colorspace to 4444modulate. Choose from <kbd>HSB</kbd>, <kbd>HSL</kbd> (the default), or 4445<kbd>HWB</kbd>. For example,</p> 4446 4447<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -set option:modulate:colorspace hsb -modulate 120,90 modulate.png</span></p> 4448 4449<div style="margin: auto;"> 4450 <h4><a id="monitor"></a>-monitor</h4> 4451</div> 4452 4453<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>monitor progress.</td><td style='text-align:right;'></td></tr></table> 4454 4455 4456<div style="margin: auto;"> 4457 <h4><a id="monochrome"></a>-monochrome</h4> 4458</div> 4459 4460<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>transform the image to black and white.</td><td style='text-align:right;'></td></tr></table> 4461 4462 4463<div style="margin: auto;"> 4464 <h4><a id="morph"></a>-morph <em class="arg">frames</em></h4> 4465</div> 4466 4467<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>morphs an image sequence.</td><td style='text-align:right;'></td></tr></table> 4468 4469<p>Both the image pixels and size are linearly interpolated to give the 4470appearance of a meta-morphosis from one image to the next, over all the images 4471in the current image list. The added images are the equivalent of a <a 4472href="#blend">-blend</a> composition. The <em class="arg">frames</em> 4473argument determine how many images to interpolate between each image. </p> 4474 4475 4476<div style="margin: auto;"> 4477 <h4><a id="morphology"></a>-morphology</h4> 4478 <h4>-morphology <em class="arg">method</em> <em class="arg">kernel</em></h4> 4479</div> 4480 4481<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>apply a morphology method to the image.</td><td style='text-align:right;'></td></tr></table> 4482 4483<p>Until I get around to writing a option summary for this, see <a 4484href="http://www.imagemagick.org/Usage/morphology/" >IM Usage Examples, 4485Morphology</a>. </p> 4486 4487 4488<div style="margin: auto;"> 4489 <h4><a id="mosaic"></a>-mosaic</h4> 4490</div> 4491 4492<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>an simple alias for the <a href="#layers" >-layers</a> method "mosaic"</td><td style='text-align:right;'></td></tr></table> 4493 4494 4495<div style="margin: auto;"> 4496 <h4><a id="motion-blur"></a>-motion-blur <em class="arg">radius</em><br />-motion-blur <em class="arg">radius</em>x<em class="arg">sigma</em>+<em class="arg">angle</em></h4> 4497</div> 4498 4499<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate motion blur.</td><td style='text-align:right;'></td></tr></table> 4500 4501<p>Blur with the given radius, standard deviation (sigma), and angle. The 4502angle given is the angle toward which the image is blurred. That is the 4503direction people would consider the object is coming from. </p> 4504 4505<p>Note that the blur is not uniform distribution, giving the motion a 4506definite sense of direction of movement. </p> 4507 4508<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4509pixels which are outside the image proper are blurred into the final result. 4510</p> 4511 4512<div style="margin: auto;"> 4513 <h4><a id="name"></a>-name</h4> 4514</div> 4515 4516<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>name an image.</td><td style='text-align:right;'></td></tr></table> 4517<div style="margin: auto;"> 4518 <h4><a id="negate"></a>-negate</h4> 4519</div> 4520 4521<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>replace each pixel with its complementary color.</td><td style='text-align:right;'></td></tr></table> 4522 4523<p>The red, green, and blue intensities of an image are negated. White becomes black, yellow becomes blue, etc. Use <a href="#negate">+negate</a> to only negate the grayscale pixels of the image.</p> 4524 4525<div style="margin: auto;"> 4526 <h4><a id="noise"></a>-noise <em class="arg">geometry</em><br/> 4527 +noise <em class="arg">type</em></h4> 4528</div> 4529 4530<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Add or reduce noise in an image.</td><td style='text-align:right;'></td></tr></table> 4531 4532<p>The principal function of noise peak elimination filter is to smooth the objects within an image without losing edge information and without creating undesired structures. The central idea of the algorithm is to replace a pixel with its next neighbor in value within a pixel window, if this pixel has been found to be noise. A pixel is defined as noise if and only if this pixel is a maximum or minimum within the pixel window.</p> 4533 4534<p>Use <kbd><a href="#noise">-noise</a> <em class="arg">radius</em></kbd> to specify the width of the neighborhood when reducing noise.</p> 4535 4536<p>Use <a href="#noise">+noise</a> followed by a noise <em class="arg">type</em> to add noise to an image. Choose from these noise types:</p> 4537 4538<pre class="text"> 4539 Gaussian 4540 Impulse 4541 Laplacian 4542 Multiplicative 4543 Poisson 4544 Random 4545 Uniform 4546</pre> 4547 4548<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p> 4549 4550<p>Also see the <a href="#evaluate">-evaluate</a> noise functions that allos 4551the use of a controlling value to specify teh amount of noise that should be 4552added to an image. </p> 4553 4554 4555<div style="margin: auto;"> 4556 <h4><a id="normalize"></a>-normalize</h4> 4557</div> 4558 4559<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Increase the contrast in an image by <em>stretching</em> the range of intensity values.</td><td style='text-align:right;'></td></tr></table> 4560 4561<p>The intensity values are stretched to cover the entire range of possible 4562values. While doing so, black-out at most <em>2%</em> of the pixels and 4563white-out at most <em>1%</em> of the pixels.</p> 4564 4565<p>Note that as of ImageMagick 6.4.7-0, <a href="#normalize" >-normalize</a> 4566is equivalent to <a href="#contrast-stretch" >-contrast-stretch 2%x1%</a>. 4567(Before this version, it was equivalent to <a href="#contrast-stretch" 4568>-contrast-stretch 2%x99%</a>).</p> 4569 4570<p>All the channels are normalized in concert by the came amount so as to 4571preserve color integrity, when the default <a href="#channel" >+channel</a> 4572setting is in use. Specifying any other <a href="#channel" >-channel</a> 4573setting will normalize the RGB channels independently.</p> 4574 4575<p>See <a href="#contrast-stretch" >-contrast-stretch</a> for more details. 4576Also see <a href="#auto-level" >-auto-level</a> for a 'perfect' normalization 4577that is better suited to mathematically generated images. </p> 4578 4579<p>This operator is under review for re-development. </p> 4580 4581 4582<div style="margin: auto;"> 4583 <h4><a id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4> 4584</div> 4585 4586<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>dither the image using a pre-defined ordered dither <em 4587class="arg">threshold map</em> specified, and a uniform color map with the 4588given number of <em class="arg">levels</em> per color channel . </td><td style='text-align:right;'></td></tr></table> 4589 4590<p>You can choose from these standard threshold maps:</p> 4591 4592<pre class="text"> 4593 threshold 1x1 Threshold 1x1 (non-dither) 4594 checks 2x1 Checkerboard 2x1 (dither) 4595 o2x2 2x2 Ordered 2x2 (dispersed) 4596 o3x3 3x3 Ordered 3x3 (dispersed) 4597 o4x4 4x4 Ordered 4x4 (dispersed) 4598 o8x8 8x8 Ordered 8x8 (dispersed) 4599 h4x4a 4x1 Halftone 4x4 (angled) 4600 h6x6a 6x1 Halftone 6x6 (angled) 4601 h8x8a 8x1 Halftone 8x8 (angled) 4602 h4x4o Halftone 4x4 (orthogonal) 4603 h6x6o Halftone 6x6 (orthogonal) 4604 h8x8o Halftone 8x8 (orthogonal) 4605 h16x16o Halftone 16x16 (orthogonal) 4606 c5x5b c5x5 Circles 5x5 (black) 4607 c5x5w Circles 5x5 (white) 4608 c6x6b c6x6 Circles 6x6 (black) 4609 c6x6w Circles 6x6 (white) 4610 c7x7b c7x7 Circles 7x7 (black) 4611 c7x7w Circles 7x7 (white) 4612</pre> 4613 4614<p> The <kbd>threshold</kbd> generated a simple 50% threshold of the image. 4615This could be used with <em class="arg" >level</em> to do the equivalent of <a 4616href="#posterize" >-posterize</a> to reduce an image to basic primary colors. 4617</p> 4618 4619<p>The <kbd>checks</kbd> pattern produces a 3 level checkerbord dither 4620pattern. That is a grayscale will become a pattern of solid black, solid 4621white, and mid-tone colors into a checkerboard pattern of black and white. 4622</p> 4623 4624<p>You can define your own <em class="arg" >threshold map</em> for ordered 4625dithering and halftoning your images, in either personal or system 4626<kbd>thresholds.xml</kbd> XML file. See <a href="resources.html" >Resources</A> 4627for more details of configuration files. </p> 4628 4629<p>To print a complete list of the thresholds that have been defined, use the 4630<a href="#list" >-list threshold</a> option.</p> 4631 4632<p>Note that at this time the same threshold dithering map is used for all 4633color channels, no attempt is made to offset or rotate the map for different 4634channels is made, to create an offset printing effect. Also as the maps are 4635simple threshold levels, the halftone and circle maps will create incomplete 4636circles along the edges of a colored area. Also all the effects are purely 4637on/off boolean effects, without anti-aliasing to make the circles smooth 4638looking. Large dots can be made to look better with a small amount of blurring 4639after being created. </p> 4640 4641 4642<div style="margin: auto;"> 4643 <h4><a id="opaque"></a>-opaque <em class="arg">color</em></h4> 4644</div> 4645 4646<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>change this color to the fill color within the image.</td><td style='text-align:right;'></td></tr></table> 4647 4648<p>The <em class="arg">color</em> argument is defined using the format 4649described under the <a href="#fill" >-fill</a> option. The <a href="#fuzz" 4650>-fuzz</a> setting can be used to match and replace colors similar to the one 4651given.</p> 4652 4653<p>Use <a href="#opaque">+opaque</a> to paint any pixel that does not match 4654the target color. </p> 4655 4656<p>The <a href="#transparent">-transparent</a> operator is exactly the same 4657as <a href="#opaque" >-opaque</a> but replaces the matching color with 4658transparency rather than the current <a href="#fill">-fill</a> color setting. 4659To ensure that it can do this it also ensures that the image has an alpha 4660channel enabled, as per "<kbd><a href="#alpha" >-alpha</a> set</kbd>", for 4661the new transparent colors, and does not require you to modify the <a 4662href="#channel">-channel</a> to enable alpha channel handling. </p> 4663 4664 4665<div style="margin: auto;"> 4666 <h4><a id="orient"></a>-orient <em class="arg">image orientation</em></h4> 4667</div> 4668 4669<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>specify orientation of a digital camera image.</td><td style='text-align:right;'></td></tr></table> 4670 4671<p>Choose from these orientations:</p> 4672 4673<pre class="text"> 4674 bottom-left 4675 bottom-right 4676 left-bottom 4677 left-top 4678 right-bottom 4679 right-top 4680 top-left 4681 top-right 4682 undefined 4683</pre> 4684 4685<p>To print a complete list of orientations, use the <a href="#list" >-list 4686orientation</a> option.</p> 4687 4688 4689<div style="margin: auto;"> 4690 <h4><a id="page"></a>-page <em class="arg">geometry</em><br/> 4691 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!<></em>}]<br/> 4692 +page 4693 </h4> 4694</div> 4695 4696<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the size and location of an image on the larger virtual canvas.</td><td style='text-align:right;'></td></tr></table> 4697 4698<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 4699 4700<p>For convenience you can specify the page size using <em class="arg">media</em> (see below). Offsets can then be added as with other <em class="arg">geometry</em> arguments (e.g. <a href="#page">-page</a> <kbd>Letter+43+43</kbd>).</p> 4701 4702<p>Use <em class="arg">media</em> as shorthand to specify the dimensions (<em class="arg">width</em>x<em class="arg">height</em>) of the <em class="arg">PostScript</em> page in dots per inch or a TEXT page in pixels. The choices for a PostScript page are:</p> 4703<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;"> 4704<thead> 4705 <tr valign="top"> 4706 <th align="center"><em class="arg">media</em></th> 4707 <th align="center"><em class="arg">width</em></th> 4708 <th align="center"><em class="arg">height</em></th> 4709 </tr> 4710</thead> 4711<tbody> 4712<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr> 4713<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr> 4714<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr> 4715<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4716<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4717<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr> 4718<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr> 4719<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr> 4720<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr> 4721<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr> 4722<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr> 4723<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr> 4724<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr> 4725<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr> 4726<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4727<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4728<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr> 4729<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr> 4730<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr> 4731<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr> 4732<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr> 4733<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr> 4734<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr> 4735<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr> 4736<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr> 4737<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr> 4738<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr> 4739<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr> 4740<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr> 4741<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr> 4742<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr> 4743<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr> 4744<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr> 4745<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr> 4746<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr> 4747<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4748<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4749<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr> 4750</tbody> 4751</table> 4752 4753 4754 4755 4756<p>This option is also used to place subimages when writing to a multi-image format that supports offsets, such as GIF89 and MNG. When used for this purpose the offsets are always measured from the top left corner of the canvas and are not affected by the <a href="#gravity">-gravity</a> option. To position a GIF or MNG image, use <a href="#page">-page</a><em class="arg">{+-}x{+-}y</em> (e.g. -page +100+200). When writing to a MNG file, a <a href="#page">-page</a> option appearing ahead of the first image in the sequence with nonzero width and height defines the width and height values that are written in the <kbd>MHDR</kbd> chunk. Otherwise, the MNG width and height are computed from the bounding box that contains all images in the sequence. When writing a GIF89 file, only the bounding box method is used to determine its dimensions.</p> 4757 4758<p>For a PostScript page, the image is sized as in <a href="#geometry">-geometry</a> but positioned relative to the <em>lower left-hand corner</em> of the page by {+-}<kbd>x</kbd><em class="arg">offset</em>{+-}<kbd>y</kbd> <em class="arg">offset</em>. Use <a href="#page">-page 612x792</a>, for example, to center the image within the page. If the image size exceeds the PostScript page, it is reduced to fit the page. The default gravity for the <a href="#page">-page</a> option is <em class="arg">NorthWest</em>, i.e., positive <kbd>x</kbd> and <kbd>y</kbd> <em class="arg">offset</em> are measured rightward and downward from the top left corner of the page, unless the <a href="#gravity">-gravity</a> option is present with a value other than <em class="arg">NorthWest</em>.</p> 4759 4760<p>The default page dimensions for a TEXT image is 612x792.</p> 4761 4762<p>This option is used in concert with <a href="#density">-density</a>.</p> 4763 4764<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p> 4765 4766<div style="margin: auto;"> 4767 <h4><a id="paint"></a>-paint <em class="arg">radius</em></h4> 4768</div> 4769 4770<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate an oil painting.</td><td style='text-align:right;'></td></tr></table> 4771 4772<p>Each pixel is replaced by the most frequent color in a circular neighborhood whose width is specified with <em class="arg">radius</em>.</p> 4773 4774<div style="margin: auto;"> 4775 <h4><a id="path"></a>-path <em class="arg">path</em></h4></div> 4776 4777<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>write images to this path on disk.</td><td style='text-align:right;'></td></tr></table> 4778 4779<div style="margin: auto;"> 4780 <h4><a id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4> 4781</div> 4782 4783<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Pause between animation loops.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>]</td></tr></table> 4784 4785<p>Pause for the specified number of seconds before repeating the animation.</p> 4786 4787<div style="margin: auto;"> 4788 <h4><a id="pause_import_"></a>-pause <em class="arg">seconds</em></h4> 4789</div> 4790 4791<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Pause between snapshots.</td><td style='text-align:right;'>[<a href="/www/import.html">import</a>]</td></tr></table> 4792 4793<p>Pause for the specified number of seconds before taking the next snapshot.</p> 4794 4795<div style="margin: auto;"> 4796 <h4><a id="ping"></a>-ping</h4> 4797</div> 4798 4799<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>efficiently determine image characteristics.</td><td style='text-align:right;'></td></tr></table> 4800 4801<div style="margin: auto;"> 4802 <h4><a id="pointsize"></a>-pointsize <em class="arg">value</em></h4> 4803</div> 4804 4805<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>pointsize of the PostScript, OPTION1, or TrueType font.</td><td style='text-align:right;'></td></tr></table> 4806 4807<div style="margin: auto;"> 4808 <h4><a id="polaroid"></a>-polaroid <em class="arg">angle</em></h4> 4809</div> 4810 4811<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate a Polaroid picture.</td><td style='text-align:right;'></td></tr></table> 4812 4813<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p> 4814 4815<div style="margin: auto;"> 4816 <h4><a id="posterize"></a>-posterize <em class="arg">levels</em></h4> 4817</div> 4818 4819<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>reduce the image to a limited number of color levels.</td><td style='text-align:right;'></td></tr></table> 4820 4821<div style="margin: auto;"> 4822 <h4><a id="precision"></a>-precision <em class="arg">value</em></h4> 4823</div> 4824 4825<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the maximum number of significant digits to be printed.</td><td style='text-align:right;'></td></tr></table> 4826 4827<div style="margin: auto;"> 4828 <h4><a id="preview"></a>-preview <em class="arg">type</em></h4> 4829</div> 4830 4831<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>image preview type.</td><td style='text-align:right;'></td></tr></table> 4832 4833<p>Use this option to affect the preview operation of an image (e.g. <kbd>convert file.png -preview Gamma Preview:gamma.png</kbd>). Choose from these previews:</p> 4834 4835<pre class="text"> 4836 Rotate Shear Roll Hue 4837 Saturation Brightness Gamma Spiff 4838 Dull Grayscale Quantize Despeckle 4839 ReduceNoise Add Noise Sharpen Blur 4840 Threshold EdgeDetect Spread Shade 4841 Raise Segment Solarize Swirl 4842 Implode Wave OilPaint CharcoalDrawing 4843 JPEG 4844</pre> 4845 4846<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p> 4847 4848<p>The default preview is <kbd>JPEG</kbd>.</p> 4849 4850<div style="margin: auto;"> 4851 <h4><a id="print"></a>-print <em class="arg">string</em></h4> 4852</div> 4853 4854<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>interpret string and print to console.</td><td style='text-align:right;'></td></tr></table> 4855 4856<div style="margin: auto;"> 4857 <h4><a id="process"></a>-process <em class="arg">command</em></h4> 4858</div> 4859 4860<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>process the image with a custom image filter.</td><td style='text-align:right;'></td></tr></table> 4861 4862<p>The command arguments has the form <kbd>"module arg1 arg2 arg3 ... argN"</kbd> where <kbd>module</kbd> is the name of the module to invoke (e.g. "Analyze") and arg1 arg2 arg3 ... argN are an arbitrary number of arguments to pass to the process module.</p> 4863 4864<div style="margin: auto;"> 4865 <h4><a id="profile"></a>-profile <em class="arg">filename</em><br/> 4866 +profile <em class="arg">profile_name</em></h4> 4867</div> 4868 4869<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Manage ICM, IPTC, or generic profiles in an image.</td><td style='text-align:right;'></td></tr></table> 4870 4871<p>Using <a href="#profile">-profile</a> <em class="arg">filename</em> adds an ICM (ICC color management), IPTC (newswire information), or a generic profile to the image.</p> 4872 4873<p>Use <a href="#profile">+profile <em class="arg">profile_name</em></a> to remove the indicated profile. ImageMagick uses standard filename globbing, so wildcard expressions may be used to remove more than one profile. Here we remove all profiles from the image except for the XMP profile: <kbd>+profile "!xmp,*"</kbd>. </p> 4874 4875<p>Use <kbd>identify -verbose</kbd> to find out which profiles are in the image file. Use <a href="#strip">-strip</a> to remove all profiles (and comments).</p> 4876 4877<p>To extract a profile, the <a href="#profile">-profile</a> option is not used. Instead, simply write the file to an image format such as <em class="arg">APP1, 8BImageMagick, ICM,</em> or <em class="arg">IPTC</em>.</p> 4878 4879<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p> 4880 4881<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p> 4882<p>It is important to note that results may depend on whether or not the original image already has an included profile. Also, keep in mind that <a href="#profile">-profile</a> is an "operator" (as opposed to a "setting") and therefore a conversion is made each time it is encountered, in order, in the command-line. For instance, in the following example, if the original image is CMYK with profile, a CMYK-CMYK-RGB conversion results.</p> 4883 4884<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert CMYK.tif -profile "CMYK.icc" -profile "RGB.icc" RGB.tiff</span></p> 4885<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results. 4886CMYK profiles are often very asymmetric since they involve 3−>4 and 4−>3 channel mapping. 4887</p> 4888 4889<div style="margin: auto;"> 4890 <h4><a id="quality"></a>-quality <em class="arg">value</em></h4> 4891</div> 4892 4893<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>JPEG/MIFF/PNG compression level.</td><td style='text-align:right;'></td></tr></table> 4894 4895<p>For the JPEG and MPEG image formats, quality is 1 (lowest image quality and 4896highest compression) to 100 (best quality but least effective compression). 4897The default is to use the estimated quality of your input image if it can 4898be determined, otherwise 92. When the quality is greater than 90, then the 4899chroma channels are not downsampled. 4900Use the <a href="#sampling-factor">-sampling-factor</a> option to specify the 4901factors for chroma downsampling.</p> 4902 4903<p>For the MIFF image format, quality/10 is the zlib compression level, which is 0 (worst but fastest compression) to 9 (best but slowest). It has no effect on the image appearance, since the compression is always lossless.</p> 4904 4905<p>For the JPEG-2000 image format, quality is mapped using a non-linear equation to the compression ratio required by the Jasper library. This non-linear equation is intended to loosely approximate the quality provided by the JPEG v1 format. The default quality value 100, a request for non-lossy compression. A quality of 75 results in a request for 16:1 compression.</p> 4906 4907<p>For the MNG and PNG image formats, the quality value sets the zlib 4908compression level (quality / 10) and filter-type (quality % 10). The default 4909PNG "quality" is 75, which means compression level 7 with adaptive PNG 4910filtering, unless the image has a color map, in which case it means 4911compression level 7 with no PNG filtering.</p> 4912 4913<p>For compression level 0, the Huffman-only strategy is used, which is fastest but not necessarily the worst compression.</p> 4914 4915<p>If filter-type is 4 or less, the specified PNG filter-type is used for 4916all scanlines:</p> 4917 4918<pre class="text"> 4919 0: none 4920 1: sub 4921 2: up 4922 3: average 4923 4: Paeth 4924</pre> 4925 4926<p>If filter-type is 5, adaptive filtering is used when quality is greater 4927than 50 and the image does not have a color map, otherwise no filtering is 4928used.</p> 4929 4930<p>If filter-type is 6, adaptive filtering 4931with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p> 4932 4933<p>Only if the output is MNG, if filter-type is 7, the LOCO color 4934transformation (intrapixel differencing) and adaptive filtering 4935with <em class="arg">minimum-sum-of-absolute-values</em> are used.</p> 4936 4937<p>If the filter-type is 8 the zlib Z_RLE compression strategy is used with 4938 no PNG filtering.</p> 4939 4940<p>If the filter-type is 9 the zlib Z_RLE compression strategy is used with 4941 adaptive PNG filtering.</p> 4942 4943<p>The quality setting has no effect on the appearance or signature of PNG 4944and MNG images, since the compression is always lossless.</p> 4945 4946<p>Not all combinations of compression level, strategy, and PNG filter type 4947can be obtained using the -quality option. For more precise control, 4948you can use the PNG:compression-level=N, PNG:compression-strategy=N, and 4949PNG:compression-filter=N defines, respectively, instead. 4950See <a href="#define">-define</a>. Values from the defines take precedence 4951over values from the -quality option.</p> 4952 4953<p>For further information, see 4954the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p> 4955 4956<div style="margin: auto;"> 4957 <h4><a id="quantize"></a>-quantize <em class="arg">colorspace</em></h4> 4958</div> 4959 4960<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>reduce colors using this colorspace.</td><td style='text-align:right;'></td></tr></table> 4961 4962<p>This setting defines the colorspace used to sort out and reduce the number 4963of colors needed by an image (for later dithering) by operators such as <a 4964href="#colors" >-colors</a>, Note that color reducion also happens 4965automatically when saving images to color-limited image file formats, such as 4966GIF, and PNG8.</p> 4967 4968 4969<div style="margin: auto;"> 4970 <h4><a id="quiet"></a>-quiet</h4> 4971</div> 4972 4973<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>suppress all warning messages. Error messages are still reported.</td><td style='text-align:right;'></td></tr></table> 4974 4975<div style="margin: auto;"> 4976 <h4><a id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4> 4977</div> 4978 4979<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Blur around the center of the image.</td><td style='text-align:right;'></td></tr></table> 4980 4981<p>Note that this is actually a rotational blur rather than a radial and as 4982such actually mis-named. </p> 4983 4984<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4985pixels which are outside the image proper are blurred into the final result. 4986</p> 4987 4988 4989<div style="margin: auto;"> 4990 <h4><a id="raise"></a>-raise <em class="arg">thickness</em></h4> 4991</div> 4992 4993<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Lighten or darken image edges.</td><td style='text-align:right;'></td></tr></table> 4994 4995<p>This will create a 3-D effect. Use <a href="#raise">-raise</a> to create a raised effect, otherwise use <a href="#raise">+raise</a>. 4996</p> 4997 4998<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p> 4999 5000<div style="margin: auto;"> 5001 <h4><a id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4> 5002</div> 5003 5004<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply a random threshold to the image.</td><td style='text-align:right;'></td></tr></table> 5005 5006<div style="margin: auto;"> 5007 <h4><a id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4> 5008</div> 5009 5010<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the red chromaticity primary point.</td><td style='text-align:right;'></td></tr></table> 5011 5012<div style="margin: auto;"> 5013 <h4><a id="regard-warnings"></a>-regard-warnings</h4> 5014</div> 5015 5016<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Pay attention to warning messages.</td><td style='text-align:right;'></td></tr></table> 5017 5018<div style="margin: auto;"> 5019 <h4><a id="remap"></a>-remap <em class="arg">filename</em></h4> 5020</div> 5021 5022<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Reduce the number of colors in an image to the colors used by this image.</td><td style='text-align:right;'></td></tr></table> 5023 5024<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then 5025the given colors are dithered over the image as necessary, otherwise the closest 5026color (in RGB colorspace) is selected to replace that pixel in the image. </p> 5027 5028<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all 5029images in the current image sequence, all the images will have the same color 5030table. That means that when saved to a file format such as GIF, it will use 5031that color table as a single common or global color table, for all the images, 5032without requiring extra local color tables. </p> 5033 5034<p>Use <a href="#remap">+remap</a> to reduce all images in the current image 5035sequence to use a common color map over all the images. This equivalent to 5036appending all the images together (without extra background colors) and color 5037reducing those images using <a href="#colors">-colors</a> with a 256 color 5038limit, then <a href="#remap">-remap</a> those colors over the original list of 5039images. This ensures all the images follow a single color map. </p> 5040 5041<p>If the number of colors over all the images is less than 256, then <a 5042href="#remap">+remap</a> should not perform any color reduction or dithering, as 5043no color changes are needed. In that case, its only effect is to force the use 5044of a global color table. This recommended after using either <a 5045href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to 5046reduce the number of colors in an animated image sequence. </p> 5047 5048<div style="margin: auto;"> 5049 <h4><a id="region"></a>-region <em class="arg">geometry</em></h4> 5050</div> 5051 5052<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set a region in which subsequent operations apply.</td><td style='text-align:right;'></td></tr></table> 5053 5054<p>The <em class="arg">x</em> and <em class="arg">y</em> offsets are treated in the same manner as in <a href="#crop">-crop</a>.</p> 5055 5056<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 5057 5058<div style="margin: auto;"> 5059 <h4><a id="remote"></a>-remote</h4> 5060</div> 5061 5062<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>perform a remote operation.</td><td style='text-align:right;'></td></tr></table> 5063 5064<p>The only command recognized is the name of an image file to load.</p> 5065 5066<p>If you have more than one <a href="/www/display.html">display</a> application running simultaneously, use the <a href="#window"> window</a> option to specify which application to control.</p> 5067 5068<div style="margin: auto;"> 5069 <h4><a id="render"></a>-render</h4> 5070</div> 5071 5072<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>render vector operations.</td><td style='text-align:right;'></td></tr></table> 5073 5074<p>Use <a href="#render">+render</a> to turn off rendering vector operations. This useful when saving the result to vector formats such as MVG or SVG.</p> 5075 5076<div style="margin: auto;"> 5077<h4><a id="repage"></a>-repage <em class="arg">geometry</em></h4> 5078</div> 5079 5080<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Adjust the canvas and offset information of the image.</td><td style='text-align:right;'></td></tr></table> 5081 5082<p>This option is like <a href="#page">-page</a> but acts as an image operator 5083rather than a setting. You can separately set the canvas size or the offset 5084of the image on that canvas by only providing those components. </p> 5085 5086<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 5087 5088<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing 5089offset to move the image relative to its previous position. This useful for 5090animation sequences. </p> 5091 5092<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to 5093recalculate the canvas size so the image (at its current offset) will appear 5094completely on that canvas (unless it has a negative offset).</p> 5095 5096<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual 5097canvas meta-data from the images. </p> 5098 5099<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to 5100directly assign virtual canvas meta-data. </p> 5101 5102 5103<div style="margin: auto;"> 5104 <h4><a id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4> 5105</div> 5106 5107<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Resample image to specified horizontal and vertical resolution.</td><td style='text-align:right;'></td></tr></table> 5108 5109<p>Resize the image so that its rendered size remains the same as the original at the specified target resolution. For example, if a 300 DPI image renders at 3 inches by 2 inches on a 300 DPI device, when the image has been resampled to 72 DPI, it will render at 3 inches by 2 inches on a 72 DPI device. Note that only a small number of image formats (e.g. JPEG, PNG, and TIFF) are capable of storing the image resolution. For formats which do not support an image resolution, the original resolution of the image must be specified via <a href="#density">-density</a> on the command line prior to specifying the resample resolution.</p> 5110 5111<p>Note that Photoshop stores and obtains image resolution from a proprietary embedded profile. If this profile exists in the image, then Photoshop will continue to treat the image using its former resolution, ignoring the image resolution specified in the standard file header.</p> 5112 5113<div style="margin: auto;"> 5114 <h4><a id="resize"></a>-resize <em class="arg">geometry</em></h4> 5115</div> 5116 5117<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Resize an image.</td><td style='text-align:right;'></td></tr></table> 5118 5119<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets, if present in the geometry string, are ignored, and the <a href="#gravity">-gravity</a> option has no effect.</p> 5120 5121<p>If the <a href="#filter">-filter</a> option precedes the <a href="#resize">-resize</a> option, the image is resized with the specified filter.</p> 5122 5123<p>Many image processing algorithms assume your image is in a linear-light coding. If your image is gamma-corrected, you can remove the nonlinear gamma correction, apply the transform, then restore it like this:</p> 5124 5125<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert portrait.jpg -gamma .45455 -resize 25% -gamma 2.2 \ <br/> -quality 92 passport.jpg</span></p> 5126<div style="margin: auto;"> 5127 <h4><a id="respect-parentheses"></a>-respect-parentheses</h4> 5128</div> 5129 5130<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>settings remain in effect until parenthesis boundary.</td><td style='text-align:right;'></td></tr></table> 5131 5132<div style="margin: auto;"> 5133 <h4><a id="reverse"></a>-reverse</h4> 5134</div> 5135 5136<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Reverse the order of images in the current image list.</td><td style='text-align:right;'></td></tr></table> 5137 5138 5139<div style="margin: auto;"> 5140 <h4><a id="roll"></a>-roll {<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em></h4> 5141</div> 5142 5143<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>roll an image vertically or horizontally by the amount given.</td><td style='text-align:right;'></td></tr></table> 5144 5145<p>A negative <em class="arg">x</em> offset rolls the image left-to-right. A negative <em class="arg">y</em> offset rolls the image top-to-bottom.</p> 5146 5147 5148<div style="margin: auto;"> 5149 <h4><a id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg"><</em>}{<em class="arg">></em>}</h4> 5150</div> 5151 5152<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply Paeth image rotation (using shear operations) to the image.</td><td style='text-align:right;'></td></tr></table> 5153 5154<p>Use <kbd>></kbd> to rotate the image only if its width exceeds the height. <kbd><</kbd> rotates the image <em>only</em> if its width is less than the height. For example, if you specify <kbd>-rotate "-90>"</kbd> and the image size is 480x640, the image is not rotated. However, if the image is 640x480, it is rotated by -90 degrees. If you use <kbd>></kbd> or <kbd><</kbd>, enclose it in quotation marks to prevent it from being misinterpreted as a file redirection.</p> 5155 5156<p>Empty triangles in the corners, left over from rotating the image, are 5157filled with the <kbd>background</kbd> color. </p> 5158 5159<p>See also the <a href="#distort">-distort</a> operator and specifically the 5160'<kbd>ScaleRotateTranslate</kbd>' distort method. </p> 5161 5162 5163<div style="margin: auto;"> 5164 <h4><a id="sample"></a>-sample <em class="arg">geometry</em></h4> 5165</div> 5166 5167<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>minify/magnify the image using pixel subsampling and pixel replication, respectively.</td><td style='text-align:right;'></td></tr></table> 5168 5169<p>Change the image size simply by directly sampling the pixels original 5170image. When magnifying, pixels are replicated in blocks. When minifying, 5171pixels are sub-sampled (i.e., some rows and columns are skipped over). </p> 5172 5173<p>The results are thus equivalent to using <a href="#resize">-resize</a> with 5174a <a href="#filter">-filter</a> setting of <kbd>point</kbd> (nearest 5175neighbour), though <a href="#sample">-sample</a> is a lot faster, as it 5176avoids all the filter processing of the image. As such it completely ignores 5177the current <a href="#filter">-filter</a> setting. </p> 5178 5179<p>The key feature of the <a href="#sample">-sample</a> is that no new colors 5180will be added to the resulting image, though some colors may disappear. </p> 5181 5182<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Offsets, if present in the geometry string, are 5183ignored, unlike <a href="#resize">-resize</a>. </p> 5184 5185 5186<div style="margin: auto;"> 5187 <h4><a id="sampling-factor"></a>-sampling-factor <em class="arg">horizontal-factor</em>x<em class="arg">vertical-factor</em></h4> 5188</div> 5189 5190<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>sampling factors used by JPEG or MPEG-2 encoder and YUV decoder/encoder.</td><td style='text-align:right;'></td></tr></table> 5191 5192<p>This option specifies the sampling factors to be used by the JPEG encoder for chroma downsampling. If this option is omitted, the JPEG library will use its own default values. When reading or writing the YUV format and when writing the M2V (MPEG-2) format, use <a href="#sampling-factor">-sampling-factor 2x1</a> or <a href="#sampling-factor">-sampling-factor 4:2:2</a> to specify the 4:2:2 downsampling method.</p> 5193 5194<div style="margin: auto;"> 5195 <h4><a id="scale"></a>-scale <em class="arg">geometry</em></h4> 5196</div> 5197 5198<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>minify/magnify the image using pixel block averaging and pixel replication, respectively.</td><td style='text-align:right;'></td></tr></table> 5199 5200<p>Change the image size simply by replacing pixels by averaging pixels 5201together when minifying, or replacing pixels when magnifing. </p> 5202 5203<p>The results are thus equivalent to using <a href="#resize">-resize</a> with 5204a <a href="#filter">-filter</a> setting of <kbd>box</kbd>. Though it is a lot 5205faster, as it avoids all the filter processing of the image. As such it 5206completely ignores the current <a href="#filter">-filter</a> setting. </p> 5207 5208<p>If when shrinking (minifying) images the original image is some integer 5209multiple of the new image size, the number of pixels avergaed together to 5210produce the new pixel color is the same across the whole image. This is 5211a special case known as 'binning' and is often used as a method of reducing 5212noise in image such as those generated by digital cameras, especially in low 5213light conditions. </p> 5214 5215 5216<div style="margin: auto;"> 5217 <h4><a id="scene"></a>-scene <em class="arg">value</em></h4> 5218</div> 5219 5220<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set scene number.</td><td style='text-align:right;'></td></tr></table> 5221 5222<p>This option sets the scene number of an image or the first image in an image sequence.</p> 5223 5224<div style="margin: auto;"> 5225 <h4><a id="screen"></a>-screen</h4> 5226</div> 5227 5228<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>specify the screen to capture.</td><td style='text-align:right;'></td></tr></table> 5229 5230<p>This option indicates that the GetImage request used to obtain the image should be done on the root window, rather than directly on the specified window. In this way, you can obtain pieces of other windows that overlap the specified window, and more importantly, you can capture menus or other popups that are independent windows but appear over the specified window.</p> 5231 5232<div style="margin: auto;"> 5233 <h4><a id="seed"></a>-seed</h4> 5234</div> 5235 5236<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>seed a new sequence of pseudo-random numbers</td><td style='text-align:right;'></td></tr></table> 5237 5238<div style="margin: auto;"> 5239 <h4><a id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4> 5240</div> 5241 5242<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>segment the colors of an image.</td><td style='text-align:right;'></td></tr></table> 5243 5244<p>Segment an image by analyzing the histograms of the color components and identifying units that are homogeneous with the fuzzy c-means technique. This is part of the ImageMagick color quantization routines. </p> 5245 5246<p>Specify <em class="arg">cluster threshold</em> as the number of pixels in each cluster that must exceed the cluster threshold to be considered valid. <em class="arg">Smoothing threshold</em> eliminates noise in the second derivative of the histogram. As the value is increased, you can expect a smoother second derivative. The default is 1.5.</p> 5247 5248<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report 5249of the color clusters is returned.</p> 5250 5251 5252<div style="margin: auto;"> 5253 <h4><a id="selective-blur"></a>-selective-blur <em class="arg">radius</em><br />-selective-blur <em class="arg">radius</em>x<em class="arg">sigma</em>{<em class="arg">+threshold</em>}</h4> 5254</div> 5255 5256<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Selectively blur pixels within a contrast threshold.</td><td style='text-align:right;'></td></tr></table> 5257 5258<p>Blurs those pixels that are less than or equal to the threshold in contrast. The threshold may be expressed as a fraction of <em class="QR">QuantumRange</em> or as a percentage.</p> 5259 5260<div style="margin: auto;"> 5261 <h4><a id="separate"></a>-separate</h4> 5262</div> 5263 5264<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>separate an image channel into a grayscale image. Specify the channel with <a href="#channel">-channel</a>.</td><td style='text-align:right;'></td></tr></table> 5265 5266<div style="margin: auto;"> 5267 <h4><a id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4> 5268</div> 5269 5270<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate a sepia-toned photo.</td><td style='text-align:right;'></td></tr></table> 5271 5272<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p> 5273 5274<p>This option applies a special effect to the image, similar to the effect achieved in a photo darkroom by sepia toning. Threshold ranges from 0 to <em class="QR">QuantumRange</em> and is a measure of the extent of the sepia toning. A threshold of 80% is a good starting point for a reasonable tone.</p> 5275 5276 5277 5278<div style="margin: auto;"> 5279 <h4><a id="set"></a>-set <em class="arg">key value</em></h4> 5280 <h4>+set <em class="arg">key</em></h4> 5281</div> 5282 5283<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>sets image attributes and properties for images in the current 5284image sequence.</td><td style='text-align:right;'></td></tr></table> 5285 5286<p>This will assign (or modify) specific settings attached to all the images 5287in the current image sequence. Using the <a href="#set">+set</a> form of the 5288option will either remove, or reset that setting to a default state, as 5289appropriate. </p> 5290 5291<p>For example, it will modify specific well known image meta-data 5292'attributes' such as those normally overridden by: the options <a 5293href="#delay" >-delay</a>, <a href="#dispose" >-dispose</a>, and <a 5294href="#page" >-page</a>, <a href="#colorspace" >-colorspace</a>; generally 5295assigned before the image is read in, by using a <em class="arg">key</em> of 5296the same name. </p> 5297 5298<p>If the given <em class="arg">key</em> does not match a specific known 5299'attribute ', such as shown above, the setting is stored as a a free form 5300'property' string. Such settings are listed in <a href="#verbose" 5301>-verbose</a> information ("<kbd>info:</kbd>" output format) as "Properties". 5302</p> 5303 5304<p>This includes string 'properties' that are set by and assigned to images 5305using the options <a href="#comment" >-comment</a>, <a href="#label" 5306>-label</a>, <a href="#caption" >-caption</a>. These options actually assign 5307a global 'artifact' which are automatically assigned (and any <a href="/www/escape.html" >Format Percent 5308Escapes</a> expanded) to images as they are read in. For example:</p> 5309 5310<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -set comment 'Rose is a rose is a rose is a rose' rose.png</span><span class='crtout'>identify -format %c rose.png</span><span class="crtprompt"> $magick> </span><span class='crtin'>Rose is a rose is a rose is a rose</span></p> 5311<p>The set value can also make use of <a href="/www/escape.html" >Format and Print Image 5312Properties</a> in the defined value. For example:</p> 5313 5314<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -set origsize '%wx%h' -resize 50% \</span><span class='crtout'> -format 'Old size = %[origsize] New size = %wx%h' info:</span><span class="crtprompt"> $magick> </span><span class='crtin'>Old size = 70x46 New size = 35x23</span></p> 5315<p>Other well known 'properties' that are availible include: 5316'<kbd>date:create</kbd>' and '<kbd>date:modify</kbd>' and 5317'<kbd>signature</kbd>'. </p> 5318 5319<p>The <a href="#repage">-repage</a> operator will also allow you to modify 5320the '<kbd>page</kbd>' attribute of an image for images already in memory (also 5321see <a href="#repage">-page</a>). However it is designed to provide a finer 5322control of the sub-parts of this 'attribute'. The <a href="#set">-set page</a> 5323option will only provide a direct, unmodified assignment of '<kbd>page</kbd>' 5324attribute. </p> 5325 5326<p>This option can also associate a colorspace or profile with your image. 5327For example,</p> 5328 5329<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.psd -set profile ISOcoated_v2_eci.icc image-icc.psd</span></p> 5330<p>Some 'properties' must be defined in a specific way to be used. For 5331example only 'properties' prefixed with "<kbd>filename:</kbd>" can be used to 5332modify the output filename of an image. For example</p> 5333 5334<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -set filename:mysize '%wx%h' 'rose_%[filename:mysize].png'</span></p> 5335<p>If the setting value is prefixed with "<kbd>option:</kbd>" the setting will 5336be saved as a global "Artifact" exactly as if it was set using the <a 5337href="#define" >-define</a> option. As such settings are global in scope, they 5338can be used to pass 'attributes' and 'properties' of one specific image, 5339in a way that allows you to use them in a completely different image, even if 5340the original image has long since been modified or destroyed. For example: </p> 5341 5342<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -set option:rosesize '%wx%h' -delete 0 \</span><span class='crtout'> label:'%[rosesize]' label_size_of_rose.gif</span></p> 5343<p>Note that <a href="/www/escape.html" >Format Percent Escapes</a> will only match 5344a 'artifact' if the given <em class="arg">key</em> does not match an existing 5345'attribute' or 'property'. </p> 5346 5347<p>You can set the attributes of the image registry by prefixing the value 5348with <kbd>registry:</kbd>.</p> 5349 5350<p>The <a href="#set">-set profile</a> option can also be used to inject 5351previously-formatted ancillary chunks into the output PNG file, using 5352the commandline option as shown below or by setting the profile via a 5353programming interface:</p> 5354 5355<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert in.png -set profile PNG-chunk-x:<filename> out.png</span></p> 5356<p>where <em>x</em> is a location flag and 5357<em class="arg">filename</em> is a file containing the chunk 5358name in the first 4 bytes, then a colon (":"), followed by the chunk data. 5359This encoder will compute the chunk length and CRC, so those must not 5360be included in the file.</p> 5361 5362<p>"x" can be "b" (before PLTE), "m" (middle, i.e., between PLTE and IDAT), 5363or "e" (end, i.e., after IDAT). If you want to write multiple chunks 5364of the same type, then add a short unique string after the "x" to prevent 5365subsequent profiles from overwriting the preceding ones, e.g.,</p> 5366 5367 5368<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert in.png -set profile PNG-chunk-b01:file01 / <br/> 5369 -profile PNG-chunk-b02:file02 out.png</span></p> 5370<p> </p> 5371 5372 5373<div style="margin: auto;"> 5374 <h4><a id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4> 5375</div> 5376 5377<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>shade the image using a distant light source.</td><td style='text-align:right;'></td></tr></table> 5378 5379<p>Specify <em class="arg">azimuth</em> and <em class="arg">elevation</em> as the position of the light source. Use <a href="#shade">+shade</a> to return the shading results as a grayscale image.</p> 5380 5381<div style="margin: auto;"> 5382 <h4><a id="shadow"></a>-shadow <em class="arg">percent-opacity</em>{x<em class="arg">sigma</em>}{<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em>{<em class="arg">%</em>}</h4> 5383</div> 5384 5385<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate an image shadow.</td><td style='text-align:right;'></td></tr></table> 5386 5387<div style="margin: auto;"> 5388 <h4><a 5389id="shared-memory"></a>-shared-memory</h4> 5390</div> 5391 5392<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>use shared memory.</td><td style='text-align:right;'></td></tr></table> 5393 5394<p>This option specifies whether the utility should attempt to use shared memory for pixmaps. ImageMagick must be compiled with shared memory support, and the display must support the <em class="arg">MIT-SHM</em> extension. Otherwise, this option is ignored. The default is <kbd>True</kbd>.</p> 5395 5396<div style="margin: auto;"> 5397 <h4><a id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4> 5398</div> 5399 5400<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>sharpen the image.</td><td style='text-align:right;'></td></tr></table> 5401 5402<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p> 5403 5404<div style="margin: auto;"> 5405 <h4><a id="shave"></a>-shave <em class="arg">geometry</em></h4> 5406</div> 5407 5408<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Shave pixels from the image edges.</td><td style='text-align:right;'></td></tr></table> 5409 5410<p>The <em class="arg">size</em> portion of the <em class="arg">geometry</em> argument specifies the width of the region to be removed from both sides of the image and the height of the regions to be removed from top and bottom. Offsets are ignored.</p> 5411 5412<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 5413 5414<div style="margin: auto;"> 5415 <h4><a id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4> 5416</div> 5417 5418<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Shear the image along the x-axis and/or y-axis.</td><td style='text-align:right;'></td></tr></table> 5419 5420<p>The shear angles may be positive, negative, or zero. When <em class="arg">Ydegrees</em> is omitted it defaults to 0. When both angles are given, the horizontal component of the shear is performed before the vertical component.</p> 5421 5422<p>Shearing slides one edge of an image along the x-axis or y-axis (i.e., horizontally or vertically, respectively),creating a parallelogram. The amount of each is controlled by the respective shear angle. For horizontal shears, <em class="arg">Xdegrees</em> is measured clockwise relative to "up" (the negative y-axis), sliding the top edge to the right when 0°<<em class="arg">Xdegrees</em><90° and to the left when 90°<<em class="arg">Xdegrees</em><180°. For vertical shears <em class="arg">Ydegrees</em> is measured clockwise relative to "right" (the positive x-axis), sliding the right edge down when 0°<<em class="arg">Ydegrees</em><90° and up when 90°<<em class="arg">Ydegrees</em><180°.</p> 5423 5424<p>Empty triangles left over from shearing the image are filled with the color defined by the <a href="#fill">-background</a> option. The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5425 5426<p>The horizontal shear is performed before the vertical part. This is important to note, since horizontal and vertical shears do not <em>commute</em>, i.e., the order matters in a sequence of shears. For example, the following two commands are not equivalent.</p> 5427 5428<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: -shear 20x0 -shear 0x60 logo-sheared.png</span><span class='crtout'></span><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: -shear 0x60 -shear 20x0 logo-sheared.png</span></p> 5429<p>The first of the two commands above is equivalent to the following, except for the amount of empty space created; the command that follows generates a smaller image, and so is a better choice in terms of time and space.</p> 5430 5431<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p> 5432<div style="margin: auto;"> 5433 <h4><a id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4> 5434</div> 5435 5436<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>increase the contrast without saturating highlights or shadows.</td><td style='text-align:right;'></td></tr></table> 5437 5438<p>Increase the contrast of the image using a sigmoidal transfer function without saturating highlights or shadows. <em class="arg">Contrast</em> indicates how much to increase the contrast (0 is none; 3 is typical; 20 is a lot); <em class="arg">mid-point</em> indicates where midtones fall in the resultant image (0 is white; 50% is middle-gray; 100% is black). By default the image contrast is increased, use <em class="arg">+sigmoidal-contrast</em> to decrease the contrast.</p> 5439 5440<div style="margin: auto;"> 5441 <h4><a id="silent"></a>-silent</h4> 5442</div> 5443 5444<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>operate silently.</td><td style='text-align:right;'></td></tr></table> 5445 5446<div style="margin: auto;"> 5447 <h4><a id="size"></a>-size <em class="arg">width</em>[x<em class="arg">height</em>][<em class="arg">+offset</em>]</h4> 5448</div> 5449 5450<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the width and height of the image.</td><td style='text-align:right;'></td></tr></table> 5451 5452<p>Use this option to specify the width and height of raw images whose dimensions are unknown such as <kbd>GRAY</kbd>, <kbd>RGB</kbd>, or <kbd>CMYK</kbd>. In addition to width and height, use <a href="#size">-size</a> with an offset to skip any header information in the image or tell the number of colors in a <kbd>MAP</kbd> image file, (e.g. -size 640x512+256).</p> 5453 5454<p>For Photo CD images, choose from these sizes:</p> 5455 5456<pre class="text"> 5457 192x128 5458 384x256 5459 768x512 5460 1536x1024 5461 3072x2048 5462</pre> 5463 5464<div style="margin: auto;"> 5465 <h4><a id="sketch"></a>-sketch <em class="arg">radius</em><br />-sketch <em class="arg">radius</em>x<em class="arg">sigma</em>+<em class="arg">angle</em></h4> 5466</div> 5467 5468<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>simulate a pencil sketch.</td><td style='text-align:right;'></td></tr></table> 5469 5470<p>Sketch with the given radius, standard deviation (sigma), and angle. The angle given is the angle toward which the image is sketched. That is the direction people would consider the object is coming from. </p> 5471 5472<div style="margin: auto;"> 5473 <h4><a id="smush"></a>-smush <em class="arg">offset</em></h4> 5474</div> 5475 5476<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>smush an image sequence together.</td><td style='text-align:right;'></td></tr></table> 5477 5478<div style="margin: auto;"> 5479 <h4><a id="snaps"></a>-snaps <em class="arg">value</em></h4> 5480</div> 5481 5482<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the number of screen snapshots.</td><td style='text-align:right;'>[<a href="/www/import.html">import</a>]</td></tr></table> 5483 5484<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p> 5485 5486<div style="margin: auto;"> 5487 <h4><a id="solarize"></a>-solarize <em class="arg">threshold</em></h4> 5488</div> 5489 5490<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>negate all pixels above the threshold level.</td><td style='text-align:right;'></td></tr></table> 5491 5492<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p> 5493 5494<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p> 5495 5496<div style="margin: auto;"> 5497 <h4><a id="sparse-color"></a>-sparse-color <em 5498 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4> 5499</div> 5500 5501<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'> color the given image using the specified points of color, and filling the other intervening colors using the given methods. </td><td style='text-align:right;'></td></tr></table> 5502 5503 5504<table class="doc"> 5505 <tbody> 5506 <tr valign="top"> 5507 <th align="left" style="width: 8%">Method</th> 5508 <th align="left">Description</th> 5509 </tr> 5510 5511 <tr valign="top"> 5512 <td valign="top">barycentric</td> 5513 <td valign="top">three point triangle of color given 3 points. 5514 Giving only 2 points will form a linear gradient between those points. 5515 The gradient generated extends beyond the triangle created by those 5516 3 points. </td> 5517 </tr> 5518 5519 <tr valign="top"> 5520 <td valign="top">bilinear</td> 5521 <td valign="top">Like barycentric but for 4 points. Less than 4 points 5522 fall back to barycentric. </td> 5523 </tr> 5524 <tr valign="top"> 5525 <td valign="top">voronoi</td> 5526 <td valign="top">Simply map each pixel to the to nearest color point 5527 given. The result are polygonal 'cells' of solid color. </td> 5528 </tr> 5529 5530 <tr valign="top"> 5531 <td valign="top">shepards</td> 5532 <td valign="top">Colors points biased on the ratio of inverse distance 5533 squared. Generating spots of color in a sea of the average of 5534 colors. </td> 5535 </tr> 5536 5537 <tr valign="top"> 5538 <td valign="top">inverse</td> 5539 <td valign="top">Colors points biased on the ratio of inverse distance. 5540 This generates sharper points of color rather than rounded spots of 5541 '<kbd>shepards</kbd>' Generating spots of color in a sea of the 5542 average of colors. </td> 5543 </tr> 5544 5545 </tbody> 5546</table> 5547 5548<p>The points are placed according to the images location on the virtual 5549canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a> 5550offset), and do not actually have to exist on the given image, but may be 5551some point beyond the edge of the image. All points are floating point values. 5552</p> 5553 5554<p>Only the color channels defined by the <a href="#channel" >-channel</a> are 5555modified, which means that by default matte/alpha transparency channel is not 5556effected. Typically transparency channel is turned off either before or after 5557the operation. </P> 5558 5559Of course if some color points are transparent to generate a transparent 5560gradient, then the image also requires transparency enabled to store the 5561values. </p> 5562 5563<p>All the above methods when given a single point of color will replace all 5564the colors in the image with the color given, regardless of the point. This is 5565logical, and provides an alternative technique to recolor a image to some 5566default value. </p> 5567 5568 5569<div style="margin: auto;"> 5570 <h4><a id="splice"></a>-splice <em class="arg">geometry</em></h4> 5571</div> 5572 5573<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Splice the current background color into the image.</td><td style='text-align:right;'></td></tr></table> 5574 5575<p>This will add rows and columns of the current <a 5576href="#background">-background</a> color into the given image according to the 5577given <a href="#gravity">-gravity</a> effectd geometry setting. >See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. Essentually <a href="#splice">-splice</a> will divide the 5578image into four quadrants, separating them by the inserted rows and columns. 5579</P> 5580 5581If a dimension of geometry is zero no rows or columns will be added for that 5582dimension. Similarly using a zero offset with the appropriate <a 5583href="#gravity">-gravity</a> setting will add rows and columns to the edges of 5584the image, padding the image only along that one edge. Edge padding is what <a 5585href="#splice">-splice</a> is most commonly used for. </p> 5586 5587<p>If the exact same <em class="arg">geometry</em> and <a 5588href="#gravity">-gravity</a> is later used with <a href="#chop">-chop</a> the 5589added added all splices removed. </p> 5590 5591<div style="margin: auto;"> 5592 <h4><a id="spread"></a>-spread <em class="arg">amount</em></h4> 5593</div> 5594 5595<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>displace image pixels by a random amount.</td><td style='text-align:right;'></td></tr></table> 5596 5597<p>The argument <em class="arg">amount</em> defines the size of the neighborhood around each pixel from which to choose a candidate pixel to swap.</p> 5598 5599<div style="margin: auto;"> 5600 <h4><a id="statistic"></a>-statistic <em class="arg">type</em> <em class="arg">geometry</em></h4> 5601</div> 5602 5603<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>replace each pixel with corresponding statistic from the neighborhood.</td><td style='text-align:right;'>[<a href="/www/convert.html">convert</a>, <a href="/www/mogrify.html">mogrify</a>]</td></tr></table> 5604 5605<p>Choose from these statistic types:</p> 5606<pre class="text"> 5607 Gradient maximum difference in area 5608 Maximum maximum value per channel in neighborhood 5609 Minimum minimum value per channel in neighborhood 5610 Mean average value per channel in neighborhood 5611 Median median value per channel in neighborhood 5612 Mode mode (most frequent) value per channel in neighborhood 5613 Nonpeak value just before or after the median value per channel in neighborhood 5614</pre> 5615 5616<div style="margin: auto;"> 5617 <h4><a id="stegano"></a>-stegano <em class="arg">offset</em></h4> 5618</div> 5619 5620<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>hide watermark within an image.</td><td style='text-align:right;'></td></tr></table> 5621 5622<p>Use an offset to start the image hiding some number of pixels from the beginning of the image. Note this offset and the image size. You will need this information to recover the steganographic image (e.g. display -size 320x256+35 stegano:image.png).</p> 5623 5624<div style="margin: auto;"> 5625 <h4><a id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4> 5626</div> 5627 5628<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>composite two images to create a stereo anaglyph.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 5629 5630<p>The left side of the stereo pair is saved as the red channel of the output image. The right side is saved as the green channel. Red-green stereo glasses are required to properly view the stereo image.</p> 5631 5632<div style="margin: auto;"> 5633 <h4><a id="storage-type"></a>-storage-type <em class="arg">type</em></h4> 5634</div> 5635 5636<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>pixel storage type. Here are the valid types:</td><td style='text-align:right;'></td></tr></table> 5637 5638<pre class="text"> 5639 char unsigned characters 5640 double doubles 5641 float floats 5642 integer integers 5643 long longs 5644 quantum pixels in the native depth of your ImageMagick distribution 5645 short unsigned shorts 5646</pre> 5647 5648<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels 5649values range from 0 to the maximum value the storage type can support.</p> 5650 5651<div style="margin: auto;"> 5652 <h4><a id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4> 5653</div> 5654 5655<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set a type of stretch style for fonts.</td><td style='text-align:right;'></td></tr></table> 5656 5657<p>This setting suggests a type of stretch that ImageMagick should try to apply to the currently selected font family. Select <em class="arg">fontStretch</em> from the following.</p> 5658 5659<pre class="text"> 5660 Any 5661 Condensed 5662 Expanded 5663 ExtraCondensed 5664 ExtraExpanded 5665 Normal 5666 SemiCondensed 5667 SemiExpanded 5668 UltraCondensed 5669 UltraExpanded 5670</pre> 5671 5672<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p> 5673 5674<p>For other settings that affect fonts, see the options <a href="#font">-font</a>, <a href="#family">-family</a>, <a href="#style">-style</a>, and <a href="#weight">-weight</a>. </p> 5675 5676<div style="margin: auto;"> 5677 <h4><a id="strip"></a>-strip</h4> 5678</div> 5679 5680<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>strip the image of any profiles or comments.</td><td style='text-align:right;'></td></tr></table> 5681 5682<div style="margin: auto;"> 5683 <h4><a id="stroke"></a>-stroke <em class="arg">color</em></h4> 5684</div> 5685 5686<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>color to use when stroking a graphic primitive.</td><td style='text-align:right;'></td></tr></table> 5687 5688<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5689 5690<p>See <a href="#draw">-draw</a> for further details.</p> 5691 5692<div style="margin: auto;"> 5693 <h4><a id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4> 5694</div> 5695 5696<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the stroke width.</td><td style='text-align:right;'></td></tr></table> 5697 5698<p>See <a href="#draw">-draw</a> for further details.</p> 5699 5700<div style="margin: auto;"> 5701 <h4><a id="style"></a>-style <em class="arg">fontStyle</em></h4> 5702</div> 5703 5704<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set a font style for text.</td><td style='text-align:right;'></td></tr></table> 5705 5706<p>This setting suggests a font style that ImageMagick should try to apply to 5707the currently selected font family. Select <em class="arg">fontStyle</em> from 5708the following.</p> 5709 5710<pre class="text"> 5711 Any 5712 Italic 5713 Normal 5714 Oblique 5715</pre> 5716 5717<p>For other settings that affect fonts, see the options <a href="#font">-font</a>, <a href="#family">-family</a>, <a href="#stretch">-stretch</a>, and <a href="#weight">-weight</a>. </p> 5718 5719<div style="margin: auto;"> 5720 <h4><a id="subimage-search"></a>-subimage-search</h4> 5721</div> 5722 5723<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>search for subimage.</td><td style='text-align:right;'>[<a href="/www/compare.html">compare</a>]</td></tr></table> 5724 5725<p>This option is required to have compare search for the best match location 5726of a small image within a larger image. This search will produce two images 5727(or two frames). The first is the "difference" image and the second will 5728be the "match score" image.</p> 5729 5730<p>The "match-score" image is smaller containing a pixel for ever possible 5731position of the top-left corner of the given sub-image. that is its size will 5732be the size of the larger_image - sub_image + 1. The brightest location in 5733this image is the location s the locate on the best match that is also 5734reported. Note that this may or may nor be a perfect match, and the actual 5735brightness will reflect this. Other bright 'peaks' can be used to locate other 5736possible matching loctions. </p> 5737 5738<p>Note that the search will try to compare teh sub-image at every possible 5739location in the larger image, as such it can be very slow. The smaller the 5740sub-image the faster this search is. </p> 5741 5742 5743<div style="margin: auto;"> 5744 <h4><a id="swap"></a>-swap <em class="arg">index,index</em></h4> 5745</div> 5746 5747<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Swap the positions of two images in the image sequence.</td><td style='text-align:right;'></td></tr></table> 5748 5749<p>For example, <a href="#swap">-swap 0,2</a> swaps the first and the third 5750images in the current image sequence. Use <a href="#swap">+swap</a> to switch 5751the last two images in the sequence.</p> 5752 5753<div style="margin: auto;"> 5754 <h4><a id="swirl"></a>-swirl <em class="arg">degrees</em></h4> 5755</div> 5756 5757<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>swirl image pixels about the center.</td><td style='text-align:right;'></td></tr></table> 5758 5759<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p> 5760 5761<div style="margin: auto;"> 5762 <h4><a id="synchronize"></a>-synchronize</h4> 5763</div> 5764 5765<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>synchronize image to storage device.</td><td style='text-align:right;'></td></tr></table> 5766 5767<div style="margin: auto;"> 5768 <h4><a id="taint"></a>-taint</h4> 5769</div> 5770 5771<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mark the image as modified.</td><td style='text-align:right;'></td></tr></table> 5772 5773<div style="margin: auto;"> 5774 <h4><a id="text-font"></a>-text-font <em class="arg">name</em></h4> 5775</div> 5776 5777<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>font for writing fixed-width text.</td><td style='text-align:right;'></td></tr></table> 5778 5779<p>Specifies the name of the preferred font to use in fixed (typewriter style) formatted text. The default is 14 point <em class="arg">Courier</em>.</p> 5780 5781<p>You can tag a font to specify whether it is a PostScript, TrueType, or OPTION1 font. For example, <kbd>Courier.ttf</kbd> is a TrueType font and <kbd>x:fixed</kbd> is OPTION1.</p> 5782 5783<div style="margin: auto;"> 5784 <h4><a id="texture"></a>-texture <em class="arg">filename</em></h4> 5785</div> 5786 5787<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>name of texture to tile onto the image background.</td><td style='text-align:right;'></td></tr></table> 5788 5789<div style="margin: auto;"> 5790 <h4><a id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 5791</div> 5792 5793<!-- {<em class="arg">green,blue,opacity</em>} 5794<p>If the green or blue value is omitted, these channels use the same value as the first one provided. If all three color values are the same, the result is a bi-level image. If the opacity threshold is omitted, OpaqueOpacity is used and any partially transparent pixel becomes fully transparent.</p> 5795--> 5796 5797<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Apply simultaneous black/white threshold to the image.</td><td style='text-align:right;'></td></tr></table> 5798 5799<p>Any pixel values (more specifically, those channels set using <a href="/www/command-line-options.html#channel">‑channel</a>) that exceed the specified threshold are reassigned the maximum channel value, while all other values are assigned the minimum.</p> 5800 5801<p> The threshold value can be given as a percentage or as an absolute integer value corresponding to the desired channel value. When given as an integer, the minimum attainable value is 0 (corresponding to black when all channels are affected), but the maximum value (corresponding to white) is that of the <kbd>quantum depth</kbd> of the particular build of ImageMagick, and is therefore dependent on the installation. For that reason, a reasonable recommendation for most applications is to specify the threshold values as a percentage. 5802</p> 5803 5804<p> The following would force pixels with red values above 50% to have 100% red values, while those at or below 50% red would be set to 0 in the red channel. The green, blue, and alpha channels (if present) would be unchanged. </p> 5805 5806<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p> 5807<p>As (possibly) impractical but instructive examples, the following would generate an all-black and an all-white image with the same dimensions as the input image.</p> 5808 5809 5810<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert in.png -threshold 100% black.png</span><span class='crtout'></span><span class="crtprompt"> $magick> </span><span class='crtin'>convert in.png -threshold -1 white.png</span></p> 5811<p>Note that the values of the transparency channel is treated as 'matte' 5812values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 5813 5814<p> See also <a href="/www/command-line-options.html#black-threshold">‑black‑threshold</a> and <a href="/www/command-line-options.html#white-threshold">‑white‑threshold</a>. 5815</p> 5816 5817<div style="margin: auto;"> 5818 <h4><a id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4> 5819</div> 5820 5821<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Create a thumbnail of the image.</td><td style='text-align:right;'></td></tr></table> 5822 5823<p>This is similar to <a href="#resize">-resize</a>, except it is optimized for speed and any image profile, other than a color profile, is removed to reduce the thumbnail size. To strip the color profiles as well, add <a href="#strip">-strip</a> just before of after this option.</p> 5824 5825<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 5826 5827<div style="margin: auto;"> 5828 <h4><a id="tile"></a>-tile <em class="arg">filename</em></h4> 5829</div> 5830 5831<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the tile image used for filling a subsequent graphic primitive.</td><td style='text-align:right;'></td></tr></table> 5832 5833<div style="margin: auto;"> 5834 <h4>-tile <em class="arg">geometry</em></h4> 5835</div> 5836 5837<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify the layout of images .</td><td style='text-align:right;'>[<a href="/www/montage.html">montage</a>]</td></tr></table> 5838 5839<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument.</p> 5840 5841<div style="margin: auto;"> 5842 <h4>-tile</h4> 5843</div> 5844 5845<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specifies that a subsequent composite operation is repeated across and down image.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 5846 5847<div style="margin: auto;"> 5848 <h4><a id="tile-offset"></a>-tile-offset {<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em></h4> 5849</div> 5850 5851<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify the offset for tile images, relative to the background image it is tiled on.</td><td style='text-align:right;'></td></tr></table> 5852 5853<p>This should be set before the tiling image is set by <a href="#tile" >-tile</a> or <a href="#texture" >-texture</a>, or directly applied for creating a tiled canvas using <kbd>TILE:</kbd> or <kbd>PATTERN:</kbd> input formats. </p> 5854 5855<p>Internally ImageMagick does a <a href="#roll" >-roll</a> of the tile image by the arguments given when the tile image is set. </p> 5856 5857<div style="margin: auto;"> 5858 <h4><a id="tint"></a>-tint <em class="arg">value</em></h4> 5859</div> 5860 5861<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Tint the image with the fill color.</td><td style='text-align:right;'></td></tr></table> 5862 5863<p>Tint the image with the fill color.</p> 5864 5865<p>Specify the amount of tinting as a percentage. Pure colors like black, white red, yellow, will not be affected by -tint. Only mid-range colors such as the various shades of grey.</p> 5866 5867<div style="margin: auto;"> 5868 <h4><a id="title"></a>-title <em class="arg">string</em></h4> 5869</div> 5870 5871<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Assign a title to displayed image.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>, <a href="/www/display.html">display</a>, <a href="/www/montage.html">montage</a>]</td></tr></table> 5872 5873<p>Use this option to assign a specific title to the image. This assigned to the image window and is typically displayed in the window title bar. Optionally you can include the image filename, type, width, height, Exif data, or other image attribute by embedding special format characters described under the <a href="#format">-format</a> option.</p> 5874 5875<p>For example,</p> 5876 5877<p class="crtsnip"> 5878 -title "%m:%f %wx%h" 5879</p> 5880 5881<p>produces an image title of <kbd>MIFF:bird.miff 512x480</kbd> for an image titled <kbd>bird.miff</kbd> and whose width is 512 and height is 480.</p> 5882 5883 5884<div style="margin: auto;"> 5885 <h4><a id="transform"></a>-transform</h4> 5886</div> 5887 5888<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>transform the image.</td><td style='text-align:right;'></td></tr></table> 5889 5890<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p> 5891 5892<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -affine 2,2,-2,2,0,0 -transform bird.ppm bird.jpg</span></p> 5893 5894<p>This operator has been now been superseded by the <a 5895href="#distort">-distort</a> '<kbd>AffineProjection</kbd>' method. </p> 5896 5897 5898<div style="margin: auto;"> 5899 <h4><a id="transparent"></a>-transparent <em class="arg">color</em></h4> 5900</div> 5901 5902<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Make this color transparent within the image.</td><td style='text-align:right;'></td></tr></table> 5903 5904<p>The <em class="arg">color</em> argument is defined using the format 5905described under the <a href="#fill">-fill</a> option. The <a href="#fuzz" 5906>-fuzz</a> setting can be used to match and replace colors similar to the one 5907given. </p> 5908 5909<p>Use <a href="#transparent" >+transparent</a> to invert the pixels matched. 5910that is make all non-matching colors transparent. </p> 5911 5912<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a 5913href="#transparent" >-transparent</a> but replaces the matching color with the 5914current <a href="#fill">-fill</a> color setting, rather than transparent. 5915However the <a href="#transparent" >-transparent</a> operator also ensures 5916that the image has an alpha channel enabled, as per "<kbd><a href="#alpha" 5917>-alpha</a> set</kbd>", and does not require you to modify the <a 5918href="#channel">-channel</a> to enable alpha channel handling. </p> 5919 5920<p>Note that this does not define the color as being the 'transparency color' 5921used for color-mapped image formats, such as GIF. For that use <a 5922href="#transparent-color" >-transparent-color</a> </p> 5923 5924 5925<div style="margin: auto;"> 5926 <h4><a id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4> 5927</div> 5928 5929<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the transparent color.</td><td style='text-align:right;'></td></tr></table> 5930 5931<p>Sometimes this is used for saving to image formats such as 5932GIF and PNG8 which uses this color to represent boolean transparency. This 5933does not make a color transparent, it only defines what color the transparent 5934color is in the color palette of the saved image. Use <a 5935href="#transparent">-transparent</a> to make an opaque color transparent.</p> 5936 5937<p>This option allows you to have both an opaque visible color, as well as a 5938transparent color of the same color value without conflict. That is, you can 5939use the same color for both the transparent and opaque color areas within an 5940image. This, in turn, frees to you to select a transparent color that is 5941appropriate when an image is displayed by an application that does not handle a 5942transparent color index, while allowing ImageMagick to correctly handle images of this 5943type. </p> 5944 5945<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p> 5946 5947<div style="margin: auto;"> 5948 <h4><a id="transpose"></a>-transpose</h4> 5949</div> 5950 5951<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mirror the image along the top-left to bottom-right diagonal.</td><td style='text-align:right;'></td></tr></table> 5952 5953<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>. 5954</p> 5955 5956<div style="margin: auto;"> 5957 <h4><a id="transverse"></a>-transverse</h4> 5958</div> 5959 5960<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mirror the image along the images bottom-left top-right diagonal. Equivalent to the operations <kbd>-flop -rotate 90</kbd>.</td><td style='text-align:right;'></td></tr></table> 5961 5962 5963<div style="margin: auto;"> 5964 <h4><a id="treedepth"></a>-treedepth <em class="arg">value</em></h4> 5965</div> 5966 5967<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>tree depth for the color reduction algorithm.</td><td style='text-align:right;'></td></tr></table> 5968 5969<p>Normally, this integer value is zero or one. A value of zero or one causes the use of an optimal tree depth for the color reduction algorithm.</p> 5970 5971<p>An optimal depth generally allows the best representation of the source image with the fastest computational speed and the least amount of memory. However, the default depth is inappropriate for some images. To assure the best representation, try values between 2 and 8 for this parameter. Refer to the <a href="/www/quantize.html">color reduction algorithm</a> for more details.</p> 5972 5973<p>The <a href="#colors">-colors</a> or <a href="#monochrome">-monochrome</a> option, or writing to an image format which requires color reduction, is required for this option to take effect.</p> 5974 5975<div style="margin: auto;"> 5976 <h4><a id="trim"></a>-trim</h4> 5977</div> 5978 5979<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>trim an image.</td><td style='text-align:right;'></td></tr></table> 5980 5981<p>This option removes any edges that are exactly the same color as the corner pixels. Use <a href="#fuzz">-fuzz</a> to make <a href="#trim">-trim</a> remove edges that are nearly the same color as the corner pixels.</p> 5982 5983<p>The page or virtual canvas information of the image is preserved allowing 5984you to extract the result of the <a href="#trim">-trim</a> operation from the 5985image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page 5986information if it is unwanted.</p> 5987 5988<p>If the trimmed image 'disappears' an warning is produced, and a special 5989single pixel transparent 'missed' image is returned, in the same way as when a 5990<a href="#crop">-crop</a> operation 'misses' the image proper. </p> 5991 5992 5993<div style="margin: auto;"> 5994 <h4><a id="type"></a>-type <em class="arg">type</em></h4> 5995</div> 5996 5997<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the image type.</td><td style='text-align:right;'></td></tr></table> 5998 <p>Choose from: <kbd>Bilevel</kbd>, <kbd>Grayscale</kbd>, <kbd>GrayscaleMatte</kbd>, <kbd>Palette</kbd>, <kbd>PaletteMatte</kbd>, <kbd>TrueColor</kbd>, <kbd>TrueColorMatte</kbd>, <kbd>ColorSeparation</kbd>, or <kbd>ColorSeparationMatte</kbd>.</p> 5999 6000<p>Normally, when a format supports different subformats such as grayscale and truecolor, the encoder will try to choose an efficient subformat. The <a href="#type">-type</a> option can be used to overrride this behavior. For example, to prevent a JPEG from being written in grayscale format even though only gray pixels are present, use.</p> 6001 6002<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p> 6003<p>Similarly, use <a href="#type">-type TrueColorMatte</a> to force the encoder to write an alpha channel even though the image is opaque, if the output format supports transparency.</p> 6004 6005<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p> 6006 6007<div style="margin: auto;"> 6008 <h4><a id="undercolor"></a>-undercolor <em class="arg">color</em></h4> 6009</div> 6010 6011<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the color of the annotation bounding box.</td><td style='text-align:right;'></td></tr></table> 6012 6013<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 6014 6015<p>See <a href="#draw">-draw</a> for further details.</p> 6016 6017 6018<div style="margin: auto;"> 6019 <h4><a id="update"></a>-update <em class="arg">seconds</em></h4> 6020</div> 6021 6022<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>detect when image file is modified and redisplay.</td><td style='text-align:right;'></td></tr></table> 6023 6024<p>Suppose that while you are displaying an image the file that is currently displayed is over-written. <kbd>display</kbd> will automagically detect that the input file has been changed and update the displayed image accordingly.</p> 6025 6026 6027<div style="margin: auto;"> 6028 <h4><a id="unique-colors"></a>-unique-colors</h4> 6029</div> 6030 6031<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>discard all but one of any pixel color.</td><td style='text-align:right;'></td></tr></table> 6032 6033 6034<div style="margin: auto;"> 6035 <h4><a id="units"></a>-units <em class="arg">type</em></h4> 6036</div> 6037 6038<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the units of image resolution.</td><td style='text-align:right;'></td></tr></table> 6039 6040<p>Choose from: <kbd>Undefined</kbd>, <kbd>PixelsPerInch</kbd>, or <kbd>PixelsPerCentimeter</kbd>. This option is normally used in conjunction with the <a href="#density">-density</a> option.</p> 6041 6042 6043<div style="margin: auto;"> 6044 <h4><a id="unsharp"></a>-unsharp <em class="arg">radius</em><br />-unsharp <em class="arg">radius</em>x<em class="arg">sigma</em>{<em class="arg">+amount</em>}{<em class="arg">+threshold</em>}</h4> 6045</div> 6046 6047<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>sharpen the image with an unsharp mask operator.</td><td style='text-align:right;'></td></tr></table> 6048 6049<p>The <a href="#unsharp">-unsharp</a> option sharpens an image. The image is convolved with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, radius should be larger than sigma. Use a radius of 0 to have the method select a suitable radius.</p> 6050 6051<p>The parameters are:</p> 6052 6053<pre class="text"> 6054 radius The radius of the Gaussian, in pixels, not counting the center 6055 pixel (default 0). 6056 sigma The standard deviation of the Gaussian, in pixels (default 1.0). 6057 amount The fraction of the difference between the original and the blur 6058 image that is added back into the original (default 1.0). 6059 threshold The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the 6060 difference amount (default 0.05). 6061</pre> 6062 6063 6064<div style="margin: auto;"> 6065 <h4><a id="verbose"></a>-verbose</h4> 6066</div> 6067 6068<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>print detailed information about the image when this option precedes the <a href="#identify">-identify</a> option or <kbd>info:</kbd>.</td><td style='text-align:right;'></td></tr></table> 6069 6070 6071<div style="margin: auto;"> 6072 <h4><a id="version"></a>-version</h4> 6073</div> 6074 6075<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>print ImageMagick version string and exit.</td><td style='text-align:right;'></td></tr></table> 6076 6077 6078<div style="margin: auto;"> 6079 <h4><a id="view"></a>-view <em class="arg">string</em></h4> 6080</div> 6081 6082<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>FlashPix viewing parameters.</td><td style='text-align:right;'></td></tr></table> 6083 6084 6085<div style="margin: auto;"> 6086 <h4><a id="vignette"></a>-vignette <em class="arg">radius</em>{x<em class="arg">sigma</em>}{<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em>{<em class="arg">%</em>}</h4> 6087</div> 6088 6089<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>soften the edges of the image in vignette style.</td><td style='text-align:right;'></td></tr></table> 6090 6091 6092<div style="margin: auto;"> 6093 <h4><a id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4> 6094</div> 6095 6096<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify contents of <em>virtual pixels</em>.</td><td style='text-align:right;'></td></tr></table> 6097 6098<p>This option defines what color source should be used if and when a color 6099lookup completely 'misses' the source image. The color(s) that appear to 6100surround the source image. Generally this color is derived from the source 6101image, but could also be set to a specify background color. </p> 6102 6103<p>Choose from these methods:</p> 6104 6105<pre class="text"> 6106 background the area surrounding the image is the background color 6107 black the area surrounding the image is black 6108 checker-tile alternate squares with image and background color 6109 dither non-random 32x32 dithered pattern 6110 edge extend the edge pixel toward infinity 6111 gray the area surrounding the image is gray 6112 horizontal-tile horizontally tile the image, background color above/below 6113 horizontal-tile-edge horizontally tile the image and replicate the side edge pixels 6114 mirror mirror tile the image 6115 random choose a random pixel from the image 6116 tile tile the image (default) 6117 transparent the area surrounding the image is transparent blackness 6118 vertical-tile vertically tile the image, sides are background color 6119 vertical-tile-edge vertically tile the image and replicate the side edge pixels 6120 white the area surrounding the image is white 6121</pre> 6122 6123<p>The default value is "edge".</p> 6124 6125<p>This most important for distortion operators such as <a href="#distort" 6126>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>. 6127However it also effects operations that may access pixels just outside the 6128image proper, such as <a href="#convolve">-convolve</a>, <a 6129href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p> 6130 6131<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p> 6132 6133 6134<div style="margin: auto;"> 6135 <h4><a id="visual"></a>-visual <em class="arg">type</em></h4> 6136</div> 6137 6138<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Animate images using this X visual type.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>, <a href="/www/display.html">display</a>]</td></tr></table> 6139 6140<p>Choose from these visual classes:</p> 6141 6142<pre class="text"> 6143 StaticGray 6144 GrayScale 6145 StaticColor 6146 PseudoColor 6147 TrueColor 6148 DirectColor 6149 default 6150 visual id 6151</pre> 6152 6153<p>The X server must support the visual you choose, otherwise an error occurs. If a visual is not specified, the visual class that can display the most simultaneous colors on the default screen is chosen.</p> 6154 6155 6156<div style="margin: auto;"> 6157 <h4><a id="watermark"></a>-watermark <em 6158 class="arg">brightness</em>x<em class="arg">saturation</em></h4> 6159</div> 6160 6161<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Watermark an image using the given percentages of brightness and 6162saturation.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 6163 6164<p>Take a grayscale image (with alpha mask) and modify the destination image's 6165brightness according to watermark image's grayscale value and the <em 6166class="arg">brightness</em> percentage. The destinations color saturation 6167attribute is just direct modified by the <em class="arg">saturation</em> 6168percentage, which defaults to 100 percent (no color change). </p> 6169 6170 6171<div style="margin: auto;"> 6172 <h4><a id="wave"></a>-wave <em class="arg">amplitude</em><br />-wave <em class="arg">amplitude</em>x<em class="arg">wavelength</em></h4> 6173</div> 6174 6175<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Shear the columns of an image into a sine wave.</td><td style='text-align:right;'></td></tr></table> 6176 6177<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p> 6178 6179<div style="margin: auto;"> 6180 <h4><a id="weight"></a>-weight <em class="arg">fontWeight</em></h4> 6181</div> 6182 6183<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set a font weight for text.</td><td style='text-align:right;'></td></tr></table> 6184 6185<p>This setting suggests a font weight that ImageMagick should try to apply to the currently selected font family. Use a positive integer for <em class="arg">fontWeight</em> or select from the following.</p> 6186 6187<table class="doc"> 6188 <col width="25%" /> 6189 <col width="75%" /> 6190 <thead> 6191 <tr> 6192 <th><em class="arg">fontWeight</em></th> 6193 <th>Description</th> 6194 </tr> 6195 </thead> 6196 <tbody> 6197 <tr><td>All </td> <td>No effect. </td></tr> 6198 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr> 6199 <tr><td>Bolder </td> <td>Add 100 to font weight if currently ≤ 800.</td></tr> 6200 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently ≤ 100.</td></tr> 6201 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr> 6202 </tbody> 6203 </table> 6204 6205<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p> 6206 6207<p>For other settings that affect fonts, see the options <a href="#font">-font</a>, <a href="#family">-family</a>, <a href="#stretch">-stretch</a>, and <a href="#style">-style</a>. </p> 6208 6209<div style="margin: auto;"> 6210 <h4><a id="white-point"></a>-white-point <em class="arg">x,y</em></h4> 6211</div> 6212 6213<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>chromaticity white point.</td><td style='text-align:right;'></td></tr></table> 6214 6215<div style="margin: auto;"> 6216 <h4><a id="white-threshold"></a>-white-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 6217</div> 6218 6219<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Force to white all pixels above the threshold while leaving all pixels at or below the threshold unchanged.</td><td style='text-align:right;'></td></tr></table> 6220 6221<p> The threshold value can be given as a percentage or as an absolute integer value within [0, <em class="QR">QuantumRange</em>] corresponding to the desired <a href="/www/command-line-options.html#channel">‑channel</a> value. See <a href="/www/command-line-options.html#threshold">‑threshold</a> for more details on thresholds and resulting values. 6222</p> 6223 6224<div style="margin: auto;"> 6225 <h4><a id="window"></a>-window <em class="arg">id</em></h4> 6226</div> 6227 6228<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Make the image the background of a window.</td><td style='text-align:right;'>[<a href="/www/animate.html">animate</a>, <a href="/www/display.html">display</a>]</td></tr></table> 6229 6230<p><em class="arg">id</em> can be a window id or name. Specify <kbd>root</kbd> to select X's root window as the target window.</p> 6231 6232<p>By default the image is tiled onto the background of the target window. If <kbd>backdrop</kbd> or <a href="#geometry">-resize</a> are specified, the image is surrounded by the background color. Refer to <kbd>X RESOURCES</kbd> for details.</p> 6233 6234<p>The image will not display on the root window if the image has more unique colors than the target window colormap allows. Use <a href="#colors">-colors</a> to reduce the number of colors.</p> 6235 6236<div style="margin: auto;"> 6237 <h4><a id="window-group"></a>-window-group</h4> 6238</div> 6239 6240<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>specify the window group.</td><td style='text-align:right;'></td></tr></table> 6241 6242<div style="margin: auto;"> 6243 <h4><a id="write"></a>-write <em class="arg">filename</em></h4> 6244</div> 6245 6246<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>write an image sequence.</td><td style='text-align:right;'></td></tr></table> 6247 <p>The image sequence preceding the <a href="#write">-write</a> <em class="arg">filename</em> option is written out, and processing continues with the same image in its current state if there are additional options. To restore the image to its original state after writing it, use the <a href="#write">+write</a> <em class="arg">filename</em> option.</p> 6248 6249<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p> 6250</div> 6251</div> 6252 6253</div> 6254 6255<div id="linkbar"> 6256 <span id="linkbar-west"> </span> 6257 <span id="linkbar-center"> 6258 <a href="http://www.imagemagick.org/discourse-server/">Discourse Server</a> • 6259 <a href="http://www.imagemagick.org/MagickStudio/scripts/MagickStudio.cgi">Studio</a> 6260 </span> 6261 <span id="linkbar-east"> </span> 6262 </div> 6263 <div class="footer"> 6264 <span id="footer-west">© 1999-2011 ImageMagick Studio LLC</span> 6265 <span id="footer-east"> <a href="http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span> 6266 </div> 6267 <div style="clear: both; margin: 0; width: 100%; "></div> 6268 <script type="text/javascript"> 6269 var _gaq = _gaq || []; 6270 _gaq.push(['_setAccount', 'UA-17690367-1']); 6271 _gaq.push(['_trackPageview']); 6272 6273 (function() { 6274 var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; 6275 ga.src = ('https:' == document.location.protocol ? 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