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href="/www/command-line-options.html#limit">‑limit</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#linear-stretch">‑linear‑stretch</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#linewidth">‑linewidth</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#liquid-rescale">‑liquid‑rescale</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#list">‑list</a> <span 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> 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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#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> 200 201<div class="doc-section"> 202 203<p>Below is list of command-line options recognized by the ImageMagick <a 204href="/www/command-line-tools.html">command-line 205tools</a>. If you want a description of a particular option, click on the 206option name in the navigation bar above and you will go right to it. Unless 207otherwise noted, each option is recognized by the commands <a href="/www/convert.html">convert</a>, <a href="/www/mogrify.html">mogrify</a>.</p> 208 209<div style="margin: auto;"> 210 <h4><a id="adaptive-blur"></a>-adaptive-blur <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4> 211</div> 212 213<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> 214<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> 215 216<div style="margin: auto;"> 217 <h4><a id="adaptive-resize"></a>-adaptive-resize <em class="arg">geometry</em></h4> 218</div> 219 220<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> 221 222<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> 223 224<div style="margin: auto;"> 225 <h4><a id="adaptive-sharpen"></a>-adaptive-sharpen <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4> 226</div> 227 228<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> 229 230<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> 231 232<div style="margin: auto;"> 233 <h4><a id="adjoin"></a>-adjoin</h4> 234</div> 235 236<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> 237 238<p>This option is enabled by default. An attempt is made to save all 239images of an image sequence into the given output file. 240However, some formats, such as JPEG and PNG, do not support more than one 241image per file, and in that case ImageMagick is forced to write each image as a separate file. As 242such, if more than one image needs to be written, the filename given is 243modified by adding a <a href="#scene">-scene</a> number before the 244suffix, in order to make distinct names for each image. </p> 245 246<p>Use <a href="#adjoin">+adjoin</a> to force each image to be written 247to separate files, whether or not the file format allows multiple images 248per file (for example, GIF, MIFF, and TIFF). </p> 249 250<p>Including a C-style integer format string in the output filename will automagically enable <a href="#adjoin">+adjoin</a> and are used to specify where the <a href="#scene">-scene</a> number is placed in the filenames. These strings, such as '<kbd>%d</kbd>' or '<kbd>%03d</kbd>', are familiar to those who have used the standard <kbd>printf()</kbd>' C-library function. As an example, the command</p> 251 252<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: rose: -morph 15 my%02dmorph.jpg</span></p> 253<p>will create a sequence of 17 images named my00morph.jpg, my01morph.jpg, my02morph.jpg, ..., my16morph.jpg. 254</p> 255 256<p>In summary, ImageMagick tries to write all images to one file, but will use 257multiple files if either<br /> 258 (1) the output image's file format does not allow multi-image files,<br /> 259 (2) the <a href="#adjoin">+adjoin</a> option is given, or<br /> 260 (3) a printf() integer format string (eg: "%d") is present in the output filename. </p> 261 262 263<div style="margin: auto;"> 264 <h4><a id="affine"></a>-affine <em class="arg">s<sub>x</sub></em>,<em class="arg">r<sub>x</sub></em>,<em class="arg">r<sub>y</sub></em>,<em class="arg">s<sub>y</sub></em>,<em class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em><br/> 265 -affine <em class="arg">s<sub>x</sub></em>,<em class="arg">r<sub>x</sub></em>,<em class="arg">r<sub>y</sub></em>,<em class="arg">s<sub>y</sub></em></h4> 266</div> 267 268<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> 269 270<p>This option sets a transformation matrix, encoded as (<em class="arg">s<sub>x</sub></em>, <em class="arg">r<sub>x</sub></em>, <em class="arg">r<sub>y</sub></em>, <em class="arg">s<sub>y</sub></em>, <em class="arg">t<sub>x</sub></em>, <em class="arg">t<sub>y</sub></em>), for use by subsequent <a href="#draw">-draw</a> or <a href="#transform">-transform</a> options.</p> 271 272<p>The matrix entries are entered as comma-separated numeric values <i>with no spaces</i>. </p> 273 274<p>Internally, the transformation matrix has 3x3 elements, but three of them are omitted from the input because they are constant. 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 original image are calculated using the following matrix equation.</p> 275 276<div class="eqn"> 277<img alt="affine transformation" src="/images/affine.png"/> 278</div> 279 280<p> 281The size of the resulting image is that of the smallest rectangle that contains the transformed source image. The parameters <em class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em> subsequently shift the image pixels so that those that are moved out of the image area are cut off.</p> 282 283<p>The transformation matrix complies with the left-handed pixel coordinate system: positive <em class="arg">x</em> and <em class="arg">y</em> directions are rightward and downward, resp.; positive rotation is clockwise.</p> 284 285<p> If the translation coefficients <em class="arg">t<sub>x</sub></em> and <em class="arg">t<sub>y</sub></em> are omotted they default to 0,0. Therefore, four parameters suffice for rotation and scaling without translation.</p> 286 287<p>Scaling by the factors <em class="arg">s<sub>x</sub></em> and <em class="arg">s<sub>y</sub></em> in the <em>x</em> and <em>y</em> directions, respectively, is accomplished with the following.</p> 288 289<p class="crtsnip"> 290 -affine <em class="arg">s<sub>x</sub></em>,0,0,<em class="arg">s<sub>y</sub></em> 291</p> 292 293<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> 294 295<p class="crtsnip"> 296 -affine 1,0,0,1,<em class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em> 297</p> 298 299<p>Rotate clockwise about the origin (the upper left-hand corner) by an angle <em>a</em> by letting 300<em>c</em> = cos(<em>a</em>), <em>s</em> = sin(<em>a</em>), and using the following.</p> 301 302<p class="crtsnip"> 303 -affine <em>c</em>,<em>s</em>,-<em>s</em>,<em>c</em> 304</p> 305 306<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> 307 308<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> 309 310<div style="margin: auto;"> 311 <h4><a id="alpha"></a>-alpha <em class="arg">type</em></h4> 312</div> 313 314<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> 315 316<p>Used to set a flag on an image indicating whether or not to use existing alpha 317channel 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> 318 319 320<table class="doc"> 321 <tbody> 322 <tr valign="top"> 323 <th align="left" style="width: 8%">type</th> 324 <th align="left">Description</th> 325 </tr> 326 327 <tr valign="top"> 328 <td valign="top"><kbd>Activate</kbd> or <kbd>On</kbd></td> 329 <td valign="top"> 330 Enable the image's transparency channel. Note normally <kbd>Set</kbd> 331 should be used instead of this, unless you specifically need to 332 preserve existing (but specifically turned <kbd>Off</kbd>) transparency 333 channel. </td></tr> 334 335 <tr valign="top"> 336 <td valign="top"><kbd>Deactivate</kbd> or <kbd>Off</kbd></td> 337 <td valign="top"> 338 Disables the image's transparency channel. Does not delete or change the 339 existing data, just turns off the use of that data.</td></tr> 340 341 <tr valign="top"> 342 <td valign="top"><kbd>Set</kbd></td> 343 <td valign="top"> 344 Activates the alpha/matte channel. If it was previously turned off 345 then it also resets the channel to opaque. If the image already had 346 the alpha channel turned on, it will have no effect.</td></tr> 347 348 <tr valign="top"> 349 <td valign="top"><kbd>Opaque</kbd></td> 350 <td valign="top"> 351 Enables the alpha/matte channel and forces it to be fully opaque. 352 </td></tr> 353 354 <tr valign="top"> 355 <td valign="top"><kbd>Transparent</kbd></td> 356 <td valign="top"> 357 Activates the alpha/matte channel and forces it to be fully 358 transparent. This effectively creates a fully transparent image the 359 same size as the original and with all its original RGB data still 360 intact, but fully transparent. </td></tr> 361 362 <tr valign="top"> 363 <td valign="top"><kbd>Extract</kbd></td> 364 <td valign="top"> 365 Copies the alpha channel values into all the color channels and turns 366 '<kbd>Off</kbd>' the the image's transparency, so as to generate 367 a gray-scale mask of the image's shape. The alpha channel data is left 368 intact just deactivated. This is the inverse of '<kbd>Copy</kbd>'. 369 </td></tr> 370 371 <tr valign="top"> 372 <td valign="top"><kbd>Copy</kbd></td> 373 <td valign="top"> 374 Turns '<kbd>On</kbd>' the alpha/matte channel, then copies the 375 gray-scale intensity of the image, into the alpha channel, converting 376 a gray-scale mask into a transparent shaped mask ready to be colored 377 appropriately. The color channels are not modified. </td></tr> 378 379 <tr valign="top"> 380 <td valign="top"><kbd>Shape</kbd></td> 381 <td valign="top"> 382 As per '<kbd>Copy</kbd>' but also colors the resulting shape mask with 383 the current background color. That is the RGB color channels is 384 replaced, with appropriate alpha shape. 385 </td></tr> 386 387 <tr valign="top"> 388 <td valign="top"><kbd>Background</kbd></td> 389 <td valign="top"> 390 Set any fully-transparent pixel to the background color, while leaving 391 it fully-transparent. This can make some image file formats, such as 392 PNG, smaller as the RGB values of transparent pixels are more uniform, 393 and thus can compress better. 394 </td></tr> 395 </tbody> 396</table> 397 398<p>Note that while the <a href="#matte" >+matte</a> operation is the same as 399"<kbd><a href="#alpha" >-alpha</a> Off</kbd>", the <a href="#matte" 400>-matte</a> operation is the same as "<kbd><a href="#alpha" >-alpha</a> 401Set</kbd>" and not "<kbd><a href="#alpha" >-alpha</a> On</kbd>". </p> 402 403 404<div style="margin: auto;"> 405 <h4><a id="annotate"></a> 406 -annotate <em class="arg">degrees</em> <em class="arg">text</em><br /> 407 -annotate <em class="arg">Xdegrees</em>x<em class="arg">Ydegrees</em> <em class="arg">text</em><br /> 408 -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> 409</div> 410 411<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> 412 413<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> 414 415 416<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> 417 418<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> 419 420<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> 421<div class="eqn"><img alt="annotate transformation" src="/images/annotate.png"/></div> 422 423<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> 424 425<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> 426 427<div style="margin: auto;"> 428 <h4><a id="antialias"></a>-antialias</h4> 429</div> 430 431<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 432drawing fonts and lines.</td><td style='text-align:right;'></td></tr></table> 433 434<p>By default, objects (e.g. text, lines, polygons, etc.) are antialiased when 435drawn. Use <a href="#antialias">+antialias</a> to disable the addition of 436antialiasing edge pixels. This will then reduce the number of colors added to 437an image to just the colors being directly drawn. That is, no mixed colors 438are added when drawing such objects. </p> 439 440<div style="margin: auto;"> 441 <h4><a id="append"></a>-append</h4> 442</div> 443 444<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> 445 446<p>This option creates a single longer image image, by joining all the current 447images in sequence top-to-bottom. Use <a href="#append">+append</a> to 448stack images left-to-right. </p> 449 450<p>If they are not of the same width, narrower images are padded with the 451current <a href="#background">-background</a> color setting, and their 452position relative to each other can be controlled by the current <a 453href="#gravity">-gravity</a> setting. </p> 454 455 456<div style="margin: auto;"> 457 <h4><a id="attenuate"></a>-attenuate <em class="arg">value</em></h4> 458</div> 459 460<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> 461 462 463<div style="margin: auto;"> 464 <h4><a id="authenticate"></a>-authenticate <em class="arg">password</em></h4> 465</div> 466 467<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> 468 469<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> 470 471<p>For a different encryption method, see <a href="#encipher">-encipher</a> and <a href="#decipher">-decipher</a>. </p> 472 473 474 475<div style="margin: auto;"> 476 <h4><a id="auto-gamma"></a>-auto-gamma</h4> 477</div> 478 479<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> 480 481<p>This calculates the mean values of an image, then applies a calculated <a 482href="#gamma" >-gamma</a> adjustment so that is the mean color exists in the 483image it will get a have a value of 50%. </p> 484 485<p>This means that any solid 'gray' image becomes 50% gray. </p> 486 487<p>This works well for real-life images with little or no extreme dark and 488light areas, but tend to fail for images with large amounts of bright sky or 489dark shadows. It also does not work well for diagrams or cartoon like images. 490</p> 491 492<p>It uses the <a href="#channel" >-channel</a> setting, (including the 493'<em>sync</em>' flag for channel syncronization), to determine which color 494values is used and modified. As the default <a href="#channel" 495>-channel</a> setting is '<em>RGB,sync</em>', channels are modified 496together by the same gamma value, preserving colors. </p> 497 498 499 500<div style="margin: auto;"> 501 <h4><a id="auto-level"></a>-auto-level</h4> 502</div> 503 504<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> 505 506<p>This is a 'perfect' image normalization operator. It finds the exact 507minimum and maximum color values in the image and then applies a <a 508href="#level" >-level</a> operator to stretch the values to the full range of 509values. </p> 510 511<p>The operator is not typically used for real-life images, image scans, or 512JPEG format images, as a single 'out-rider' pixel can set a bad min/max values 513for the <a href="#level" >-level</a> operation. On the other hand it is the 514right operator to use for color stretching gradient images being used to 515generate Color lookup tables, distortion maps, or other 'mathematically' 516defined images. </p> 517 518<p>The operator is very similar to the <a href="#normalize">-normalize</a>, <a 519href="#contrast-stretch" >-contrast-stretch</a>, and <a href="#linear-stretch" 520>-linear-stretch</a> operators, but without 'histogram binning' or 'clipping' 521problems that these operators may have. That is <a href="#auto-level" 522>-auto-level</a> is the perfect or ideal version these operators. </p> 523 524<p>It uses the <a href="#channel" >-channel</a> setting, (including the 525special '<em>sync</em>' flag for channel syncronization), to determine 526which color values are used and modified. As the default <a 527href="#channel" >+channel</a> setting is '<em>RGB,sync</em>', the 528'<em>sync</em>' ensures that the color channels will are modified 529together by the same gamma value, preserving colors, and ignoring 530transparency. </p> 531 532 533<div style="margin: auto;"> 534 <h4><a id="auto-orient"></a>-auto-orient</h4> 535</div> 536 537<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> 538 539<p>This operator reads and resets the EXIF image profile setting 'Orientation' 540and then performs the appropriate 90 degree rotation on the image to orient 541the image, for correct viewing. </p> 542 543<p>This EXIF profile setting is usually set using a gravity sensor in digital 544camara, however photos taken directly downward or upward may not have an 545appropriate value. Also images that have been orientation 'corrected' without 546reseting this setting, may be 'corrected' again resulting in a incorrect 547result. If the he EXIF profile was previously stripped, the <a 548href="#auto-orient" >-auto-orient</a> operator will do nothing. </p> 549 550 551<div style="margin: auto;"> 552 <h4><a id="average"></a>-average</h4> 553</div> 554 555<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> 556 557<p>An error results if the images are not identically sized.</p> 558 559 560<div style="margin: auto;"> 561 <h4><a id="backdrop"></a>-backdrop</h4> 562</div> 563 564<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> 565 566<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> 567 568<div style="margin: auto;"> 569 <h4><a id="background"></a>-background <em class="arg">color</em></h4> 570</div> 571 572<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> 573 574<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> 575 576<div style="margin: auto;"> 577 <h4><a id="bench"></a>-bench <em class="arg">iterations</em></h4> 578</div> 579 580<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> 581 582<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> 583 584<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> 585<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> 586 587<div style="margin: auto;"> 588 <h4><a id="bias"></a>-bias <em class="arg">value</em>{<em class="arg">%</em>}</h4> 589</div> 590 591<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> 592 593<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> 594 595<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> 596 597<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 598negative results without clipping to the color value range 599(0..QuantumRange).</p> 600 601<p>See the discussion on HDRI implementations of ImageMagick on the page 602<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. 603</p> 604 605<div style="margin: auto;"> 606 <h4><a id="black-point-compensation"></a>-black-point-compensation</h4> 607</div> 608 609<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> 610 611<div style="margin: auto;"> 612 <h4><a id="black-threshold"></a>-black-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 613</div> 614 615<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> 616 617<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. 618</p> 619 620 621<div style="margin: auto;"> 622 <h4><a id="blend"></a>-blend <em class="arg">geometry</em></h4> 623</div> 624 625<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> 626 627<p>Blend will average the images together ('plus') according to the 628percentages given and each pixels transparency. If only a single percentage 629value is given it sets the weight of the composite or 'source' image, while 630the background image is weighted by the exact opposite amount. That is a 631<kbd>-blend 30%</kbd> merges 30% of the 'source' image with 70% of the 632'destination' image. Thus it is equivalent to <kbd>-blend 30x70%</kbd>.</p> 633 634 635<div style="margin: auto;"> 636 <h4><a id="blue-primary"></a>-blue-primary <em class="arg">x</em>,<em class="arg">y</em></h4> 637</div> 638 639<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> 640 641<div style="margin: auto;"> 642 <h4><a id="blue-shift"></a>-blue-shift <em class="arg">factor</em></h4> 643</div> 644 645<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> 646 647<div style="margin: auto;"> 648 649<div style="margin: auto;"> 650 <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> 651</div> 652 653<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> 654 655<p>Convolve the image with a Gaussian or normal distribution using the given 656<em class="arg" >Sigma</em> value. The formula is:</p> 657 658<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 659</div> 660 661<p>The <em class="arg" >Sigma</em> value is the important argument, and 662determines the actual amount of blurring that will take place. </p> 663 664<p>The <em class="arg" >Radius</em> is only used to determine the size of the 665array which will hold the calculated Gaussian distribution. It should be an 666integer. If not given, or set to zero, IM will calculate the largest possible 667radius that will provide meaningful results for the Gaussian distribution. 668</p> 669 670<p>The larger the <em class="arg" >Radius</em> the radius the slower the 671operation is. However too small a <em class="arg" >Radius</em>, and sever 672aliasing effects may result. As a guideline, <em class="arg" >Radius</em> 673should be at least twice the <em class="arg" >Sigma</em> value, though three 674times will produce a more accurite result. </p> 675 676<p>This option differs from <a href="#gaussian-blur">-gaussian-blur</a> simply 677by taking advantage of the separability properties of the distribution. Here 678we apply a single-dimensional Gaussian matrix in the horizontal direction, 679then repeat the process in the vertical direction.</p> 680 681<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 682pixels which are outside the image proper are blurred into the final result. 683</p> 684 685 686<div style="margin: auto;"> 687 <h4>-blur <em class="arg">Width</em>[x<em class="arg">Height</em>[+<em class="arg">Angle</em>]]</h4> 688</div> 689 690<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> 691 692<p>Each pixel in the overlaid region is replaced with an Elliptical Weighted 693Average (EWA) of the source image, scaled according to the grayscale 694mapping. </p> 695 696<p>The ellipse is weighted with sigma set to the given <em class="arg" 697>Width</em> and <em class="arg" >Height</em>. The <em class="arg" >Height</em> 698defaults to the <em class="arg" >Width</em> for a normal circular Guassian 699weighting. The <em class="arg" >Angle</em> will rotate the ellipse from 700horizontal clock-wise. </p> 701 702<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 703pixels which are outside the image proper are blurred into the final result. 704</p> 705 706 707<div style="margin: auto;"> 708 <h4><a id="border"></a>-border <em class="arg">geometry</em></h4> 709</div> 710 711<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> 712 713<p>Set the width and height using the <em class="arg">size</em> portion of the 714<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 715ignored. </p> 716 717<p>Set the border color by preceding with the <a 718href="#bordercolor">-bordercolor</a> setting.</p> 719 720<p>The <a href="#border">-border</a> operation is affected by the current <a 721href="#compose">-compose</a> setting and assumes that this is using the default 722'<kbd>Over</kbd>' composition method. It generates a image of the appropriate 723size colors by the current <a href="#bordercolor">-bordercolor</a> before 724overlaying the original image in the center of this net image. This means that 725with the default compose method of '<kbd>Over</kbd>' any transparent parts may 726be replaced by the current <a href="#bordercolor">-bordercolor</a> setting.</p> 727<p>See also the <a href="#frame">-frame</a> option, which has more 728functionality.</p> 729 730<div style="margin: auto;"> 731 <h4><a id="bordercolor"></a>-bordercolor <em class="arg">color</em></h4> 732</div> 733 734<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> 735 736<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 737 738<p>The default border color is <kbd>#DFDFDF</kbd>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p> 739 740<div style="margin: auto;"> 741 <h4><a id="borderwidth"></a>-borderwidth <em class="arg">geometry</em> </h4> 742</div> 743 744<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> 745 746<div style="margin: auto;"> 747 <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> 748</div> 749 750<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> 751 752<p>Brightness and Contrast values apply changes to the input image. They are 753not absolute settings. A brightness or contrast value of zero means no change. 754The range of values is -100 to +100 on each. Positive values increase the 755brightness or contrast and negative values decrease the brightness or contrast. 756To control only contrast, set the brightness=0. To control only brightness, 757set contrast=0 or just leave it off.</p> 758 759<p>You may also use <a href="#fill">-channel</a> to control which channels to 760apply the brightness and/or contrast change. The default is to apply the same 761transformation to all channels.</p> 762 763<p>Brightness and Contrast arguments are converted to offset and slope of a 764linear transform and applied 765using <a href="#fill">-function polynomial "slope,offset"</a>.</p> 766 767<p>The slope varies from 0 at contrast=-100 to almost vertical at 768contrast=+100. For brightness=0 and contrast=-100, the result are totally 769midgray. For brightness=0 and contrast=+100, the result will approach but 770not quite reach a threshold at midgray; that is the linear transformation 771is a very steep vertical line at mid gray.</p> 772 773<p>Negative slopes, i.e. negating the image, are not possible with this 774function. All achievable slopes are zero or positive.</p> 775 776<p>The offset varies from -0.5 at brightness=-100 to 0 at brightness=0 to +0.5 777at brightness=+100. Thus, when contrast=0 and brightness=100, the result is 778totally white. Similarly, when contrast=0 and brightness=-100, the result is 779totally black.</p> 780 781<p>As the range of values for the arguments are -100 to +100, adding the '%' 782symbol is no different than leaving it off.</p> 783 784<div style="margin: auto;"> 785 <h4><a id="cache"></a>-cache <em class="arg">threshold</em></h4> 786</div> 787 788<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> 789 790<div style="margin: auto;"> 791 <h4><a id="caption"></a>-caption <em class="arg">string</em></h4> 792</div> 793 794<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> 795 796<p>This option sets the caption meta-data of an image read in after this 797option has been given. To modify a caption of images already in memory use 798"<kbd><a href="#set">-set</a> caption</kbd>". </p> 799 800<p>The caption can contain special format characters listed in the <a 801href="/www/escape.html">Format and 802Print Image Properties</a>. These attributes are expanded when the caption 803is finally assigned to the individual images. </p> 804 805<p>If the first character of <em class="arg">string</em> is <em 806class="arg">@</em>, the image caption is read from a file titled by the 807remaining characters in the string. Comments read in from a file are literal; 808no embedded formatting characters are recognized.</p> 809 810<p>Caption meta-data ais not visible on the image itself. To do that use the 811<a href="#annotate">-annotate</a> or <a href="#draw">-draw</a> options 812instead.</p> 813 814<p>For example,</p> 815 816<p class="crtsnip"> 817 -caption "%m:%f %wx%h" bird.miff 818</p> 819 820<p>produces an image caption of <kbd>MIFF:bird.miff 512x480</kbd> (assuming 821that the image <kbd>bird.miff</kbd> has a width of 512 and a height of 822480.</p> 823 824 825<div style="margin: auto;"> 826 <h4><a id="cdl"></a>-cdl <em class="arg">filename</em></h4> 827</div> 828 829<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> 830 831<p>Here is an example color correction collection:</p> 832 833<pre class="text"> 834<?xml version="1.0" encoding="UTF-8"?> 835<ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2"> 836 <ColorCorrection id="cc06668"> 837 <SOPNode> 838 <Slope> 0.9 1.2 0.5 </Slope> 839 <Offset> 0.4 -0.5 0.6 </Offset> 840 <Power> 1.0 0.8 1.5 </Power> 841 </SOPNode> 842 <SATNode> 843 <Saturation> 0.85 </Saturation> 844 </SATNode> 845 </ColorCorrection> 846</ColorCorrectionCollection> 847</pre> 848 849<div style="margin: auto;"> 850 <h4><a id="channel"></a>-channel <em class="arg">type</em></h4> 851</div> 852 853<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> 854 855<p>Choose from: <kbd>Red</kbd>, <kbd>Green</kbd>, <kbd>Blue</kbd>, 856<kbd>Alpha</kbd>, <kbd>Cyan</kbd>, <kbd>Magenta</kbd>, <kbd>Yellow</kbd>, 857<kbd>Black</kbd>, <kbd>Opacity</kbd>, <kbd>Index</kbd>, <kbd>RGB</kbd>, 858<kbd>RGBA</kbd>, <kbd>CMYK</kbd>, or <kbd>CMYKA</kbd>.</p> 859 860<p>The channels above can also be specified as a comma-separated list or can be 861abbreviated as a concatenation of the letters '<kbd>R</kbd>', '<kbd>G</kbd>', 862'<kbd>B</kbd>', '<kbd>A</kbd>', '<kbd>O</kbd>', '<kbd>C</kbd>', 863'<kbd>M</kbd>', '<kbd>Y</kbd>', '<kbd>K</kbd>'. 864 865For example, to only select the <kbd>Red</kbd> and <kbd>Blue</kbd> channels 866you can either use </p> 867<p class="crtsnip"> 868 -channel Red,Blue 869</p> 870<p>or you can use the short hand form</p> 871<p class="crtsnip"> 872 -channel RB 873</p> 874 875<p>All the channels that is present in an image can be specified using the 876special channel type <kbd>All</kbd>. Not all operators are 'channel capable', 877but generally any operators that are generally 'grey-scale' image operators, 878will understand this setting. See individual operator documentation. </p> 879 880<br /> 881 882<p>On top of the normal channel selection a extra flag can be specified, 883'<kbd>Sync</kbd>'. This is turned on by default and if set means that 884operators that understand this flag should perform: cross-channel 885syncronization of the channels. If not specified, then most grey-scale 886operators will apply their image processing operations to each individual 887channel (as specified by the rest of the <a href="#channel">-channel</a> 888setting) completely independently from each other. </p> 889 890<p>For example for operators such as <a href="#auto-level">-auto-level</a> and 891<a href="#auto-gamma">-auto-gamma</a> the color channels are modified 892together in exactly the same way so that colors will remain in-sync. Without 893it being set, then each channel is modified separately and 894independently, which may produce color distortion. </p> 895 896<p>The <a href="#morphology">-morphology</a> '<kbd>Convolve</kbd>' method 897and the <a href="#compose">-compose</a> mathematical methods, also understands 898the '<kbd>Sync</kbd>' flag to modify the behaviour of pixel colors according 899to the alpha channel (if present). That is to say it will modify the image 900processing with the understanding that fully-transparent colors should not 901contribute to the final result. </p> 902 903<p>Basically, by default, operators work with color channels in syncronous, and 904treats transparency as special, unless the <a href="#channel">-channel</a> 905setting is modified so as to remove the effect of the '<kbd>Sync</kbd>' flag. 906How each operator does this depends on that operators current implementation. 907Not all operators understands this flag at this time, but that is changing. 908</p> 909 910<p>To print a complete list of channel types, use <a href="#list">-list 911channel</a>.</p> 912 913<br /> 914 915<p>By default, ImageMagick sets <a href="#channel">-channel</a> to the value 916'<kbd>RGBK,sync</kbd>', which specifies that operators act on all color 917channels except the transparency channel, and that all the color channels are 918to be modified in exactly the same way, with a understanding of transprancy 919(depending on the operation being applied). The 'plus' form <a 920href="#channel" >+channel</a> will reset the value back to this default. </p> 921 922<p>Options that are affected by the <a href="#channel" >-channel</a> setting 923include the following. 924 925<a href="#auto-gamma">-auto-gamma</a>, 926<a href="#auto-level">-auto-level</a>, 927<a href="#black-threshold">-black-threshold</a>, 928<a href="#blur">-blur</a>, 929<a href="#clamp">-clamp</a>, 930<a href="#clut">-clut</a>, 931<a href="#combine">-combine</a>, 932<a href="#composite">-composite</a> (Mathematical compose methods only), 933<a href="#convolve">-convolve</a>, 934<a href="#contrast-stretch">-contrast-stretch</a>, 935<a href="#evaluate">-evaluate</a>, 936<a href="#function">-function</a>, 937<a href="#fx">-fx</a>, 938<a href="#gaussian-blur">-gaussian-blur</a>, 939<a href="#hald-clut">-hald-clut</a>, 940<a href="#motion-blur">-motion-blur</a>, 941<a href="#morphology">-morphology</a>, 942<a href="#negate">-negate</a>, 943<a href="#normalize">-normalize</a>, 944<a href="#ordered-dither">-ordered-dither</a>, 945<a href="#radial-blur">-radial-blur</a>, 946<a href="#random-threshold">-random-threshold</a>, 947<a href="#separate">-separate</a>, 948<a href="#threshold">-threshold</a>, and 949<a href="#white-threshold">-white-threshold</a>. 950</p> 951 952<p>Warning, some operators behave differently when the <a href="#channel" 953>+channel</a> default setting is in effect, verses ANY user defined <a 954href="#channel" >-channel</a> setting (including the equivalent of the 955default). These operators have yet to be made to understand the newer 'Sync' 956flag. </p> 957 958<p>For example <a href="#threshold">-threshold</a> will by default gray-scale 959the image before thresholding, if no <a href="#channel" >-channel</a> setting 960has been defined. This is not 'Sync flag controlled, yet. </p> 961 962<p>Also some operators such as <a href="#blur">-blur</a>, <a 963href="#gaussian-blur">-gaussian-blur</a>, will modify their handling of the 964color channels if the '<kbd>alpha</kbd>' channel is also enabled by <a 965href="#channel" >-channel</a>. Generally this done to ensure that 966fully-transparent colors are treated as being fully-transparent, and thus any 967underlying 'hidden' color has no effect on the final results. Typically 968resulting in 'halo' effects. The newer <a href="#morphology">-morphology</a> 969convolution equivalents however does have a understanding of the 'Sync' flag 970and will thus handle transparency correctly by default. </p> 971 972<p>As a alpha channel is optional within images, some operators will read the 973color channels of an image as a greyscale alpha mask, when the image has no 974alpha channel present, and the <a href="#channel" >-channel</a> setting tells 975the operator to apply the operation using alpha channels. The <a 976href="#clut">-clut</a> operator is a good example of this. </p> 977 978 979<div style="margin: auto;"> 980 <h4><a id="clamp"></a>-clamp</h4> 981</div> 982 983<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> 984 985<div style="margin: auto;"> 986 <h4><a id="charcoal"></a>-charcoal <em class="arg">factor</em></h4> 987</div> 988 989<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> 990 991<div style="margin: auto;"> 992 <h4><a id="chop"></a>-chop <em class="arg">geometry</em></h4> 993</div> 994 995<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> 996 997<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> 998and <em class="arg">height</em> given in the of the <em class="arg">size</em> 999portion of the <em class="arg">geometry</em> argument give the number of 1000columns and rows to remove. The <em class="arg">offset</em> portion of 1001the <em class="arg">geometry</em> argument is influenced by 1002a <a href="#gravity">-gravity</a> setting, if present.</p> 1003 1004<p>The <a href="#chop">-chop</a> option removes entire rows and columns, 1005and moves the remaining corner blocks leftward and upward to close the gaps.</p> 1006 1007<p>While it can remove internal rows and columns of pixels, it is more typically 1008used with as <a href="#gravity">-gravity</a> setting and a '<kbd>+0+0</kbd>' offset 1009so as to remove a single edge from an image. Compare this to <a href="#shave" 1010>-shave</a> whcih removes equal numbers of pixels from oppisite sides of the image. 1011</p> 1012 1013<p>Using <a href="#chop">-chop</a> will effectivally undo the results of a 1014<a href="#splice">-splice</a> that was given the same <em class="arg">geometry</em> 1015and <a href="#gravity">-gravity</a> settings. </p> 1016 1017 1018<div style="margin: auto;"> 1019 <h4><a id="clip"></a>-clip</h4> 1020</div> 1021 1022<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> 1023 1024<p>If a clipping path is present, it is applied to subsequent operations.</p> 1025 1026<p>For example, in the command</p> 1027 1028<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -clip -negate cockatoo.tif negated.tif</span></p> 1029<p>only the pixels within the clipping path are negated.</p> 1030 1031<p>The <a href="#clip">-clip</a> feature requires the XML library. If the XML library is not present, the option is ignored.</p> 1032 1033<div style="margin: auto;"> 1034 <h4><a id="clip-mask"></a>-clip-mask</h4> 1035</div> 1036 1037<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> 1038 1039<div style="margin: auto;"> 1040 <h4><a id="clip-path"></a>-clip-path <em class="arg">id</em></h4> 1041</div> 1042 1043<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> 1044 1045<div style="margin: auto;"> 1046 <h4><a id="clone"></a>-clone <em class="arg">index(s)</em></h4> 1047</div> 1048 1049<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Make a copy of an image (or images).</td><td style='text-align:right;'></td></tr></table> 1050 1051<p>Inside parenthesis (where the operator is normally used) it will make a 1052clone of the images from the last 'pushed' image sequence, and adds them to 1053the end of the current image sequence. Outside parenthesis 1054(not recommended) it clones the images from the current image sequence. </p> 1055 1056<p>Specify the image by its index in the sequence. The first image is index 10570. Negative indexes are relative to the end of the sequence; for 1058example, <kbd>−1</kbd> 1059represents the last image of the sequence. Specify a range of images with a 1060dash (e.g. <kbd>0−4</kbd>). Separate multiple indexes with commas but no 1061spaces (e.g. <kbd>0,2,5</kbd>). A value of '<kbd>0−−1</kbd> will 1062effectivally clone all the images. </p> 1063 1064<p>The <a href="#clone">+clone</a> will simply make a copy of the last image 1065in the image sequence, and is thus equivelent to using a argument of 1066'<kbd>−1</kbd>'. </p> 1067 1068<div style="margin: auto;"> 1069 <h4><a id="clut"></a>-clut</h4> 1070</div> 1071 1072<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 1073corresponding channel in the second image as a <b>c</b>olor 1074<b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style='text-align:right;'></td></tr></table> 1075 1076<p>The second (LUT) image is ordinarily a gradient image containing the 1077histogram mapping of how each channel should be modified. Typically it is a 1078either a single row or column image of replacement color values. If larger 1079than a single row or column, values are taken from a diagonal line from 1080top-left to bottom-right corners.</p> 1081 1082<p>The lookup is further controlled by the <a 1083href="#interpolate">-interpolate</a> setting, which is especially handy for an 1084LUT which is not the full length needed by the ImageMagick installed Quality 1085(Q) level. Good settings for this are the '<kbd>bilinear</kbd>' and 1086'<kbd>bicubic</kbd>' interpolation settings, which give smooth color 1087gradients, and the '<kbd>integer</kbd>' setting for a direct, unsmoothed 1088lookup of color values. </p> 1089 1090<p>This operator is especially suited to replacing a grayscale image with a 1091specific color gradient from the CLUT image. </p> 1092 1093<p>Only the channel values defined by the <a href="#channel">-channel</a> 1094setting will have their values replaced. In particular, since the default <a 1095href="#channel">-channel</a> setting is <kbd>RGB</kbd>, this means that 1096transparency (alpha/matte channel) is not affected, unless the <a 1097href="#channel">-channel</a> setting is modified. When the alpha channel is 1098set, it is treated by the <a href="#clut" >-clut</a> operator in the same way 1099as the other channels, implying that alpha/matte values are replaced using the 1100alpha/matte values of the original image. </p> 1101 1102<p>If either the image being modified, or the lookup image, contains no 1103transparency (i.e. <a href="#alpha" >-alpha</a> is turned 'off') but the <a 1104href="#channel">-channel</a> setting includes alpha replacement, then it is 1105assumed that image represents a gray-scale gradient which is used for the 1106replacement alpha values. That is you can use a gray-scale CLUT image to 1107adjust a existing images alpha channel, or you can color a gray-scale image 1108using colors form CLUT containing the desired colors, including transparency. 1109</p> 1110 1111<p>See also <a href="#hald-clut" >-hald-clut</a> which replaces colors 1112according to the lookup of the full color RGB value from a 2D representation 1113of a 3D color cube. </p> 1114 1115 1116<div style="margin: auto;"> 1117 <h4><a id="coalesce"></a>-coalesce</h4> 1118</div> 1119 1120<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> 1121 1122<p>Overlay each image in an image sequence according to 1123its <a href="#dispose">-dispose</a> meta-data, to reproduce the look of 1124an animation at each point in the animation sequence. All images should be 1125the same size, and are assigned appropriate GIF disposal settings for the 1126animation to continue working as expected as a GIF animation. Such frames 1127are more easily viewed and processed than the highly optimized GIF overlay 1128images. </p> 1129 1130<p>The animation can be re-optimized after processing using 1131the <a href="#layers">-layers</a> method '<kbd>optimize</kbd>', although 1132there is no guarantee that the restored GIF animation optimization is 1133better than the original. </p> 1134 1135 1136<div style="margin: auto;"> 1137 <h4><a id="colorize"></a>-colorize <em class="arg">value</em></h4> 1138</div> 1139 1140<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> 1141 1142<p>Specify the amount of colorization as a percentage. Separate colorization 1143values can be applied to the red, green, and blue channels of the image with 1144a comma-delimited list of colorization 1145values (e.g., <kbd>-colorize 0,0,50</kbd>).</p> 1146 1147<div style="margin: auto;"> 1148 <h4><a id="colormap"></a>-colormap <em class="arg">type</em></h4> 1149</div> 1150 1151<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> 1152 1153<p>The <em class="arg">type</em> can be <kbd>shared</kbd> or <kbd>private</kbd>.</p> 1154 1155<p>This option only applies when the default X server visual 1156is <kbd>PseudoColor</kbd> or <kbd>GrayScale</kbd>. Refer 1157to <a href="#visual">-visual</a> for more details. By default, 1158a shared colormap is allocated. The image shares colors with 1159other X clients. Some image colors could be approximated, 1160therefore your image may look very different than intended. 1161If <kbd>private</kbd> is chosen, the image colors appear exactly 1162as they are defined. However, other clients may go <em>technicolor</em> 1163when the image colormap is installed.</p> 1164 1165<div style="margin: auto;"> 1166 <h4><a id="colors"></a>-colors <em class="arg">value</em></h4> 1167</div> 1168 1169<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> 1170 1171<p>The actual number of colors in the image may be less than your request, 1172but never more. Note that this a color reduction option. Images with fewer 1173unique colors than specified by <em class="arg">value</em> will have any 1174duplicate or unused colors removed. The ordering of an existing color 1175palette may be altered. When converting an image from color to grayscale, 1176it is more efficient to convert the image to the gray colorspace before 1177reducing the number of colors. Refer to 1178the <a href="/www/quantize.html"> 1179color reduction algorithm</a> for more details.</p> 1180 1181<div style="margin: auto;"> 1182 <h4><a id="color-matrix"></a>-color-matrix <em class="arg">matrix</em></h4> 1183</div> 1184 1185<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> 1186 1187<p>This option permits saturation changes, hue rotation, luminance to alpha, 1188and various other effects. Although variable-sized transformation matrices 1189can be used, typically one uses a 5x5 matrix for an RGBA image and a 6x6 1190for CMYKA (or RGBA with offsets). The matrix is similar to those used by 1191Adobe Flash except offsets are in column 6 rather than 5 (in support of 1192CMYKA images) and offsets are normalized (divide Flash offset by 255).</p> 1193 1194<p>As an example, to add contrast to an image with offsets, try this command:</p> 1195 1196<pre class="text"> 1197convert kittens.jpg -color-matrix \ 1198 " 1.5 0.0 0.0 0.0, 0.0, -0.157 \ 1199 0.0 1.5 0.0 0.0, 0.0, -0.157 \ 1200 0.0 0.0 1.5 0.0, 0.0, -0.157 \ 1201 0.0 0.0 0.0 1.0, 0.0, 0.0 \ 1202 0.0 0.0 0.0 0.0, 1.0, 0.0 \ 1203 0.0 0.0 0.0 0.0, 0.0, 1.0" kittens.png 1204</pre> 1205<div style="margin: auto;"> 1206 <h4><a id="colorspace"></a>-colorspace <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%'>Set the image colorspace.</td><td style='text-align:right;'></td></tr></table> 1210 1211<p>Choices are:</p> 1212 1213<pre class="text"> 1214 CMY 1215 CMYK 1216 Gray 1217 HSB 1218 HSL 1219 HWB 1220 Lab 1221 Log 1222 OHTA 1223 Rec601Luma 1224 Rec601YCbCr 1225 Rec709Luma 1226 Rec709YCbCr 1227 RGB 1228 sRGB 1229 Transparent 1230 XYZ 1231 YCbCr 1232 YCC 1233 YIQ 1234 YPbPr 1235 YUV 1236</pre> 1237 1238<p>To print a complete list of colorspaces, use <a href="#list">-list colorspace</a>.</p> 1239 1240<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> 1241 1242<table class="doc"> 1243 <caption>Conversion Of RGB To Other Color Spaces</caption> 1244 <tr><th align="left" valign="middle">CMY</th></tr> 1245 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>−R</td></tr> 1246 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>−G</td></tr> 1247 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>−B</td></tr> 1248 <tr><th align="left" valign="middle">CMYK — starts with CMY from above</th></tr> 1249 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr> 1250 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1251 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1252 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1253 1254 <tr><th align="left" valign="middle">Gray</th></tr> 1255 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 1256 1257 <tr><th align="left" valign="middle">HSB — Hue, Saturation, Brightness; like a cone peak downward</th></tr> 1258 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1259 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1260 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr> 1261 1262 <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> 1263 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1264 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1265 <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> 1266 1267 <tr><th align="left" valign="middle">HWB — Hue, Whiteness, Blackness</th></tr> 1268 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr> 1269 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr> 1270 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr> 1271 1272 <tr><th align="left" valign="middle">LAB</th></tr> 1273 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr> 1274 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr> 1275 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr> 1276 1277 <tr><th align="left" valign="middle">LOG</th></tr> 1278 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr> 1279 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr> 1280 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr> 1281 1282 <tr><th align="left" valign="middle">OHTA — approximates principal components transformation</th></tr> 1283 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr> 1284 <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> 1285 <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> 1286 1287 <tr><th align="left" valign="middle">Rec601Luma</th></tr> 1288 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 1289 1290 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr> 1291 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1292 <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> 1293 <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> 1294 1295 <tr><th align="left" valign="middle">Rec709Luma</th></tr> 1296 <tr><td align="left" valign="middle">Gray=0.21260*R+0.71520*G+0.07220*B</td></tr> 1297 1298 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr> 1299 <tr><td align="left" valign="middle">Y=0.212600*R+0.715200*G+0.072200*B; <em>intensity-like</em></td></tr> 1300 <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> 1301 <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> 1302 1303 <tr><th align="left" valign="middle">sRGB</th></tr> 1304 <tr><td align="left" valign="middle">if Rs ≤ .03928 then Rs=R/12.92 else Rs=((R+.055)/1.055)^2.4</td></tr> 1305 <tr><td align="left" valign="middle">if Gs ≤ .03928 then Gs=B/12.92 else Gs=((G+.055)/1.055)^2.4</td></tr> 1306 <tr><td align="left" valign="middle">if Bs ≤ .03928 then Bs=B/12.92 else Bs=((B+.055)/1.055)^2.4</td></tr> 1307 1308 <tr><th align="left" valign="middle">XYZ</th></tr> 1309 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr> 1310 <tr><td align="left" valign="middle">Y=0.2126560*R+0.7151580*G+0.0721856*B</td></tr> 1311 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr> 1312 1313 <tr><th align="left" valign="middle">YCC</th></tr> 1314 <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> 1315 <tr><td align="left" valign="middle">C1=(−0.29900*R−0.58700*G+0.88600*B) (with complicated scaling)</td></tr> 1316 <tr><td align="left" valign="middle">C2=(0.70100*R−0.58700*G−0.11400*B) (with complicated scaling)</td></tr> 1317 1318 <tr><th align="left" valign="middle">YCbCr</th></tr> 1319 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1320 <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> 1321 <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> 1322 1323 <tr><th align="left" valign="middle">YIQ</th></tr> 1324 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1325 <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> 1326 <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> 1327 1328 <tr><th align="left" valign="middle">YPbPr</th></tr> 1329 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1330 <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> 1331 <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> 1332 1333 <tr><th align="left" valign="middle">YUV</th></tr> 1334 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1335 <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> 1336 <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> 1337</table> 1338 1339<div style="margin: auto;"> 1340 <h4><a id="combine"></a>-combine</h4> 1341</div> 1342 1343<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> 1344 1345<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> 1346 1347<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. 1348</p> 1349 1350<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> 1351<div style="margin: auto;"> 1352 <h4><a id="comment"></a>-comment <em class="arg">string</em></h4> 1353</div> 1354 1355<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> 1356 1357<p>This option sets the comment meta-data of an image read in after this 1358option has been given. To modify a comment of images already in memory use 1359"<kbd><a href="#set">-set</a> comment</kbd>". </p> 1360 1361<p>The comment can contain special format characters listed in the <a 1362href="/www/escape.html">Format and 1363Print Image Properties</a>. These attributes are expanded when the comment 1364is finally assigned to the individual images. </p> 1365 1366<p>If the first character of <em class="arg">string</em> is <em 1367class="arg">@</em>, the image comment is read from a file titled by the 1368remaining characters in the string. Comments read in from a file are literal; 1369no embedded formatting characters are recognized.</p> 1370 1371<p>Comment meta-data are not visible on the image itself. To do that use the 1372<a href="#annotate">-annotate</a> or <a href="#draw">-draw</a> options 1373instead.</p> 1374 1375<p>For example,</p> 1376 1377<p class="crtsnip"> 1378 -comment "%m:%f %wx%h" bird.miff 1379</p> 1380 1381<p>produces an image comment of <kbd>MIFF:bird.miff 512x480</kbd> (assuming 1382that the image <kbd>bird.miff</kbd> has a width of 512 and a height of 1383480.</p> 1384 1385<div style="margin: auto;"> 1386 <h4><a id="compose"></a>-compose <em class="arg">operator</em></h4> 1387</div> 1388 1389<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> 1390 1391<p>See <a href="/www/compose.html">Alpha Compositing</a> for 1392a detailed discussion of alpha compositing.</p> 1393 1394<p>This setting effects image processing operators that merge two (or more) 1395images together in some way. This includes the operators, 1396<a href="#composite">-composite</a>, 1397<a href="#layers">-layers</a> composite, 1398<a href="#flatten">-flatten</a>, 1399<a href="#mosaic">-mosaic</a>, 1400<a href="#layers">-layers</a> merge, 1401<a href="#border">-border</a>, 1402<a href="#frame">-frame</a>, 1403and <a href="#extent">-extent</a>. </p> 1404 1405<p>It is also one of the primary options for the "<kbd>composite</kbd>" 1406command. </p> 1407 1408 1409<div style="margin: auto;"> 1410 <h4><a id="composite"></a>-composite</h4> 1411</div> 1412 1413<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> 1414 1415<p>Take the first image 'destination' and overlay the second 'source' image 1416according to the current <a href="#compose">-compose</a> setting. The location 1417of the 'source' or 'overlay' image is controlled according to <a 1418href="#geometry" >-geometry</a>, and <a href="#geometry" >-geometry</a> 1419settings. </p> 1420 1421<p>If a third image is given this is treated as a gray-scale 'mask' image 1422relative to the first 'destination' image. This mask will limit what parts of 1423the destination can be modified by the image composition. However for the 1424'<kbd>displace</kbd>' compose method, the mask is used to provide a separate 1425Y-displacement image instead. </p> 1426 1427<p>If a <a href="#compose">-compose</a> method requires extra numerical 1428arguments or flags these can be provided by setting the <a 1429href="#set">-set</a> '<kbd class="arg">option:compose:args</kbd>' 1430appropriately for the compose method. </p> 1431 1432<p>Some <a href="#compose">-compose</a> methods can modify the 'destination' 1433image outside the overlay area. You can disable this by setting the special <a 1434href="#set">-set</a> '<kbd class="arg">option:compose:outside-overlay</kbd>' 1435to '<kbd>false</kbd>'. </p> 1436 1437 1438<div style="margin: auto;"> 1439 <h4><a id="compress"></a>-compress <em class="arg">type</em></h4> 1440</div> 1441 1442<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> 1443 1444<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> 1445 1446<p>To print a complete list of compression types, use <a href="#list">-list compress</a>.</p> 1447 1448<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> 1449 1450<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> 1451 1452<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> 1453 1454<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> 1455 1456<div style="margin: auto;"> 1457 <h4><a id="contrast"></a>-contrast</h4> 1458</div> 1459 1460<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> 1461 1462<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> 1463 1464<p>For a more pronounced effect you can repeat the option:</p> 1465 1466<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -contrast -contrast rose_c2.png</span></p> 1467<div style="margin: auto;"> 1468 <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> 1469</div> 1470 1471<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> 1472 1473<p>While performing the stretch, black-out at most <em 1474class="arg" >black-point</em> pixels and white-out at most <em 1475class="arg" >white-point</em> pixels. Or, if percent is used, black-out at most 1476<em class="arg" >black-point %</em> pixels and white-out at most <em 1477class="arg" >white-point %</em> pixels.</p> 1478 1479<p>Prior to ImageMagick 6.4.7-0, <a href="#contrast-stretch" 1480>-contrast-stretch</a> will black-out at most <em class="arg" 1481>black-point</em> pixels and white-out at most <em class="arg" >total pixels 1482minus white-point</em> pixels. Or, if percent is used, black-out at most <em 1483class="arg">black-point %</em> pixels and white-out at most <em class="arg" 1484>100% minus white-point %</em> pixels.</p> 1485 1486<p>Note that <kbd>-contrast-stretch 0</kbd> will modify the image such that 1487the image's min and max values are stretched to 0 and <em class="QR" 1488>QuantumRange</em>, respectively, without any loss of data due to burn-out or 1489clipping at either end. This is not the same as <a href="#normalize" 1490>-normalize</a>, which is equivalent to <kbd>-contrast-stretch 0.15x0.05%</kbd> (or 1491prior to ImageMagick 6.4.7-0, <kbd>-contrast-stretch 2%x99%</kbd>).</p> 1492 1493<p>Internally operator works by creating a histogram bin, and then uses that 1494bin to modify the image. As such some colors may be merged together when they 1495originally fell into the same 'bin'. </p> 1496 1497<p>All the channels are normalized in concert by the came amount so as to 1498preserve color integrity, when the default <a href="#channel" >+channel</a> 1499setting is in use. Specifying any other <a href="#channel" >-channel</a> 1500setting will normalize the RGB channels independently.</p> 1501 1502<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 1503normalization of mathematical images. </p> 1504 1505<p>This operator is under review for re-development. </p> 1506 1507 1508<div style="margin: auto;"> 1509 <h4><a id="convolve"></a>-convolve <em class="arg">kernel</em></h4> 1510</div> 1511 1512<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> 1513 1514<p>The <em class="arg">kernel</em> is a matrix specified as 1515a comma-separated list of integers (with no spaces), ordered left-to right, 1516starting with the top row. Presently, only odd-dimensioned kernels are 1517supported, and therefore the number of entries in the specified <em 1518class="arg">kernel</em> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25, 15197<sup>2</sup>=49, etc. </p> 1520 1521<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 1522positive and negative results are relative to a user-specified bias value. 1523This is important for non-HDRI compilations of ImageMagick when dealing with 1524convolutions that contain negative as well as positive values. This is 1525especially the case with convolutions involving high pass filters or edge 1526detection. Without an output bias, the negative values is clipped at zero. 1527</p> 1528 1529<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 1530negative results without clipping to the color value range (0..QuantumRange). 1531See the discussion on HDRI implementations of ImageMagick on the page <a 1532href="/www/high-dynamic-range.html">High 1533Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a 1534href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this 1535<a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> 1536entry. </p> 1537 1538 1539<div style="margin: auto;"> 1540 <h4><a id="crop"></a>-crop <em class="arg">geometry</em></h4> 1541</div> 1542 1543<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> 1544 1545<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> 1546 1547<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> 1548 1549<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> 1550 1551<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> 1552 1553<p>By adding a exclamation character flag to the geometry argument, the 1554cropped images virtual canvas page size and offset is set as if the 1555geometry argument was a viewport or window. This means the canvas page size 1556is set to exactly the same size you specified, the image offset set 1557relative top left corner of the region cropped. </p> 1558 1559<p>If the cropped image 'missed' the actual image on its virtual canvas, a 1560special single pixel transparent 'missed' image is returned, and a 'crop 1561missed' warning given. </p> 1562 1563<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> 1564 1565<div style="margin: auto;"> 1566 <h4><a id="cycle"></a>-cycle <em class="arg">amount</em></h4> 1567</div> 1568 1569<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> 1570 1571<p><em class="arg">Amount</em> defines the number of positions each 1572colormap entry is shifted.</p> 1573 1574 1575<div style="margin: auto;"> 1576 <h4><a id="debug"></a>-debug <em class="arg">events</em></h4> 1577</div> 1578 1579<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> 1580 1581<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> 1582 1583 1584<p>For example, to log cache and blob events, use.</p> 1585 1586<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p> 1587<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p> 1588 1589<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p> 1590 1591<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p> 1592 1593<p>Use <a href="#debug">+debug</a> to turn off all logging.</p> 1594 1595<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> 1596 1597 1598<div style="margin: auto;"> 1599 <h4><a id="decipher"></a>-decipher <em class="arg">filename</em></h4> 1600</div> 1601 1602<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> 1603 1604<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 1605 1606<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 1607 1608 1609<div style="margin: auto;"> 1610 <h4><a id="deconstruct"></a>-deconstruct</h4> 1611</div> 1612 1613<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> 1614 1615<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> 1616 1617<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> 1618 1619<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p> 1620 1621 1622<div style="margin: auto;"> 1623 <h4><a id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4> 1624</div> 1625 1626<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 1627coders and image processing operations.</td><td style='text-align:right;'></td></tr></table> 1628 1629<p>This option creates one or more definitions for coders and decoders to use 1630while reading and writing image data. Definitions are generally used to 1631control image file format coder modules, and image processing operations, 1632beyond what is provided by normal means. Defined settings are listed in <a 1633href="#verbose" >-verbose</a> information ("<kbd>info:</kbd>" output format) 1634as "Artifacts". </p> 1635 1636<p>If <em class="arg">value</em> is missing for a definition, an empty-valued 1637definition of a flag is created with that name. This used to control on/off 1638options. Use <a href="#define">+define key</a> to remove definitions 1639previously created. Use <a href="#define">+define "*"</a> to remove all 1640existing definitions.</p> 1641 1642<p>The same 'artifact' settings can also be defined using the <a 1643href="#set" >-set "option:<em class="arg">key</em>" "<em class="arg" 1644>value</em>"</a> option, which also allows the use of <a href="/www/escape.html" >Format and Print Image 1645Properties</a> in the defined value. </p> 1646 1647<p>The <em>option</em> and <em>key</em> are case-independent (they are 1648converted to lowercase for use within the decoders) while the <em>value</em> 1649is case-dependent.</p> 1650 1651<p>Such settings are global in scope, and effect all images and operations. </p> 1652 1653<p>The following definitions are just some of the artifacts that are 1654available:</p> 1655 1656<dl> 1657<dt>dcm:display-range=reset</dt> 1658<dd>Set the display range to the minimum and maximum pixel values for the 1659 DCM image format.</dd> 1660 1661<dt>dot:layout-engine=<em class="arg">value</em></dt> 1662<dd>Set the specify the layout engine for the DOT image format (e.g. 1663 <kbd>neato</kbd>).</dd> 1664 1665<dt>jpeg:extent=<em class="arg">value</em></dt> 1666<dd>Restrict the maximum JPEG file size, for example <kbd>-define 1667 jpeg:extent=400kb</kbd>.</dd> 1668 1669<dt>jpeg:size=<em class="arg">geometry</em></dt> 1670<dd>Set the size hint of a JPEG image, for example, -define jpeg:size=128x128. 1671 It is most useful for increasing performance and reducing the memory 1672 requirements when reducing the size of a large JPEG image.</dd> 1673 1674<dt>jp2:rate=<em class="arg">value</em></dt> 1675<dd>Specify the compression factor to use while writing JPEG-2000 files. The 1676 compression factor is the reciprocal of the compression ratio. The valid 1677 range is 0.0 to 1.0, with 1.0 indicating lossless compression. If defined, 1678 this value overrides the -quality setting. A quality setting of 75 1679 results in a rate value of 0.06641.</dd> 1680 1681<dt>mng:need-cacheoff</dt> 1682 <dd>turn playback caching off for streaming MNG.</dd> 1683 1684<dt>png:bit-depth=<em class="arg">value</em></dt> 1685<dt>png:color-type=<em class="arg">value</em></dt> 1686<dd>desired bit-depth and color-type for PNG output. You can force the PNG 1687 encoder to use a different bit-depth and color-type than it would have 1688 normally selected, but only if this does not cause any loss of image 1689 quality. Any attempt to reduce image quality is treated as an error and no 1690 PNG file is written. E.g., if you have a 1-bit black-and-white image, you 1691 can use these "defines" to cause it to be written as an 8-bit grayscale, 1692 indexed, or even a 64-bit RGBA. But if you have a 16-million color image, 1693 you cannot force it to be written as a grayscale or indexed PNG. If you 1694 wish to do this, you must use the appropriate <a href="#depth">-depth</a>, 1695 <a href="#colors">-colors</a>, or <a href="#type">-type</a> directives to 1696 reduce the image quality prior to using the PNG encoder. Note that in 1697 indexed PNG files, "bit-depth" refers to the number of bits per index, 1698 which can be 1, 2, 4, or 8. In such files, the color samples always have 1699 8-bit depth.</dd> 1700 1701<dt>png:exclude-chunk=<em class="arg">value</em></dt> 1702<dt>png:include-chunk=<em class="arg">value</em></dt> 1703<dd>ancillary chunks to be excluded from or included in PNG output. 1704 1705 <p>The<em class="arg">value</em> can be the name of a PNG chunk-type such 1706 as <em class="arg">bKGD</em>, a comma-separated list of chunk-types, 1707 or the word <em class="arg">all</em> or 1708 the word <em class="arg">none</em>. There must be no spaces in the 1709 list. Although PNG chunk-names are case-dependent, you can use 1710 all lowercase names if you prefer.</p> 1711 1712 <p>As a special case, if the <kbd>sRGB</kbd> chunk is excluded and 1713 the <kbd>gAMA</kbd> chunk is included, the <kbd>gAMA</kbd> chunk will 1714 only be written if gamma is not 1/2.2, since most decoders assume 1715 sRGB and gamma=1/2.2 when no colorspace information is included in 1716 the PNG file. Because the list is processed from left to right, you 1717 can achieve this with a single define:</p> 1718 1719<pre class="text"> 1720 -define png:include-chunk=none,gAMA 1721</pre> 1722 1723 <p>The critical PNG chunks <kbd>IHDR</kbd>, <kbd>PLTE</kbd>, 1724 <kbd>IDAT</kbd>, and <kbd>IEND</kbd> cannot be excluded. Any of 1725 these entries appearing in the list will be ignored.</p> 1726 1727 <p>If the ancillary PNG <kbd>tRNS</kbd> chunk is excluded and the 1728 image has transparency, the PNG colortype is forced to be 4 or 6 1729 (GRAY_ALPHA or RGBA). If the image is not transparent, then the 1730 <kbd>tRNS</kbd> chunk isn't written anyhow, and there is no effect 1731 on the PNG colortype of the output image.</p> 1732 1733 <p>The <a href="#strip">-strip</a> option does the equivalent of the 1734 following for PNG output:</p> 1735 1736<pre class="text"> 1737 -define png:include-chunk=none,gama 1738</pre> 1739 1740 <p>The default behavior is to include all known PNG ancillary chunks 1741 plus ImageMagick's private <kbd>vpAg</kbd> ("virtual page") chunk, 1742 and to exclude all PNG chunks that are unknown to ImageMagick, 1743 regardless of their PNG "copy-safe" status as described in the 1744 PNG specification.</p> 1745 </dd> 1746 1747<dt>ps:imagemask</dt> 1748<dd>If the ps:imagemask flag is defined, the PS3 and EPS3 coders will create 1749 Postscript files that render bilevel images with the Postscript imagemask 1750 operator instead of the image operator.</dd> 1751 1752<dt>quantum:format=<em class="arg">type</em></dt> 1753<dd>Set the type to <kbd>floating-point</kbd> to specify a floating-point 1754 format for raw files (e.g. GRAY:) or for MIFF and TIFF images in HDRI mode 1755 to preserve negative values. If <a href="#depth">-depth</a> 16 is 1756 included, the result is a single precision floating point format. 1757 If <a href="#depth">-depth</a> 32 is included, the result is 1758 double precision floating point format.</dd> 1759 1760</dl> 1761 1762<p>For example, to create a postscript file that will render only the black 1763pixels of a bilevel image, use:</p> 1764 1765<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p> 1766<p>Set attributes of the image registry by prefixing the value with 1767<kbd>registry:</kbd>. For example, to set a temporary path to put work files, 1768use:</p> 1769 1770<p class="crtsnip"> 1771-define registry:temporary-path=/data/tmp 1772</p> 1773 1774 1775 1776<div style="margin: auto;"> 1777 <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> 1778</div> 1779 1780<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> 1781 1782<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> 1783 1784<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> 1785 1786 1787<div style="margin: auto;"> 1788 <h4><a id="delete"></a>-delete <em class="arg">index</em></h4> 1789</div> 1790 1791<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> 1792 1793<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> 1794 1795 1796<div style="margin: auto;"> 1797 <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> 1798</div> 1799 1800<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> 1801 1802<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> 1803 1804<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> 1805 1806<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> 1807 1808<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> 1809 1810<div style="margin: auto;"> 1811 <h4><a id="depth"></a>-depth <em class="arg">value</em></h4> 1812</div> 1813 1814<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> 1815 1816<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> 1817 1818<div style="margin: auto;"> 1819 <h4><a id="descend"></a>-descend</h4> 1820</div> 1821 1822<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> 1823 1824<div style="margin: auto;"> 1825 <h4><a id="deskew"></a>-deskew <em class="arg">threshold</em></h4> 1826</div> 1827 1828<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> 1829 1830<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> 1831 1832<div style="margin: auto;"> 1833 <h4><a id="despeckle"></a>-despeckle</h4> 1834</div> 1835 1836<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> 1837 1838<div style="margin: auto;"> 1839 <h4><a id="direction"></a>-direction <em class="arg">type</em></h4> 1840</div> 1841 1842<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> 1843 1844<div style="margin: auto;"> 1845 <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> 1846</div> 1847 1848<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> 1849 1850<p>With this option, the 'overlay' image, and optionally the 'mask' image, 1851is used as a displacement map, which is used to displace the lookup of 1852what part of the 'background' image is seen at each point of the overlaid 1853area. Much like the displacement map is a 'lens' that redirects light shining 1854through it so as to present a distorted view the original 'background' image 1855behind it. </p> 1856 1857<p>Any perfect grey areas of the displacement map produce a zero 1858displacement of the image. Black areas produce the given maximum negative 1859displacement of the lookup point, while white produce a maximum positive 1860displacement of the lookup. </p> 1861 1862<p>Note that it is the lookup of the 'background' that is displaced, not a 1863displacement of the image itself. As such an area of the displacement map 1864containing 'white' will have the lookup point 'shifted' by a positive amount, 1865and thus generating a copy of the destination image to the right/downward from 1866the correct position. That is the image will look like it may have been 1867'shifted' in a negative left/upward direction. Understanding this is a very 1868important in understanding how displacement maps work. </p> 1869 1870<p>The given arguments define the maximum amount of displacement in pixels 1871that a particular map can produce. If the displacement scale is large enough 1872it is also possible to lookup parts of the 'background' image that lie well 1873outside the bounds of the displacement map itself. That is you could very 1874easily copy a section of the original image from outside the overlay area 1875into the overlay area. </p> 1876 1877<p>The '%' flag makes the displacement scale relative to the size of the 1878overlay image (100% = half width/height of image). Using '!' switches 1879percentage arguments to refer to the destination image size instead. 1880these flags were added as of IM v6.5.3-5.</p> 1881 1882<p>Normally a single grayscale displacement map is provided, which with the 1883given scaling values will determine a single direction (vector) in which 1884displacements can occur (positively or negatively). However, if you also 1885specify a third image which is normally used as a <em class="arg">mask</em>, 1886the <em class="arg">composite image</em> is used for horizontal X 1887displacement, while the <em class="arg">mask image</em> is used for vertical Y 1888displacement. This allows you to define completely different displacement 1889values for the X and Y directions, and allowing you to lookup any point within 1890the <em class="arg">scale</em> bounds. In other words each pixel can lookup 1891any other nearby pixel, producing complex 2 dimensional displacements, rather 1892than a simple 1 dimensional vector displacements. </p> 1893 1894<p>Alteratively rather than suppling two separate images, as of IM v6.4.4-0, 1895you can use the 'red' channel of the overlay image to specify the horizontal 1896or X displacement, and the 'green' channel for the vertical or Y displacement. 1897</p> 1898 1899<p>As of IM v6.5.3-5 any alpha channel in the overlay image is used as a 1900mask the transparency of the destination image. However areas outside the 1901overlaid areas will not be effected. </p> 1902 1903 1904<div style="margin: auto;"> 1905 <h4><a id="display"></a>-display <em class="arg">host:display[.screen]</em></h4> 1906</div> 1907 1908<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> 1909 1910<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p> 1911 1912<div style="margin: auto;"> 1913 <h4><a id="dispose"></a>-dispose <em class="arg">method</em></h4> 1914</div> 1915 1916<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> 1917 1918<p>The layer disposal method defines the way each the displayed image is to be 1919modified after the current 'frame' of an animation has finished being 1920displayed (after its 'delay' period), but before the next frame on an 1921animation is to be overlaid onto the display. </p> 1922 1923<p>Here are the valid methods:</p> 1924 1925<pre class="text"> 1926Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>'). 1927None 1 Do not dispose, just overlay next frame image. 1928Background 2 Clear the frame area with the background color. 1929Previous 3 Clear to the image prior to this frames overlay. 1930</pre> 1931 1932<p>You can also use the numbers given above, which is what the GIF format 1933uses internally to represent the above settings. </p> 1934 1935<p>To print a complete list of dispose methods, use <a href="#list">-list dispose</a>.</p> 1936 1937<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent 1938resetting the layer disposal methods of images being read in. </p> 1939 1940<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image 1941disposal method for images already in memory.</p> 1942 1943<div style="margin: auto;"> 1944 <h4><a id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4> 1945</div> 1946 1947<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> 1948 1949 1950<div style="margin: auto;"> 1951 <h4><a id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4> 1952</div> 1953 1954<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> 1955 1956<p>The opacity of the composite image is multiplied by the given percent, then 1957it is composited 'over' the main image. If <em class="arg">src_percent</em> 1958is greater than 100, start dissolving the main image so it becomes 1959transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages 1960are given, each image are dissolved to the percentages given. </p> 1961 1962<p>Note that dissolve percentages do not add, two opaque images dissolved 1963'50,50', produce a 75% transparency. For a 50% + 50% blending of the two 1964images, you would need to use dissolve values of '50,100'. </p> 1965 1966<div style="margin: auto;"> 1967 <h4><a id="distort"></a>-distort <em class="arg">method arguments</em></h4> 1968</div> 1969 1970<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> 1971 1972<p>The <em class="arg">arguments</em> is a single string containing a list 1973of floating point numbers separated by commas or spaces. The number of 1974and meaning of the floating point values depends on the distortion <em 1975class="arg">method</em> being used. </p> 1976 1977<p>Choose from these distortion types:</p> 1978 1979<table class="doc"> 1980 <tr valign="top"> 1981 <th align="left" style="width: 8%">Method</th> 1982 <th align="left">Description</th> 1983 </tr> 1984 1985 <tr valign="top"> 1986 <td valign="top"><kbd>ScaleRotateTranslate</kbd> 1987 <br/>or <kbd>SRT</kbd></td> 1988 <td valign="top"> 1989 Distort image by first scaling and rotating about a given 'center', 1990 before translating that 'center' to the new location, in that order. It 1991 is an alternative method of specifying a '<kbd>Affine</kbd>' type of 1992 distortion, but without shearing effects. It also provides a good way 1993 of rotating and displacing a smaller image for tiling onto a larger 1994 background (IE 2-dimensional animations). <br/> 1995 1996 The number of arguments determine the specific meaning of each 1997 argument for the scales, rotation, and translation operations. <br/> 1998 1999 <table style="margin-left:auto; margin-right:auto;"> 2000 <tr><td># </td><td>arguments meaning</td></tr> 2001 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr> 2002 <tr><td>2:</td><td><em>Scale Angle</em></td></tr> 2003 <tr><td>3:</td><td><em>X,Y Angle</em></td></tr> 2004 <tr><td>4:</td><td><em>X,Y Scale Angle</em></td></tr> 2005 <tr><td>5:</td> 2006 <td><em>X,Y ScaleX,ScaleY Angle</em></td></tr> 2007 <tr><td>6:</td> 2008 <td><em>X,Y Scale Angle NewX,NewY</em></td></tr> 2009 <tr><td>7:</td> 2010 <td><em>X,Y ScaleX,ScaleY Angle 2011 NewX,NewY</em></td></tr> 2012 </table> 2013 2014 This is actually an alternative way of specifying a 2 dimensional linear 2015 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr> 2016 2017 <tr valign="top"> 2018 <td valign="top"><kbd>Affine</kbd></td> 2019 <td valign="top"> 2020 Distort the image linearly by moving a list of at least 3 or more sets 2021 of control points (as defined below). Ideally 3 sets or 12 floating 2022 point values are given allowing the image to be linearly scaled, 2023 rotated, sheared, and translated, according to those three points. See 2024 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>' 2025 distortions. <br/> 2026 2027 More than 3 sets given control point pairs (12 numbers) is least 2028 squares fitted to best match a lineary affine distortion. If only 2 2029 control point pairs (8 numbers) are given a two point image translation 2030 rotation and scaling is performed, without any possible shearing, 2031 flipping or changes in aspect ratio to the resulting image. If only one 2032 control point pair is provides the image is only translated, (which may 2033 be a floating point non-integer translation). <br/> 2034 2035 This distortion does not include any form of perspective distortion. 2036 </td> 2037 2038 </tr> 2039 2040 <tr valign="top"> 2041 <td valign="top"><kbd>AffineProjection</kbd></td> 2042 <td valign="top"> 2043 Linearly distort an image using the given Affine Matrix of 6 2044 pre-calculated coefficients forming a set of Affine Equations to map 2045 the source image to the destination image. 2046 2047 <div style="text-align: center"><em> 2048 s<sub>x</sub>, r<sub>x</sub>, 2049 r<sub>y</sub>, s<sub>y</sub>, 2050 t<sub>x</sub>, t<sub>y</sub> 2051 </em></div> 2052 2053 See <a href="#affine" >-affine</a> setting for more detail, and 2054 meanings of these coefficients. <br/> 2055 2056 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide 2057 alternative methods of defining this distortion, with ImageMagick doing 2058 the calculations needed to generate the required coefficients. You can 2059 see the internally generated coefficients, by using a <a 2060 href="#verbose" >-verbose</a> setting with those other varients. </td> 2061 2062 </tr> 2063 2064 <tr valign="top"> 2065 <td valign="top"><kbd>BilinearForward</kbd><br/> 2066 <kbd>BilinearReverse</kbd></td> 2067 <td valign="top"> 2068 Bilinear Distortion, given a minimum of 4 sets of coordinate pairs, or 2069 16 values (see below). Not that lines may not appear straight after 2070 distortion, though the distance between coordinates will remain 2071 consistent. <br/> 2072 2073 The '<kbd>BilinearForward</kbd>' is used to map rectangles to any 2074 quadrilateral, while the '<kbd>BilinearReverse</kbd>' form maps any 2075 quadrilateral to a rectangle, while preserving the straigth line edges 2076 in each case. <br/> 2077 2078 Note that '<kbd>BilinearForward</kbd>' can generate invalid pixels 2079 which will be colored using the <a href="#mattecolor" >-mattecolor</a> 2080 color setting. Also if the quadraterial becomes 'flipped' the image 2081 may dissappear. <br/> 2082 2083 There are future plans to produce a true Bilinear distortion that will 2084 attempt to map any quadrilateral to any other quadrilateral, while 2085 preserving edges (and edge distance ratios). 2086 2087 </td> 2088 </tr> 2089 2090 <tr valign="top"> 2091 <td valign="top"><kbd>Perspective</kbd></td> 2092 <td valign="top"> 2093 Perspective distort the images, using a list of 4 or more sets of 2094 control points (as defined below). More that 4 sets (16 numbers) of 2095 control points provide least squares fitting for more accurate 2096 distortions (for the purposes of image registration and panarama 2097 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>' 2098 linear distortion. <br/> 2099 2100 Perspective Distorted images ensures that straight lines remain 2101 straight, but the scale of the distorted image will vary. The horizon 2102 is anti-aliased, and the 'sky' color may be set using the 2103 <a href="#mattecolor" >-mattecolor</a> setting. </td> 2104 </tr> 2105 2106 <tr valign="top"> 2107 <td valign="top"><kbd>PerspectiveProjection</kbd> </td> 2108 <td valign="top"> 2109 Do a '<kbd>Perspective</kbd>' distortion biased on a set of 8 2110 pre-calculated coefficients. You can get these coefficients by looking 2111 at the <a href="#verbose" >-verbose</a> output of a 2112 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself. 2113 If the last two perspective scaling coefficients are zero, the 2114 remaining 6 represents a transposed 'Affine Matrix'. </td> 2115 2116 </tr> 2117 2118 <tr valign="top"> 2119 <td valign="top"><kbd>Arc</kbd></td> 2120 <td valign="top"> 2121 Arc the image (variation of polar mapping) over the angle given around 2122 a circle. <br/> 2123 <table width="90%" style = "margin-left: auto; margin-right: auto;"> 2124 <tr valign="top"><td>Argument</td> 2125 <td>Meaning</td></tr> 2126 <tr valign="top"><td><em>arc_angle</em></td> 2127 <td>The angle over which to arc the image side-to-side</td></tr> 2128 <tr valign="top"><td><em>rotate_angle</em></td> 2129 <td>Angle to rotate resulting image from vertical center</td></tr> 2130 <tr valign="top"><td><em>top_radius</em></td> 2131 <td>Set top edge of source image at this radius</td></tr> 2132 <tr valign="top"><td><em>bottom_radius</em> </td> 2133 <td>Set bottom edge to this radius (radial scaling)</td></tr> 2134 </table> 2135 2136 The resulting image is always resized to best fit the resulting image, 2137 (as if using <a href="#distort" >+distort</a>) while attempting to 2138 preserve scale and aspect ratio of the original image as much as 2139 possible with the arguments given by the user. All four arguments will 2140 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/> 2141 2142 This a variation of a polar distortion designed to try to preserve the 2143 aspect ratio of the image rather than direct Cartesian to Polar 2144 conversion. </td> 2145 </tr> 2146 2147 <tr valign="top"> 2148 <td valign="top"><kbd>Polar</kbd></td> 2149 <td valign="top"> 2150 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of 2151 the image. that is the height of the input image is mapped to the 2152 radius limits, while the width is wrapped around between the 2153 angle limits. <br/> 2154 2155 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/> 2156 2157 All arguments are optional. With <em>Rmin</em> defaulting to zero, the 2158 center to the center of the image, and the angles going from -180 (top) 2159 to +180 (top). If <em>Rmax</em> is given the special value of 2160 '<code>0</code>', the the distance from the center to the nearest edge 2161 is used for the radius of the output image, which will ensure the whole 2162 image is visible (though scaled smaller). However a special value of 2163 '<code>-1</code>' will use the distance from the center to the furthest 2164 corner, This may 'clip' the corners from the input rectangular image, 2165 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with 2166 the same arguments. <br/> 2167 2168 If the plus form of distort (<a href="#distort" >+distort</a>) is used 2169 output image center will default to <code>0,0</code> of the virtual 2170 canvas, and the image size adjusted to ensure the whole input image is 2171 made visible in the output image on the virtual canvas. </td> 2172 2173 </tr> 2174 2175 <tr valign="top"> 2176 <td valign="top"><kbd>DePolar</kbd></td> 2177 <td valign="top"> 2178 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion 2179 but generates the reverse Polar to Cartesian distortion. <br/> 2180 2181 The special <em>Rmax</em> setting of '<code>0</code>' may however clip 2182 the corners of the input image. However using the special 2183 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner 2184 distance) will ensure the whole distorted image is preserved in the 2185 generated result, so that the same argument to '<kbd>Polar</kbd>' will 2186 reverse the distortion re-producing the original. 2187 2188 Note that as this distortion requires the area resampling of a circular 2189 arc, which can not be handled by the builtin EWA resampling function. 2190 As such the normal EWA filters are turned off. It is recommended some 2191 form of 'super-sampling' image processing technique be used to produce 2192 a high quality result. </td> 2193 2194 </tr> 2195 2196 <tr valign="top"> 2197 <td valign="top"><kbd>Barrel</kbd></td> 2198 <td valign="top"> 2199 Given the four coefficients (A,B,C,D) as defined by <a 2200 href="http://www.all-in-one.ee/~dersch/barrel/barrel.html" >Helmut 2201 Dersch</a>, perform a barrell or pin-cushion distortion appropriate to 2202 correct radial lens distortions. That is in photographs, make straight 2203 lines straight again. <br/> 2204 2205 Arguments: <em>A B C</em> [ <em>D</em> [ 2206 <em>X</em> , <em>Y</em> ] ] <br/> 2207 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> 2208 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> 2209 [ <em>X</em> , <em>Y</em> ] <br/> 2210 So that it forms the function <br/> 2211 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2212 <em>C</em>*r + <em>D</em> )<br/> 2213 2214 Where <em>X</em>,<em>Y</em> is the optional center of the distortion 2215 (defaulting to the center of the image). <br/> 2216 The second form is typically used to distort images, rather than 2217 correct lens distortions. <br/> 2218 </td> 2219 2220 </tr> 2221 2222 <tr valign="top"> 2223 <td valign="top"><kbd>BarrelInverse</kbd></td> 2224 <td valign="top"> 2225 This is very simular to '<kbd>Barrel</kbd>' with the same set of 2226 arguments, and argument handling. However it uses the inverse 2227 of the radial polynomial, 2228 so that it forms the function <br/> 2229 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2230 <em>C</em>*r + <em>D</em> )<br/> 2231 Note that this is not the reverse of the '<kbd>Barrel</kbd>' 2232 distortion, just a different barrel-like radial distortion method. 2233 2234 </td> 2235 </tr> 2236 2237 <tr valign="top"> 2238 <td valign="top"><kbd>Shepards</kbd></td> 2239 <td valign="top"> 2240 Distort the given list control points (any number) using an Inverse 2241 Squared Distance Interpolation Method (<a 2242 href="http://en.wikipedia.org/wiki/Shepard%27s_method" >Shepards 2243 Method</a>). The control points in effect do 'localized' displacement 2244 of the image around the given control point (preserving the look and 2245 the rotation of the area near the control points. For best results 2246 extra control points should be added to 'lock' the positions of the 2247 corners, edges and other unchanging parts of the image, to prevent 2248 their movement. <br/> 2249 2250 The distortion has been likened to 'taffy pulling' using nails, or 2251 pins' stuck in a block of 'jelly' which is then moved to the new 2252 position, distorting te surface of the jelly. <br/> 2253 2254 Internally it is equivelent to generating a displacement map (see <a 2255 href="#displace" >-displace</a>) for source image color look-up using 2256 the <a href="#sparse-color" >-sparse-color</a> method of the same name. 2257 2258 </td> 2259 </tr> 2260 2261</table> 2262 2263<p>To print a complete list of distortion methods, use <a href="#list">-list 2264distort</a>.</p> 2265 2266<p>Many of the above distortion methods such as '<kbd>Affine</kbd>', 2267'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points 2268defining how these points in the given image should be distorted in the 2269destination image. Each set of four floating point values represent a source 2270image coordinate, followed immediately by the destination image coordinate. 2271This produces a list of values such as...</p> 2272<div style="text-align: center"><em> 2273 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> 2274 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> 2275 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> 2276 ... 2277 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> 2278</em></div> 2279<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the 2280destination image. </p> 2281 2282<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion, 2283needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the 2284perspective distortion of the built-in "rose:" image. Note how spaces were 2285used to group the 4 sets of coordinate pairs, to make it easier to read and 2286understand.</p> 2287 2288<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'> 2289convert rose: -virtual-pixel black \<br/> 2290 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \<br/> 2291 rose_3d_rotated.gif</span></p> 2292<p>If more that the required number of coordinate pairs are given for 2293a distortion, the distortion method is 'least squares' fitted to produce the 2294best result for all the coordinate pairs given. If less than the ideal number 2295of points are given, the distort will generally fall back to a simpler form of 2296distortion that can handles the smaller number of coordinates (usally a linear 2297'<kbd>Affine</kbd>' distortion). </p> 2298 2299<p>By using more coordinates you can make use of image registration tool to 2300find matching coordinate pairs in overlapping images, so as to improve the 2301'fit' of the distortion. Of course a bad coordinate pair can also make the 2302'fit' worse. Caution is always advised. </p> 2303 2304<p>Colors are acquired from the source image according to the <a 2305href="#interpolate" >-interpolate</a> color lookup setting, when the image is 2306magnified. However if the viewed image is minified (image becomes smaller), 2307a special area resampling function (added ImageMagick v6.3.5-9), is used to 2308produce a higher quality image. For example you can use 2309a '<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all 2310the way to the horizon. </p> 2311 2312<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'> 2313convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \<br/> 2314 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \<br/> 2315 checks_tiled.jpg</span></p> 2316<p>Note that a infinitely tiled perspective images involving the horizon can 2317be very slow to generate due to the use of the high quality 'area resampling' 2318function (added ImageMagick v6.3.5-9). You can turn off 'area resampling' 2319using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>' 2320(recommended if you plan to use super-sampling instead). </p> 2321 2322<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last 2323'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a> 2324will use the current <a href="#mattecolor" >-mattecolor</a> setting for these 2325pixels. If you do not what these pixels to be visible, set the color to match 2326the rest of the ground. </p> 2327 2328<p>The output image size will by default be the same as the input image. This 2329means that if the part of the distorted image falls outside the viewed area of 2330the 'distorted space', those parts is clipped and lost. However if you use 2331the plus form of the operator (<a href="#distort" >+distort</a>) the operator 2332will attempt (if possible) to show the whole of the distorted image, while 2333retaining a correct 'virtual canvas' offset, for image layering. This offset 2334may need to be removed using <a href="#repage" >+repage</a>, to remove if it 2335is unwanted. </p> 2336 2337<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a> 2338option:distort:viewport {geometry_string}</kbd>" setting which will specify 2339the size and the offset of the generated 'viewport' image of the distorted 2340image space.</p> 2341 2342<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale 2343{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by 2344that factor without changing the viewed contents of the distorted image. This 2345can be used either for 'super-sampling' the image for a higher quality result, 2346or for panning and zooming around the image (with appropriate viewport 2347changes, or post-distort cropping and resizing). </p> 2348 2349<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a 2350href="#distort" >-distort</a> to attempt to output the internal coefficients, 2351and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study, 2352and debugging purposes. This many not be available for all distorts. </p> 2353 2354<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to 2355produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a> 2356and/or <a href="#shear" >-shear</a> operation, with more control of due to the 2357above settings. It is algorithmically slower however, though that may not be 2358the case in ImageMagick's implementation. </p> 2359 2360 2361<div style="margin: auto;"> 2362 <h4><a id="dither"></a>-dither <em class="arg">method</em></h4> 2363</div> 2364 2365<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> 2366 2367<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> 2368 2369<p>Dithering is turned on by default, to turn it off use the plus form of the 2370setting, <a href="#dither">+dither</a>. This will also also render PostScript 2371without text or graphic aliasing. Disabling dithering often (but not always) 2372leads to faster process, a smaller number of colors, but more cartoon like 2373image coloring. Generally resulting in 'color banding' effects in areas with 2374color gradients. </p> 2375 2376<p>The color reduction operators <a href="#colors">-colors</a>, <a 2377href="#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> 2378 2379<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> 2380 2381 2382<div style="margin: auto;"> 2383 <h4><a id="draw"></a>-draw <em class="arg">string</em></h4> 2384</div> 2385 2386<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> 2387 2388<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> 2389 2390<p>The shape primitives:</p> 2391 2392<pre class="text"> 2393 point x,y 2394 line x0,y0 x1,y1 2395 rectangle x0,y0 x1,y1 2396 roundRectangle x0,y0 x1,y1 wc,hc 2397 arc x0,y0 x1,y1 a0,a1 2398 ellipse x0,y0 rx,ry a0,a1 2399 circle x0,y0 x1,y1 2400 polyline x0,y0 ... xn,yn 2401 polygon x0,y0 ... xn,yn 2402 bezier x0,y0 ... xn,yn 2403 path path specification 2404 image operator x0,y0 w,h filename 2405</pre> 2406 2407<p>The text primitive:</p> 2408 2409<pre class="text"> 2410 text x0,y0 string 2411</pre> 2412<p>The text gravity primitive:</p> 2413 2414<pre class="text"> 2415 gravity NorthWest, North, NorthEast, West, Center, 2416 East, SouthWest, South, or SouthEast 2417</pre> 2418 2419<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> 2420 2421<p>The transformation primitives:</p> 2422 2423<pre class="text"> 2424 rotate degrees 2425 translate dx,dy 2426 scale sx,sy 2427 skewX degrees 2428 skewY degrees 2429</pre> 2430 2431<p>The pixel operation primitives:</p> 2432 2433<pre class="text"> 2434 color x0,y0 method 2435 matte x0,y0 method 2436</pre> 2437 2438<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> 2439 2440<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> 2441 2442<p>A <kbd>line</kbd> primitive requires a start point and end point.</p> 2443 2444<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p> 2445 2446<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> 2447 2448<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p> 2449 2450<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> 2451 2452<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> 2453 2454<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>. 2455</p> 2456 2457<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p> 2458 2459<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p> 2460 2461<p class="crtsnip"> 2462 -draw 'circle 100,100 150,150' 2463</p> 2464 2465<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 2466draw 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> 2467 2468<p class="crtsnip"> 2469 -draw 'bezier 20,50 45,100 45,0 70,50' 2470</p> 2471<p class="crtsnip"> 2472 -draw 'bezier 70,50 95,100 95,0 120,50' 2473</p> 2474 2475 2476<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> 2477 2478<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> 2479 2480<p class="crtsnip"> 2481 -draw 'image SrcOver 100,100 225,225 image.jpg' 2482</p> 2483 2484<p>You can use 0,0 for the image size, which means to use the actual 2485dimensions found in the image header. Otherwise, it is scaled to the given 2486dimensions. See <a href="/www/compose.html">Alpha Compositing</a> for 2487a detailed discussion of alpha composition methods that are available. </p> 2488 2489<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> 2490 2491<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p> 2492 2493<p class="crtsnip"> 2494 -draw 'text 100,100 "Works like magick!"' 2495</p> 2496 2497<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p> 2498 2499<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> 2500 2501<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p> 2502 2503<p>The <kbd>scale</kbd> primitive scales them.</p> 2504 2505<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> 2506 2507<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 2508matrix.</p> 2509 2510<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> 2511 2512<pre class="text"> 2513 point 2514 replace 2515 floodfill 2516 filltoborder 2517 reset 2518</pre> 2519 2520<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> 2521 2522<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> 2523 2524<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> 2525 2526<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p> 2527 2528<p>Drawing primitives conform to the <a href="/www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p> 2529 2530 2531<div style="margin: auto;"> 2532 <h4><a id="edge"></a>-edge <em class="arg">radius</em></h4> 2533</div> 2534 2535<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> 2536 2537<div style="margin: auto;"> 2538 <h4><a id="emboss"></a>-emboss <em class="arg">radius</em></h4> 2539</div> 2540 2541<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> 2542 2543<div style="margin: auto;"> 2544 <h4><a id="encipher"></a>-encipher <em class="arg">filename</em></h4> 2545</div> 2546 2547<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> 2548 2549<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 2550 2551<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 2552 2553 2554 2555<div style="margin: auto;"> 2556 <h4><a id="encoding"></a>-encoding <em class="arg">type</em></h4> 2557</div> 2558 2559<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> 2560 2561<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> 2562 2563<div style="margin: auto;"> 2564 <h4><a id="endian"></a>-endian <em class="arg">type</em></h4> 2565</div> 2566 2567<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> 2568 2569<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p> 2570 2571<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p> 2572 2573 2574<div style="margin: auto;"> 2575 <h4><a id="enhance"></a>-enhance</h4> 2576</div> 2577 2578<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> 2579 2580 2581<div style="margin: auto;"> 2582 <h4><a id="equalize"></a>-equalize</h4> 2583</div> 2584 2585<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> 2586 2587<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> 2588 2589<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p> 2590 2591<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> 2592 2593<div style="margin: auto;"> 2594 <h4><a id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4> 2595</div> 2596 2597<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> 2598 2599<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> 2600 2601<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> 2602 2603<table class="doc"> 2604 <col width="25%" /> 2605 <col width="75%" /> 2606 <thead> 2607 <tr> 2608 <th><em class="arg">operator</em></th> 2609 <th>Summary (see further below for details)</th> 2610 </tr> 2611 </thead> 2612 <tbody> 2613 2614 <tr><td>Abs </td> <td>Add <em class="arg">value</em> to pixels and return absolute value. </td></tr> 2615 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr> 2616 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr> 2617 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr> 2618 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2619 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr> 2620 <tr><td>Exp </td> <td>base-e exponential function</td></tr> 2621 <tr><td>Exponential </td> <td>base-e exponential function</td></tr> 2622 <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> 2623 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr> 2624 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr> 2625 <tr><td>Mean </td> <td>Add the <em class="arg">value</em> and divide by 2.</td></tr> 2626 <tr><td>Median </td> <td>Choose the median value from an image sequence.</td></tr> 2627 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr> 2628 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr> 2629 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr> 2630 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr> 2631 <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> 2632 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr> 2633 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2634 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr> 2635 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr> 2636 2637 <tr><td> </td></tr> 2638 2639 <tr><td>Gaussian-noise</td></tr> 2640 <tr><td>Impulse-noise</td></tr> 2641 <tr><td>Laplacian-noise</td></tr> 2642 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr> 2643 <tr><td>PoissonNoise</td></tr> 2644 <tr><td>Uniform-noise</td></tr> 2645 2646 <tr><td> </td></tr> 2647 2648 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr> 2649 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr> 2650 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr> 2651 </tbody> 2652 </table> 2653 2654<p>The specified functions are applied only to each previously set <a 2655href="#channel" >-channel</a> in the image. If necessary, the results of the 2656calculations are truncated (clipped) to fit in the interval [0, <em 2657class="QR">QuantumRange</em>]. The transparency channel of the image is 2658represented as a 'alpha' values (0 = fully transparent), so, for example, a 2659<kbd>Divide</kbd> by 2 of the alpha channel will make the image 2660semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value 2661as a percentage of the <em class="QR">QuantumRange</em>.</p> 2662 2663<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use 2664<a href="#list">-list evaluate</a>.</p> 2665 2666<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and 2667<kbd>Multiply</kbd> methods can also be achieved using either the <a 2668href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with 2669appropriate argument, to linearly modify the overall range of color values. 2670Please note, however, that <a href="#level" >-level</a> treats transparency as 2671'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with 2672'alpha' values.</p> 2673 2674<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> 2675 2676<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> 2677 2678 <div style="text-align:center;"> 2679 exp(<em class="arg">value</em> × <b><em>u</em></b>) 2680 </div> 2681 2682<p> If the input image is squared, for example, using <a 2683href="#-function" >-function polynomial "2 0 0"</a>, then a decaying Gaussian function will be the result.</p> 2684 2685<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> 2686 2687 <div style="text-align:center;"> 2688 log(<em class="arg">value</em> × <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1) 2689 </div> 2690 2691<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on 2692normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a 2693href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent 2694to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used 2695with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used 2696with <kbd>Pow</kbd>.</p> 2697 2698<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and 2699converts the image values into a value according to a (co)sine wave function. 2700The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output 2701is biased 50% and normalized by 50% so as to fit in the respective color value 2702range. The <em class="arg">value</em> scaling of the <em>period</em> of the 2703function (its frequency), and thus determines the number of 'waves' that will 2704be generated over the input color range. For example, if the <em 2705class="arg">value</em> is 1, the effective period is simply the <em 2706class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is 2, 2707then the effective period is the <em>half</em> the <em 2708class="QR">QuantumRange</em>.</p> 2709 2710 <div style="text-align:center;"> 2711 0.5 + 0.5 × cos(2 π <b><em>u</em></b> × <em class="arg">value</em>). 2712 </div> 2713 2714<p>See also the <a href="#function" >-function</a> operator, which is a 2715multi-value version of evaluate. </p> 2716 2717<div style="margin: auto;"> 2718 <h4><a id="evaluate-sequence"></a>-evaluate-sequence <em class="arg">operator</em></h4> 2719</div> 2720 2721<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> 2722 2723<div style="margin: auto;"> 2724 <h4><a id="extent"></a>-extent <em class="arg">geometry</em></h4> 2725</div> 2726 2727<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> 2728 2729<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> 2730<p>This command reduces or expands a JPEG image to fit on an 800x600 2731display. If the aspect ratio of the input image isn't exactly 4:3, then the 2732image is centered on an 800x600 black canvas: </p> 2733 2734<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> 2735 2736 2737<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> 2738 2739<div style="margin: auto;"> 2740 <h4><a id="extract"></a>-extract <em class="arg">geometry</em></h4> 2741</div> 2742 2743<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> 2744 2745<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p> 2746 2747<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> 2748 2749<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> 2750<p>the image is <em>resized</em> to the specified dimensions instead, 2751equivalent to:</p> 2752 2753<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -resize 640x480 image.rgb image.png</span></p> 2754<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> 2755 2756<div style="margin: auto;"> 2757 <h4><a id="family"></a>-family <em class="arg">fontFamily</em></h4> 2758</div> 2759 2760<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> 2761 2762<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). 2763</p> 2764 2765<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>. 2766</p> 2767 2768<div style="margin: auto;"> 2769 <h4><a id="features"></a>-features <em class="arg">distance</em></h4> 2770</div> 2771 2772<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> 2773 2774<div style="margin: auto;"> 2775 <h4><a id="fft"></a>-fft</h4> 2776</div> 2777 2778<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> 2779 2780<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> 2781 2782<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> 2783 2784<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> 2785 2786<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p> 2787<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> 2788 2789<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.png</span></p> 2790<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> 2791 2792<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> 2793 2794<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> 2795 2796<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br /> 2797 -evaluate log 1000 fft_image_spectrum.png</span></p> 2798<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> 2799 2800<p>The <a href="http://www.fftw.org/">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>.</p> 2801 2802<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> 2803 2804<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> 2805 2806<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> 2807 2808<p>See the discussion on HDRI implementations of ImageMagick on the page 2809<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. 2810</p> 2811 2812 2813<div style="margin: auto;"> 2814 <h4><a id="fill"></a>-fill <em class="arg">color</em></h4> 2815</div> 2816 2817<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> 2818 2819<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> 2820 2821<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p> 2822 2823<p>For example,</p> 2824 2825<p class="crtsnip"> 2826 -fill blue 2827</p> 2828<p class="crtsnip"> 2829 -fill "#ddddff" 2830</p> 2831<p class="crtsnip"> 2832 -fill "rgb(255,255,255)" 2833</p> 2834 2835<p>See <a href="#draw">-draw</a> for further details.</p> 2836 2837<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p> 2838 2839<div style="margin: auto;"> 2840 <h4><a id="filter"></a>-filter <em class="arg">type</em></h4> 2841</div> 2842 2843<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 2844distorting an image.</td><td style='text-align:right;'></td></tr></table> 2845 2846<p>Use this option to affect the resizing operation of an image during 2847operations such as <a href="#resize">-resize</a> and <a href="#distort" 2848>-distort</a>. For example you can use a simple resize filter such as:</p> 2849 2850<pre class="text"> 2851 Point Hermite Cubic 2852 Box Gaussian Catrom 2853 Triangle Quadratic Mitchell 2854</pre> 2855 2856<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided (as well 2857as a faster <kbd>SincFast</kbd> equivalent form). However these filters are 2858generally useless on their own as they are infinite filters that are being 2859clipped to the filters support size. Their direct use is not recommended 2860except via expert settings (see below). </p> 2861 2862<p>Instead these special filter functions are typically windowed by a windowing 2863function that the <a href="#filter" >-filter</a> setting defines. That is 2864using these functions will define a 'Windowed' filter, appropriate to the 2865operator involved. Windowed filters include: </p> 2866 2867<pre class="text"> 2868 Lanczos Hamming Parzen 2869 Blackman Kaiser Welsh 2870 Hanning Bartlett Bohman 2871</pre> 2872 2873<p>Also one special self-windowing filter is also provided 2874<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending 2875on the current 'support' or 'lobes' expert settings (see below).</p> 2876 2877<p>If you do not select a filter with this option, the filter defaults to 2878<kbd>Mitchell</kbd> for a colormapped image, a image with a matte channel, or 2879if the image is enlarged. Otherwise the filter default to 2880<kbd>Lanczos</kbd>.</p> 2881 2882<p>To print a complete list of resize filters, use the <a href="#list">-list 2883filter</a> option.</p> 2884 2885<p>You can modify how the filter behaves as it scales your image through the 2886use of these expert settings (see also <a href="#define" >-define</a> and <a 2887href="#set" >-set</a>):-</p> 2888 2889<dl class="doc"> 2890<dt>-define filter:blur=<em>factor</em></dt> 2891<dd>Scale the X axis of the filter (and its window). Use > 1.0 for 2892 blurry or < 1.0 for sharp. This should only be used with Gaussian and 2893 Gaussian-like filters simple filters, or you may not get the expected 2894 results. </dd> 2895 2896<dt>-define filter:support=<em>radius</em></dt> 2897<dd>Set the filter support radius. Defines how large the filter should be and 2898 thus directly defines how slow the filtered resampling process is. All 2899 filters have a default 'prefered' support size. Some filters like 2900 <kbd>Lagrange</kbd> and windowed filters adjust themselves depending on 2901 this value. With simple filters this value either does nothing (but slow 2902 the resampling), or will clip the filter function in a detrimental way. 2903 </dd> 2904 2905<dt>-define filter:lobes=<em>count</em></dt> 2906<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an 2907 alternative way of specifying the 'support' range of the filter, that is 2908 designed to be more suited to windowed filters, especially when used for 2909 image distorts.</dd> 2910 2911<dt>-define filter:b=<em>b-spline_factor</em></dt> 2912<dt>-define filter:c=<em>keys_alpha_factor</em></dt> 2913<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>, 2914 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as 2915 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values 2916 are defined, the other is set so as to generate a 'Keys' type cubic 2917 filter. Values meaning was defined by a research paper by 2918 Mitchell-Netravali.</dd> 2919 2920<dt>-define filter:filter=<em>filter_function</em></dt> 2921<dd>Use this function directly as the scaling filter. This will allow 2922 you to directly use a windowing filter such as <kbd>Blackman</kbd>, 2923 rather than as its normal usage as a windowing function for 'Sinc' or 2924 'Bessel' functions. If defined, no windowing function is used, unless the 2925 following expert setting is also defined.</dd> 2926 2927<dt>-define filter:window=<em>filter_function</em></dt> 2928<dd>The IIR (infinite impulse response) filters <kbd>Bessel</kbd> and 2929 <kbd>Sinc</kbd> are windowed (brought down to zero over the defined 2930 support range) with the given filter. This allows you to specify a filter 2931 function that is not normally used as a windowing function, such as 2932 <kbd>Box</kbd>, (which effectively turns off the windowing function), 2933 to window a <kbd>Sinc</kbd>, or the function the previous setting defined. 2934 </dd> 2935 2936<dt>-define filter:verbose=<em>1</em></dt> 2937<dd>This causes IM to print information on the final internal filter 2938 selection to standard output. This includes a commented header on the 2939 filter settings being used, and data allowing the filter weights to be 2940 easily graphed. </dd> 2941 2942<dd>Note however that some filters are internally defined in terms of other 2943 filters. The <kbd>Lanczos</kbd> filter for example is defined in terms of 2944 a <kbd>SincFast</kbd> windowed <kbd>SincFast</kbd> filter, while 2945 <kbd>Mitchell</kbd> is defined as a <kbd>Cubic</kbd> filter with specific 2946 'B' and 'C' settings. </dd> 2947 2948</dl> 2949 2950<p>For example, to get a 8 lobe Bessel windowed Bessel filter:</p> 2951 2952<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -filter bessel \ <br/> 2953 -set filter:window=bessel -set filter:lobes=8 \ <br/> 2954 -resize 150% image.jpg</span></p> 2955<p>Or a raw un-windowed Sinc filter with 4 lobes:</p> 2956 2957<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/> 2958 -resize 150% image.jpg</span></p> 2959<p>Note that the use of expert options (except for 'blur' with simple resize 2960filters, and 'verbose' for viewing the internal filter selection), are 2961provided for image processing experts who have studied and understood how 2962resize filters work. Without this knowledge, and an understanding of the 2963definition of the actual filters involved, using expert settings are more 2964likely to be detrimental to your image resizing.</p> 2965 2966 2967<div style="margin: auto;"> 2968 <h4><a id="flatten"></a>-flatten</h4> 2969</div> 2970 2971<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> 2972 2973 2974<div style="margin: auto;"> 2975 <h4><a id="flip"></a>-flip</h4> 2976</div> 2977 2978<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> 2979 2980<p>reflect the scanlines in the vertical direction.</p> 2981 2982<div style="margin: auto;"> 2983 <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> 2984</div> 2985 2986<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. Using <a href="#fuzz" >-fuzz</a> to floodfill pixels which only change by a small amount.</td><td style='text-align:right;'></td></tr></table> 2987 2988<div style="margin: auto;"> 2989 <h4><a id="flop"></a>-flop</h4> 2990</div> 2991 2992<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> 2993 2994<p>reflect the scanlines in the horizontal direction.</p> 2995 2996 2997<div style="margin: auto;"> 2998 <h4><a id="font"></a>-font <em class="arg">name</em></h4> 2999</div> 3000 3001<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> 3002 3003<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> 3004 3005<p>In addition to the fonts specified by the above pre-defined list, you can 3006also specify a font from a specific source. For example <kbd>Arial.ttf</kbd> 3007is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and 3008<kbd>x:fixed</kbd> is X11 font.</p> 3009 3010<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> 3011 3012 3013<div style="margin: auto;"> 3014 <h4><a id="foreground"></a>-foreground <em class="arg">color</em></h4> 3015</div> 3016 3017<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> 3018 3019<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 3020 3021<p>The default foreground color is black.</p> 3022 3023<div style="margin: auto;"> 3024 <h4><a id="format"></a>-format <em class="arg">type</em></h4> 3025</div> 3026 3027<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> 3028 3029<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> 3030 3031<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> 3032 3033<div style="margin: auto;"> 3034 <h4><a id="format_identify_"></a>-format <em class="arg">string</em></h4> 3035</div> 3036 3037<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> 3038 3039<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> 3040 3041<div style="margin: auto;"> 3042 <h4><a id="frame"></a>-frame <em class="arg">geometry</em></h4> 3043</div> 3044 3045<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> 3046 3047<p>The color of the border is specified with the <a href="#mattecolor" 3048>-mattecolor</a> command line option. </p> 3049 3050<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 3051class="arg">geometry</em> argument indicates the amount of extra width and 3052height that is added to the dimensions of the image. If no offsets are given 3053in the <em class="arg">geometry</em> argument, then the border added is 3054a solid color. Offsets <em>x</em> and <em>y</em>, if present, specify that 3055the width and height of the border is partitioned to form an outer bevel of 3056thickness <em>x</em> pixels and an inner bevel of thickness 3057<em>y</em> pixels. Negative offsets make no sense as frame arguments. 3058</p> 3059 3060<p>The <a href="#frame">-frame</a> option is affected by the current <a 3061href="#compose">-compose</a> setting and assumes that this is using the default 3062'<kbd>Over</kbd>' composition method. It generates a image of the appropriate 3063size with the current <a href="#bordercolor">-bordercolor</a> setting, and then 3064draws the frame of four distinct colors close to the current <a 3065href="#mattecolor">-mattecolor</a>. The original image is then overlaid onto 3066center of this image. This means that with the default compose method of 3067'<kbd>Over</kbd>' any transparent parts may be replaced by the current <a 3068href="#bordercolor">-bordercolor</a> setting.</p> 3069 3070<p>The image composition is not 3071affected by the <a href="#gravity">-gravity</a> option.</p> 3072 3073 3074<div style="margin: auto;"> 3075 <h4><a id="frame_import_"></a>-frame</h4> 3076</div> 3077 3078<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> 3079 3080<div style="margin: auto;"> 3081 <h4><a id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4> 3082</div> 3083 3084<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> 3085 3086<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> 3087 3088<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> 3089 3090<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> 3091 3092<pre class="text"> 3093 Polynomial 3094 Sinusoid 3095 Arcsin 3096 Arctan 3097</pre> 3098 3099<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p> 3100 3101<dl class="doc"> 3102<dt><kbd>Polynomial</kbd></dt> 3103<dd> 3104<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> 3105 3106<div style="text-align: center"> 3107 -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> 3108</div> 3109 3110<p>will invoke a polynomial function given by</p> 3111 3112<div style="text-align: center"> 3113 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> + 3114 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> + 3115 ··· <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>, 3116</div> 3117 3118<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p> 3119 3120<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> 3121 3122<table class="doc"> 3123 <col width="35%" /> 3124 <col width="35%" /> 3125 <col width="30%" /> 3126 <tr> 3127 <td>-evaluate Set <em class="arg">value</em> </td> 3128 <td>-function Polynomial <em class="arg">value</em></td> 3129 <td>(Constant functions; set <em class="arg">value</em>×100% gray when channels are RGB.)</td> 3130 </tr> 3131 <tr> 3132 <td>-evaluate Add <em class="arg">value</em> </td> 3133 <td>-function Polynomial 1,<em class="arg">value</em></td> 3134 </tr> 3135 <tr> 3136 <td>-evaluate Subtract <em class="arg">value</em> </td> 3137 <td>-function Polynomial 1,−<em class="arg">value</em></td> 3138 </tr> 3139 <tr> 3140 <td>-evaluate Multiply <em class="arg">value</em> </td> 3141 <td>-function Polynomial <em class="arg">value</em>,0</td> 3142 </tr> 3143 <tr> 3144 <td>+level black% x white%</td> 3145 <td>-function Polynomial A,B</td> 3146 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td> 3147 </tr> 3148</table> 3149 3150<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> 3151</dd> 3152 3153<dt><kbd>Sinusoid</kbd></dt> 3154<dd> 3155<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> 3156 3157<div style="text-align: center"> 3158 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]] 3159</div> 3160 3161<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> 3162 3163<div style="text-align: center"> 3164<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> 3165</div> 3166 3167<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> 3168 3169<p class="crtsnip"> 3170 -function Sinusoid 3,-90,.2,.7 3171</p> 3172 3173<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> 3174 3175<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> 3176 3177<table class="doc"> 3178 <tr> 3179 <td>-evaluate Sin <em class="arg">freq</em> </td> 3180 <td>-function Sinusoid <em class="arg">freq</em>,0 </td> 3181 </tr> 3182 <tr> 3183 <td>-evaluate Cos <em class="arg">freq</em> </td> 3184 <td>-function Sinusoid <em class="arg">freq</em>,90 </td> 3185 </tr> 3186</table> 3187</dd> 3188 3189<dt><kbd>ArcSin</kbd></dt> 3190<dd> 3191<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid, 3192and can be used to generate cylindrical distortion and displacement maps. 3193The curve can be adjusted relative to both the input values and output range 3194of values.</p> 3195 3196<p style="text-align: center"> 3197 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3198</p> 3199 3200<p>with all values given in terms of noramlize color values (0.0 for black, 32011.0 for white). Defaulting to values covering the full range from 0.0 to 1.0 3202for bout input (<em class="arg">width</em>), and output (<em 3203class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p> 3204 3205<p style="text-align: center"> 3206<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> 3207</p> 3208 3209</dd> 3210 3211<dt><kbd>ArcTan</kbd></dt> 3212<dd> 3213<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from 3214limit values at infinities, though a center using the given slope value. 3215All these values can be adjusted via the arguments.</p> 3216 3217<p style="text-align: center"> 3218 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3219</p> 3220 3221<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'. 3222</p> 3223 3224<p style="text-align: center"> 3225<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> 3226</p> 3227 3228</dd> 3229 3230</dl> 3231 3232 3233<div style="margin: auto;"> 3234 <h4><a id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4> 3235</div> 3236 3237<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> 3238 3239<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> 3240 3241<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> 3242 3243 3244<div style="margin: auto;"> 3245 <h4><a id="fx"></a>-fx <em class="arg">expression</em></h4> 3246</div> 3247 3248<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> 3249 3250<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> 3251 3252<p>See <a href="/www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p> 3253 3254 3255<div style="margin: auto;"> 3256 <h4><a id="gamma"></a>-gamma <em class="arg">value</em></h4> 3257</div> 3258 3259<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> 3260 3261<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> 3262 3263<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> 3264 3265<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> 3266 3267<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> 3268 3269<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p> 3270 3271<div style="margin: auto;"> 3272 <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> 3273</div> 3274 3275<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> 3276 3277<p>Convolve the image with a Gaussian or normal distribution using the given 3278<em class="arg" >Sigma</em> value. The formula is:</p> 3279 3280<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 3281</div> 3282 3283<p>The <em class="arg" >Sigma</em> value is the important argument, and 3284determines the actual amount of blurring that will take place. </p> 3285 3286<p>The <em class="arg" >Radius</em> is only used to determine the size of the 3287array which will hold the calculated Gaussian distribution. It should be an 3288integer. If not given, or set to zero, IM will calculate the largest possible 3289radius that will provide meaningful results for the Gaussian distribution. 3290</p> 3291 3292<p>The larger the <em class="arg" >Radius</em> the radius the slower the 3293operation is. However too small a <em class="arg" >Radius</em>, and sever 3294aliasing effects may result. As a guideline, <em class="arg" >Radius</em> 3295should be at least twice the <em class="arg" >Sigma</em> value, though three 3296times will produce a more accurite result. </p> 3297 3298<p>This differs from the faster <a href="#blur">-blur</a> operator in that a 3299full 2-dimensional convolution is used to generate the weighted average of the 3300neighboring pixels. </p> 3301 3302<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 3303pixels which are outside the image proper are blurred into the final result. 3304</p> 3305 3306 3307<div style="margin: auto;"> 3308 <h4><a id="geometry"></a>-geometry <em class="arg">geometry</em></h4> 3309</div> 3310 3311<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> 3312 3313<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> 3314 3315<div style="margin: auto;"> 3316 <h4><a id="gravity"></a>-gravity <em class="arg">type</em></h4> 3317</div> 3318 3319<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> 3320 3321<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>, 3322<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>, 3323<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete 3324list of <a href="#gravity">-gravity</a> settings available in your ImageMagick 3325installation.</p> 3326 3327<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> 3328 3329<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> 3330 3331<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> 3332 3333<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> 3334<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> 3335 3336<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> 3337 3338 3339<div style="margin: auto;"> 3340 <h4><a id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4> 3341</div> 3342 3343<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> 3344 3345 3346<div style="margin: auto;"> 3347 <h4><a id="hald-clut"></a>-hald-clut</h4> 3348</div> 3349 3350<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> 3351 3352<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2 3353dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You 3354can apply any color transformation to the Hald image and then use this option 3355to apply the transform to the image. </p> 3356 3357<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p> 3358<p>This option provides a convenient method for you to use Gimp or Photoshop 3359to make color corrections to the Hald CLUT image and subsequently apply them 3360to multiple images using an ImageMagick script. </p> 3361 3362<p>Note that the representation is only of the normal RGB color space and that 3363the whole color value triplet is used for the interpolated lookup of the 3364represented Hald color cube image. Because of this the operation is not <a 3365href="#channel" >-channel</a> setting effected, nor can it adjust or modify an 3366images transparency or alpha/matte channel.</p> 3367 3368<p>See also <a href="#clut" >-clut</a> which provides color value replacement 3369of the individual color channels, usally involving a simplier gray-scale 3370image. E.g: gray-scale to color replacement, or modification by a histogram 3371mapping. </p> 3372 3373 3374<div style="margin: auto;"> 3375 <h4><a id="help"></a>-help</h4> 3376</div> 3377 3378<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> 3379 3380<div style="margin: auto;"> 3381 <h4><a id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4> 3382</div> 3383 3384<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> 3385 3386<div style="margin: auto;"> 3387 <h4><a id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4> 3388</div> 3389 3390<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> 3391 3392<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> 3393 3394<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> 3395 3396<div style="margin: auto;"> 3397 <h4><a id="iconic"></a>-iconic</h4> 3398</div> 3399 3400<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> 3401 3402<div style="margin: auto;"> 3403 <h4><a id="identify"></a>-identify</h4> 3404</div> 3405 3406<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> 3407 3408<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> 3409 3410<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> 3411 3412<p>If <a href="#verbose">-verbose</a> precedes this option, copious 3413amounts of image properties are displayed including image statistics, profiles, 3414image histogram, and others.</p> 3415 3416<div style="margin: auto;"> 3417 <h4><a id="ift"></a>-ift</h4> 3418</div> 3419 3420<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> 3421 3422<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> 3423 3424<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> 3425 3426<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p> 3427<p>or</p> 3428 3429<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> 3430 3431<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> 3432 3433<p>The <a href="http://www.fftw.org/">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>.</p> 3434 3435<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> 3436 3437<div style="margin: auto;"> 3438 <h4><a id="immutable"></a>-immutable</h4> 3439</div> 3440 3441<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> 3442 3443<div style="margin: auto;"> 3444 <h4><a id="implode"></a>-implode <em class="arg">factor</em></h4> 3445</div> 3446 3447<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> 3448 3449<div style="margin: auto;"> 3450 <h4><a id="insert"></a>-insert <em class="arg">index</em></h4> 3451</div> 3452 3453<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> 3454 3455<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> 3456 3457<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> 3458 3459<div style="margin: auto;"> 3460 <h4><a id="intent"></a>-intent <em class="arg">type</em></h4> 3461</div> 3462 3463<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> 3464 3465<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> 3466 3467<p>The default intent is undefined.</p> 3468 3469<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p> 3470 3471<div style="margin: auto;"> 3472 <h4><a id="interlace"></a>-interlace <em class="arg">type</em></h4> 3473</div> 3474 3475<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> 3476 3477<p>Choose from:</p> 3478 3479<pre class="text"> 3480 none 3481 line 3482 plane 3483 partition 3484 JPEG 3485 GIF 3486 PNG 3487</pre> 3488 3489<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> 3490 3491<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p> 3492 3493<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p> 3494 3495<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p> 3496 3497<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R, 3498image.G, and image.B).</p> 3499 3500<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> 3501image.</p> 3502 3503<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p> 3504 3505<div style="margin: auto;"> 3506 <h4><a id="interpolate"></a>-interpolate <em class="arg">type</em></h4> 3507</div> 3508 3509<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> 3510 3511<p>When looking up the color of a pixel using a non-integer floating point 3512value, you typically fall in between the pixel colors defined by the source 3513image. This setting determines how the color is determined from the colors of 3514the pixels surrounding that point. That is how to determine the color of a 3515point that falls between two, or even four different colored pixels. </p> 3516 3517<pre class="text"> 3518 integer: The color of the top-left pixel (floor function) 3519 nearest-neighbor: The nearest pixel to the lookup point (rounded function) 3520 average: The average color of the surrounding four pixels 3521 bilinear A double linear interpolation of pixels (the default) 3522 mesh Divide area into two flat triangular interpolations 3523 bicubic Fitted bicubic-spines of surrounding 16 pixels 3524 spline Direct spline curves (colors are blurred) 3525 filter Use resize <a href="#filter">-filter</a> settings 3526</pre> 3527 3528<p>This most important for distortion operators such as <a href="#distort" 3529>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform" 3530>-transform</a> and <a href="#fx" >-fx</a>. </p> 3531 3532<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p> 3533 3534<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the 3535lookup for positions outside the boundaries of the image. </p> 3536 3537 3538<div style="margin: auto;"> 3539 <h4><a id="interline-spacing"></a>-interline-spacing <em class="arg">value</em></h4> 3540</div> 3541 3542<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> 3543 3544<div style="margin: auto;"> 3545 <h4><a id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4> 3546</div> 3547 3548<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> 3549 3550<div style="margin: auto;"> 3551 <h4><a id="kerning"></a>-kerning <em class="arg">value</em></h4> 3552</div> 3553 3554<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> 3555 3556<div style="margin: auto;"> 3557 <h4><a id="label"></a>-label <em class="arg">name</em></h4> 3558</div> 3559 3560<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> 3561 3562<p>Use this option to assign a specific label to the image, as it is read in 3563or created. You can use the <a href="#set" >-set</a> operation to re-assign 3564a the labels of images already read in. Image formats such as TIFF, PNG, 3565MIFF, supports saving the label information with the image.</p> 3566 3567<p>When saving an image to a <em class="arg">PostScript</em> file, any label 3568assigned to an image is used as a header string to print above the postscript 3569image. </p> 3570 3571<p>You can include the image filename, type, width, height, or other image 3572attribute by embedding special format character. See <a href="/www/escape.html">Format and Print Image 3573Properties</a> for details of the percent escape codes.</p> 3574 3575<p>For example,</p> 3576 3577<p class="crtsnip"> 3578 -label "%m:%f %wx%h" bird.miff 3579</p> 3580 3581<p>assigns an image label of <kbd>MIFF:bird.miff 512x480</kbd> to the 3582"<kbd>bird.miff</kbd>" image and whose width is 512 and height is 480, as it 3583is read in. If a <a href="#label">+label</a> option was used instead, any 3584existing label present in the image would be used. You can remove all labels 3585from an image by assigning the empty string. </p> 3586 3587<p>A label is not drawn on the image, but is embedded in the image datastream 3588via <em>Label</em> tag or similar mechanism. If you want the label to be 3589visible on the image itself, use the <a href="#draw">-draw</a> option, or 3590during the final processing in the creation of a image montage.</p> 3591 3592<p>If the first character of <em class="arg">string</em> is <em 3593class="arg">@</em>, the image label is read from a file titled by the 3594remaining characters in the string. Labels in a file are literal, no embedded 3595formatting characters are recognized.</p> 3596 3597 3598<div style="margin: auto;"> 3599 <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> 3600</div> 3601 3602<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> 3603 3604<p>Adaptively threshold each pixel based on the value of pixels in a 3605surrounding window. If the current pixel is lighter than this average plus 3606the optional <kbd>offset</kbd>, then it is made white, otherwise it is made 3607black. Small variations in pixel values such as found in scanned documents 3608can be ignored if offset is positive. A negative offset will make it more 3609sensitive to those small variations. </p> 3610 3611<p>This is commonly used to threshold images with an uneven background. It is 3612based on the assumption that average color of the small window is the 3613the local background color, from which to separate the forground color. </p> 3614 3615 3616<div style="margin: auto;"> 3617 <h4><a id="layers"></a>-layers <em class="arg">method</em></h4> 3618</div> 3619 3620<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> 3621 3622<p>Perform various image operation methods to a ordered sequence of images 3623which may represent either a set of overlaid 'image layers', a GIF disposal 3624animation, or a fully-'coalesced' animation sequence. </p> 3625 3626<table class="doc"> 3627 <tbody> 3628 <tr valign="top"> 3629 <th align="left" style="width: 8%">Method</th> 3630 <th align="left">Description</th> 3631 </tr> 3632 3633 <tr valign="top"> 3634 <td valign="top">compare-any</td> 3635 <td valign="top">Crop the second and later frames to the smallest rectangle 3636 that contains all the differences between the two images. No GIF <a 3637 href="#dispose" >-dispose</a> methods are taken into account. </td> 3638 </tr> 3639 3640 <tr><td></td><td>This exactly the same as the <a href="#deconstruct" 3641 >-deconstruct</a> operator, and does not preserve animations normal 3642 working, especially when animation used layer disposal methods such as 3643 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td> 3644 </tr> 3645 3646 <tr valign="top"> 3647 <td valign="top">compare-clear</td> 3648 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any 3649 opaque pixels which become transparent in the second frame. That is the 3650 smallest image needed to mask or erase pixels for the next frame. </td> 3651 </tr> 3652 3653 <tr valign="top"> 3654 <td valign="top">compare-overlay</td> 3655 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add 3656 extra color to the next image, as a result of overlaying color pixels. 3657 That is the smallest single overlaid image to add or change colors. </td> 3658 </tr> 3659 3660 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha 3661 composition method '<kbd>change-mask</kbd>', to reduce the image to 3662 just the pixels that need to be overlaid. </td> 3663 </tr> 3664 3665 <tr valign="top"> 3666 <td valign="top">coalesce</td> 3667 <td valign="top">Equivalent to a call to the <a href="#coalesce" 3668 >-coalesce</a> operator. Apply the layer disposal methods set in the 3669 current image sequence to form a fully defined animation sequence, as 3670 it should be displayed. Effectively converting a GIF animation into a 3671 'film strip'-like animation. </td> 3672 </tr> 3673 3674 <tr valign="top"> 3675 <td valign="top">composite</td> 3676 <td valign="top">Alpha Composition of two image lists, separated by a 3677 "<kbd>null:</kbd>" image, with the destination image list first, and 3678 the source images last. An image from each list are composited 3679 together until one list is finished. The separator image and source 3680 image lists are removed. </td> 3681 </tr> 3682 3683 3684 <tr><td></td> 3685 <td>The <a href="#geometry" >-geometry</a> offset is adjusted according 3686 to <a href="#gravity" >-gravity</a> in accordance of the virtual 3687 canvas size of the first image in each list. Unlike a normal <a 3688 href="#composite" >-composite</a> operation, the canvas offset is also 3689 added to the final composite positioning of each image. </td> </tr> 3690 3691 <tr><td></td> 3692 <td>If one of the image lists only contains one image, that image is 3693 applied to all the images in the other image list, regardless of which 3694 list it is. In this case it is the image meta-data of the list which 3695 preserved. </td> 3696 </tr> 3697 3698 3699 <tr valign="top"> 3700 <td valign="top">dispose</td> 3701 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of 3702 the animation after the layer disposal method has been applied, before 3703 the next sub-frame image is overlaid. That is the 'dispose' image that 3704 results from the application of the GIF <a href="#dispose" 3705 >-dispose</a> method. This allows you to check what 3706 is going wrong with a particular animation you may be developing. 3707 </td> 3708 </tr> 3709 3710 <tr valign="top"> 3711 <td valign="top">flatten</td> 3712 <td valign="top">Create a canvas the size of the first images virtual 3713 canvas using the current <a href="#background" >-background</a> color, 3714 and <a href="#compose" >-compose</a> each image in turn onto that 3715 canvas. Images falling outside that canvas is clipped. Final 3716 image will have a zero virtual canvas offset. </td> 3717 </tr> 3718 3719 <tr><td></td> 3720 <td>This usally used as one of the final 'image layering' operations 3721 overlaying all the prepared image layers into a final image. </td> 3722 </tr> 3723 3724 <tr><td></td> 3725 <td>For a single image this method can also be used to fillout a virtual 3726 canvas with real pixels, or to underlay a opaque color to remove 3727 transparency from an image.</td> 3728 </tr> 3729 3730 3731 <tr valign="top"> 3732 <td valign="top">merge</td> 3733 <td valign="top">As 'flatten' method but merging all the given image 3734 layers into a new layer image just large enough to hold all the image 3735 without clipping or extra space. The new images virtual offset will 3736 prevere the position of the new layer, even if this offset is 3737 negative. the virtual canvas size of the first image is preserved. 3738 </td> 3739 </tr> 3740 3741 <tr><td></td><td>Caution is advised when handling image layers with negative offsets 3742 as few image file formats handle them correctly. </td> 3743 </tr> 3744 3745 <tr valign="top"> 3746 <td valign="top">mosaic</td> 3747 <td valign="top">As 'flatten' method but expanding the initial canvas size 3748 of the first image so as to hold all the image layers. However as a 3749 virtual canvas is 'locked' to the origin, by definition, image layers 3750 with a negative offsets will still be clipped by the top and left 3751 edges.</td> 3752 </tr> 3753 3754 <tr><td></td><td>This method is commonly used to layout individual image using various 3755 offset but without knowing the final canvas size. The resulting image 3756 will, like 'flatten' not have any virtual offset, so can be saved to 3757 any image file format. </td> 3758 </tr> 3759 3760 3761 <tr valign="top"> 3762 <td valign="top">optimize</td> 3763 <td valign="top">Optimize a coalesced animation, into GIF animation using 3764 a number of general techniques. This currently a short cut to 3765 apply both the '<kbd>optimize-frame</kbd>', and 3766 '<kbd>optimize-transparency</kbd>' methods but may be expanded to 3767 include other optimization methods as they are developed. </td> 3768 </tr> 3769 3770 <tr valign="top"> 3771 <td valign="top">optimize-frame</td> 3772 <td valign="top">Optimize a coalesced animation, into GIF animation by 3773 reducing the number of pixels per frame as much as possible by 3774 attempting to pick the best layer disposal method to use, while ensuring 3775 the result will continue to animate properly. </td> 3776 </tr> 3777 3778 <tr><td></td><td> There is no guarantee that the best optimization is found. But 3779 then no reasonably fast GIF optimization algorithm can do this. 3780 However this does seem to do better than most other GIF frame 3781 optimizers seen. </td> 3782 </tr> 3783 3784 <tr valign="top"> 3785 <td valign="top">optimize-plus</td> 3786 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the 3787 overall optimization by adding extra frames to the animation, without 3788 changing the final look or timing of the animation. The frames are 3789 added to attempt to separate the clearing of pixels from the 3790 overlaying of new additional pixels from one animation frame to the 3791 next. If this does not improve the optimization (for the next frame 3792 only), it will fall back to the results of the previous normal 3793 '<kbd>optimize-frame</kbd>' technique. </td> 3794 </tr> 3795 3796 <tr><td></td><td>There is the possibility that the change in the disposal style will 3797 result in a worsening in the optimization of later frames, though this 3798 is unlikely. In other words there no guarantee that it is better than 3799 the normal '<kbd>optimize-frame</kbd>' technique. For some animations 3800 however you can get a vast improvement in the final animation size. </td> 3801 </tr> 3802 3803 <tr valign="top"> 3804 <td valign="top">optimize-transparency</td> 3805 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame 3806 overlay images with transparency, if it does not change the resulting 3807 animation by more than the current <a href="#fuzz" >-fuzz</a> factor. 3808 </td> 3809 </tr> 3810 3811 <tr><td></td><td>This should allow a existing frame optimized GIF animation to compress 3812 into a smaller file size due to larger areas of one (transparent) 3813 color rather than a pattern of multiple colors repeating the current 3814 disposed image of the last frame. </td> 3815 </tr> 3816 3817 <tr valign="top"> 3818 <td valign="top">remove-dups</td> 3819 <td valign="top">Remove (and merge time delays) of duplicate consecutive 3820 images, so as to simplify layer overlays of coalesced animations. 3821 </td> 3822 </tr> 3823 3824 <tr><td></td><td>Usually this a result of using a constant time delay across the 3825 whole animation, or after a larger animation was split into smaller 3826 sub-animations. The duplicate frames could also have been used as 3827 part of some frame optimization methods. </td> 3828 </tr> 3829 3830 <tr valign="top"> 3831 <td valign="top">remove-zero</td> 3832 <td valign="top">Remove any image with a zero time delay, unless ALL the 3833 images have a zero time delay (and is not a proper timed animation, a 3834 warning is then issued). </td> 3835 </tr> 3836 3837 <tr><td></td><td>In a GIF animation, such images are usually frames which provide 3838 partial intermediary updates between the frames that are actually 3839 displayed to users. These frames are usally added for improved frame 3840 optimization in GIF animations. </td> 3841 </tr> 3842 3843 <tr valign="top"> 3844 <td valign="top">trim-bounds</td> 3845 <td valign="top">Find the bounds of all the images in the current 3846 image sequence, then adjust the offsets so all images are contained on 3847 a minimal positive canvas. None of the image data is modified, only 3848 there virtual canvas size and offset. The all the image is given 3849 the same canvas size, and and will have a positive offset, but will 3850 remain in the same position relative to each other. As a result of the 3851 minimal canvas size at least one image will touch every edge of that 3852 canvas. The image data however may be transparent. 3853 </td> 3854 </tr> 3855 3856 </tbody> 3857</table> 3858 3859<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p> 3860 3861<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct" 3862>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic" 3863>-mosaic</a> are only aliases for the above methods. Also see <a 3864href="#page" >-page</a>, <a href="#repage" >-repage</a> operators, the <a 3865href="#compose" >-compose</a> setting, and the GIF <a href="#dispose" 3866>-dispose</a> and <a href="#delay" >-delay</a> settings. </p> 3867 3868 3869<div style="margin: auto;"> 3870 <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> 3871</div> 3872 3873<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> 3874 3875<p>Given one, two or three values delimited with commas: black-point, 3876white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and 3877white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white 3878point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center 3879contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string, 3880both black and white points are percentages of the full color range. Gamma 3881will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is 3882omitted, the default of 1.0 (no gamma correction) is assumed.</p> 3883 3884<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that 3885the given '<kbd>black_point</kbd>' value in the original image is set to 3886zero (or black), while the given '<kbd>white_point</kbd>' value is set to 3887<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments 3888to the image. The '<kbd>gamma</kbd>' of the resulting image will then be 3889adjusted. </p> 3890 3891<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or 3892adding the special '!' flag anywhere in the argument list, will cause the 3893operator to do the reverse of the level adjustment. That is a zero, or 3894<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is 3895adjusted to the given level values, allowing you to de-contrast, or compress 3896the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p> 3897 3898<p>Only the channels defined by the current <a href="#channel">-channel</a> 3899setting are adjusted (defaults to RGB color channels only), allowing you to 3900limit the effect of this operator. </p> 3901 3902<p>Please note that the transparency channel is treated as 'matte' 3903values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 3904 3905 3906<div style="margin: auto;"> 3907 <h4><a id="level-colors"></a>-level-colors {<em 3908 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4> 3909</div> 3910 3911<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> 3912 3913<p>This function is exactly like <a href="#level">-level</a>, except that the 3914value value for each color channel is determined by the 3915'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as 3916described under the <a href="#fill">-fill</a> option). </p> 3917 3918<p>This effectually means the colors provided to <kbd>-level-colors</kbd> 3919is mapped to become 'black' and 'white' respectively, with all the other 3920colors linearly adjusted (or clipped) to match that change. Each channel is 3921adjusted separately using the channel values of the colors specified. </p> 3922 3923<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>) 3924will map the image color 'black' and 'white' to the given colors 3925respectively, resulting in a gradient (de-contrasting) tint of the image to 3926those colors. This can also be used to convert a plain gray-scale image into a 3927one using the gradient of colors specified. </p> 3928 3929<p>By supplying a single color with a comma separator either before or after 3930that color, will just replace the respective 'black' or 'white' point 3931respectively. But if no comma separator is provided, the given color is 3932used for both the black and white color points, making the operator either 3933threshold the images around that color (- form) or set all colors to that 3934color (+ form). </p> 3935 3936 3937<div style="margin: auto;"> 3938 <h4><a id="limit"></a>-limit <em class="arg">type value</em></h4> 3939</div> 3940 3941<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> 3942 3943<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> 3944 3945<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> 3946 3947<p class="crtsnip"> 3948 -limit memory 32MiB -limit map 64MiB 3949</p> 3950 3951<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p> 3952 3953<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>identify -list resource</span><span class='crtout'></span></p><pre class="text"> 3954File Area Memory Map Disk Thread Time 3955------------------------------------------------------------------------------ 3956 768 12.404GB 8.6642GiB 23.104GiB 18.446744EB 8 unlimited 3957</pre> 3958 3959<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> 3960 3961<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> 3962 3963<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> 3964 3965<p class="crtsnip"> 3966-limit area 10mb 3967</p> 3968 3969<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> 3970 3971<p class="crtsnip"> 3972-limit area 10mb -limit disk 500mb 3973</p> 3974 3975<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p> 3976 3977<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> 3978 3979<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. 3980</p> 3981 3982<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. 3983</p> 3984 3985<div style="margin: auto;"> 3986 <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> 3987</div> 3988 3989<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> 3990 3991<p>This is very similar to <a href="#contrast-stretch" >-contrast-stretch</a>, 3992and uses a 'histogram bin' to determine the range of color values that needs to 3993be stretched. However it then stretchs those colors using the <a 3994href="#level" >-level</a> operator.</p> 3995 3996<p>As such while the initial determination may have 'binning' round off 3997effects, the image colors are stretched mathematically, rather than using the 3998histogram bins. This makes the operator more accurate. </p> 3999 4000<p>note however that a <a href="#linear-stretch" >-linear-stretch</a> of 4001'<kbd>0</kbd>' does nothing, while a value of '<kbd>1</kbd>' does a near 4002perfect stretch of the color range. </p> 4003 4004<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 4005normalization of mathematical images. </p> 4006 4007<p>This operator is under review for re-development. </p> 4008 4009 4010<div style="margin: auto;"> 4011 <h4><a id="linewidth"></a>-linewidth</h4> 4012</div> 4013 4014<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> 4015 4016<div style="margin: auto;"> 4017 <h4><a id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4> 4018</div> 4019 4020<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> 4021 4022<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> 4023 4024<div style="margin: auto;"> 4025 <h4><a id="list"></a>-list <em class="arg">type</em></h4> 4026</div> 4027 4028<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> 4029 4030<pre class="text"> 4031 Align 4032 Alpha 4033 Boolean 4034 Channel 4035 Class 4036 ClipPath 4037 Coder 4038 Color 4039 Colorspace 4040 Command 4041 Compose 4042 Compress 4043 Configure 4044 DataType 4045 Debug 4046 Decoration 4047 Delegate 4048 Direction 4049 Dispose 4050 Distort 4051 Dither 4052 Endian 4053 Evaluate 4054 FillRule 4055 Filter 4056 Font 4057 Format 4058 Function 4059 Gravity 4060 ImageList 4061 Intent 4062 Interlace 4063 Interpolate 4064 Kernel 4065 Layers 4066 LineCap 4067 LineJoin 4068 List 4069 Locale 4070 LogEvent 4071 Log 4072 Magic 4073 Method 4074 Metric 4075 Mime 4076 Mode 4077 Morphology 4078 Module 4079 Noise 4080 Orientation 4081 Policy 4082 PolicyDomain 4083 PolicyRights 4084 Preview 4085 Primitive 4086 QuantumFormat 4087 Resource 4088 SparseColor 4089 Storage 4090 Stretch 4091 Style 4092 Threshold 4093 Type 4094 Units 4095 Validate 4096 VirtualPixel 4097</pre> 4098 4099<p>These lists vary depending on your version of ImageMagick. Use "<kbd>-list 4100list</kbd>" to get a complete listing of all the "<kbd>-list</kbd>" arguments 4101available:</p> 4102 4103<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>identify -list list</span></p> 4104<div style="margin: auto;"> 4105 <h4><a id="log"></a>-log <em class="arg">string</em></h4> 4106</div> 4107 4108<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> 4109 4110<p>This option specifies the format for the log printed when the <a 4111href="#debug">-debug</a> option is active.</p> 4112 4113<p>You can display the following components by embedding special format 4114characters:</p> 4115 4116<pre class="text"> 4117 %d domain 4118 %e event 4119 %f function 4120 %l line 4121 %m module 4122 %p process ID 4123 %r real CPU time 4124 %t wall clock time 4125 %u user CPU time 4126 %% percent sign 4127 \n newline 4128 \r carriage return 4129</pre> 4130 4131<p>For example:</p> 4132 4133<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> 4134<p>The default behavior is to print all of the components.</p> 4135 4136<div style="margin: auto;"> 4137 <h4><a id="loop"></a>-loop <em class="arg">iterations</em></h4> 4138</div> 4139 4140<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> 4141 4142<p>Set iterations to zero to repeat the animation an infinite number of times, 4143otherwise the animation repeats itself up to <em class="arg">iterations</em> 4144times.</p> 4145 4146<div style="margin: auto;"> 4147 <h4><a id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4> 4148</div> 4149 4150<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> 4151 4152<div style="margin: auto;"> 4153 <h4><a id="magnify"></a>-magnify <em class="arg">factor</em></h4> 4154</div> 4155 4156<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> 4157 4158 4159<div style="margin: auto;"> 4160 <h4><a id="map"></a>-map <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%'>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> 4164 4165<p>Choose from these <em class="arg">Standard Colormap</em> types:</p> 4166 4167<pre class="text"> 4168 best 4169 default 4170 gray 4171 red 4172 green 4173 blue 4174</pre> 4175 4176<p>The <em class="arg">X server</em> must support the <em class="arg">Standard 4177Colormap</em> you choose, otherwise an error occurs. Use <kbd>list</kbd> as 4178the type and <kbd>display</kbd> searches the list of colormap types in 4179<kbd>top-to-bottom</kbd> order until one is located. See <em 4180class="arg">xstdcmap(1)</em> for one way of creating Standard Colormaps.</p> 4181 4182 4183<div style="margin: auto;"> 4184 <h4><a id="map_stream_"></a>-map <em class="arg">components</em></h4> 4185</div> 4186 4187<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> 4188 4189<p>Here are the valid components of a map:</p> 4190 4191<pre class="text"> 4192 r red pixel component 4193 g green pixel component 4194 b blue pixel component 4195 a alpha pixel component (0 is transparent) 4196 o opacity pixel component (0 is opaque) 4197 i grayscale intensity pixel component 4198 c cyan pixel component 4199 m magenta pixel component 4200 y yellow pixel component 4201 k black pixel component 4202 p pad component (always 0) 4203</pre> 4204 4205<p>You can specify as many of these components as needed in any order (e.g. 4206bgr). The components can repeat as well (e.g. rgbr).</p> 4207 4208 4209<div style="margin: auto;"> 4210 <h4><a id="mask"></a>-mask 4211<em class="arg">filename</em></h4> 4212</div> 4213 4214<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Composite the image pixels as defined by the mask.</td><td style='text-align:right;'></td></tr></table> 4215 4216<p>Use <a href="#mask">+mask</a> to remove the image mask.</p> 4217 4218<div style="margin: auto;"> 4219 <h4><a id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4> 4220</div> 4221 4222<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> 4223 4224<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 4225 4226<p>The default matte color is <kbd>#BDBDBD</kbd>, <span 4227style="background-color: #bdbdbd;">this shade of gray</span>.</p> 4228 4229<div style="margin: auto;"> 4230 <h4><a id="maximum"></a>-maximum</h4> 4231</div> 4232 4233<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> 4234 4235<div style="margin: auto;"> 4236 <h4><a id="median"></a>-median <em class="arg">radius</em></h4> 4237</div> 4238 4239<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> 4240 4241<div style="margin: auto;"> 4242 <h4><a id="metric"></a>-metric <em class="arg">type</em></h4> 4243</div> 4244 4245<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> 4246 4247<p>Choose from:</p> 4248 4249<pre class="text"> 4250 AE absolute error count, number of different pixels (-fuzz effected) 4251 FUZZ mean color distance 4252 MAE mean absolute error (normalized), average channel error distance 4253 MEPP mean error per pixel (normalized mean error, normalized peak error) 4254 MSE mean error squared, average of the channel error squared 4255 NCC normalized cross correlation 4256 PAE peak absolute (normalize peak absolute) 4257 PSNR peak signal to noise ratio 4258 RMSE root mean squared (normalized root mean squared) 4259</pre> 4260 4261<p>Control the '<kbd>AE</kbd>', or absolute count of pixels that are different, 4262with the <a href="#fuzz" >-fuzz</a> factor (ignore pixels which 4263only changed by a small amount). Use '<kbd>PAE</kbd>' to find the 4264size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels 4265'similar', while '<kbd>MAE</kbd>' dtermines the factor needed 4266for about half the pixels to be similar. </p> 4267 4268<p>The '<kbd>MEPP</kbd>' metric returns three different metrics 4269('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>' 4270normalized) from a single comparison run. </p> 4271 4272<p>To print a complete list of metrics, use the <a href="#list">-list 4273metrics</a> option.</p> 4274 4275 4276<div style="margin: auto;"> 4277 <h4><a id="minimum"></a>-minimum</h4> 4278</div> 4279 4280<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> 4281 4282 4283<div style="margin: auto;"> 4284 <h4><a id="mode"></a>-mode <em class="arg">value</em></h4> 4285</div> 4286 4287<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> 4288 4289<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame, 4290Unframe, or Concatenate</kbd></p> 4291 4292<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>' argument 4293for a list of <a href="#mode" >-mode</a> arguments available in your 4294ImageMagick installation.</p> 4295 4296 4297<div style="margin: auto;"> 4298 <h4><a id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4> 4299</div> 4300 4301<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 4302class="arg">saturation</em>, and <em class="arg">hue</em> of an image.</td><td style='text-align:right;'></td></tr></table> 4303 4304<p>The arguments are given as a percentages of variation. A value of 100 means 4305no change, and any missing values are taken to mean 100.</p> 4306 4307<p>The <em class="arg">brightness</em> is a multiplier of the overall 4308brightness of the image, so 0 means pure black, 50 is half as bright, 200 is 4309twice as bright. To invert its meaning <a href="#negate">-negate</a> the image 4310before and after. </p> 4311 4312<p>The <em class="arg">saturation</em> controls the amount of color in an 4313image. For example, 0 produce a grayscale image, while a large value such as 4314200 produce a very colorful, 'cartoonish' color.</p> 4315 4316<p>The <em class="arg">hue</em> argument causes a "rotation" of the colors 4317within the image by the amount specified. For example, 50 results in 4318a counter-clockwise rotation of 90, mapping red shades to purple, and so on. 4319A value of either 0 or 200 results in a complete 180 degree rotation of the 4320image. Using a value of 300 is a 360 degree rotation resulting in no change to 4321the original image. </p> 4322 4323<p>For example, to increase the color brightness by 20% and decrease the color 4324saturation by 10% and leave the hue unchanged, use <a 4325href="#modulate">-modulate 120,90</a>.</p> 4326 4327<p>Use <a href="#set">-set</a> attribute of '<kbd 4328class="arg">option:modulate:colorspace</kbd>' to specify which colorspace to 4329modulate. Choose from <kbd>HSB</kbd>, <kbd>HSL</kbd> (the default), or 4330<kbd>HWB</kbd>. For example,</p> 4331 4332<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> 4333 4334<div style="margin: auto;"> 4335 <h4><a id="monitor"></a>-monitor</h4> 4336</div> 4337 4338<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> 4339 4340 4341<div style="margin: auto;"> 4342 <h4><a id="monochrome"></a>-monochrome</h4> 4343</div> 4344 4345<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> 4346 4347 4348<div style="margin: auto;"> 4349 <h4><a id="morph"></a>-morph <em class="arg">frames</em></h4> 4350</div> 4351 4352<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> 4353 4354<p>Both the image pixels and size are linearly interpolated to give the 4355appearance of a meta-morphosis from one image to the next, over all the images 4356in the current image list. The added images are the equivalent of a <a 4357href="#blend">-blend</a> composition. The <em class="arg">frames</em> 4358argument determine how many images to interpolate between each image. </p> 4359 4360 4361<div style="margin: auto;"> 4362 <h4><a id="morphology"></a>-morphology</h4> 4363 <h4>-morphology <em class="arg">method</em> <em class="arg">kernel</em></h4> 4364</div> 4365 4366<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> 4367 4368<p>Until I get around to writing a option summary for this, see <a 4369href="http://www.imagemagick.org/Usage/morphology/" >IM Usage Examples, 4370Morphology</a>. </p> 4371 4372 4373<div style="margin: auto;"> 4374 <h4><a id="mosaic"></a>-mosaic</h4> 4375</div> 4376 4377<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> 4378 4379 4380<div style="margin: auto;"> 4381 <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> 4382</div> 4383 4384<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> 4385 4386<p>Blur with the given radius, standard deviation (sigma), and angle. The 4387angle given is the angle toward which the image is blurred. That is the 4388direction people would consider the object is coming from. </p> 4389 4390<p>Note that the blur is not uniform distribution, giving the motion a 4391definite sense of direction of movement. </p> 4392 4393<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4394pixels which are outside the image proper are blurred into the final result. 4395</p> 4396 4397<div style="margin: auto;"> 4398 <h4><a id="name"></a>-name</h4> 4399</div> 4400 4401<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> 4402<div style="margin: auto;"> 4403 <h4><a id="negate"></a>-negate</h4> 4404</div> 4405 4406<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> 4407 4408<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> 4409 4410<div style="margin: auto;"> 4411 <h4><a id="noise"></a>-noise <em class="arg">radius</em><br/> 4412 +noise <em class="arg">type</em></h4> 4413</div> 4414 4415<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> 4416 4417<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> 4418 4419<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> 4420 4421<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> 4422 4423<pre class="text"> 4424Gaussian 4425Impulse 4426Laplacian 4427Multiplicative 4428Poisson 4429Random 4430Uniform 4431</pre> 4432 4433<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p> 4434 4435<p>Also see the <a href="#evaluate">-evaluate</a> noise functions that allos 4436the use of a controlling value to specify teh amount of noise that should be 4437added to an image. </p> 4438 4439 4440<div style="margin: auto;"> 4441 <h4><a id="normalize"></a>-normalize</h4> 4442</div> 4443 4444<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> 4445 4446<p>The intensity values are stretched to cover the entire range of possible 4447values. While doing so, black-out at most <em>2%</em> of the pixels and 4448white-out at most <em>1%</em> of the pixels.</p> 4449 4450<p>Note that as of ImageMagick 6.4.7-0, <a href="#normalize" >-normalize</a> 4451is equivalent to <a href="#contrast-stretch" >-contrast-stretch 2%x1%</a>. 4452(Before this version, it was equivalent to <a href="#contrast-stretch" 4453>-contrast-stretch 2%x99%</a>).</p> 4454 4455<p>All the channels are normalized in concert by the came amount so as to 4456preserve color integrity, when the default <a href="#channel" >+channel</a> 4457setting is in use. Specifying any other <a href="#channel" >-channel</a> 4458setting will normalize the RGB channels independently.</p> 4459 4460<p>See <a href="#contrast-stretch" >-contrast-stretch</a> for more details. 4461Also see <a href="#auto-level" >-auto-level</a> for a 'perfect' normalization 4462that is better suited to mathematically generated images. </p> 4463 4464<p>This operator is under review for re-development. </p> 4465 4466 4467<div style="margin: auto;"> 4468 <h4><a id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4> 4469</div> 4470 4471<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 4472class="arg">threshold map</em> specified, and a uniform color map with the 4473given number of <em class="arg">levels</em> per color channel . </td><td style='text-align:right;'></td></tr></table> 4474 4475<p>You can choose from these standard threshold maps:</p> 4476 4477<pre class="text"> 4478threshold 1x1 Threshold 1x1 (non-dither) 4479checks 2x1 Checkerboard 2x1 (dither) 4480o2x2 2x2 Ordered 2x2 (dispersed) 4481o3x3 3x3 Ordered 3x3 (dispersed) 4482o4x4 4x4 Ordered 4x4 (dispersed) 4483o8x8 8x8 Ordered 8x8 (dispersed) 4484h4x4a 4x1 Halftone 4x4 (angled) 4485h6x6a 6x1 Halftone 6x6 (angled) 4486h8x8a 8x1 Halftone 8x8 (angled) 4487h4x4o Halftone 4x4 (orthogonal) 4488h6x6o Halftone 6x6 (orthogonal) 4489h8x8o Halftone 8x8 (orthogonal) 4490h16x16o Halftone 16x16 (orthogonal) 4491c5x5b c5x5 Circles 5x5 (black) 4492c5x5w Circles 5x5 (white) 4493c6x6b c6x6 Circles 6x6 (black) 4494c6x6w Circles 6x6 (white) 4495c7x7b c7x7 Circles 7x7 (black) 4496c7x7w Circles 7x7 (white) 4497</pre> 4498 4499<p> The <kbd>checks</kbd> pattern produces a 3 level checkerbord dither 4500pattern. Or you can define your own <em class="arg" >threshold map</em> in a 4501personal or system <kbd>thresholds.xml</kbd> XML file. </p> 4502 4503<p>To print a complete list of threshold, use the <a href="#list" >-list 4504threshold</a> option.</p> 4505 4506<p>It is recommended that the <a href="#map" >+map</a> operator be used after 4507applying <a href="#ordered-dither" >-ordered-dither</a> to reduce the number of 4508colors an animated image sequence, to less that 256 colors. This ensures that 4509a common or global color table is used when saving the result to a color 4510limited file format such as GIF. </p> 4511 4512<p>Note that at this time the exact same threshold dithering map is used for 4513all color channels, no attempt is made to offset or rotate the map for 4514different channels is made, to create an offset printing effect. (possible 4515future expansion) </p> 4516 4517 4518<div style="margin: auto;"> 4519 <h4><a id="opaque"></a>-opaque <em class="arg">color</em></h4> 4520</div> 4521 4522<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> 4523 4524<p>The <em class="arg">color</em> argument is defined using the format 4525described under the <a href="#fill" >-fill</a> option. The <a href="#fuzz" 4526>-fuzz</a> setting can be used to match and replace colors similar to the one 4527given.</p> 4528 4529<p>Use <a href="#opaque">+opaque</a> to paint any pixel that does not match 4530the target color. </p> 4531 4532<p>The <a href="#transparent">-transparent</a> operator is exactly the same 4533as <a href="#opaque" >-opaque</a> but replaces the matching color with 4534transparency rather than the current <a href="#fill">-fill</a> color setting. 4535To ensure that it can do this it also ensures that the image has an alpha 4536channel enabled, as per "<kbd><a href="#alpha" >-alpha</a> set</kbd>", for 4537the new transparent colors, and does not require you to modify the <a 4538href="#channel">-channel</a> to enable alpha channel handling. </p> 4539 4540 4541<div style="margin: auto;"> 4542 <h4><a id="orient"></a>-orient <em class="arg">image orientation</em></h4> 4543</div> 4544 4545<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> 4546 4547<p>Choose from these orientations:</p> 4548 4549<pre class="text"> 4550 bottom-left 4551 bottom-right 4552 left-bottom 4553 left-top 4554 right-bottom 4555 right-top 4556 top-left 4557 top-right 4558 undefined 4559</pre> 4560 4561<p>To print a complete list of orientations, use the <a href="#list" >-list 4562orientation</a> option.</p> 4563 4564 4565<div style="margin: auto;"> 4566 <h4><a id="page"></a>-page <em class="arg">geometry</em><br/> 4567 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!<></em>}]<br/> 4568 +page 4569 </h4> 4570</div> 4571 4572<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> 4573 4574<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> 4575 4576<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> 4577 4578<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> 4579<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;"> 4580<thead> 4581 <tr valign="top"> 4582 <th align="center"><em class="arg">media</em></th> 4583 <th align="center"><em class="arg">width</em></th> 4584 <th align="center"><em class="arg">height</em></th> 4585 </tr> 4586</thead> 4587<tbody> 4588<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr> 4589<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr> 4590<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr> 4591<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4592<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4593<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr> 4594<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr> 4595<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr> 4596<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr> 4597<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr> 4598<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr> 4599<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr> 4600<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr> 4601<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr> 4602<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4603<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4604<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr> 4605<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr> 4606<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr> 4607<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr> 4608<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr> 4609<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr> 4610<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr> 4611<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr> 4612<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr> 4613<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr> 4614<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr> 4615<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr> 4616<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr> 4617<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr> 4618<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr> 4619<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr> 4620<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr> 4621<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr> 4622<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr> 4623<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4624<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4625<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr> 4626</tbody> 4627</table> 4628 4629 4630 4631 4632<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> 4633 4634<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> 4635 4636<p>The default page dimensions for a TEXT image is 612x792.</p> 4637 4638<p>This option is used in concert with <a href="#density">-density</a>.</p> 4639 4640<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p> 4641 4642<div style="margin: auto;"> 4643 <h4><a id="paint"></a>-paint <em class="arg">radius</em></h4> 4644</div> 4645 4646<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> 4647 4648<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> 4649 4650<div style="margin: auto;"> 4651 <h4><a id="path"></a>-path <em class="arg">path</em></h4></div> 4652 4653<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> 4654 4655<div style="margin: auto;"> 4656 <h4><a id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4> 4657</div> 4658 4659<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> 4660 4661<p>Pause for the specified number of seconds before repeating the animation.</p> 4662 4663<div style="margin: auto;"> 4664 <h4><a id="pause_import_"></a>-pause <em class="arg">seconds</em></h4> 4665</div> 4666 4667<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> 4668 4669<p>Pause for the specified number of seconds before taking the next snapshot.</p> 4670 4671<div style="margin: auto;"> 4672 <h4><a id="ping"></a>-ping</h4> 4673</div> 4674 4675<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> 4676 4677<div style="margin: auto;"> 4678 <h4><a id="pointsize"></a>-pointsize <em class="arg">value</em></h4> 4679</div> 4680 4681<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> 4682 4683<div style="margin: auto;"> 4684 <h4><a id="polaroid"></a>-polaroid <em class="arg">angle</em></h4> 4685</div> 4686 4687<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> 4688 4689<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p> 4690 4691<div style="margin: auto;"> 4692 <h4><a id="posterize"></a>-posterize <em class="arg">levels</em></h4> 4693</div> 4694 4695<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> 4696 4697<div style="margin: auto;"> 4698 <h4><a id="precision"></a>-precision <em class="arg">value</em></h4> 4699</div> 4700 4701<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> 4702 4703<div style="margin: auto;"> 4704 <h4><a id="preview"></a>-preview <em class="arg">type</em></h4> 4705</div> 4706 4707<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> 4708 4709<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> 4710 4711<pre class="text"> 4712 Rotate 4713 Shear 4714 Roll 4715 Hue 4716 Saturation 4717 Brightness 4718 Gamma 4719 Spiff 4720 Dull 4721 Grayscale 4722 Quantize 4723 Despeckle 4724 ReduceNoise 4725 Add Noise 4726 Sharpen 4727 Blur 4728 Threshold 4729 EdgeDetect 4730 Spread 4731 Shade 4732 Raise 4733 Segment 4734 Solarize 4735 Swirl 4736 Implode 4737 Wave 4738 OilPaint 4739 CharcoalDrawing 4740 JPEG 4741</pre> 4742 4743<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p> 4744 4745<p>The default preview is <kbd>JPEG</kbd>.</p> 4746 4747<div style="margin: auto;"> 4748 <h4><a id="print"></a>-print <em class="arg">string</em></h4> 4749</div> 4750 4751<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> 4752 4753<div style="margin: auto;"> 4754 <h4><a id="process"></a>-process <em class="arg">command</em></h4> 4755</div> 4756 4757<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> 4758 4759<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> 4760 4761<div style="margin: auto;"> 4762 <h4><a id="profile"></a>-profile <em class="arg">filename</em><br/> 4763 +profile <em class="arg">profile_name</em></h4> 4764</div> 4765 4766<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> 4767 4768<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> 4769 4770<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> 4771 4772<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> 4773 4774<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> 4775 4776<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p> 4777 4778<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p> 4779<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> 4780 4781<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert CMYK.tif -profile "CMYK.icc" -profile "RGB.icc" RGB.tiff</span></p> 4782<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results. 4783CMYK profiles are often very asymmetric since they involve 3−>4 and 4−>3 channel mapping. 4784</p> 4785 4786<p>The <a href="#profile">-profile</a> option can also be used to inject 4787previously-formatted ancillary chunks into the output PNG file, using 4788the commandline option as shown below or by setting the profile via a 4789programming interface:</p> 4790 4791<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>-profile PNG-chunk-x:<filename></span></p> 4792<p>where <em>x</em> is a location flag and 4793<em class="arg">filename</em> is a file containing the chunk 4794name in the first 4 bytes, then a colon (":"), followed by the chunk data. 4795This encoder will compute the chunk length and CRC, so those must not 4796be included in the file.</p> 4797 4798<p>"x" can be "b" (before PLTE), "m" (middle, i.e., between PLTE and IDAT), 4799or "e" (end, i.e., after IDAT). If you want to write multiple chunks 4800of the same type, then add a short unique string after the "x" to prevent 4801subsequent profiles from overwriting the preceding ones, e.g.,</p> 4802 4803 4804<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>-profile PNG-chunk-b01:file01 -profile PNG-chunk-b02:file02</span></p> 4805<div style="margin: auto;"> 4806 <h4><a id="quality"></a>-quality <em class="arg">value</em></h4> 4807</div> 4808 4809<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> 4810 4811<p>For the JPEG and MPEG image formats, quality is 1 (lowest image quality and highest compression) to 100 (best quality but least effective compression). The default is to use the estimate quality of your input image otherwise 92. Use the <a href="#sampling-factor">-sampling-factor</a> option to specify the factors for chroma downsampling.</p> 4812 4813<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> 4814 4815<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> 4816 4817<p>For the MNG and PNG image formats, the quality value sets the zlib compression level (quality / 10) and filter-type (quality % 10). For compression level 0, the Huffman-only strategy is used, which is fastest but not necessarily the worst compression. The default PNG compression is 75.</p> 4818 4819<p>If filter-type is 4 or less, the specified filter-type is used for all scanlines:</p> 4820 4821<pre class="text"> 4822 0: none 4823 1: sub 4824 2: up 4825 3: average 4826 4: Paeth 4827</pre> 4828 4829<p>If filter-type is 5, adaptive filtering is used when quality is greater than 50 and the image does not have a color map, otherwise no filtering is used.</p> 4830 4831<p>If filter-type is 6, adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p> 4832 4833<p>Only if the output is MNG, if filter-type is 7, the LOCO color transformation and adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> are used.</p> 4834 4835<p>The quality setting has no effect on the appearance of PNG and MNG images, since the compression is always lossless.</p> 4836 4837<p>For further information, see the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p> 4838 4839<div style="margin: auto;"> 4840 <h4><a id="quantize"></a>-quantize <em class="arg">colorspace</em></h4> 4841</div> 4842 4843<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> 4844 4845<p>This setting defines the colorspace used to sort out and reduce the number 4846of colors needed by an image (for later dithering) by operators such as <a 4847href="#colors" >-colors</a>, Note that color reducion also happens 4848automatically when saving images to color-limited image file formats, such as 4849GIF, and PNG8.</p> 4850 4851 4852<div style="margin: auto;"> 4853 <h4><a id="quiet"></a>-quiet</h4> 4854</div> 4855 4856<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> 4857 4858<div style="margin: auto;"> 4859 <h4><a id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4> 4860</div> 4861 4862<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> 4863 4864<p>Note that this is actually a rotational blur rather than a radial and as 4865such actually mis-named. </p> 4866 4867<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4868pixels which are outside the image proper are blurred into the final result. 4869</p> 4870 4871 4872<div style="margin: auto;"> 4873 <h4><a id="raise"></a>-raise <em class="arg">thickness</em></h4> 4874</div> 4875 4876<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> 4877 4878<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>. 4879</p> 4880 4881<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p> 4882 4883<div style="margin: auto;"> 4884 <h4><a id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4> 4885</div> 4886 4887<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> 4888 4889<div style="margin: auto;"> 4890 <h4><a id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4> 4891</div> 4892 4893<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> 4894 4895<div style="margin: auto;"> 4896 <h4><a id="regard-warnings"></a>-regard-warnings</h4> 4897</div> 4898 4899<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> 4900 4901<div style="margin: auto;"> 4902 <h4><a id="remap"></a>-remap <em class="arg">filename</em></h4> 4903</div> 4904 4905<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> 4906 4907<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then 4908the given colors are dithered over the image as necessary, otherwise the closest 4909color (in RGB colorspace) is selected to replace that pixel in the image. </p> 4910 4911<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all 4912images in the current image sequence, all the images will have the same color 4913table. That means that when saved to a file format such as GIF, it will use 4914that color table as a single common or global color table, for all the images, 4915without requiring extra local color tables. </p> 4916 4917<p>Use <a href="#remap">+remap</a> to reduce all images in the current image 4918sequence to use a common color map over all the images. This equivalent to 4919appending all the images together (without extra background colors) and color 4920reducing those images using <a href="#colors">-colors</a> with a 256 color 4921limit, then <a href="#remap">-remap</a> those colors over the original list of 4922images. This ensures all the images follow a single color map. </p> 4923 4924<p>If the number of colors over all the images is less than 256, then <a 4925href="#remap">+remap</a> should not perform any color reduction or dithering, as 4926no color changes are needed. In that case, its only effect is to force the use 4927of a global color table. This recommended after using either <a 4928href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to 4929reduce the number of colors in an animated image sequence. </p> 4930 4931<div style="margin: auto;"> 4932 <h4><a id="region"></a>-region <em class="arg">geometry</em></h4> 4933</div> 4934 4935<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> 4936 4937<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> 4938 4939<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> 4940 4941<div style="margin: auto;"> 4942 <h4><a id="remote"></a>-remote</h4> 4943</div> 4944 4945<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> 4946 4947<p>The only command recognized is the name of an image file to load.</p> 4948 4949<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> 4950 4951<div style="margin: auto;"> 4952 <h4><a id="render"></a>-render</h4> 4953</div> 4954 4955<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> 4956 4957<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> 4958 4959<div style="margin: auto;"> 4960<h4><a id="repage"></a>-repage <em class="arg">geometry</em></h4> 4961</div> 4962 4963<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> 4964 4965<p>This option is like <a href="#page">-page</a> but acts as an image operator 4966rather than a setting. You can separately set the canvas size or the offset 4967of the image on that canvas by only providing those components. </p> 4968 4969<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> 4970 4971<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing 4972offset to move the image relative to its previous position. This useful for 4973animation sequences. </p> 4974 4975<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to 4976recalculate the canvas size so the image (at its current offset) will appear 4977completely on that canvas (unless it has a negative offset).</p> 4978 4979<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual 4980canvas meta-data from the images. </p> 4981 4982<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to 4983directly assign virtual canvas meta-data. </p> 4984 4985 4986<div style="margin: auto;"> 4987 <h4><a id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4> 4988</div> 4989 4990<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> 4991 4992<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> 4993 4994<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> 4995 4996<div style="margin: auto;"> 4997 <h4><a id="resize"></a>-resize <em class="arg">geometry</em></h4> 4998</div> 4999 5000<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> 5001 5002<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> 5003 5004<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> 5005 5006<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> 5007 5008<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> 5009<div style="margin: auto;"> 5010 <h4><a id="respect-parentheses"></a>-respect-parentheses</h4> 5011</div> 5012 5013<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> 5014 5015<div style="margin: auto;"> 5016 <h4><a id="reverse"></a>-reverse</h4> 5017</div> 5018 5019<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> 5020 5021 5022<div style="margin: auto;"> 5023 <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> 5024</div> 5025 5026<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> 5027 5028<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> 5029 5030 5031<div style="margin: auto;"> 5032 <h4><a id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg"><</em>}{<em class="arg">></em>}</h4> 5033</div> 5034 5035<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> 5036 5037<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> 5038 5039<p>Empty triangles in the corners, left over from rotating the image, are 5040filled with the <kbd>background</kbd> color. </p> 5041 5042<p>See also the <a href="#distort">-distort</a> operator and specifically the 5043'<kbd>ScaleRotateTranslate</kbd>' distort method. </p> 5044 5045 5046<div style="margin: auto;"> 5047 <h4><a id="sample"></a>-sample <em class="arg">geometry</em></h4> 5048</div> 5049 5050<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> 5051 5052<p>Change the image size simply by directly sampling the pixels original 5053image. When magnifying, pixels are replicated in blocks. When minifying, 5054pixels are sub-sampled (i.e., some rows and columns are skipped over). </p> 5055 5056<p>The results are thus equivalent to using <a href="#resize">-resize</a> with 5057a <a href="#filter">-filter</a> setting of <kbd>point</kbd> (nearest 5058neighbour), though <a href="#sample">-sample</a> is a lot faster, as it 5059avoids all the filter processing of the image. As such it completely ignores 5060the current <a href="#filter">-filter</a> setting. </p> 5061 5062<p>The key feature of the <a href="#sample">-sample</a> is that no new colors 5063will be added to the resulting image, though some colors may disappear. </p> 5064 5065<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 5066ignored, unlike <a href="#resize">-resize</a>. </p> 5067 5068 5069<div style="margin: auto;"> 5070 <h4><a id="sampling-factor"></a>-sampling-factor <em class="arg">horizontal-factor</em>x<em class="arg">vertical-factor</em></h4> 5071</div> 5072 5073<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> 5074 5075<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> 5076 5077<div style="margin: auto;"> 5078 <h4><a id="scale"></a>-scale <em class="arg">geometry</em></h4> 5079</div> 5080 5081<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> 5082 5083<p>Change the image size simply by replacing pixels by averaging pixels 5084together when minifying, or replacing pixels when magnifing. </p> 5085 5086<p>The results are thus equivalent to using <a href="#resize">-resize</a> with 5087a <a href="#filter">-filter</a> setting of <kbd>box</kbd>. Though it is a lot 5088faster, as it avoids all the filter processing of the image. As such it 5089completely ignores the current <a href="#filter">-filter</a> setting. </p> 5090 5091<p>If when shrinking (minifying) images the original image is some integer 5092multiple of the new image size, the number of pixels avergaed together to 5093produce the new pixel color is the same across the whole image. This is 5094a special case known as 'binning' and is often used as a method of reducing 5095noise in image such as those generated by digital cameras, especially in low 5096light conditions. </p> 5097 5098 5099<div style="margin: auto;"> 5100 <h4><a id="scene"></a>-scene <em class="arg">value</em></h4> 5101</div> 5102 5103<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> 5104 5105<p>This option sets the scene number of an image or the first image in an image sequence.</p> 5106 5107<div style="margin: auto;"> 5108 <h4><a id="screen"></a>-screen</h4> 5109</div> 5110 5111<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> 5112 5113<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> 5114 5115<div style="margin: auto;"> 5116 <h4><a id="seed"></a>-seed</h4> 5117</div> 5118 5119<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> 5120 5121<div style="margin: auto;"> 5122 <h4><a id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4> 5123</div> 5124 5125<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> 5126 5127<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> 5128 5129<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> 5130 5131<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report 5132of the color clusters is returned.</p> 5133 5134 5135<div style="margin: auto;"> 5136 <h4><a id="selective-blur"></a>-selective-blur <em class="arg">geometry</em></h4> 5137</div> 5138 5139<div style="margin: auto;"> 5140 <h4>-selective-blur <em class="arg">radius</em><br />-unsharp <em class="arg">radius</em>x<em class="arg">sigma</em>{<em class="arg">+threshold</em>}</h4> 5141</div> 5142 5143<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> 5144 5145<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> 5146 5147<div style="margin: auto;"> 5148 <h4><a id="separate"></a>-separate</h4> 5149</div> 5150 5151<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> 5152 5153<div style="margin: auto;"> 5154 <h4><a id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4> 5155</div> 5156 5157<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> 5158 5159<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p> 5160 5161<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> 5162 5163 5164 5165<div style="margin: auto;"> 5166 <h4><a id="set"></a>-set <em class="arg">key value</em></h4> 5167 <h4>+set <em class="arg">key</em></h4> 5168</div> 5169 5170<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 5171image sequence.</td><td style='text-align:right;'></td></tr></table> 5172 5173<p>This will assign (or modify) specific settings attached to all the images 5174in the current image sequence. Using the <a href="#set">+set</a> form of the 5175option will either remove, or reset that setting to a default state, as 5176appropriate. </p> 5177 5178<p>For example, it will modify specific well known image meta-data 5179'attributes' such as those normally overridden by: the options <a 5180href="#delay" >-delay</a>, <a href="#dispose" >-dispose</a>, and <a 5181href="#page" >-page</a>, <a href="#colorspace" >-colorspace</a>; generally 5182assigned before the image is read in, by using a <em class="arg">key</em> of 5183the same name. </p> 5184 5185<p>If the given <em class="arg">key</em> does not match a specific known 5186'attribute ', such as shown above, the setting is stored as a a free form 5187'properity' string. Such settings are listed in <a href="#verbose" 5188>-verbose</a> information ("<kbd>info:</kbd>" output format) as "Properties". 5189</p> 5190 5191<p>This includes string 'properities' that are set by and assigned to images 5192using the options <a href="#comment" >-comment</a>, <a href="#label" 5193>-label</a>, <a href="#caption" >-caption</a>. These options actually assign 5194a global 'artifact' which are automatically assigned (and any <a href="/www/escape.html" >Format Percent 5195Escapes</a> expanded) to images as they are read in. For example:</p> 5196 5197<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> 5198<p>The set value can also make use of <a href="/www/escape.html" >Format and Print Image 5199Properties</a> in the defined value. For example:</p> 5200 5201<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> 5202<p>Other well known 'properities' that can be include: 5203'<kbd>date:create</kbd>' and '<kbd>date:modify</kbd>' and 5204'<kbd>signature</kbd>'. </p> 5205 5206<p>The <a href="#repage">-repage</a> operator will also allow you to modify 5207the '<kbd>page</kbd>' attribute of an image for images already in memory (also 5208see <a href="#repage">-page</a>). However it is designed to provide a finer 5209control of the sub-parts of this 'attribute'. The <a href="#set">-set page</a> 5210option will only provide a direct, unmodified assignment of '<kbd>page</kbd>' 5211attribute. </p> 5212 5213<p>This option can also associate a colorspace or profile with your image. 5214For example,</p> 5215 5216<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> 5217<p>Some 'properties' must be defined in a specific way to be used. For 5218example only 'properties' prefixed with "<kbd>filename:</kbd>" can be used to 5219modify the output filename of an image. For example</p> 5220 5221<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -set filename:mysize '%wx%h' 'rose_%[filename:mysize].png'</span></p> 5222<p>If the setting value is prefixed with "<kbd>option:</kbd>" the setting will 5223be saved as a global "Artifact" exactly as if it was set using the <a 5224href="#define" >-define</a> option. As such settings are globel in scope, they 5225can be used to pass 'attributes' and 'properities' of one specific image, 5226in a way that allows you to use them in a completely different image, even if 5227the original image has long since been modified or destroyed. For example: </p> 5228 5229<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> 5230<p>Note that <a href="/www/escape.html" >Format Percent Escapes</a> will only match 5231a 'artifact' if the given <em class="arg">key</em> does not match an existing 5232'attribute' or 'properity'. </p> 5233 5234<p>You can set the attributes of the image registry by prefixing the value 5235with <kbd>registry:</kbd>.</p> 5236 5237 5238 5239<div style="margin: auto;"> 5240 <h4><a id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4> 5241</div> 5242 5243<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> 5244 5245<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> 5246 5247<div style="margin: auto;"> 5248 <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> 5249</div> 5250 5251<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> 5252 5253<div style="margin: auto;"> 5254 <h4><a 5255id="shared-memory"></a>-shared-memory</h4> 5256</div> 5257 5258<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> 5259 5260<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> 5261 5262<div style="margin: auto;"> 5263 <h4><a id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4> 5264</div> 5265 5266<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> 5267 5268<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p> 5269 5270<div style="margin: auto;"> 5271 <h4><a id="shave"></a>-shave <em class="arg">geometry</em></h4> 5272</div> 5273 5274<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> 5275 5276<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> 5277 5278<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> 5279 5280<div style="margin: auto;"> 5281 <h4><a id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4> 5282</div> 5283 5284<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> 5285 5286<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> 5287 5288<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> 5289 5290<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> 5291 5292<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> 5293 5294<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> 5295<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> 5296 5297<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p> 5298<div style="margin: auto;"> 5299 <h4><a id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4> 5300</div> 5301 5302<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> 5303 5304<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> 5305 5306<div style="margin: auto;"> 5307 <h4><a id="silent"></a>-silent</h4> 5308</div> 5309 5310<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> 5311 5312<div style="margin: auto;"> 5313 <h4><a id="size"></a>-size <em class="arg">width</em>[x<em class="arg">height</em>][<em class="arg">+offset</em>]</h4> 5314</div> 5315 5316<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> 5317 5318<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> 5319 5320<p>For Photo CD images, choose from these sizes:</p> 5321 5322<pre class="text"> 5323 192x128 5324 384x256 5325 768x512 5326 1536x1024 5327 3072x2048 5328</pre> 5329 5330<div style="margin: auto;"> 5331 <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> 5332</div> 5333 5334<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> 5335 5336<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> 5337 5338<div style="margin: auto;"> 5339 <h4><a id="smush"></a>-smush <em class="arg">offset</em></h4> 5340</div> 5341 5342<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> 5343 5344<div style="margin: auto;"> 5345 <h4><a id="snaps"></a>-snaps <em class="arg">value</em></h4> 5346</div> 5347 5348<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> 5349 5350<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p> 5351 5352<div style="margin: auto;"> 5353 <h4><a id="solarize"></a>-solarize <em class="arg">threshold</em></h4> 5354</div> 5355 5356<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> 5357 5358<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p> 5359 5360<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p> 5361 5362<div style="margin: auto;"> 5363 <h4><a id="sparse-color"></a>-sparse-color <em 5364 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4> 5365</div> 5366 5367<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> 5368 5369 5370<table class="doc"> 5371 <tbody> 5372 <tr valign="top"> 5373 <th align="left" style="width: 8%">Method</th> 5374 <th align="left">Description</th> 5375 </tr> 5376 5377 <tr valign="top"> 5378 <td valign="top">voronoi</td> 5379 <td valign="top">Simply map each pixel to the to nearest color point 5380 given. The result are polygonal 'cells' of solid color. </td> 5381 </tr> 5382 5383 <tr valign="top"> 5384 <td valign="top">shepards</td> 5385 <td valign="top">Colors points biased on the ratio of inverse distance 5386 squared. Generating spots of color in a sea of the average of 5387 colors. </td> 5388 </tr> 5389 5390 <tr valign="top"> 5391 <td valign="top">barycentric</td> 5392 <td valign="top">three point triangle of color given 3 points. 5393 Giving only 2 points will form a linear gradient between those points. 5394 Gradient is however not restricted to just the triangle or line. </td> 5395 </tr> 5396 5397 <tr valign="top"> 5398 <td valign="top">bilinear</td> 5399 <td valign="top">Like barycentric but for 4 points. Less than 4 points 5400 fall back to barycentric. </td> 5401 </tr> 5402 5403 </tbody> 5404</table> 5405 5406<p>The points are placed according to the images location on the virtual 5407canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a> 5408offset), and do not actually have to exist on the given image, but may be 5409some point beyond the edge of the image. All points are floating point values. 5410</p> 5411 5412<p>Only the color channels defined by the <a href="#channel" >-channel</a> are 5413modified, whcih means the matte/alpha transparency channel is not effected by 5414default. If enabled, the image also needs a the matte/alpha channel to be 5415enabled for this operator to effect an images transparency. This is typical 5416transparency handling for images. </p> 5417 5418<p>All the above methods when given a single point of color will replace all 5419the colors in the image with the color given, regardless of the point. This is 5420logical, and provides an alternative technique to recolor a image to some 5421default value. </p> 5422 5423 5424<div style="margin: auto;"> 5425 <h4><a id="splice"></a>-splice <em class="arg">geometry</em></h4> 5426</div> 5427 5428<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> 5429 5430<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. See <a href="#background">-background</a> to reset the background color.</p> 5431 5432<div style="margin: auto;"> 5433 <h4><a id="spread"></a>-spread <em class="arg">amount</em></h4> 5434</div> 5435 5436<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> 5437 5438<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> 5439 5440<div style="margin: auto;"> 5441 <h4><a id="stegano"></a>-stegano <em class="arg">offset</em></h4> 5442</div> 5443 5444<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> 5445 5446<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> 5447 5448<div style="margin: auto;"> 5449 <h4><a id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4> 5450</div> 5451 5452<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> 5453 5454<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> 5455 5456<div style="margin: auto;"> 5457 <h4><a id="storage-type"></a>-storage-type <em class="arg">type</em></h4> 5458</div> 5459 5460<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> 5461 5462<pre class="text"> 5463 char store pixels as unsigned characters 5464 double store pixels as doubles 5465 float store pixels as floats 5466 integer store pixels as integers 5467 long store pixels as longs 5468 quantum store pixels in the native depth of your ImageMagick distribution 5469 short store pixels as unsigned shorts 5470</pre> 5471 5472<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels 5473values range from 0 to the maximum value the storage type can support.</p> 5474 5475<div style="margin: auto;"> 5476 <h4><a id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4> 5477</div> 5478 5479<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> 5480 5481<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> 5482 5483<pre class="text"> 5484 Any 5485 Condensed 5486 Expanded 5487 ExtraCondensed 5488 ExtraExpanded 5489 Normal 5490 SemiCondensed 5491 SemiExpanded 5492 UltraCondensed 5493 UltraExpanded 5494</pre> 5495 5496<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p> 5497 5498<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> 5499 5500<div style="margin: auto;"> 5501 <h4><a id="strip"></a>-strip</h4> 5502</div> 5503 5504<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> 5505 5506<div style="margin: auto;"> 5507 <h4><a id="stroke"></a>-stroke <em class="arg">color</em></h4> 5508</div> 5509 5510<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> 5511 5512<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5513 5514<p>See <a href="#draw">-draw</a> for further details.</p> 5515 5516<div style="margin: auto;"> 5517 <h4><a id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4> 5518</div> 5519 5520<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> 5521 5522<p>See <a href="#draw">-draw</a> for further details.</p> 5523 5524<div style="margin: auto;"> 5525 <h4><a id="style"></a>-style <em class="arg">fontStyle</em></h4> 5526</div> 5527 5528<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> 5529 5530<p>This setting suggests a font style that ImageMagick should try to apply to 5531the currently selected font family. Select <em class="arg">fontStyle</em> from 5532the following.</p> 5533 5534<pre class="text"> 5535 Any 5536 Italic 5537 Normal 5538 Oblique 5539</pre> 5540 5541<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> 5542 5543<div style="margin: auto;"> 5544 <h4><a id="subimage-search"></a>-subimage-search</h4> 5545</div> 5546 5547<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> 5548 5549<p>This option is required to have compare search for the best match location 5550of a small image within a larger image. This search will produce two images 5551(or two frames). The first is the "difference" image and the second will 5552be the "match score" image.</p> 5553 5554<p>The "match-score" image is smaller containing a pixel for ever possible 5555position of the top-left corner of the given sub-image. that is its size will 5556be the size of the larger_image - sub_image + 1. The brightest location in 5557this image is the location s the locate on the best match that is also 5558reported. Note that this may or may nor be a perfect match, and the actual 5559brightness will reflect this. Other bright 'peaks' can be used to locate other 5560possible matching loctions. </p> 5561 5562<p>Note that the search will try to compare teh sub-image at every possible 5563location in the larger image, as such it can be very slow. The smaller the 5564sub-image the faster this search is. </p> 5565 5566 5567<div style="margin: auto;"> 5568 <h4><a id="swap"></a>-swap <em class="arg">index,index</em></h4> 5569</div> 5570 5571<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> 5572 5573<p>For example, <a href="#swap">-swap 0,2</a> swaps the first and the third 5574images in the current image sequence. Use <a href="#swap">+swap</a> to switch 5575the last two images in the sequence.</p> 5576 5577<div style="margin: auto;"> 5578 <h4><a id="swirl"></a>-swirl <em class="arg">degrees</em></h4> 5579</div> 5580 5581<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> 5582 5583<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p> 5584 5585<div style="margin: auto;"> 5586 <h4><a id="synchronize"></a>-synchronize</h4> 5587</div> 5588 5589<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> 5590 5591<div style="margin: auto;"> 5592 <h4><a id="taint"></a>-taint</h4> 5593</div> 5594 5595<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> 5596 5597<div style="margin: auto;"> 5598 <h4><a id="text-font"></a>-text-font <em class="arg">name</em></h4> 5599</div> 5600 5601<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> 5602 5603<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> 5604 5605<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> 5606 5607<div style="margin: auto;"> 5608 <h4><a id="texture"></a>-texture <em class="arg">filename</em></h4> 5609</div> 5610 5611<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> 5612 5613<div style="margin: auto;"> 5614 <h4><a id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 5615</div> 5616 5617<!-- {<em class="arg">green,blue,opacity</em>} 5618<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> 5619--> 5620 5621<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> 5622 5623<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> 5624 5625<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. 5626</p> 5627 5628<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> 5629 5630<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p> 5631<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> 5632 5633 5634<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> 5635<p>Note that the values of the transparency channel is treated as 'matte' 5636values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 5637 5638<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>. 5639</p> 5640 5641<div style="margin: auto;"> 5642 <h4><a id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4> 5643</div> 5644 5645<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> 5646 5647<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> 5648 5649<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> 5650 5651<div style="margin: auto;"> 5652 <h4><a id="tile"></a>-tile <em class="arg">filename</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 the tile image used for filling a subsequent graphic primitive.</td><td style='text-align:right;'></td></tr></table> 5656 5657<div style="margin: auto;"> 5658 <h4>-tile <em class="arg">geometry</em></h4> 5659</div> 5660 5661<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> 5662 5663<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> 5664 5665<div style="margin: auto;"> 5666 <h4>-tile</h4> 5667</div> 5668 5669<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> 5670 5671<div style="margin: auto;"> 5672 <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> 5673</div> 5674 5675<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> 5676 5677<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> 5678 5679<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> 5680 5681<div style="margin: auto;"> 5682 <h4><a id="tint"></a>-tint <em class="arg">value</em></h4> 5683</div> 5684 5685<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> 5686 5687<p>Tint the image with the fill color.</p> 5688 5689<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> 5690 5691<div style="margin: auto;"> 5692 <h4><a id="title"></a>-title <em class="arg">string</em></h4> 5693</div> 5694 5695<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> 5696 5697<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> 5698 5699<p>For example,</p> 5700 5701<p class="crtsnip"> 5702 -title "%m:%f %wx%h" 5703</p> 5704 5705<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> 5706 5707 5708<div style="margin: auto;"> 5709 <h4><a id="transform"></a>-transform</h4> 5710</div> 5711 5712<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> 5713 5714<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p> 5715 5716<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> 5717 5718<p>This operator has been now been superseded by the <a 5719href="#distort">-distort</a> '<kbd>AffineProjection</kbd>' method. </p> 5720 5721 5722<div style="margin: auto;"> 5723 <h4><a id="transparent"></a>-transparent <em class="arg">color</em></h4> 5724</div> 5725 5726<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> 5727 5728<p>The <em class="arg">color</em> argument is defined using the format 5729described under the <a href="#fill">-fill</a> option. The <a href="#fuzz" 5730>-fuzz</a> setting can be used to match and replace colors similar to the one 5731given. </p> 5732 5733<p>Use <a href="#transparent" >+transparent</a> to invert the pixels matched. 5734that is make all non-matching colors transparent. </p> 5735 5736<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a 5737href="#transparent" >-transparent</a> but replaces the matching color with the 5738current <a href="#fill">-fill</a> color setting, rather than transparent. 5739However the <a href="#transparent" >-transparent</a> operator also ensures 5740that the image has an alpha channel enabled, as per "<kbd><a href="#alpha" 5741>-alpha</a> set</kbd>", and does not require you to modify the <a 5742href="#channel">-channel</a> to enable alpha channel handling. </p> 5743 5744<p>Note that this does not define the color as being the 'transparency color' 5745used for color-mapped image formats, such as GIF. For that use <a 5746href="#transparent-color" >-transparent-color</a> </p> 5747 5748 5749<div style="margin: auto;"> 5750 <h4><a id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4> 5751</div> 5752 5753<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> 5754 5755<p>Sometimes this is used for saving to image formats such as 5756GIF and PNG8 which uses this color to represent boolean transparency. This 5757does not make a color transparent, it only defines what color the transparent 5758color is in the color palette of the saved image. Use <a 5759href="#transparent">-transparent</a> to make an opaque color transparent.</p> 5760 5761<p>This option allows you to have both an opaque visible color, as well as a 5762transparent color of the same color value without conflict. That is, you can 5763use the same color for both the transparent and opaque color areas within an 5764image. This, in turn, frees to you to select a transparent color that is 5765appropriate when an image is displayed by an application that does not handle a 5766transparent color index, while allowing ImageMagick to correctly handle images of this 5767type. </p> 5768 5769<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p> 5770 5771<div style="margin: auto;"> 5772 <h4><a id="transpose"></a>-transpose</h4> 5773</div> 5774 5775<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> 5776 5777<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>. 5778</p> 5779 5780<div style="margin: auto;"> 5781 <h4><a id="transverse"></a>-transverse</h4> 5782</div> 5783 5784<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> 5785 5786 5787<div style="margin: auto;"> 5788 <h4><a id="treedepth"></a>-treedepth <em class="arg">value</em></h4> 5789</div> 5790 5791<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> 5792 5793<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> 5794 5795<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> 5796 5797<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> 5798 5799<div style="margin: auto;"> 5800 <h4><a id="trim"></a>-trim</h4> 5801</div> 5802 5803<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> 5804 5805<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> 5806 5807<p>The page or virtual canvas information of the image is preserved allowing 5808you to extract the result of the <a href="#trim">-trim</a> operation from the 5809image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page 5810information if it is unwanted.</p> 5811 5812<p>If the trimmed image 'disappears' an warning is produced, and a special 5813single pixel transparent 'missed' image is returned, in the same way as when a 5814<a href="#crop">-crop</a> operation 'misses' the image proper. </p> 5815 5816 5817<div style="margin: auto;"> 5818 <h4><a id="type"></a>-type <em class="arg">type</em></h4> 5819</div> 5820 5821<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> 5822 <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> 5823 5824<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> 5825 5826<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p> 5827<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> 5828 5829<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p> 5830 5831<div style="margin: auto;"> 5832 <h4><a id="undercolor"></a>-undercolor <em class="arg">color</em></h4> 5833</div> 5834 5835<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> 5836 5837<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5838 5839<p>See <a href="#draw">-draw</a> for further details.</p> 5840 5841 5842<div style="margin: auto;"> 5843 <h4><a id="update"></a>-update <em class="arg">seconds</em></h4> 5844</div> 5845 5846<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> 5847 5848<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> 5849 5850 5851<div style="margin: auto;"> 5852 <h4><a id="unique-colors"></a>-unique-colors</h4> 5853</div> 5854 5855<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> 5856 5857 5858<div style="margin: auto;"> 5859 <h4><a id="units"></a>-units <em class="arg">type</em></h4> 5860</div> 5861 5862<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> 5863 5864<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> 5865 5866 5867<div style="margin: auto;"> 5868 <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> 5869</div> 5870 5871<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> 5872 5873<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> 5874 5875<p>The parameters are:</p> 5876 5877<pre class="text"> 5878 radius: The radius of the Gaussian, in pixels, not counting the center 5879 pixel (default 0). 5880 sigma: The standard deviation of the Gaussian, in pixels (default 1.0). 5881 amount: The fraction of the difference between the original and the blur 5882 image that is added back into the original (default 1.0). 5883 threshold: The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the 5884 difference amount (default 0.05). 5885</pre> 5886 5887 5888<div style="margin: auto;"> 5889 <h4><a id="verbose"></a>-verbose</h4> 5890</div> 5891 5892<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> 5893 5894 5895<div style="margin: auto;"> 5896 <h4><a id="version"></a>-version</h4> 5897</div> 5898 5899<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> 5900 5901 5902<div style="margin: auto;"> 5903 <h4><a id="view"></a>-view <em class="arg">string</em></h4> 5904</div> 5905 5906<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> 5907 5908 5909<div style="margin: auto;"> 5910 <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> 5911</div> 5912 5913<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> 5914 5915 5916<div style="margin: auto;"> 5917 <h4><a id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4> 5918</div> 5919 5920<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> 5921 5922<p>This option defines what color source should be used if and when a color 5923lookup completely 'misses' the source image. The color(s) that appear to 5924surround the source image. Generally this color is derived from the source 5925image, but could also be set to a specify background color. </p> 5926 5927<p>Choose from these methods:</p> 5928 5929<pre class="text"> 5930 background: the area surrounding the image is the background color 5931 black: the area surrounding the image is black 5932 checker-tile: alternate squares with image and background color 5933 dither: non-random 32x32 dithered pattern 5934 edge: extend the edge pixel toward infinity 5935 gray: the area surrounding the image is gray 5936 horizontal-tile: horizontally tile the image, background color above/below 5937 horizontal-tile-edge: horizontally tile the image and replicate the side edge pixels 5938 mirror: mirror tile the image 5939 random: choose a random pixel from the image 5940 tile: tile the image (default) 5941 transparent: the area surrounding the image is transparent blackness 5942 vertical-tile: vertically tile the image, sides are background color 5943 vertical-tile-edge: vertically tile the image and replicate the side edge pixels 5944 white: the area surrounding the image is white 5945</pre> 5946 5947<p>The default value is "edge".</p> 5948 5949<p>This most important for distortion operators such as <a href="#distort" 5950>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>. 5951However it also effects operations that may access pixels just outside the 5952image proper, such as <a href="#convolve">-convolve</a>, <a 5953href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p> 5954 5955<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p> 5956 5957 5958<div style="margin: auto;"> 5959 <h4><a id="visual"></a>-visual <em class="arg">type</em></h4> 5960</div> 5961 5962<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> 5963 5964<p>Choose from these visual classes:</p> 5965 5966<pre class="text"> 5967 StaticGray 5968 GrayScale 5969 StaticColor 5970 PseudoColor 5971 TrueColor 5972 DirectColor 5973 default 5974 visual id 5975</pre> 5976 5977<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> 5978 5979 5980<div style="margin: auto;"> 5981 <h4><a id="watermark"></a>-watermark <em 5982 class="arg">brightness</em>x<em class="arg">saturation</em></h4> 5983</div> 5984 5985<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 5986saturation.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 5987 5988<p>Take a grayscale image (with alpha mask) and modify the destination image's 5989brightness according to watermark image's grayscale value and the <em 5990class="arg">brightness</em> percentage. The destinations color saturation 5991attribute is just direct modified by the <em class="arg">saturation</em> 5992percentage, which defaults to 100 percent (no color change). </p> 5993 5994 5995<div style="margin: auto;"> 5996 <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> 5997</div> 5998 5999<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> 6000 6001<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p> 6002 6003<div style="margin: auto;"> 6004 <h4><a id="weight"></a>-weight <em class="arg">fontWeight</em></h4> 6005</div> 6006 6007<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> 6008 6009<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> 6010 6011<table class="doc"> 6012 <col width="25%" /> 6013 <col width="75%" /> 6014 <thead> 6015 <tr> 6016 <th><em class="arg">fontWeight</em></th> 6017 <th>Description</th> 6018 </tr> 6019 </thead> 6020 <tbody> 6021 <tr><td>All </td> <td>No effect. </td></tr> 6022 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr> 6023 <tr><td>Bolder </td> <td>Add 100 to font weight if currently ≤ 800.</td></tr> 6024 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently ≤ 100.</td></tr> 6025 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr> 6026 </tbody> 6027 </table> 6028 6029<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p> 6030 6031<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> 6032 6033<div style="margin: auto;"> 6034 <h4><a id="white-point"></a>-white-point <em class="arg">x,y</em></h4> 6035</div> 6036 6037<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> 6038 6039<div style="margin: auto;"> 6040 <h4><a id="white-threshold"></a>-white-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 6041</div> 6042 6043<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> 6044 6045<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. 6046</p> 6047 6048<div style="margin: auto;"> 6049 <h4><a id="window"></a>-window <em class="arg">id</em></h4> 6050</div> 6051 6052<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> 6053 6054<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> 6055 6056<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> 6057 6058<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> 6059 6060<div style="margin: auto;"> 6061 <h4><a id="window-group"></a>-window-group</h4> 6062</div> 6063 6064<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> 6065 6066<div style="margin: auto;"> 6067 <h4><a id="write"></a>-write <em class="arg">filename</em></h4> 6068</div> 6069 6070<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> 6071 <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> 6072 6073<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p> 6074</div> 6075</div> 6076 6077</div> 6078 6079<div id="linkbar"> 6080 <span id="linkbar-west"> </span> 6081 <span id="linkbar-center"> 6082 <a href="http://www.imagemagick.org/discourse-server/">Discourse Server</a> • 6083 <a href="http://www.imagemagick.org/MagickStudio/scripts/MagickStudio.cgi">Studio</a> 6084 </span> 6085 <span id="linkbar-east"> </span> 6086 </div> 6087 <div class="footer"> 6088 <span id="footer-west">© 1999-2011 ImageMagick Studio LLC</span> 6089 <span id="footer-east"> <a href="http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span> 6090 </div> 6091 <div style="clear: both; margin: 0; width: 100%; "></div> 6092 <script type="text/javascript"> 6093 var _gaq = _gaq || []; 6094 _gaq.push(['_setAccount', 'UA-17690367-1']); 6095 _gaq.push(['_trackPageview']); 6096 6097 (function() { 6098 var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; 6099 ga.src = ('https:' == document.location.protocol ? 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