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</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#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#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#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> 161 162<p>Below is list of command-line options recognized by the ImageMagick <a 163href="/www/command-line-tools.html">command-line 164tools</a>. If you want a description of a particular option, click on the 165option name in the navigation bar above and you will go right to it. Unless 166otherwise noted, each option is recognized by the commands <a href="/www/convert.html">convert</a>, <a href="/www/mogrify.html">mogrify</a>, and .... </p> 167 168<div style="margin: auto;"> 169 <h4><a name="adaptive-blur" id="adaptive-blur"></a>-adaptive-blur <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4> 170</div> 171 172<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> 173 "direction", 174<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> 175 176<div style="margin: auto;"> 177 <h4><a name="adaptive-resize" id="adaptive-resize"></a>-adaptive-resize <em class="arg">geometry</em></h4> 178</div> 179 180<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> 181 182<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> 183 184<div style="margin: auto;"> 185 <h4><a name="adaptive-sharpen" id="adaptive-sharpen"></a>-adaptive-sharpen <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4> 186</div> 187 188<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> 189 190<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> 191 192<div style="margin: auto;"> 193 <h4><a name="adjoin" id="adjoin"></a>-adjoin</h4> 194</div> 195 196<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> 197 198<p>This option is enabled by default. An attempt is made to save all 199images of an image sequence into the given output file. 200However, some formats, such as JPEG and PNG, do not support more than one 201image per file, and in that case ImageMagick is forced to write each image as a separate file. As 202such, if more than one image needs to be written, the filename given is 203modified by adding a <a href="#scene">-scene</a> number before the 204suffix, in order to make distinct names for each image. </p> 205 206<p>Use <a href="#adjoin">+adjoin</a> to force each image to be written 207to separate files, whether or not the file format allows multiple images 208per file (for example, GIF, MIFF, and TIFF). </p> 209 210<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> 211 212<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: rose: -morph 15 my%02dmorph.jpg</span></p> 213<p>will create a sequence of 17 images named my00morph.jpg, my01morph.jpg, my02morph.jpg, ..., my16morph.jpg. 214</p> 215 216<p>In summary, ImageMagick tries to write all images to one file, but will use 217multiple files if either (1) the output image's file format does not allow multi-image files, 218(2) the <a href="#adjoin">+adjoin</a> option is given, or (3) a C-style integer format string is 219present in the output filename. </p> 220 221 222<div style="margin: auto;"> 223 <h4><a name="affine" 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/> 224 -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> 225</div> 226 227<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> 228 229<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> 230 231<p>The matrix entries are entered as comma-separated numeric values <i>with no spaces</i>. </p> 232 233<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> 234 235<div class="eqn"> 236<img alt="affine transformation" src="/images/affine.png"/> 237</div> 238 239<p> 240The 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> 241 242<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> 243 244<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> 245 246<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> 247 248<p class="crtsnip"> 249 -affine <em class="arg">s<sub>x</sub></em>,0,0,<em class="arg">s<sub>y</sub></em> 250</p> 251 252<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> 253 254<p class="crtsnip"> 255 -affine 1,0,0,1,<em class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em> 256</p> 257 258<p>Rotate clockwise about the origin (the upper left-hand corner) by an angle <em>a</em> by letting 259<em>c</em> = cos(<em>a</em>), <em>s</em> = sin(<em>a</em>), and using the following.</p> 260 261<p class="crtsnip"> 262 -affine <em>c</em>,<em>s</em>,-<em>s</em>,<em>c</em> 263</p> 264 265<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> 266 267<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> 268 269<div style="margin: auto;"> 270 <h4><a name="alpha" id="alpha"></a>-alpha <em class="arg">type</em></h4> 271</div> 272 273<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> 274 275<p>Used to set a flag on an image indicating whether or not to use existing alpha 276channel 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> 277 278 279<table class="doc"> 280 <tbody> 281 <tr valign="top"> 282 <th align="left" style="width: 8%">type</th> 283 <th align="left">Description</th> 284 </tr> 285 286 <tr valign="top"> 287 <td valign="top"><kbd>Activate</kbd> or 288 <kbd>Activate</kbd></td> 289 <td valign="top"> 290 Enable the image's transparency channel. Use the <kbd>Set</kbd> argument instead if the alpha channel has not yet been initialized.</td></tr> 291 292 <tr valign="top"> 293 <td valign="top"><kbd>Deactivate</kbd> or 294 <kbd>Deactivate</kbd></td> 295 <td valign="top"> 296 Disables the image's transparency channel. Does not delete or change the 297 existing data, just turns off the use of that data.</td></tr> 298 299 <tr valign="top"> 300 <td valign="top"><kbd>Set</kbd></td> 301 <td valign="top"> 302 Activates the alpha/matte channel and if it was previously 303 turned off resets the channel to opaque. If the image already had the 304 alpha channel turned on, it will have no effect.</td></tr> 305 306 <tr valign="top"> 307 <td valign="top"><kbd>Opaque</kbd></td> 308 <td valign="top"> 309 Enables the alpha/matte channel and forces it to be fully opaque. </td></tr> 310 311 <tr valign="top"> 312 <td valign="top"><kbd>Transparent</kbd></td> 313 <td valign="top"> 314 Activates the alpha/matte channel and forces it to be fully 315 transparent. This effectively creates a fully transparent image the same 316 size as the original and with all its original RGB data still intact, 317 but fully transparent. </td></tr> 318 319 <tr valign="top"> 320 <td valign="top"><kbd>Extract</kbd></td> 321 <td valign="top"> 322 Copies the alpha channel values into all the color channels and turns 323 '<kbd>Off</kbd>' the the image's transparency, so as to generate a 324 gray-scale mask of the image's shape. This is the inverse of 325 '<kbd>Copy</kbd>'. </td></tr> 326 327 <tr valign="top"> 328 <td valign="top"><kbd>Copy</kbd></td> 329 <td valign="top"> 330 Turns '<kbd>On</kbd>' the alpha/matte channel, then copies the 331 gray-scale intensity of the image, as an alpha mask, into the alpha 332 channel, converting a gray-scale mask into a transparent shaped image 333 ready to be colored appropriately. The color channels are not modified. 334 </td></tr> 335 336 <tr valign="top"> 337 <td valign="top"><kbd>Shape</kbd></td> 338 <td valign="top"> 339 As per '<kbd>Copy</kbd>' but also colors the resulting shape mask with 340 the current background color. That is the RGB color channels is 341 replaced, with appropriate alpha shape. 342 </td></tr> 343 344 <tr valign="top"> 345 <td valign="top"><kbd>Background</kbd></td> 346 <td valign="top"> 347 Set any fully-transparent pixel to the background color, while leaving 348 it fully-transparent. This can make some image file formats, such as 349 PNG, smaller as the RGB values of transparent pixels are more uniform, 350 and thus can compress better. 351 </td></tr> 352 </tbody> 353</table> 354 355<p>Note that while the <a href="#matte" >+matte</a> operation is the same as 356"<kbd><a href="#alpha" >-alpha</a> off</kbd>", the <a href="#matte" 357>-matte</a> operation is the same as "<kbd><a href="#alpha" >-alpha</a> 358set</kbd>" and not "<kbd><a href="#alpha" >-alpha</a> on</kbd>". That is, 359"<kbd><a href="#alpha" >-alpha</a> set</kbd>" will ensure that the written 360image is opaque if the original image had no transparency channel enabled, 361regardless if transparency data is already present. </p> 362 363 364<div style="margin: auto;"> 365 <h4><a name="annotate" id="annotate"></a> 366 -annotate <em class="arg">degrees</em> <em class="arg">text</em><br /> 367 -annotate <em class="arg">Xdegrees</em>x<em class="arg">Ydegrees</em> <em class="arg">text</em><br /> 368 -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> 369</div> 370 371<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> 372 373<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> 374 375 376<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> 377 378<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> 379 380<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> 381<div class="eqn"><img alt="annotate transformation" src="/images/annotate.png"/></div> 382 383<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> 384 385<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> 386 387<div style="margin: auto;"> 388 <h4><a name="antialias" id="antialias"></a>-antialias</h4> 389</div> 390 391<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 392drawing fonts and lines.</td><td style='text-align:right;'></td></tr></table> 393 394<p>By default, objects (e.g. text, lines, polygons, etc.) are antialiased when 395drawn. Use <a href="#antialias">+antialias</a> to disable the addition of 396antialiasing edge pixels. This will then reduce the number of colors added to 397an image to just the colors being directly drawn. That is, no mixed colors 398will be added when drawing such objects. </p> 399 400<div style="margin: auto;"> 401 <h4><a name="append" id="append"></a>-append</h4> 402</div> 403 404<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> 405 406<p>This option creates a single longer image image, by joining all the current 407images in sequence top-to-bottom. Use <a href="#append">+append</a> to 408stack images left-to-right. </p> 409 410<p>If they are not of the same width, narrower images are padded with the 411current <a href="#background">-background</a> color setting, and their 412position relative to each other can be controled by the current <a 413href="#gravity">-gravity</a> setting. </p> 414 415 416<div style="margin: auto;"> 417 <h4><a name="attenuate" id="attenuate"></a>-attenuate <em class="arg">value</em></h4> 418</div> 419 420<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> 421 422 423<div style="margin: auto;"> 424 <h4><a name="authenticate" id="authenticate"></a>-authenticate <em class="arg">password</em></h4> 425</div> 426 427<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> 428 429<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> 430 431<p>For a different encryption method, see <a href="#encipher">-encipher</a> and <a href="#decipher">-decipher</a>. </p> 432 433 434 435<div style="margin: auto;"> 436 <h4><a name="auto-gamma" id="auto-gamma"></a>-auto-gamma</h4> 437</div> 438 439<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> 440 441<p>This calculates the mean values of an image, then applies a calculated <a 442href="#gamma" >-gamma</a> adjustment so that is the mean color exists in the 443image it will get a have a value of 50%. </p> 444 445<p>This means that any solid 'gray' image will become 50% gray. </p> 446 447<p>This works well for real-life images with little or no extreme dark and 448light areas, but tend to fail for images with large amounts of bright sky or 449dark shadows. It also does not work well for diagrmas or cartoon like images. 450</p> 451 452<p>It uses the <a href="#channel" >-channel</a> setting, (including the 453'<CODE>sync</CODE>' flag for channel syncronization), to determine which color 454values will be used and modified. As the default <a href="#channel" 455>-channel</a> setting is '<CODE>RGB,sync</CODE>', channels will be modified 456together by the same gamma value, preserving colors. </p> 457 458 459 460<div style="margin: auto;"> 461 <h4><a name="auto-level" id="auto-level"></a>-auto-level</h4> 462</div> 463 464<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> 465 466<p>This is a 'perfect' image normalization operator. It finds the exact 467mimimum and maximum color values in the image and then applies a <a 468href="#level" >-level</a> operator to stretch the values to the full range of 469values. </p> 470 471<p>The operator is not typically used for real-life images, image scans, or 472JPEG format images, as a single 'out-rider' pixel can set a bad min/max values 473for the <a href="#level" >-level</a> operation. On the other hand it is the 474right operator to use for color stretching gradient images being used to 475generate Color lookup tables, distortion maps, or other 'mathematically' 476defined images. </p> 477 478<p>The operator is very similar to the <a href="#normalize">-normalize</a>, <a 479href="#contrast-stretch" >-contrast-stretch</a>, and <a href="#linear-stretch" 480>-linear-stretch</a> operators, but without 'histogram binning' or 'clipping' 481problems that these operators may have. That is <a href="#auto-level" 482>-auto-level</a> is the perfect or ideal version these operators. </p> 483 484<p>It uses the <a href="#channel" >-channel</a> setting, (including the 485special '<CODE>sync</CODE>' flag for channel syncronization), to determine 486which color values will be used and modified. As the default <a 487href="#channel" >+channel</a> setting is '<CODE>RGB,sync</CODE>', the 488'<CODE>sync</CODE>' will ensure that the color channels will be modified 489together by the same gamma value, preserving colors, and ignoring 490transparency. </p> 491 492 493 494<div style="margin: auto;"> 495 <h4><a name="auto-orient" id="auto-orient"></a>-auto-orient</h4> 496</div> 497 498<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> 499 500<p>This operator reads and resets the EXIF image profile setting 'Orientation' 501and then performs the appropriate 90 degree rotation on the image to orient 502the image, for correct viewing. </p> 503 504<p>This EXIF profile setting is usually set using a gravity sensor in digital 505camara, however photos taken directly downward or upward may not have an 506appropriate value. Also images that have been orientation 'corrected' without 507reseting this setting, may be 'corrected' again resulting in a incorrect 508result. If the he EXIF profile was previously stripped, the <a 509href="#auto-orient" >-auto-orient</a> operator will do nothing. </p> 510 511 512<div style="margin: auto;"> 513 <h4><a name="average" id="average"></a>-average</h4> 514</div> 515 516<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> 517 518<p>An error results if the images are not identically sized.</p> 519 520 521<div style="margin: auto;"> 522 <h4><a name="backdrop" id="backdrop"></a>-backdrop</h4> 523</div> 524 525<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> 526 527<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> 528 529<div style="margin: auto;"> 530 <h4><a name="background" id="background"></a>-background <em class="arg">color</em></h4> 531</div> 532 533<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> 534 535<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> 536 537<div style="margin: auto;"> 538 <h4><a name="bench" id="bench"></a>-bench <em class="arg">iterations</em></h4> 539</div> 540 541<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> 542 543<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> 544 545<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> 546<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> 547 548<div style="margin: auto;"> 549 <h4><a name="bias" id="bias"></a>-bias <em class="arg">value</em>{<em class="arg">%</em>}</h4> 550</div> 551 552<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> 553 554<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> 555 556<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> 557 558<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 559negative results without clipping to the color value range 560(0..QuantumRange).</p> 561 562<p>See the discussion on HDRI implementations of ImageMagick on the page 563<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. 564</p> 565 566<div style="margin: auto;"> 567 <h4><a name="black-point-compensation" id="black-point-compensation"></a>-black-point-compensation</h4> 568</div> 569 570<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> 571 572<div style="margin: auto;"> 573 <h4><a name="black-threshold" id="black-threshold"></a>-black-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 574</div> 575 576<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> 577 578<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. 579</p> 580 581 582<div style="margin: auto;"> 583 <h4><a name="blend" id="blend"></a>-blend <em class="arg">geometry</em></h4> 584</div> 585 586<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> 587 588<p>Blend will average the images together ('plus') according to the 589percentages given and each pixels transparency. If only a single percentage 590value is given it sets the weight of the composite or 'source' image, while 591the background image is weighted by the exact opposite amount. That is a 592<kbd>-blend 30%</kbd> merges 30% of the 'source' image with 70% of the 593'destination' image. Thus it is equivalent to <kbd>-blend 30x70%</kbd>.</p> 594 595 596<div style="margin: auto;"> 597 <h4><a name="blue-primary" id="blue-primary"></a>-blue-primary <em class="arg">x</em>,<em class="arg">y</em></h4> 598</div> 599 600<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> 601 602<div style="margin: auto;"> 603 <h4><a name="blue-shift" id="blue-shift"></a>-blue-shift <em class="arg">factor</em></h4> 604</div> 605 606<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> 607 608<div style="margin: auto;"> 609 610<div style="margin: auto;"> 611 <h4><a name="blur" id="blur"></a>-blur <em class="arg">radius</em><br />-blur <em class="arg">radius</em>x<em class="arg">sigma</em></h4> 612</div> 613 614<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> 615 616<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p> 617 618<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 619</div> 620 621<p>Where <i>r</i> is the blur radius (<i>r</i><sup>2</sup> = <i>u</i><sup>2</sup> + <i>v</i><sup>2</sup>), and σ is the standard deviation of the Gaussian distribution. As a guideline, set <i>r</i> to approximately 3σ. If a radius of 0 is specified, ImageMagick selects a suitable radius for you.</p> 622 623<p>This option differs from <a href="#gaussian-blur">-gaussian-blur</a> simply by taking advantage of the separability properties of the distribution. Here we apply a single-dimensional Gaussian matrix in the horizontal direction, then repeat the process in the vertical direction.</p> 624 625<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 626pixels which are outside the image proper are blurred into the final result. 627</p> 628 629 630<div style="margin: auto;"> 631 <h4><a name="blur-composite" id="blur"></a>-blur <em class="arg">Width</em>[x<em class="arg">Height</em>[+<em class="arg">Angle</em>]]</h4> 632</div> 633 634<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> 635 636<p>Each pixel in the overlaid region is replaced with an Elliptical Weighted 637Average (EWA) of the source image, scaled according to the grayscale 638mapping. </p> 639 640<p>The ellipse is weighted with sigma set to the given <em class="arg" 641>Width</em> and <em class="arg" >Height</em>. The <em class="arg" >Height</em> 642defaults to the <em class="arg" >Width</em> for a normal circular Guassian 643weighting. The <em class="arg" >Angle</em> will rotate the ellipse from 644horizontal clock-wise. </p> 645 646<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 647pixels which are outside the image proper are blurred into the final result. 648</p> 649 650 651<div style="margin: auto;"> 652 <h4><a name="border" id="border"></a>-border <em class="arg">geometry</em></h4> 653</div> 654 655<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> 656 657<p>Set the width and height using the <em class="arg">size</em> portion of the <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 ignored. </p> 658 659<p>Set the border color by preceding with the <a href="#bordercolor">-bordercolor</a> setting.</p> 660 661<p>See also the <a href="#frame">-frame</a> option, which has more functionality.</p> 662 663<div style="margin: auto;"> 664 <h4><a name="bordercolor" id="bordercolor"></a>-bordercolor <em class="arg">color</em></h4> 665</div> 666 667<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> 668 669<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 670 671<p>The default border color is <kbd>#DFDFDF</kbd>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p> 672 673<div style="margin: auto;"> 674 <h4><a name="borderwidth" id="borderwidth"></a>-borderwidth <em class="arg">geometry</em> </h4> 675</div> 676 677<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> 678 679<div style="margin: auto;"> 680 <h4><a name="brightness-contrast" 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> 681</div> 682 683<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> 684 685<p>Brightness and Contrast values apply changes to the input image. They are not absolute settings. A brightness or contrast value of zero means no change. The range of values is -100 to +100 on each. Positive values increase the brightness or contrast and negative values decrease the brightness or contrast. To control only contrast, set the brightness=0. To control only brightness, set contrast=0 or just leave it off.</p> 686 687<p>You may also use <a href="#fill">-channel</a> to control which channels to apply the brightness and/or contrast change. The default is to apply the same transformation to all channels.</p> 688 689<p>Brightness and Contrast arguments are converted to offset and slope of a linear transform and applied using <a href="#fill">-function polynomial "slope,offset"</a>.</p> 690 691<p>The slope varies from 0 at contrast=-100 to almost vertical at contrast=+100. For brightness=0 and contrast=-100, the result will be totally midgray. For brightness=0 and contrast=+100, the result will approach but not quite reach a threshold at midgray; that is the linear transformation will be a a very steep vertical line at mid gray.</p> 692 693<p>Negative slopes, i.e. negating the image, are not possible with this function. All achievable slopes will be zero or positive.</p> 694 695<p>The offset varies from -0.5 at brightness=-100 to 0 at brightness=0 to +0.5 at brightness=+100. Thus, when contrast=0 and brightness=100, the result will be totally white. Similarly, when contrast=0 and brightness=-100, the result will be totally black.</p> 696 697<p>As the range of values for the arguments are -100 to +100, adding the '%' symbol will be no different than leaving it off.</p> 698 699<div style="margin: auto;"> 700 <h4><a name="cache" id="cache"></a>-cache <em class="arg">threshold</em></h4> 701</div> 702 703<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> 704 705<div style="margin: auto;"> 706 <h4><a name="caption" id="caption"></a>-caption <em class="arg">string</em></h4> 707</div> 708 709<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> 710 711<div style="margin: auto;"> 712 <h4><a name="cdl" id="cdl"></a>-cdl <em class="arg">filename</em></h4> 713</div> 714 715<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> 716 717<p>Here is an example color correction collection:</p> 718 719<pre class="text"> 720<?xml version="1.0" encoding="UTF-8"?> 721<ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2"> 722 <ColorCorrection id="cc06668"> 723 <SOPNode> 724 <Slope> 0.9 1.2 0.5 </Slope> 725 <Offset> 0.4 -0.5 0.6 </Offset> 726 <Power> 1.0 0.8 1.5 </Power> 727 </SOPNode> 728 <SATNode> 729 <Saturation> 0.85 </Saturation> 730 </SATNode> 731 </ColorCorrection> 732</ColorCorrectionCollection> 733</pre> 734 735<div style="margin: auto;"> 736 <h4><a name="channel" id="channel"></a>-channel <em class="arg">type</em></h4> 737</div> 738 739<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> 740 741<p>Choose from: <kbd>Red</kbd>, <kbd>Green</kbd>, <kbd>Blue</kbd>, <kbd>Alpha</kbd>, <kbd>Cyan</kbd>, <kbd>Magenta</kbd>, <kbd>Yellow</kbd>, <kbd>Black</kbd>, <kbd>Opacity</kbd>, <kbd>Index</kbd>, <kbd>RGB</kbd>, <kbd>RGBA</kbd>, <kbd>CMYK</kbd>, or <kbd>CMYKA</kbd>.</p> 742 743<p>The channels above can also be specified as a comma-separated list or can be 744abbreviated as a concatenation of the letters '<kbd>R</kbd>', '<kbd>G</kbd>', 745'<kbd>B</kbd>', '<kbd>A</kbd>', '<kbd>O</kbd>', '<kbd>C</kbd>', 746'<kbd>M</kbd>', '<kbd>Y</kbd>', '<kbd>K</kbd>'. 747 748For example, to only select the <kbd>Red</kbd> and <kbd>Blue</kbd> channels 749you can either use </p> 750<p class="crtsnip"> 751 -channel Red,Blue 752</p> 753<p>or you can use the short hand form</p> 754<p class="crtsnip"> 755 -channel RB 756</p> 757 758<p>All the channels that is present in an image can be specified using the 759special channel type <kbd>All</kbd>. </p> 760 761<p>On top of the normal channel selection a extra flag can be specified, 762'<kbd>Sync</kbd>'. This is turned on by default and if set means that 763operators that understand this flag should perform: normal cross-channel 764syncronization of the channels. If not specified, then most channel operators 765will apply their image processing operations to each individual channel (as 766specified by the rest of the <a href="#channel">-channel</a> setting) 767completely independantally from each other. </p> 768 769<p>For example for operators such as <a href="#auto-level">-auto-level</a> and 770<a href="#auto-gamma">-auto-gamma</a> the color channels will be modified 771together in exactly the same way so that colors will remain in-sync. Without 772it being set, then each channel will be modified separatally and 773independantally. </p> 774 775<p>Other operations will use the '<kbd>Sync</kbd>' flag to mean syncronize the 776alpha channel handling with the color channels. If not specified, then the 777operator will not treat the alpha channel as special. </p> 778 779<p>To print a complete list of channel types, use <a href="#list">-list 780channel</a>.</p> 781 782 783<p>By default, ImageMagick sets <a href="#channel">-channel</a> to the value 784'<kbd>RGB,sync</kbd>', which specifies that operators act on all channels 785except the opacity channel, and that all the color channels are to be modified 786in exactly the same way. The 'plus' form <a href="#channel" >+channel</a> 787will reset the value back to this default. </p> 788 789<p>Options that are affected by the <a href="#channel" >-channel</a> setting 790include the following. 791 792<a href="#auto-gamma">-auto-gamma</a>, 793<a href="#auto-level">-auto-level</a>, 794<a href="#black-threshold">-black-threshold</a>, 795<a href="#blur">-blur</a>, 796<a href="#clamp">-clamp</a>, 797<a href="#clut">-clut</a>, 798<a href="#combine">-combine</a>, 799<a href="#composite">-composite</a> (Math compose methods only), 800<a href="#contrast-stretch">-contrast-stretch</a>, 801<a href="#evaluate">-evaluate</a>, 802<a href="#function">-function</a>, 803<a href="#fx">-fx</a>, 804<a href="#gaussian-blur">-gaussian-blur</a>, 805<a href="#hald-clut">-hald-clut</a>, 806<a href="#motion-blur">-motion-blur</a>, 807<a href="#negate">-negate</a>, 808<a href="#normalize">-normalize</a>, 809<a href="#ordered-dither">-ordered-dither</a>, 810<a href="#radial-blur">-radial-blur</a>, 811<a href="#random-threshold">-random-threshold</a>, 812<a href="#separate">-separate</a>, and 813<a href="#threshold">-threshold</a>, and 814<a href="#white-threshold">-white-threshold</a>. 815</p> 816 817<p>Warning, some operators behave differentally when the <a href="#channel" 818>+channel</a> default setting is in effect, verses ANY user defined <a 819href="#channel" >-channel</a> setting (including the equivelent of the 820default). These operators have yet to be made to understand the newer 'Sync' 821flag. </p> 822 823<p>For example <a href="#threshold">-threshold</a> will by default 824gray-scale the image before thresholding, if no <a href="#channel" 825>-channel</a> setting has been defined. </p> 826 827<p>Also some operators such as <a href="#blur">-blur</a>, <a 828href="#gaussian-blur">-gaussian-blur</a>, will modify their handling of the 829color channels if the '<kbd>alpha</kbd>' channel is also enabled by <a 830href="#channel" >-channel</a>. Generally this done to ensure that 831fully-transparent colors are treated as being fully-transparent, and thus any 832underlying 'hidden' color has no effect on the final results. Typically 833resulting in 'halo' effects. </p> 834 835<p>As a alpha channel is optional within images some operators will read the 836color channels of an image as a greyscale alpha mask, when the image has no 837alpha channel present, but the <a href="#channel" >-channel</a> setting tells 838the operator to apply the alpha channel. The <a href="#clut">-clut</a> 839operator is a good example of this. </p> 840 841 842<div style="margin: auto;"> 843 <h4><a name="clamp" id="clamp"></a>-clamp</h4> 844</div> 845 846<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> 847 848<div style="margin: auto;"> 849 <h4><a name="charcoal" id="charcoal"></a>-charcoal <em class="arg">factor</em></h4> 850</div> 851 852<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> 853 854<div style="margin: auto;"> 855 <h4><a name="chop" id="chop"></a>-chop <em class="arg">geometry</em></h4> 856</div> 857 858<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> 859 860<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> and <em class="arg">height</em> given in the of the <em class="arg">size</em> portion of the <em class="arg">geometry</em> argument give the number of columns and rows to remove. The <em class="arg">offset</em> portion of the <em class="arg">geometry</em> argument is influenced by a <a href="#gravity">-gravity</a> setting, if present.</p> 861 862<p>The <a href="#chop">-chop</a> option removes entire rows and columns, and moves the remaining corner blocks leftward and upward to close the gaps.</p> 863 864<div style="margin: auto;"> 865 <h4><a name="clip" id="clip"></a>-clip</h4> 866</div> 867 868<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> 869 870<p>If a clipping path is present, it is applied to subsequent operations.</p> 871 872<p>For example, in the command</p> 873 874<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -clip -negate cockatoo.tif negated.tif</span></p> 875<p>only the pixels within the clipping path are negated.</p> 876 877<p>The <a href="#clip">-clip</a> feature requires the XML library. If the XML library is not present, the option is ignored.</p> 878 879<div style="margin: auto;"> 880 <h4><a name="clip-mask" id="clip-mask"></a>-clip-mask</h4> 881</div> 882 883<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> 884 885<div style="margin: auto;"> 886 <h4><a name="clip-path" id="clip-path"></a>-clip-path <em class="arg">id</em></h4> 887</div> 888 889<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> 890 891<div style="margin: auto;"> 892 <h4><a name="clone" id="clone"></a>-clone <em class="arg">index(s)</em></h4> 893</div> 894 895<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> 896 897<p>Specify the image by its index in the sequence. The first image is index 8980. Negative indexes are relative to the end of the sequence; for example, −1 899represents the last image of the sequence. Specify a range of images with a 900dash (e.g. 0−4). Separate multiple indexes with commas but no spaces (e.g. 0,2,5). Use <a 901href="#clone">+clone</a> make a copy of the last image in the image 902sequence.</p> 903 904<div style="margin: auto;"> 905 <h4><a name="clut" id="clut"></a>-clut</h4> 906</div> 907 908<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 909corresponding channel in the second image as a <b>c</b>olor 910<b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style='text-align:right;'></td></tr></table> 911 912<p>The second (LUT) image is ordinarily a gradient image containing the 913histogram mapping of how each channel should be modified. Typically it is a 914either a single row or column image of replacement color values. If larger 915than a single row or column, values are taken from a diagonal line from 916top-left to bottom-right corners.</p> 917 918<p>The lookup is further controlled by the <a 919href="#interpolate">-interpolate</a> setting, which is especially handy for an 920LUT which is not the full length needed by the ImageMagick installed Quality 921(Q) level. Good settings for this are the '<kbd>bilinear</kbd>' and 922'<kbd>bicubic</kbd>' interpolation settings, which give smooth color 923gradients, and the '<kbd>integer</kbd>' setting for a direct, unsmoothed 924lookup of color values. </p> 925 926<p>This operator is especially suited to replacing a grayscale image with a 927specific color gradient from the CLUT image. </p> 928 929<p>Only the channel values defined by the <a href="#channel">-channel</a> 930setting will have their values replaced. In particular, since the default <a 931href="#channel">-channel</a> setting is <kbd>RGB</kbd>, this means that 932transparency (alpha/matte channel) is not affected, unless the <a 933href="#channel">-channel</a> setting is modified. When the alpha channel is 934set, it is treated by the <a href="#clut" >-clut</a> operator in the same way 935as the other channels, implying that alpha/matte values are replaced using the 936alpha/matte values of the original image. </p> 937 938<p>If either the image being modified, or the lookup image, conatins no 939transparency (i.e. <a href="#alpha" >-alpha</a> is turned 'off') but the <a 940href="#channel">-channel</a> setting includes alpha replacement, then it is 941assumed that image represents a gray-scale graident which will be used for the 942replacement alpha values. That is you can use a gray-scale CLUT image to 943adjust a existing images alpha channel, or you can color a gray-scale image 944using colors form CLUT containing the desired colors, including transparency. 945</p> 946 947<p>See also <a href="#hald-clut" >-hald-clut</a> which replaces colors according 948the lookup of the full color RGB value from a 2D representation of a 3D color 949cube. </p> 950 951 952<div style="margin: auto;"> 953 <h4><a name="coalesce" id="coalesce"></a>-coalesce</h4> 954</div> 955 956<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> 957 958<p>Overlay each image in an image sequence according to its <a href="#dispose">-dispose</a> meta-data, to reproduce the look of an animation at each point in the animation sequence. All images should be the same size, and are assigned appropriate GIF disposal settings for the animation to continue working as expected as a GIF animation. Such frames are more easilly viewed and processed than the highly optimized GIF overlay images. </p> 959 960<p>The animation can be re-optimized after processing using the <a href="#layers">-layers</a> method '<kbd>optimize</kbd>', though there is no guarantee that the restored GIF animation optimization is better than the original. </p> 961 962 963<div style="margin: auto;"> 964 <h4><a name="colorize" id="colorize"></a>-colorize <em class="arg">value</em></h4> 965</div> 966 967<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> 968 969<p>Specify the amount of colorization as a percentage. Separate colorization values can be applied to the red, green, and blue channels of the image with a comma-delimited list of colorization values (e.g., <kbd>-colorize 0,0,50</kbd>).</p> 970 971<div style="margin: auto;"> 972 <h4><a name="colormap" id="colormap"></a>-colormap <em class="arg">type</em></h4> 973</div> 974 975<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> 976 977<p>The <em class="arg">type</em> can be <kbd>shared</kbd> or <kbd>private</kbd>.</p> 978 979<p>This option only applies when the default X server visual is <kbd>PseudoColor</kbd> or <kbd>GrayScale</kbd>. Refer to <a href="#visual">-visual</a> for more details. By default, a shared colormap is allocated. The image shares colors with other X clients. Some image colors could be approximated, therefore your image may look very different than intended. If <kbd>private</kbd> is chosen, the image colors appear exactly as they are defined. However, other clients may go <em>technicolor</em> when the image colormap is installed.</p> 980 981<div style="margin: auto;"> 982 <h4><a name="colors" id="colors"></a>-colors <em class="arg">value</em></h4> 983</div> 984 985<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> 986 987<p>The actual number of colors in the image may be less than your request, but never more. Note that this a color reduction option. Images with fewer unique colors than specified by <em class="arg">value</em> will have any duplicate or unused colors removed. The ordering of an existing color palette may be altered. When converting an image from color to grayscale, it is more efficient to convert the image to the gray colorspace before reducing the number of colors. Refer to the <a href="/www/quantize.html">color reduction algorithm</a> for more details.</p> 988 989<div style="margin: auto;"> 990 <h4><a name="color-matrix" id="color-matrix"></a>-color-matrix <em class="arg">matrix</em></h4> 991</div> 992 993<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> 994 995<p>This option permits saturation changes, hue rotation, luminance to alpha, and various other effects. Although variable-sized transformation matrices can be used, typically one uses a 5x5 matrix for an RGBA image and a 6x6 for CMYKA (or RGBA with offsets). The matrix is similar to those used by Adobe Flash except offsets are in column 6 rather than 5 (in support of CMYKA images) and offsets are normalized (divide Flash offset by 255).</p> 996 997<p>As an example, to add contrast to an image with offsets, try this command:</p> 998 999<pre class="text"> 1000convert kittens.jpg -color-matrix \ 1001 " 1.5 0.0 0.0 0.0, 0.0, -0.157 \ 1002 0.0 1.5 0.0 0.0, 0.0, -0.157 \ 1003 0.0 0.0 1.5 0.0, 0.0, -0.157 \ 1004 0.0 0.0 0.0 1.0, 0.0, 0.0 \ 1005 0.0 0.0 0.0 0.0, 1.0, 0.0 \ 1006 0.0 0.0 0.0 0.0, 0.0, 1.0" kittens.png 1007</pre> 1008<div style="margin: auto;"> 1009 <h4><a name="colorspace" id="colorspace"></a>-colorspace <em class="arg">value</em></h4> 1010</div> 1011 1012<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> 1013 1014<p>Choices are:</p> 1015 1016<pre class="text"> 1017 CMY 1018 CMYK 1019 Gray 1020 HSB 1021 HSL 1022 HWB 1023 Lab 1024 Log 1025 OHTA 1026 Rec601Luma 1027 Rec601YCbCr 1028 Rec709Luma 1029 Rec709YCbCr 1030 RGB 1031 sRGB 1032 Transparent 1033 XYZ 1034 YCbCr 1035 YCC 1036 YIQ 1037 YPbPr 1038 YUV 1039</pre> 1040 1041<p>To print a complete list of colorspaces, use <a href="#list">-list colorspace</a>.</p> 1042 1043<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> 1044 1045<table class="doc"> 1046 <caption>Conversion Of RGB To Other Color Spaces</caption> 1047 <tr><th align="left" valign="middle">CMY</th></tr> 1048 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>−R</td></tr> 1049 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>−G</td></tr> 1050 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>−B</td></tr> 1051 <tr><th align="left" valign="middle">CMYK — starts with CMY from above</th></tr> 1052 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr> 1053 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1054 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1055 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1056 1057 <tr><th align="left" valign="middle">Gray</th></tr> 1058 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 1059 1060 <tr><th align="left" valign="middle">HSB — Hue, Saturation, Brightness; like a cone peak downward</th></tr> 1061 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1062 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1063 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr> 1064 1065 <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> 1066 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1067 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1068 <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> 1069 1070 <tr><th align="left" valign="middle">HWB — Hue, Whiteness, Blackness</th></tr> 1071 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr> 1072 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr> 1073 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr> 1074 1075 <tr><th align="left" valign="middle">LAB</th></tr> 1076 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr> 1077 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr> 1078 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr> 1079 1080 <tr><th align="left" valign="middle">LOG</th></tr> 1081 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr> 1082 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr> 1083 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr> 1084 1085 <tr><th align="left" valign="middle">OHTA — approximates principal components transformation</th></tr> 1086 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr> 1087 <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> 1088 <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> 1089 1090 <tr><th align="left" valign="middle">Rec601Luma</th></tr> 1091 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 1092 1093 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr> 1094 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1095 <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> 1096 <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> 1097 1098 <tr><th align="left" valign="middle">Rec709Luma</th></tr> 1099 <tr><td align="left" valign="middle">Gray=0.21260*R+0.71520*G+0.07220*B</td></tr> 1100 1101 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr> 1102 <tr><td align="left" valign="middle">Y=0.212600*R+0.715200*G+0.072200*B; <em>intensity-like</em></td></tr> 1103 <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> 1104 <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> 1105 1106 <tr><th align="left" valign="middle">sRGB</th></tr> 1107 <tr><td align="left" valign="middle">if Rs ≤ .03928 then Rs=R/12.92 else Rs=((R+.055)/1.055)^2.4</td></tr> 1108 <tr><td align="left" valign="middle">if Gs ≤ .03928 then Gs=B/12.92 else Gs=((G+.055)/1.055)^2.4</td></tr> 1109 <tr><td align="left" valign="middle">if Bs ≤ .03928 then Bs=B/12.92 else Bs=((B+.055)/1.055)^2.4</td></tr> 1110 1111 <tr><th align="left" valign="middle">XYZ</th></tr> 1112 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr> 1113 <tr><td align="left" valign="middle">Y=0.2126560*R+0.7151580*G+0.0721856*B</td></tr> 1114 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr> 1115 1116 <tr><th align="left" valign="middle">YCC</th></tr> 1117 <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> 1118 <tr><td align="left" valign="middle">C1=(−0.29900*R−0.58700*G+0.88600*B) (with complicated scaling)</td></tr> 1119 <tr><td align="left" valign="middle">C2=(0.70100*R−0.58700*G−0.11400*B) (with complicated scaling)</td></tr> 1120 1121 <tr><th align="left" valign="middle">YCbCr</th></tr> 1122 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1123 <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> 1124 <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> 1125 1126 <tr><th align="left" valign="middle">YIQ</th></tr> 1127 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1128 <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> 1129 <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> 1130 1131 <tr><th align="left" valign="middle">YPbPr</th></tr> 1132 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1133 <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> 1134 <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> 1135 1136 <tr><th align="left" valign="middle">YUV</th></tr> 1137 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1138 <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> 1139 <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> 1140</table> 1141 1142<div style="margin: auto;"> 1143 <h4><a name="combine" id="combine"></a>-combine</h4> 1144</div> 1145 1146<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> 1147 1148<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> 1149 1150<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. 1151</p> 1152 1153<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> 1154<div style="margin: auto;"> 1155 <h4><a name="comment" id="comment"></a>-comment <em class="arg">string</em></h4> 1156</div> 1157 1158<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> 1159 1160<p>This option places comments in a non-pixel portion of the image file. For a comment to be visibly written on the image itself, use the <a href="#annotate">-annotate</a> or <a href="#draw">-draw</a> options.</p> 1161 1162<p>Use this option to assign a specific comment to the image, when writing to an image format that supports comments. You can include the image filename, type, width, height, or other image attribute by embedding special format characters listed under the <a href="#format">-format</a> option. The comment is not drawn on the image, but is embedded in the image datastream via "Comment" tag or similar mechanism. </p> 1163 1164<p>For example,</p> 1165 1166<p class="crtsnip"> 1167 -comment "%m:%f %wx%h" 1168</p> 1169 1170<p>produces an image comment 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> 1171 1172<p>If the first character of <em class="arg">string</em> is <em class="arg">@</em>, the image comment is read from a file titled by the remaining characters in the string. Comments in a file are literal; no embedded formatting characters are recognized.</p> 1173 1174<div style="margin: auto;"> 1175 <h4><a name="compose" id="compose"></a>-compose <em class="arg">operator</em></h4> 1176</div> 1177 1178<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> 1179 1180<p>The description of composition uses abstract terminology in order to allow 1181the description to be more precise, while avoiding constant values which are 1182specific to a particular build configuration. Each image pixel is represented 1183by red, green, and blue levels (which are equal for a gray pixel). The 1184build-dependent value <em class="QR">QuantumRange</em> is the maximum integral 1185value which may be stored, per pixel, in the red, green, or blue channels of 1186the image. Each image pixel may also optionally (if the image matte channel is 1187enabled) have an associated level of opacity, ranging from <em>opaque</em> to 1188<em>transparent</em>, which may be used to determine the influence of the pixel 1189color when compositing the pixel with another image pixel. If the image matte 1190channel is disabled, then all pixels in the image are treated as opaque. The 1191color of an opaque pixel is fully visible while the color of a transparent 1192pixel color is entirely absent (pixel color is ignored).</p> 1193 1194<p>By definition, raster images have a rectangular shape. All image rows are of 1195equal length, as are all image columns. By treating the alpha channel as a 1196visual "mask" the rectangular image may be given a "shape" by treating the 1197alpha channel as a cookie-cutter for the image. This is done by setting the 1198pixels within the shape to be opaque, with pixels outside the shape set as 1199transparent. Pixels on the boundary of the shape may be between opaque and 1200transparent in order to provide antialiasing (visually smooth edges). The 1201description of the composition operators use this concept of image "shape" in 1202order to make the description of the operators easier to understand. While it 1203is convenient to describe the operators in terms of "shapes" they are by no 1204means limited to mask-style operations since they are based on continuous 1205floating-point mathematics rather than simple boolean operations.</p> 1206 1207<p>The following alpha blending (Duff-Porter) compose methods are available:</p> 1208 1209<table class="doc"> 1210 <tbody> 1211 <tr valign="top"> 1212 <th align="left" style="width: 8%">Method</th> 1213 <th align="left">Description</th> 1214 </tr> 1215 1216 <tr valign="top"> 1217 <td valign="top">clear</td> 1218 <td valign="top">Both the color and the alpha of the destination are 1219 cleared. Neither the source nor the destination are used (except for 1220 destinations size and other meta-data which is always preserved.</td> 1221 </tr> 1222 1223 <tr valign="top"> 1224 <td valign="top">src</td> 1225 <td valign="top">The source is copied to the destination. The destination 1226 is not used as input, though it is cleared.</td> 1227 </tr> 1228 1229 <tr valign="top"> 1230 <td valign="top">dst</td> 1231 <td valign="top">The destination is left untouched. The source image is 1232 completely ignored.</td> 1233 </tr> 1234 1235 <tr valign="top"> 1236 <td valign="top">src-over</td> 1237 <td valign="top">The source is composited over the destination. this is 1238 the default alpha blending compose method, when neither the compose 1239 setting is set, nor is set in the image meta-data.</td> 1240 </tr> 1241 1242 <tr valign="top"> 1243 <td valign="top">dst-over</td> 1244 <td valign="top">The destination is composited over the source and the 1245 result replaces the destination.</td> 1246 </tr> 1247 1248 <tr valign="top"> 1249 <td valign="top">src-in</td> 1250 <td valign="top">The part of the source lying inside of the destination 1251 replaces the destination.</td> 1252 </tr> 1253 1254 <tr valign="top"> 1255 <td valign="top">dst-in</td> 1256 <td valign="top">The part of the destination lying inside of the source 1257 replaces the destination. Areas not overlaid are cleared.</td> 1258 </tr> 1259 1260 <tr valign="top"> 1261 <td valign="top">src-out</td> 1262 <td valign="top">The part of the source lying outside of the destination 1263 replaces the destination.</td> 1264 </tr> 1265 1266 <tr valign="top"> 1267 <td valign="top">dst-out</td> 1268 <td valign="top">The part of the destination lying outside of the source 1269 replaces the destination.</td> 1270 </tr> 1271 1272 <tr valign="top"> 1273 <td valign="top">src-atop</td> 1274 <td valign="top">The part of the source lying inside of the destination is 1275 composited onto the destination.</td> 1276 </tr> 1277 1278 <tr valign="top"> 1279 <td valign="top">dst-atop</td> 1280 <td valign="top">The part of the destination lying inside of the source is 1281 composited over the source and replaces the destination. Areas not 1282 overlaid are cleared. </td> 1283 </tr> 1284 1285 <tr valign="top"> 1286 <td valign="top">xor</td> 1287 <td valign="top">The part of the source that lies outside of the 1288 destination is combined with the part of the destination that lies 1289 outside of the source. Source or Destination, but not both. </td> 1290 </tr> 1291 1292 </tbody> 1293</table> 1294 1295<p>Any of the 'Src-*' methods can also be specified without the 'Src-' part. 1296For example the defaul compose method can be specified as just 'Over'.</p> 1297 1298 1299<p>The following mathemathical composition methods are also available. </p> 1300 1301<table class="doc"> 1302 <tbody> 1303 <tr valign="top"> 1304 <th align="left" style="width: 8%">Method</th> 1305 <th align="left">Description</th> 1306 </tr> 1307 1308 <tr valign="top"> 1309 <td valign="top">multiply</td> 1310 <td valign="top">The source is multiplied by the destination and replaces 1311 the destination. The resultant color is always at least as dark as 1312 either of the two constituent colors. Multiplying any color with black 1313 produces black. Multiplying any color with white leaves the original 1314 color unchanged.</td> 1315 </tr> 1316 1317 <tr valign="top"> 1318 <td valign="top">screen</td> 1319 <td valign="top">The source and destination are complemented and then 1320 multiplied and then replace the destination. The resultant color is 1321 always at least as light as either of the two constituent colors. 1322 Screening any color with white produces white. Screening any color 1323 with black leaves the original color unchanged.</td> 1324 </tr> 1325 1326 <tr valign="top"> 1327 <td valign="top">plus</td> 1328 <td valign="top">The source is added to the destination and replaces the 1329 destination. This operator is useful for averaging or a controled 1330 merger of two images, rather than a direct overlay.</td> 1331 </tr> 1332 1333 <tr valign="top"> 1334 <td valign="top">add</td> 1335 <td valign="top">As per 'plus' but transparency data is treated as matte 1336 values. As such any transparent areas in either image remain 1337 transparent. </td> 1338 </tr> 1339 1340 <tr valign="top"> 1341 <td valign="top">minus</td> 1342 <td valign="top">Subtract the colors in the source image from the 1343 destination image. When transparency is involved, opaque areas is 1344 subtracted from any destination opaque areas. </td> 1345 </tr> 1346 1347 <tr valign="top"> 1348 <td valign="top">subtract</td> 1349 <td valign="top">Subtract the colors in the source image from the 1350 destination image. When transparency is involved transparent areas are 1351 subtracted, so only the opaque areas in the source remain opaque in 1352 the destination image. </td> 1353 </tr> 1354 1355 <tr valign="top"> 1356 <td valign="top">difference</td> 1357 <td valign="top">Subtracts the darker of the two constituent colors from 1358 the lighter. Painting with white inverts the destination color. 1359 Painting with black produces no change.</td> 1360 </tr> 1361 1362 <tr valign="top"> 1363 <td valign="top">exclusion</td> 1364 <td valign="top">Produces an effect similar to that of 'difference', but 1365 appears as lower contrast. Painting with white inverts the 1366 destination color. Painting with black produces no change.</td> 1367 </tr> 1368 1369 <tr valign="top"> 1370 <td valign="top">darken</td> 1371 <td valign="top">Selects the darker of the destination and source colors. 1372 The destination is replaced with the source when the source is darker, 1373 otherwise it is left unchanged.</td> 1374 </tr> 1375 1376 <tr valign="top"> 1377 <td valign="top">lighten</td> 1378 <td valign="top">Selects the lighter of the destination and source colors. 1379 The destination is replaced with the source when the source is 1380 lighter, otherwise it is left unchanged. </td> 1381 </tr> 1382 1383 </tbody> 1384</table> 1385 1386<p>Typically these use the default 'Over' alpha blending when transparencies 1387are also involved, except for 'Plus' which uses a 'plus' alpha blending. 1388This means the alpha channel is used to not only specify that all 1389non-transparent parts of the input image is visible, but also applied color 1390channel 'weighting' of the values. This also applied to the lighting 1391composition methods below. </p> 1392 1393<p>As of IM v6.6.1-6, if the special '<kbd>Sync</kbd>' flag is not specified 1394(enabled by default) with the <a href="#channel" >-channel</a> setting, then 1395the above mathematical compositions will nolonger syncronise its actiosn with 1396the alpha channel. Instead the math composition will be applied on an 1397individual channel basis as defined by the <a href="#channel" >-channel</a>. 1398this includes the alpha channel. </p> 1399 1400<p>This special usage allows you to perform mathematics between images. </p> 1401 1402 1403<p>The following lighting composition methods are also available. </p> 1404 1405<table class="doc"> 1406 <tbody> 1407 <tr valign="top"> 1408 <th align="left" style="width: 8%">Method</th> 1409 <th align="left">Description</th> 1410 </tr> 1411 1412 <tr valign="top"> 1413 <td valign="top">linear-dodge</td> 1414 <td valign="top">This is equivelent to 'Plus' in that the color channels 1415 are simply added, however it does not 'Plus' the alpha channel, but 1416 uses the normal 'Over' alpha blending, which transparencies are 1417 involved. Produces a sort of additive multiply-like result. Added 1418 ImageMagick version 6.5.4-3. </td> 1419 </tr> 1420 1421 <tr valign="top"> 1422 <td valign="top">linear-burn</td> 1423 <td valign="top">As 'Linear-Dodge', but also subtract one from the result. 1424 Sort of a additive 'Screen' of the images. Added ImageMagick version 1425 6.5.4-3. </td> 1426 </tr> 1427 1428 <tr valign="top"> 1429 <td valign="top">color-dodge</td> 1430 <td valign="top">Brightens the destination color to reflect the source 1431 color. Painting with black produces no change.</td> 1432 </tr> 1433 1434 <tr valign="top"> 1435 <td valign="top">color-burn</td> 1436 <td valign="top">Darkens the destination color to reflect the source 1437 color. Painting with white produces no change. Fixed in ImageMagick 1438 version 6.5.4-3. </td> 1439 </tr> 1440 1441 <tr valign="top"> 1442 <td valign="top">overlay</td> 1443 <td valign="top">Multiplies or screens the colors, dependent on the 1444 destination color. Source colors overlay the destination whilst 1445 preserving its highlights and shadows. The destination color is not 1446 replaced, but is mixed with the source color to reflect the lightness 1447 or darkness of the destination.</td> 1448 </tr> 1449 1450 <tr valign="top"> 1451 <td valign="top">hard-light</td> 1452 <td valign="top">Multiplies or screens the colors, dependent on the source 1453 color value. If the source color is lighter than 0.5, the destination 1454 is lightened as if it were screened. If the source color is darker 1455 than 0.5, the destination is darkened, as if it were multiplied. The 1456 degree of lightening or darkening is proportional to the difference 1457 between the source color and 0.5. If it is equal to 0.5 the 1458 destination is unchanged. Painting with pure black or white produces 1459 black or white.</td> 1460 </tr> 1461 1462 1463 <tr valign="top"> 1464 <td valign="top">linear-light</td> 1465 <td valign="top">Like 'Hard-Light' but using linear-dodge and linear-burn 1466 instead. Increases contrast slightly with an impact on the 1467 foreground's tonal values.</td> 1468 </tr> 1469 1470 <tr valign="top"> 1471 <td valign="top">soft-light</td> 1472 <td valign="top">Darkens or lightens the colors, dependent on the source 1473 color value. If the source color is lighter than 0.5, the destination 1474 is lightened. If the source color is darker than 0.5, the destination 1475 is darkened, as if it were burned in. The degree of darkening or 1476 lightening is proportional to the difference between the source color 1477 and 0.5. If it is equal to 0.5, the destination is unchanged. Painting 1478 with pure black or white produces a distinctly darker or lighter area, 1479 but does not result in pure black or white. Fixed in ImageMagick 1480 version 6.5.4-3. </td> 1481 </tr> 1482 1483 <tr valign="top"> 1484 <td valign="top">pegtop-light</td> 1485 <td valign="top">Almost equivelent to 'Soft-Light', but using a 1486 continuious mathematical formula rather than two conditionally 1487 selected formulae. Added ImageMagick version 6.5.4-3. </td> 1488 </tr> 1489 1490 <tr valign="top"> 1491 <td valign="top">vivid-light</td> 1492 <td valign="top">A modified 'Linear-Light' designed to preserve very stong 1493 primary and secondary colors in the image. Added ImageMagick version 1494 6.5.4-3. </td> 1495 </tr> 1496 1497 <tr valign="top"> 1498 <td valign="top">pin-light</td> 1499 <td valign="top">Similar to 'Hard-Light', but using sharp linear shadings, 1500 to similate the effects of a strong 'pinhole' light source. Added 1501 ImageMagick version 6.5.4-3. </td> 1502 </tr> 1503 1504 </tbody> 1505</table> 1506 1507 1508 1509<p>Also included are these special purpose compose methods:</p> 1510 1511<table class="doc"> 1512 <tbody> 1513 <tr valign="top"> 1514 <th align="left" style="width: 8%">Method</th> 1515 <th align="left">Description</th> 1516 </tr> 1517 1518 <tr valign="top"> 1519 <td valign="top">copy-*</td> 1520 <td valign="top">Copy the specified channel (Red, Green, Blue, Cyan, 1521 Magenta, Yellow, Black, or Opacity) in the source image to the 1522 same channel in the destination image. If the channel specified 1523 does not exist in the source image, (which can only happen for methods, 1524 '<kbd>copy-opacity</kbd>' or '<kbd>copy-black</kbd>') then it is 1525 assumed that the source image is a special grayscale channel image 1526 of the values to be copied. </td> 1527 </tr> 1528 1529 <tr valign="top"> 1530 <td valign="top">change-mask</td> 1531 <td valign="top">Replace any destination pixel that is the similar to the source images pixel (as defined by the current <a href="#fuzz">-fuzz</a> factor), with transparency. </td> 1532 </tr> 1533 </tbody> 1534</table> 1535 1536<p>On top of these composed methods are a few special ones that not only require 1537the two images that are being merged or overlaid, but have some extra numerical 1538arguments, which are tabled below. </p> 1539 1540<p>In the "<code>composite</code>" command these composition methods are 1541selected using special options with the arguments needed. They are usually, 1542but not always, the same name as the composte 'method' they use, and replaces 1543the normal use of the <a href="#compose" >-compose</a> setting in the 1544"<code>composite</code>" command. For example... </p> 1545 1546<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>composite ... -blend 50x50 ...</span></p> 1547<p>As of IM v6.5.3-4 the "<code>convert</code>" command can now also supply 1548these extra arguments to its <a href="#composite" >-composite</a> operator, 1549using the special <a href="#set">-set</a> attribute of '<kbd class="arg">option:compose:args</kbd>'. This means you can now make use of 1550these special argumented <a href="#compose" >-compose</a> methods, those the 1551argument and the method both need to be set separatally. For example... </p> 1552 1553<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert ... -compose blend -set option:compose:args 50x50 -composite ...</span></p> 1554<p>The following is a table of these special 'argumented' compose methods, 1555with a brief summary of what they do. For more details see the equivalent 1556"composite" command option name. </p> 1557 1558<table class="doc"> 1559 <tbody> 1560 <tr valign="top"> 1561 <th align="left" style="width: 8%">Method</th> 1562 <th align="left">Description</th> 1563 </tr> 1564 1565 <tr valign="top"> 1566 <td valign="top">dissolve</td> 1567 <td valign="top">Arguments: 1568 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>] 1569 <br>Equivalent to "<code>composite</code>" <a href="#dissolve">-dissolve</a> 1570 <br>Dissolve the 'source' image by the percentage given before overlaying 1571 'over' the 'destination' image. If <em class="arg">src_percent</em> is 1572 greater than 100, it starts dissolving the main image so it will 1573 become transparent at a value of '<kbd class="arg">200</kbd>'. If 1574 both percentages are given, each image are dissolved to the 1575 percentages given. 1576 </td> 1577 </tr> 1578 1579 <tr valign="top"> 1580 <td valign="top">blend</td> 1581 <td valign="top">Arguments: 1582 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>] 1583 <br>Equivalent to "<code>composite</code>" <a href="#blend">-blend</a> 1584 <br>Average the images together ('plus') according to the percentages 1585 given and each pixels transparency. If only a single percentage value 1586 is given it sets the weight of the composite or 'source' image, while 1587 the background image is weighted by the exact opposite amount. That is 1588 a <kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of 1589 the 'destination' image. Thus it is equivalent to <kbd>-blend 1590 30x70</kbd>. 1591 </td> 1592 </tr> 1593 1594 <tr valign="top"> 1595 <td valign="top">mathematics</td> 1596 <td valign="top">Arguments: <em class="arg">A, B, C, D</em> 1597 <br>Not available in "<code>composite</code>" at this time. 1598 <br>Merge the source and destination images according to the formula 1599 <br> <code>A*Sc*Dc + B*Sc + C*Dc + D</code> 1600 <br>Can be used to generate a custom composition method that would 1601 otherwise need to be implemented using the slow <a href="#fx">-fx</a> 1602 DIY image operator. Added to ImageMagick version 6.5.4-3. 1603 <br>As of IM v6.6.1-6 this method will do per-channel math compositions 1604 if the 'Sync' flag is removed from <a href="#channel" >-channel</a>, 1605 just like all the other mathematical compostion methods above. 1606 </td> 1607 </tr> 1608 1609 <tr valign="top"> 1610 <td valign="top">modulate</td> 1611 <td valign="top">Arguments: 1612 <em class="arg">brightness</em>[x<em class="arg">saturation</em>] 1613 <br>Equivalent to "<code>composite</code>" <a href="#watermark">-watermark</a> 1614 <br>Take a grayscale image (with alpha mask) and modify the destination 1615 image's brightness according to watermark image's grayscale value and 1616 the <em class="arg">brightness</em> percentage. The destinations 1617 color saturation attribute is just direct modified by the <em 1618 class="arg">saturation</em> percentage, which defaults to 100 percent 1619 (no color change). 1620 1621 </td> 1622 </tr> 1623 1624 <tr valign="top"> 1625 <td valign="top">displace</td> 1626 <td valign="top">Arguments: 1627 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em>][!][%] 1628 <br>Equivalent to "<code>composite</code>" <a href="#displace">-displace</a> 1629 <br>With this option, the 'overlay' image, and optionally the 'mask' 1630 image, is used as a relative displacement map, which is used to 1631 displace the lookup of what part of the destination image is seen at 1632 each point of the overlaid area. Much like the displacement map is a 1633 'lens' that distorts the original 'background' image behind it. 1634 <br><br> 1635 The X-scale is modilated by the 'red' channel of the overlay image 1636 while the Y-scale is modulated by the green channel, (the mask image 1637 if given is rolled into green channel of the overlay image. This 1638 separation allows you to modulate the X and Y lookup displacement 1639 separatally allowing you to di 2 dimentional displacements, rather 1640 than 1 dimentional verctored displacements (using grayscale image). 1641 <br><br> 1642 If the overlay image contains transparency this is used as a mask 1643 of the resulting image to remove 'invalid' pixels. 1644 <br><br> 1645 The '%' flag makes the displacement scale relative to the size of the 1646 overlay image (100% = half width/height of image). Using '!' switches 1647 percentage arguments to refer to the destination image size instead. 1648 <br><br> 1649 Special flags were added Added to ImageMagick version 6.5.3-5. 1650 </td> 1651 </tr> 1652 1653 <tr valign="top"> 1654 <td valign="top">distort</td> 1655 <td valign="top">Arguments: 1656 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em 1657 >[+<em class="arg">X-center</em>+<em class="arg">Y-center</em>]][!][%] 1658 <br>Not available in "<code>composite</code>" at this time. 1659 <br>Exactly as per 'Displace' (above), but using absolute coordinates, 1660 relative to the center of the overlay (or that given). Basically 1661 allows you to generate absolute distortion maps where 'black' will 1662 look up the left/top edge, and 'white' looks up the bottom/right 1663 edge of the destination image, according to the scale given. 1664 <br><br> 1665 The '!' flag not only switches percentage scaling, to use the 1666 destination image, but also the image the center offset of the lookup. 1667 This means the overlay can lookup a completely different region of the 1668 destination image. 1669 <br><br> 1670 Added to ImageMagick version 6.5.3-5. 1671 </td> 1672 </tr> 1673 1674 <tr valign="top"> 1675 <td valign="top">blur</td> 1676 <td valign="top">Arguments: 1677 <em class="arg">Width</em>[x<em class="arg">Height</em 1678 >[+<em class="arg">Angle</em>]] 1679 <br>Equivalent to "<code>composite</code>" 1680 <a href="#blur-composite">-blur</a> 1681 <br>A Variable Blur Mapping Composition method, where each pixel in the 1682 overlaid region is replaced with an Elliptical Weighted Average (EWA), 1683 with an ellipse (typically a circle) of the given sigma size, scaled 1684 according to overlay (source image) grayscale mapping. 1685 <br><br> 1686 As per 'Displace' and 'Distort', the red channel will modulate the 1687 width of the ellipse, while the green channel will modulate the height 1688 of the ellipse. However at this time the ellipse angle is not 1689 modulated though this may be a future posibility (perhaps with a 1690 special flag to enable use of blur channel for this purpose). 1691 <br><br> 1692 Added to ImageMagick version 6.5.4-0. 1693 </td> 1694 </tr> 1695 1696 </tbody> 1697</table> 1698 1699<p>To print a complete list of all the available compose operators, use <a 1700href="#list">-list compose</a>.</p> 1701 1702 1703<div style="margin: auto;"> 1704 <h4><a name="composite" id="composite"></a>-composite</h4> 1705</div> 1706 1707<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Perform alpha composition on the current image sequence.</td><td style='text-align:right;'></td></tr></table> 1708 1709<p>Take the first image 'destination' and overlay the second 'source' image 1710according to the current <a href="#compose">-compose</a> setting. The location 1711of the 'source' or 'overlay' image is controlled according to <a 1712href="#geometry" >-geometry</a>, and <a href="#geometry" >-geometry</a> 1713settings. </p> 1714 1715<p>If a third image is given this is treated as a gray-scale 'mask' image 1716relative to the first 'destination' image. This mask will limit what parts of 1717the destination can be modified by the image composition. However for the 1718'<kbd>displace</kbd>' compose method, the mask is used to provide a separate 1719Y-displacement image instead. </p> 1720 1721<p>If a <a href="#compose">-compose</a> method requires extra numerical 1722arguments or flags these can be provided by setting the <a 1723href="#set">-set</a> '<kbd class="arg">option:compose:args</kbd>' 1724appropriatally for the compose method. </p> 1725 1726<p>Some <a href="#compose">-compose</a> methods can modify the 'destination' 1727image outside the overlay area. You can disable this by setting the special <a 1728href="#set">-set</a> '<kbd class="arg">option:compose:outside-overlay</kbd>' 1729to '<kbd>false</kbd>'. </p> 1730 1731 1732<div style="margin: auto;"> 1733 <h4><a name="compress" id="compress"></a>-compress <em class="arg">type</em></h4> 1734</div> 1735 1736<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> 1737 1738<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> 1739 1740<p>To print a complete list of compression types, use <a href="#list">-list compress</a>.</p> 1741 1742<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> 1743 1744<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> 1745 1746<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> 1747 1748<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> 1749 1750<div style="margin: auto;"> 1751 <h4><a name="contrast" id="contrast"></a>-contrast</h4> 1752</div> 1753 1754<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> 1755 1756<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> 1757 1758<p>For a more pronounced effect you can repeat the option:</p> 1759 1760<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -contrast -contrast rose_c2.png</span></p> 1761<div style="margin: auto;"> 1762 <h4><a name="contrast-stretch" 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> 1763</div> 1764 1765<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> 1766 1767<p>While performing the stretch, black-out at most <em 1768class="arg" >black-point</em> pixels and white-out at most <em 1769class="arg" >white-point</em> pixels. Or, if percent is used, black-out at most 1770<em class="arg" >black-point %</em> pixels and white-out at most <em 1771class="arg" >white-point %</em> pixels.</p> 1772 1773<p>Prior to ImageMagick 6.4.7-0, <a href="#contrast-stretch" 1774>-contrast-stretch</a> will black-out at most <em class="arg" 1775>black-point</em> pixels and white-out at most <em class="arg" >total pixels 1776minus white-point</em> pixels. Or, if percent is used, black-out at most <em 1777class="arg">black-point %</em> pixels and white-out at most <em class="arg" 1778>100% minus white-point %</em> pixels.</p> 1779 1780<p>Note that <kbd>-contrast-stretch 0</kbd> will modify the image such that 1781the image's min and max values are stretched to 0 and <em class="QR" 1782>QuantumRange</em>, respectively, without any loss of data due to burn-out or 1783clipping at either end. This is not the same as <a href="#normalize" 1784>-normalize</a>, which is equivalent to <kbd>-contrast-stretch 2%x1%</kbd> (or 1785prior to ImageMagick 6.4.7-0, <kbd>-contrast-stretch 2%x99%</kbd>).</p> 1786 1787<p>Internally operator works by creating a histogram bin, and then uses that 1788bin to modify the image. As such some colors may be merged together when they 1789originally fell into the same 'bin'. </p> 1790 1791<p>All the channels are normalized in concert by the came amount so as to 1792preserve color integrity, when the default <a href="#channel" >+channel</a> 1793setting is in use. Specifing any other <a href="#channel" >-channel</a> 1794setting will normalize the RGB channels independently.</p> 1795 1796<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 1797normalization of mathematical images. </p> 1798 1799<p>This operator is under review for re-development. </p> 1800 1801 1802<div style="margin: auto;"> 1803 <h4><a name="convolve" id="convolve"></a>-convolve <em class="arg">kernel</em></h4> 1804</div> 1805 1806<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> 1807 1808<p>The <em class="arg">kernel</em> is a matrix specified as 1809a comma-separated list of integers (with no spaces), ordered left-to right, 1810starting with the top row. Presently, only odd-dimensioned kernels are 1811supported, and therefore the number of entries in the specified <em 1812class="arg">kernel</em> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25, 18137<sup>2</sup>=49, etc. </p> 1814 1815<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 1816positive and negative results are relative to a user-specified bias value. 1817This is important for non-HDRI compilations of ImageMagick when dealing with 1818convolutions that contain negative as well as positive values. This is 1819especially the case with convolutions involving high pass filters or edge 1820detection. Without an output bias, the negative values is clipped at zero. 1821</p> 1822 1823<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 1824negative results without clipping to the color value range (0..QuantumRange). 1825See the discussion on HDRI implementations of ImageMagick on the page <a 1826href="/www/high-dynamic-range.html">High 1827Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a 1828href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this 1829<a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> 1830entry. </p> 1831 1832 1833<div style="margin: auto;"> 1834 <h4><a name="crop" id="crop"></a>-crop <em class="arg">geometry</em></h4> 1835</div> 1836 1837<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> 1838 1839<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> 1840 1841<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> 1842 1843<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> 1844 1845<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> 1846 1847<p>By adding a exclamation character flag to the geometry argument, the 1848cropped images virtual canvas page size and offset is set as if the 1849geometry argument was a viewport or window. This means the canvas page size 1850is set to exactly the same size you specified, the image offset set 1851relative top left corner of the region cropped. </p> 1852 1853<p>If the cropped image 'missed' the actual image on its virtual canvas, a 1854special single pixel transparent 'missed' image is returned, and a 'crop 1855missed' warning given. </p> 1856 1857<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> 1858 1859<div style="margin: auto;"> 1860 <h4><a name="cycle" id="cycle"></a>-cycle <em class="arg">amount</em></h4> 1861</div> 1862 1863<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> 1864 1865<p><em class="arg">Amount</em> defines the number of positions each 1866colormap entry is shifted.</p> 1867 1868 1869<div style="margin: auto;"> 1870 <h4><a name="debug" id="debug"></a>-debug <em class="arg">events</em></h4> 1871</div> 1872 1873<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> 1874 1875<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> 1876 1877 1878<p>For example, to log cache and blob events, use.</p> 1879 1880<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p> 1881<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p> 1882 1883<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p> 1884 1885<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p> 1886 1887<p>Use <a href="#debug">+debug</a> to turn off all logging.</p> 1888 1889<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> 1890 1891 1892<div style="margin: auto;"> 1893 <h4><a name="decipher" id="decipher"></a>-decipher <em class="arg">filename</em></h4> 1894</div> 1895 1896<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> 1897 1898<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 1899 1900<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 1901 1902 1903<div style="margin: auto;"> 1904 <h4><a name="deconstruct" id="deconstruct"></a>-deconstruct</h4> 1905</div> 1906 1907<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> 1908 1909<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> 1910 1911<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> 1912 1913<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p> 1914 1915 1916<div style="margin: auto;"> 1917 <h4><a name="define" id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4> 1918</div> 1919 1920<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>add coder/decoder specific options.</td><td style='text-align:right;'></td></tr></table> 1921 1922<p>This option creates one or more definitions for coders and decoders to use while reading and writing image data. Definitions may be passed to coders and decoders to control options that are specific to certain image formats. If <em class="arg">value</em> is missing for a definition, an empty-valued definition of a flag is created with that name. This used to control on/off options. Use <a href="#define">+define key</a> to remove definitions previously created. Use <a href="#define">+define "*"</a> to remove all existing definitions.</p> 1923 1924<p>The following definitions may be created:</p> 1925 1926<ul> 1927<dt>dcm:display-range=reset</dt> 1928 <dd>Set the display range to the minimum and maximum pixel values for the DCM image format.</dd><br /> 1929<dt>dot:layout-engine=<em class="arg">value</em></dt> 1930 <dd>Set the specify the layout engine for the DOT image format (e.g. <kbd>neato</kbd>).</dd><br /> 1931<dt>jpeg:extent=<em class="arg">value</em></dt> 1932 <dd>Restrict the maximum JPEG file size, for example <kbd>-define jpeg:extent=400kb</kbd>.</dd><br /> 1933<dt>jpeg:size=<em class="arg">geometry</em></dt> 1934 <dd>Set the size hint of a JPEG image, for example, -define jpeg:size=128x128. It is most useful for increasing performance and reducing the memory requirements when reducing the size of a large JPEG image.</dd><br /> 1935<dt>jp2:rate=<em class="arg">value</em></dt> 1936 <dd>Specify the compression factor to use while writing JPEG-2000 files. The compression factor is the reciprocal of the compression ratio. The valid range is 0.0 to 1.0, with 1.0 indicating lossless compression. If defined, this value overrides the -quality setting. A quality setting of 75 results in a rate value of 0.06641.</dd><br /> 1937<dt>mng:need-cacheoff</dt> 1938 <dd>turn playback caching off for streaming MNG.</dd><br /> 1939<dt>png:bit-depth=<em class="arg">value</em></dt> 1940<dt>png:color-type=<em class="arg">value</em></dt> 1941 <dd>desired bit-depth and color-type for PNG output. You can force the PNG encoder to use a different bit-depth and color-type than it would have normally selected, but only if this does not cause any loss of image quality. Any attempt to reduce image quality is treated as an error and no PNG file is written. E.g., if you have a 1-bit black-and-white image, you can use these "defines" to cause it to be written as an 8-bit grayscale, indexed, or even a 64-bit RGBA. But if you have a 16-million color image, you cannot force it to be written as a grayscale or indexed PNG. If you wish to do this, you must use the appropriate <a href="#depth">-depth</a>, <a href="#colors">-colors</a>, or <a href="#type">-type</a> directives to reduce the image quality prior to using the PNG encoder. Note that in indexed PNG files, "bit-depth" refers to the number of bits per index, which can range from 1 to 8. In such files, the color samples always have 8-bit depth.</dd><br /> 1942<dt>ps:imagemask</dt> 1943 <dd>If the ps:imagemask flag is defined, the PS3 and EPS3 coders will create Postscript files that render bilevel images with the Postscript imagemask operator instead of the image operator.</dd><br /> 1944<dt>quantum:format=<em class="arg">type</em></dt> 1945 <dd>Set the type to <kbd>floating-point</kbd> to specify a single precision floating-point format for raw files (e.g. GRAY:).</dd> 1946</ul> 1947 1948<p>For example, to create a postscript file that will render only the black pixels of a bilevel image, use:</p> 1949 1950<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p> 1951<p>Set attributes of the image registry by prefixing the value with <kbd>registry:</kbd>. For example, to set a temporary path to put work files, use:</p> 1952 1953<p class="crtsnip"> 1954-define registry:temporary-path=/data/tmp 1955</p> 1956 1957<div style="margin: auto;"> 1958 <h4><a name="delay" 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> 1959</div> 1960 1961<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> 1962 1963<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> 1964 1965<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> 1966 1967 1968<div style="margin: auto;"> 1969 <h4><a name="delete" id="delete"></a>-delete <em class="arg">index</em></h4> 1970</div> 1971 1972<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> 1973 1974<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> 1975 1976 1977<div style="margin: auto;"> 1978 <h4><a name="density" id="density"></a>-density <em class="arg">width</em><br />-density <em class="arg">width</em>x<em class="arg">height</em></h4> 1979</div> 1980 1981<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> 1982 1983<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> 1984 1985<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> 1986 1987<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> 1988 1989<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> 1990 1991<div style="margin: auto;"> 1992 <h4><a name="depth" id="depth"></a>-depth <em class="arg">value</em></h4> 1993</div> 1994 1995<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> 1996 1997<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> 1998 1999<div style="margin: auto;"> 2000 <h4><a name="descend" id="descend"></a>-descend</h4> 2001</div> 2002 2003<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> 2004 2005<div style="margin: auto;"> 2006 <h4><a name="deskew" id="deskew"></a>-deskew <em class="arg">threshold</em></h4> 2007</div> 2008 2009<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> 2010 2011<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> 2012 2013<div style="margin: auto;"> 2014 <h4><a name="despeckle" id="despeckle"></a>-despeckle</h4> 2015</div> 2016 2017<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> 2018 2019<div style="margin: auto;"> 2020 <h4><a name="direction" id="direction"></a>-direction <em class="arg">type</em></h4> 2021</div> 2022 2023<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> 2024 2025<div style="margin: auto;"> 2026 <h4><a name="displace" 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> 2027</div> 2028 2029<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> 2030 2031<p>With this option, the 'overlay' image, and optionally the 'mask' image, 2032will be used as a displacement map, which is used to displace the lookup of 2033what part of the 'background' image is seen at each point of the overlaid 2034area. Much like the displacement map is a 'lens' that redirects light shining 2035through it so as to present a distorted view the original 'background' image 2036behind it. </p> 2037 2038<p>Any perfect grey areas of the displacement map produce a zero 2039displacement of the image. Black areas produce the given maximum negative 2040displacement of the lookup point, while white produce a maximum positive 2041displacement of the lookup. </p> 2042 2043<p>Note that it is the lookup of the 'background' that is displaced, not a 2044displacement of the image itself. As such an area of the displacement map 2045containing 'white' will have the lookup point 'shifted' by a positive amount, 2046and thus generating a copy of the destination image to the right/downward from 2047the correct position. That is the image will look like it may have been 2048'shifted' in a negative left/upward direction. Understanding this is a very 2049important in understanding how displacement maps work. </p> 2050 2051<p>The given arguments define the maximum amount of displacement in pixels 2052that a particular map can produce. If the displacement scale is large enough 2053it is also posible to lookup parts of the 'background' image that lie well 2054outside the bounds of the displacement map itself. That is you could very 2055easilly copy a section of the original image from outside the overlay area 2056into the overlay area. </p> 2057 2058<p>The '%' flag makes the displacement scale relative to the size of the 2059overlay image (100% = half width/height of image). Using '!' switches 2060percentage arguments to refer to the destination image size instead. 2061these flags were added as of IM v6.5.3-5.</p> 2062 2063<p>Normally a single grayscale displacement map is provided, which with the 2064given scaling values will determine a single direction (vector) in which 2065displacements can occur (positivally or negativally). However, if you also 2066specify a third image which is normally used as a <em class="arg">mask</em>, 2067then the <em class="arg">composite image</em> will be used for horizontal X 2068displacement, while the <em class="arg">mask image</em> is used for vertical Y 2069displacement. This allows you to define completely different displacement 2070values for the X and Y directions, and allowing you to lookup any point within 2071the <em class="arg">scale</em> bounds. In other words each pixel can lookup 2072any other nearby pixel, producing complex 2 dimentional displacements, rather 2073than a simple 1 dimentional vector displacements. </p> 2074 2075<p>Alternativally rather than suppling two separate images, as of IM v6.4.4-0, 2076you can use the 'red' channel of the overlay image to specify the horizontal 2077or X displacement, and the 'green' channel for the vertical or Y displacement. 2078</p> 2079 2080<p>As of IM v6.5.3-5 any alpha channel in the overlay image will be used as a 2081mask the transparency of the destination image. However areas outside the 2082overlaid areas will not be effected. </p> 2083 2084 2085<div style="margin: auto;"> 2086 <h4><a name="display" id="display"></a>-display <em class="arg">host:display[.screen]</em></h4> 2087</div> 2088 2089<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> 2090 2091<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p> 2092 2093<div style="margin: auto;"> 2094 <h4><a name="dispose" id="dispose"></a>-dispose <em class="arg">method</em></h4> 2095</div> 2096 2097<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> 2098 2099<p>The layer disposal method defines the way each the displayed image is to be 2100modified after the current 'frame' of an animation has finished being 2101displayed (after its 'delay' period), but before the next frame on an 2102animation is to be overlaid onto the display. </p> 2103 2104<p>Here are the valid methods:</p> 2105 2106<pre class="text"> 2107Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>'). 2108None 1 Do not dispose, just overlay next frame image. 2109Background 2 Clear the frame area with the background color. 2110Previous 3 Clear to the image prior to this frames overlay. 2111</pre> 2112 2113<p>You can also use the numbers given above, which is what the GIF format 2114uses internally to represent the above settings. </p> 2115 2116<p>To print a complete list of dispose methods, use <a href="#list">-list dipose</a>.</p> 2117 2118<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent 2119resetting the layer disposal methods of images being read in. </p> 2120 2121<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image 2122disposal method for images already in memory.</p> 2123 2124<div style="margin: auto;"> 2125 <h4><a name="dissimilarity-threshold" id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4> 2126</div> 2127 2128<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> 2129 2130 2131<div style="margin: auto;"> 2132 <h4><a name="dissolve" id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4> 2133</div> 2134 2135<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> 2136 2137<p>The opacity of the composite image is multiplied by the given percent, then 2138it is composited 'over' the main image. If <em class="arg">src_percent</em> 2139is greater than 100, start dissolving the main image so it will become 2140transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages 2141are given, each image are dissolved to the percentages given. </p> 2142 2143<p>Note that dissolve percentages do not add, two opaque images dissolved 2144'50,50', produce a 75% transparency. For a 50% + 50% blending of the two 2145images, you would need to use dissolve values of '50,100'. </p> 2146 2147<div style="margin: auto;"> 2148 <h4><a name="distort" id="distort"></a>-distort <em class="arg">method arguments</em></h4> 2149</div> 2150 2151<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> 2152 2153<p>The <em class="arg">arguments</em> is a single string containing a list 2154of floating point numbers separated by commas or spaces. The number of 2155and meaning of the floating point values depends on the distortion <em 2156class="arg">method</em> being used. </p> 2157 2158<p>Choose from these distortion types:</p> 2159 2160<table class="doc"> 2161 <tr valign="top"> 2162 <th align="left" style="width: 8%">Method</th> 2163 <th align="left">Description</th> 2164 </tr> 2165 2166 <tr valign="top"> 2167 <td valign="top"><kbd>ScaleRotateTranslate</kbd> 2168 <br/>or <kbd>SRT</kbd></td> 2169 <td valign="top"> 2170 Distort image by first scaling and rotating about a given 'center', 2171 before translating that 'center' to the new location, in that order. It 2172 is an alternative method of specifying a '<kbd>Affine</kbd>' type of 2173 distortion, but without shearing effects. It also provides a good way 2174 of rotating and displacing a smaller image for tiling onto a larger 2175 background (IE 2-dimensional animations). <br/> 2176 2177 The number of arguments determine the specific meaning of each 2178 argument for the scales, rotation, and translation operations. <br/> 2179 2180 <table style="margin-left:auto; margin-right:auto;"> 2181 <tr><td># </td><td>arguments meaning</td></tr> 2182 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr> 2183 <tr><td>2:</td><td><em>Scale Angle</em></td></tr> 2184 <tr><td>3:</td><td><em>ScaleX,ScaleY Angle</em></td></tr> 2185 <tr><td>4:</td><td><em>X,Y Scale Angle</em></td></tr> 2186 <tr><td>5:</td> 2187 <td><em>X,Y ScaleX,ScaleY Angle</em></td></tr> 2188 <tr><td>6:</td> 2189 <td><em>X,Y Scale Angle NewX,NewY</em></td></tr> 2190 <tr><td>7:</td> 2191 <td><em>X,Y ScaleX,ScaleY Angle 2192 NewX,NewY</em></td></tr> 2193 </table> 2194 2195 This is actually an alternative way of specifing a 2 dimensional linear 2196 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr> 2197 2198 <tr valign="top"> 2199 <td valign="top"><kbd>Affine</kbd></td> 2200 <td valign="top"> 2201 Distort the image linearly by moving a list of at least 3 or more sets 2202 of control points (as defined below). Idealy 3 sets or 12 floating 2203 point values are given allowing the image to be linearly scaled, 2204 rotated, sheared, and translated, according to those three points. See 2205 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>' 2206 distortions. <br/> 2207 2208 More than 3 sets given control point pairs (12 numbers) is least 2209 squares fitted to best match a lineary affine distortion. If only 2 2210 control point pairs (8 numbers) are given a two point image translation 2211 rotation and scaling is performed, without any posible shearing, 2212 flipping or changes in aspect ratio to the resulting image. If only one 2213 control point pair is provides the image is only translated, (which may 2214 be a floating point non-integer translation). <br/> 2215 2216 This distortion does not include any form of perspective distortion. 2217 </td> 2218 2219 </tr> 2220 2221 <tr valign="top"> 2222 <td valign="top"><kbd>AffineProjection</kbd></td> 2223 <td valign="top"> 2224 Linearly distort an image using the given Affine Matrix of 6 2225 pre-calculated coefficients forming a set of Affine Equations to map 2226 the source image to the destination image. 2227 2228 <div style="text-align: center"><em> 2229 s<sub>x</sub>, r<sub>x</sub>, 2230 r<sub>y</sub>, s<sub>y</sub>, 2231 t<sub>x</sub>, t<sub>y</sub> 2232 </em></div> 2233 2234 See <a href="#affine" >-affine</a> setting for more detail, and 2235 meanings of these coefficients. <br/> 2236 2237 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide 2238 alternative methods of defining this distortion, with ImageMagick doing the 2239 calculations needed to generate the required coefficients. You can see 2240 the internally generated coefficients, by using a <a href="#verbose" 2241 >-verbose</a> setting. </td> 2242 2243 </tr> 2244 2245<!-- still under development, do not display - Anthony 2246 <tr valign="top"> 2247 <td valign="top"><kbd>Bilinear</kbd></td> 2248 <td valign="top"> 2249 Bilinear (reversed) Distortion, given a minimum of 4 sets of 2250 coordinate pairs, or 16 values (see below). Not that lines may not 2251 appear straight after distortion, though the distance between 2252 coordinates will remain consistant. </td> 2253 </tr> 2254--> 2255 2256 <tr valign="top"> 2257 <td valign="top"><kbd>Perspective</kbd></td> 2258 <td valign="top"> 2259 Perspective distort the images, using a list of 4 or more sets of 2260 control points (as defined below). More that 4 sets (16 numbers) of 2261 control points provide least squares fitting for more accurate 2262 distortions (for the purposes of image registration and panarama 2263 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>' 2264 linear distortion. <br/> 2265 2266 Perspective Distorted images ensures that straight lines remain 2267 straight, but the scale of the distorted image will vary. The horizon 2268 is anti-aliased, and the 'sky' color may be set using the 2269 <a href="#mattecolor" >-mattecolor</a> setting. </td> 2270 </tr> 2271 2272 <tr valign="top"> 2273 <td valign="top"><kbd>PerspectiveProjection</kbd> </td> 2274 <td valign="top"> 2275 Do a '<kbd>Perspective</kbd>' distortion basied on a set of 8 2276 pre-calculated coefficients. You can get these coefficients by looking 2277 at the <a href="#verbose" >-verbose</a> output of a 2278 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself. 2279 If the last two perspective scaling coefficients are zero, the 2280 remaining 6 represents a transposed 'Affine Matrix'. </td> 2281 2282 </tr> 2283 2284 <tr valign="top"> 2285 <td valign="top"><kbd>Arc</kbd></td> 2286 <td valign="top"> 2287 Arc the image (variation of polar mapping) over the angle given around 2288 a circle. <br/> 2289 <table width="90%" style = "margin-left: auto; margin-right: auto;"> 2290 <tr valign="top"><td>Argument</td> 2291 <td>Meaning</td></tr> 2292 <tr valign="top"><td><em>arc_angle</em></td> 2293 <td>The angle over which to arc the image side-to-side</td></tr> 2294 <tr valign="top"><td><em>rotate_angle</em></td> 2295 <td>Angle to rotate resulting image from vertical center</td></tr> 2296 <tr valign="top"><td><em>top_radius</em></td> 2297 <td>Set top edge of source image at this radius</td></tr> 2298 <tr valign="top"><td><em>bottom_radius</em> </td> 2299 <td>Set bottom edge to this radius (radial scaling)</td></tr> 2300 </table> 2301 2302 The resulting image is always resized to best fit the resulting image, 2303 (as if using <a href="#distort" >+distort</a>) while attempting to 2304 preserve scale and aspect ratio of the original image as much as 2305 possible with the arguments given by the user. All four arguments will 2306 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/> 2307 2308 This a variation of a polar distortion designed to try to preserve the 2309 aspect ratio of the image rather than direct Cartesian to Polar 2310 conversion. </td> 2311 </tr> 2312 2313 <tr valign="top"> 2314 <td valign="top"><kbd>Polar</kbd></td> 2315 <td valign="top"> 2316 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of 2317 the image. that is the height of the input image is mapped to the 2318 radius limits, while the width is wrapped around between the 2319 angle limits. <br/> 2320 2321 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/> 2322 2323 All arguments are optional. With <em>Rmin</em> defaulting to zero, the 2324 center to the center of the image, and the angles going from -180 (top) 2325 to +180 (top). If <em>Rmax</em> is given the special value of 2326 '<code>0</code>', the the distance from the center to the nearest edge 2327 is used for the radius of the output image, which will ensure the whole 2328 image is visible (though scaled smaller). However a special value of 2329 '<code>-1</code>' will use the distance from the center to the furthest 2330 corner, This may 'clip' the corners from the input rectangular image, 2331 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with 2332 the same arguments. <br/> 2333 2334 If the plus form of distort (<a href="#distort" >+distort</a>) is used 2335 output image center will default to <code>0,0</code> of the virtual 2336 canvas, and the image size adjusted to ensure the whole input image is 2337 made visible in the output image on the virtual canvas. </td> 2338 2339 </tr> 2340 2341 <tr valign="top"> 2342 <td valign="top"><kbd>DePolar</kbd></td> 2343 <td valign="top"> 2344 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion 2345 but generates the reverse Polar to Cartesian distortion. <br/> 2346 2347 The special <em>Rmax</em> setting of '<code>0</code>' may however clip 2348 the corners of the input image. However using the special 2349 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner 2350 distance) will ensure the whole distorted image is preserved in the 2351 generated result, so that the same argument to '<kbd>Polar</kbd>' will 2352 reverse the distortion re-producing the original. 2353 2354 Note that as this distortion requires the area resampling of a circular 2355 arc, which can not be handled by the builtin EWA resampling function. 2356 As such the normal EWA filters are turned off. It is recomended some 2357 form of 'super-sampling' image processing technique be used to produce 2358 a high quality result. </td> 2359 2360 </tr> 2361 2362 <tr valign="top"> 2363 <td valign="top"><kbd>Barrel</kbd></td> 2364 <td valign="top"> 2365 Given the four coefficients (A,B,C,D) as defined by <a 2366 href="http://www.all-in-one.ee/~dersch/barrel/barrel.html" >Helmut 2367 Dersch</a>, perform a barrell or pincussion distortion appropriate to 2368 correct radial lens distortions. That is in photographs, make straight 2369 lines straight again. <br/> 2370 2371 Arguments: <em>A B C</em> [ <em>D</em> [ 2372 <em>X</em> , <em>Y</em> ] ] <br/> 2373 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> 2374 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> 2375 [ <em>X</em> , <em>Y</em> ] <br/> 2376 So that it forms the function <br/> 2377 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2378 <em>C</em>*r + <em>D</em> )<br/> 2379 2380 Where <em>X</em>,<em>Y</em> is the optional center of the distortion 2381 (defaulting to the center of the image). <br/> 2382 The second form is typically used to distort images, rather than 2383 correct lens distortions. <br/> 2384 </td> 2385 2386 </tr> 2387 2388 <tr valign="top"> 2389 <td valign="top"><kbd>BarrelInverse</kbd></td> 2390 <td valign="top"> 2391 This is very simular to '<kbd>Barrel</kbd>' with the same set of 2392 arguments, and argument handling. However it uses the inverse 2393 of the radial polynomial, 2394 so that it forms the function <br/> 2395 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2396 <em>C</em>*r + <em>D</em> ) 2397 </td> 2398 </tr> 2399 2400 <tr valign="top"> 2401 <td valign="top"><kbd>Shepards</kbd></td> 2402 <td valign="top"> 2403 Distort the given list control points (any number) using an Inverse 2404 Squared Distance Interpolation Method (<a 2405 href="http://www.ems-i.com/smshelp/Data_Module/Interpolation/Inverse_Distance_Weighted.htm" 2406 >Shepards Method</a>). The control points in effect do 'localized' 2407 distortions of the image around the given control point. For best 2408 results extra control points should be added to 'lock' the positions of 2409 the corners and other unchanging parts of the image. <br/> 2410 2411 The distortion has been likened to 'taffy pulling' using nails, pins or 2412 sticks. It basically uses the <a href="#sparse-color" 2413 >-sparse-color</a> method of the same name to generate separate X and Y 2414 displacement maps (see <a href="#displace" >-displace</a>) for source 2415 image color look-up. </td> 2416 2417 </tr> 2418 2419</table> 2420 2421<p>To print a complete list of distortion methods, use <a href="#list">-list distort</a>.</p> 2422 2423<p>Many of the above distortion methods such as '<kbd>Affine</kbd>', 2424'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points 2425defining how these points in the given image should be distorted in the 2426destination image. Each set of four floating point values represent a source 2427image coordinate, followed immediately by the destination image coordinate. 2428This produces a list of values such as...</p> 2429<div style="text-align: center"><em> 2430 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> 2431 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> 2432 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> 2433 ... 2434 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> 2435</em></div> 2436<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the 2437destination image. </p> 2438 2439<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion, 2440needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the 2441perspective distortion of the built-in "rose:" image. Note how spaces were 2442used to group the 4 sets of coordinate pairs, to make it easier to read and 2443understand.</p> 2444 2445<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'> 2446 convert rose: -virtual-pixel black \ <br/> 2447 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \ <br/> 2448 rose_3d_rotated.gif</span></p> 2449<p>If more that the required number of coordinate pairs are given for a 2450distortion, the distortion method is 'least squares' fitted to 2451produce the best result for all the coordinate pairs given. If less than the 2452ideal number of points are given, the distort will generally fall back to a 2453simpler form of distortion that can handles the smaller number of coordinates 2454(usally a linear '<kbd>Affine</kbd>' distortion). </p> 2455 2456<p>By using more coodinates you can make use of image registration tool to 2457find matching coordinate pairs in overlaping images, so as to improve the 'fit' 2458of the distortion. Of course a bad coordinate pair can also make the 'fit' 2459worse. Caution is always advised. </p> 2460 2461<p>Colors are acquired from the source image according to the <a 2462href="#interpolate" >-interpolate</a> color lookup setting, when the image is 2463magnified. However if the viewed image is minified (image becomes smaller), a 2464special area resampling function (added ImageMagick v6.3.5-9), is used to 2465produce a higher quality image. For example you can use a 2466'<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all the 2467way to the horizon. </p> 2468 2469<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \ <br/> 2470 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \ <br/> 2471 checks_tiled.jpg</span></p> 2472<p>Note that a infinitely tiled perspective images involving the horizon can 2473be very slow to generate due to the use of the high quality 'area resampling' 2474function (added ImageMagick v6.3.5-9). You can turn off 'area resampling' 2475using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>' 2476(recommended if you plan to use super-sampling instead). </p> 2477 2478<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last 2479'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a> 2480will use the current <a href="#mattecolor" >-mattecolor</a> setting for these 2481pixels. If you do not what these pixels to be visible, set the color to match 2482the rest of the ground. </p> 2483 2484<p>The output image size will by default be the same as the input image. This 2485means that if the part of the distorted image falls outside the viewed area of 2486the 'distorted space', those parts is clipped and lost. However if you 2487use the plus form of the operator (<a href="#distort" >+distort</a>) the 2488operator will attempt (if posible) to show the whole of the distorted image, 2489while retaining a correct 'virtual canvas' offset, for image layering. This 2490offset may need to be removed using <a href="#repage" >+repage</a>, to remove 2491if it is unwanted. </p> 2492 2493<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a> 2494option:distort:viewport {geometry_string}</kbd>" setting which will specify 2495the size and the offset of the generated 'viewport' image of the distorted 2496image space.</p> 2497 2498<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale 2499{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by 2500that factor without changing the viewed contents of the distorted image. This 2501can be used either for 'super-sampling' the image for a higher quality result, 2502or for panning and zooming around the image (with appropriate viewport 2503changes, or post-distort cropping and resizing). </p> 2504 2505<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a 2506href="#distort" >-distort</a> to attempt to output the internal coefficients, 2507and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study, 2508and debugging purposes. This many not be available for all distorts. </p> 2509 2510<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to 2511produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a> 2512and/or <a href="#shear" >-shear</a> operation, with more control of due to the 2513above settings. It is algorithmically slower, though in ImageMagick it may be faster. 2514</p> 2515 2516 2517<div style="margin: auto;"> 2518 <h4><a name="dither" id="dither"></a>-dither <em class="arg">method</em></h4> 2519</div> 2520 2521<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> 2522 2523<p>Dithering places two or more colors in neighbouring 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> 2524 2525<p>Dithering is turned on by default, to turn it off use the plus form of the 2526setting, <a href="#dither">+dither</a>. This will also also render PostScript 2527without text or graphic aliasing. Disabling dithering often (but not always) 2528leads to faster process, a smaller number of colors, but more cartoon like 2529image coloring. Generally resulting in 'color banding' effects in areas with 2530color gradients. </p> 2531 2532<p>The color reduction operators <a href="#colors">-colors</a>, <a 2533href="#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> 2534 2535<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> 2536 2537 2538<div style="margin: auto;"> 2539 <h4><a name="draw" id="draw"></a>-draw <em class="arg">string</em></h4> 2540</div> 2541 2542<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> 2543 2544<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> 2545 2546<p>The shape primitives:</p> 2547 2548<pre class="text"> 2549 point x,y 2550 line x0,y0 x1,y1 2551 rectangle x0,y0 x1,y1 2552 roundRectangle x0,y0 x1,y1 wc,hc 2553 arc x0,y0 x1,y1 a0,a1 2554 ellipse x0,y0 rx,ry a0,a1 2555 circle x0,y0 x1,y1 2556 polyline x0,y0 ... xn,yn 2557 polygon x0,y0 ... xn,yn 2558 bezier x0,y0 ... xn,yn 2559 path path specification 2560 image operator x0,y0 w,h filename 2561</pre> 2562 2563<p>The text primitive:</p> 2564 2565<pre class="text"> 2566 text x0,y0 string 2567</pre> 2568<p>The text gravity primitive:</p> 2569 2570<pre class="text"> 2571 gravity NorthWest, North, NorthEast, West, Center, 2572 East, SouthWest, South, or SouthEast 2573</pre> 2574 2575<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> 2576 2577<p>The transformation primitives:</p> 2578 2579<pre class="text"> 2580 rotate degrees 2581 translate dx,dy 2582 scale sx,sy 2583 skewX degrees 2584 skewY degrees 2585</pre> 2586 2587<p>The pixel operation primitives:</p> 2588 2589<pre class="text"> 2590 color x0,y0 method 2591 matte x0,y0 method 2592</pre> 2593 2594<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> 2595 2596<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> 2597 2598<p>A <kbd>line</kbd> primitive requires a start point and end point.</p> 2599 2600<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p> 2601 2602<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> 2603 2604<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p> 2605 2606<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> 2607 2608<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> 2609 2610<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>. 2611</p> 2612 2613<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p> 2614 2615<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p> 2616 2617<p class="crtsnip"> 2618 -draw 'circle 100,100 150,150' 2619</p> 2620 2621<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 2622draw 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> 2623 2624<p class="crtsnip"> 2625 -draw 'bezier 20,50 45,100 45,0 70,50' 2626</p> 2627<p class="crtsnip"> 2628 -draw 'bezier 70,50 95,100 95,0 120,50' 2629</p> 2630 2631 2632<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> 2633 2634<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> 2635 2636<p class="crtsnip"> 2637 -draw 'image SrcOver 100,100 225,225 image.jpg' 2638</p> 2639 2640<p>You can use 0,0 for the image size, which means to use the actual dimensions found in the image header. Otherwise, it is scaled to the given dimensions. See <a href="#compose">-compose</a> for a description of the composite operators.</p> 2641 2642<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> 2643 2644<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p> 2645 2646<p class="crtsnip"> 2647 -draw 'text 100,100 "Works like magick!"' 2648</p> 2649 2650<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p> 2651 2652<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> 2653 2654<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p> 2655 2656<p>The <kbd>scale</kbd> primitive scales them.</p> 2657 2658<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> 2659 2660<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 2661matrix.</p> 2662 2663<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> 2664 2665<pre class="text"> 2666 point 2667 replace 2668 floodfill 2669 filltoborder 2670 reset 2671</pre> 2672 2673<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> 2674 2675<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> 2676 2677<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> 2678 2679<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p> 2680 2681<p>Drawing primitives conform to the <a href="/www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p> 2682 2683 2684<div style="margin: auto;"> 2685 <h4><a name="edge" id="edge"></a>-edge <em class="arg">radius</em></h4> 2686</div> 2687 2688<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> 2689 2690<div style="margin: auto;"> 2691 <h4><a name="emboss" id="emboss"></a>-emboss <em class="arg">radius</em></h4> 2692</div> 2693 2694<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> 2695 2696<div style="margin: auto;"> 2697 <h4><a name="encipher" id="encipher"></a>-encipher <em class="arg">filename</em></h4> 2698</div> 2699 2700<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> 2701 2702<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 2703 2704<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 2705 2706<div style="margin: auto;"> 2707 <h4><a name="encoding" id="encoding"></a>-encoding <em class="arg">type</em></h4> 2708</div> 2709 2710<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> 2711 2712<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> 2713 2714<div style="margin: auto;"> 2715 <h4><a name="endian" id="endian"></a>-endian <em class="arg">type</em></h4> 2716</div> 2717 2718<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> 2719 2720<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p> 2721 2722<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p> 2723 2724 2725<div style="margin: auto;"> 2726 <h4><a name="enhance" id="enhance"></a>-enhance</h4> 2727</div> 2728 2729<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> 2730 2731 2732<div style="margin: auto;"> 2733 <h4><a name="equalize" id="equalize"></a>-equalize</h4> 2734</div> 2735 2736<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> 2737 2738<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> 2739 2740<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p> 2741 2742<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> 2743 2744<div style="margin: auto;"> 2745 <h4><a name="evaluate" id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4> 2746</div> 2747 2748<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> 2749 2750<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> 2751 2752<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> 2753 2754<table class="doc"> 2755 <col width="25%" /> 2756 <col width="75%" /> 2757 <thead> 2758 <tr> 2759 <th><em class="arg">operator</em></th> 2760 <th>Summary (see further below for details)</th> 2761 </tr> 2762 </thead> 2763 <tbody> 2764 2765 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr> 2766 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr> 2767 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr> 2768 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2769 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr> 2770 <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> 2771 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr> 2772 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr> 2773 <tr><td>Mean </td> <td>Add the <em class="arg">value</em> and divide by 2.</td></tr> 2774 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr> 2775 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr> 2776 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr> 2777 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr> 2778 <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> 2779 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr> 2780 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2781 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr> 2782 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr> 2783 2784 <tr><td> </td></tr> 2785 2786 <tr><td>Gaussian-noise</td></tr> 2787 <tr><td>Impulse-noise</td></tr> 2788 <tr><td>Laplacian-noise</td></tr> 2789 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr> 2790 <tr><td>PoissonNoise</td></tr> 2791 <tr><td>Uniform-noise</td></tr> 2792 2793 <tr><td> </td></tr> 2794 2795 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr> 2796 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr> 2797 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr> 2798 </tbody> 2799 </table> 2800 2801<p>The specified functions are applied only to each previously set <a 2802href="#channel" >-channel</a> in the image. If necessary, the results of the 2803calculations are truncated (clipped) to fit in the interval [0, <em 2804class="QR">QuantumRange</em>]. The transparency channel of the image is 2805represented as a 'alpha' values (0 = fully transparent), so, for example, a 2806<kbd>Divide</kbd> by 2 of the alpha channel will make the image 2807semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value 2808as a percentage of the <em class="QR">QuantumRange</em>.</p> 2809 2810<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use 2811<a href="#list">-list evaluate</a>.</p> 2812 2813<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and 2814<kbd>Multiply</kbd> methods can also be achieved using either the <a 2815href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with 2816appropriate argument, to linearly modify the overall range of color values. 2817Please note, however, that <a href="#level" >-level</a> treats transparency as 2818'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with 2819'alpha' values.</p> 2820 2821<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> 2822 2823<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> 2824 2825 <div style="text-align:center;"> 2826 log(<em class="arg">value</em> × <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1) 2827 </div> 2828 2829<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on 2830normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a 2831href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent 2832to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used 2833with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used 2834with <kbd>Pow</kbd>.</p> 2835 2836<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and 2837converts the image values into a value according to a (co)sine wave function. 2838The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output 2839is biased 50% and normalized by 50% so as to fit in the respective color value 2840range. The <em class="arg">value</em> scaling of the <em>period</em> of the 2841function (its frequency), and thus determines the number of 'waves' that will 2842be generated over the input color range. For example, if the <em 2843class="arg">value</em> is 1, the effective period is simply the <em 2844class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is 2, 2845then the effective period is the <em>half</em> the <em 2846class="QR">QuantumRange</em>. 2847 2848 <div style="text-align:center;"> 2849 0.5 + 0.5 × cos(2 π <b><em>u</em></b> × <em class="arg">value</em>). 2850 </div> 2851 2852See also the <a href="#function" >-function</a> operator, which is a 2853multi-value version of evaluate. </P> 2854 2855<div style="margin: auto;"> 2856 <h4><a name="evaluate-sequence" id="evaluate-sequence"></a>-evaluate-sequence <em class="arg">operator</em></h4> 2857</div> 2858 2859<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> 2860 2861<div style="margin: auto;"> 2862 <h4><a name="extent" id="extent"></a>-extent <em class="arg">geometry</em></h4> 2863</div> 2864 2865<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> 2866 2867<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> 2868 2869<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> 2870 2871<div style="margin: auto;"> 2872 <h4><a name="extract" id="extract"></a>-extract <em class="arg">geometry</em></h4> 2873</div> 2874 2875<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> 2876 2877<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p> 2878 2879<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> 2880 2881<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> 2882<p>then the image will be <em>resized</em> to the specified dimensions instead, 2883equivalent to:</p> 2884 2885<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -resize 640x480 image.rgb image.png</span></p> 2886<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> 2887 2888<div style="margin: auto;"> 2889 <h4><a name="family" id="family"></a>-family <em class="arg">fontFamily</em></h4> 2890</div> 2891 2892<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> 2893 2894<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). 2895</p> 2896 2897<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>. 2898</p> 2899 2900<div style="margin: auto;"> 2901 <h4><a name="features" id="features"></a>-features <em class="arg">distance</em></h4> 2902</div> 2903 2904<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> 2905 2906<div style="margin: auto;"> 2907 <h4><a name="fft" id="fft"></a>-fft</h4> 2908</div> 2909 2910<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> 2911 2912<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" target="_blank">Fourier Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT" target="_blank">Discrete Fourier Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT" target="_blank">Fast Fourier Transform</a>.</p> 2913 2914<p>A single image name is provided as output for this option. However, the output result will have two components. It will be 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" target="_blank">Complex Numbers</a>.<p> 2915 2916<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> 2917 2918<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p> 2919<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> 2920 2921<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.png</span></p> 2922<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> 2923 2924<p>The input image can be any size, but if not square and even-dimensioned, it will be 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 will be square at this size. The kind of padding relies on the <a href="#virtual-pixel">-virtual-pixel</a> setting.</p> 2925 2926<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> 2927 2928<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br /> 2929 -evaluate log 1000 fft_image_spectrum.png</span></p> 2930<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> 2931 2932<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>. 2933 2934<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> 2935 2936<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> 2937 2938<p>The real and imaginary component images resulting from <a href="#fft">+fft</a> also will be square, even dimensioned images due to the same padding that was discussed above for the magnitude and phase component images.</a> 2939 2940<p>See the discussion on HDRI implementations of ImageMagick on the page 2941<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. 2942</p> 2943 2944 2945<div style="margin: auto;"> 2946 <h4><a name="fill" id="fill"></a>-fill <em class="arg">color</em></h4> 2947</div> 2948 2949<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> 2950 2951<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> 2952 2953<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p> 2954 2955<p>For example,</p> 2956 2957<p class="crtsnip"> 2958 -fill blue 2959</p> 2960<p class="crtsnip"> 2961 -fill "#ddddff" 2962</p> 2963<p class="crtsnip"> 2964 -fill "rgb(255,255,255)" 2965</p> 2966 2967<p>See <a href="#draw">-draw</a> for further details.</p> 2968 2969<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p> 2970 2971<div style="margin: auto;"> 2972 <h4><a name="filter" id="filter"></a>-filter <em class="arg">type</em></h4> 2973</div> 2974 2975<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 an image.</td><td style='text-align:right;'></td></tr></table> 2976 2977<p>Use this option to affect the resizing operation of an image (see <a 2978href="#resize">-resize</a>). For example you can use a simple resize filter 2979such as:</p> 2980 2981<pre class="text"> 2982 Point Hermite Cubic 2983 Box Gaussian Catrom 2984 Triangle Quadratic Mitchell 2985</pre> 2986 2987<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided, but are 2988by default <kbd>blackman</kbd>-windowed. However these filters define a 2989windowing filter for the Sinc or Bessel filter function, as appropriate for 2990the scaling operator used (usally Sinc for orthogonal <a href="#resize" 2991>-resize</a>). Windowed filters include: </p> 2992 2993<pre class="text"> 2994 Lanczos Hamming Parzen 2995 Blackman Kaiser Welsh 2996 Hanning Bartlett Bohman 2997</pre> 2998 2999<p>Also one special self-windowing filter is also provided 3000<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending 3001on the current 'support' or 'lobes' expert settings (see below).</p> 3002 3003<p>If you do not select a filter with this option, the filter defaults to <kbd>Mitchell</kbd> for a colormapped image, a image with a matte channel, or if the image is enlarged. Otherwise the filter default to <kbd>Lanczos</kbd>.</p> 3004 3005<p>To print a complete list of resize filters, use the <a href="#list">-list filter</a> option.</p> 3006 3007<p>You can modify how the filter behaves as it scales your image through the 3008use of these expert settings:</p> 3009 3010<dl class="doc"> 3011<dt>-set filter:blur <em>factor</em></dt> 3012<dd>Scale the X axis of the filter (and its window). Use > 1.0 for 3013 blurry or < 1.0 for sharp.</dd> 3014 3015<dt>-set filter:support <em>radius</em></dt> 3016<dd>Set the filter support radius.</dd> 3017 3018<dt>-set filter:lobes <em>count</em></dt> 3019<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an 3020 alternative way of specifying the 'support' range of the filter.</dd> 3021 3022<dt>-set filter:b <em>b-spline_factor</em></dt> 3023<dt>-set filter:c <em>keys_alpha_factor</em></dt> 3024<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>, 3025 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as 3026 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values 3027 are defined, the other is set so as to generate a 'Keys' type cubic 3028 filter. 3029 3030<dt>-set filter:filter <em>filter</em></dt> 3031<dd>Use this function directly as the scaling filter. This will allow 3032 you to directly use a 'windowing filter' such as <kbd>blackman</kbd>, 3033 rather than as its normal usage as a windowing function for 'Sinc' or 3034 'Bessel'. If defined, no windowing function is used, unless the following 3035 expert setting is also defined.</dd> 3036 3037<dt>-set filter:window <em>filter</em></dt> 3038<dd>The IIR (infinite impulse response) filters <kbd>bessel</kbd> and 3039 <kbd>sinc</kbd> are windowed (brought down to zero over the defined 3040 support range) with the given filter. This allows you to use a filter that 3041 is not normally used as a windowing function, such as <kbd>box</kbd>, 3042 (which effectivally turns off the windowing function). </dd> 3043 3044</dl> 3045 3046<p>For example, to get a 8 lobe Lanczos-Bessel filter:</p> 3047 3048<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -filter bessel \ <br/> 3049 -set filter:window=bessel -set filter:lobes=8 \ <br/> 3050 -resize 150% image.jpg</span></p> 3051<p>Or a raw un-windowed Sinc filter with 4 lobes:</p> 3052 3053<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/> 3054 -resize 150% image.jpg</span></p> 3055<p>Note that the use of expert options (except for 'blur' with simple resize 3056filters), are provided for image processing experts who have studied and 3057understood how resize filters work. Without this knowledge, and an 3058understanding of the defination of the actual filters involved, using expert 3059settings are more likely to be detremental to your image resizing.</p> 3060 3061 3062<div style="margin: auto;"> 3063 <h4><a name="flatten" id="flatten"></a>-flatten</h4> 3064</div> 3065 3066<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> 3067 3068 3069<div style="margin: auto;"> 3070 <h4><a name="flip" id="flip"></a>-flip</h4> 3071</div> 3072 3073<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> 3074 3075<p>reflect the scanlines in the vertical direction.</p> 3076 3077<div style="margin: auto;"> 3078 <h4><a name="floodfill" 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> 3079</div> 3080 3081<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> 3082 3083<div style="margin: auto;"> 3084 <h4><a name="flop" id="flop"></a>-flop</h4> 3085</div> 3086 3087<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> 3088 3089<p>reflect the scanlines in the horizontal direction.</p> 3090 3091 3092<div style="margin: auto;"> 3093 <h4><a name="font" id="font"></a>-font <em class="arg">name</em></h4> 3094</div> 3095 3096<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> 3097 3098<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> 3099 3100<p>In addition to the fonts specified by the above pre-defined list, you can 3101also specify a font from a specific source. For example <kbd>Arial.ttf</kbd> 3102is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and 3103<kbd>x:fixed</kbd> is X11 font.</p> 3104 3105<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> 3106 3107 3108<div style="margin: auto;"> 3109 <h4><a name="foreground" id="foreground"></a>-foreground <em class="arg">color</em></h4> 3110</div> 3111 3112<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> 3113 3114<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 3115 3116<p>The default foreground color is black.</p> 3117 3118<div style="margin: auto;"> 3119 <h4><a name="format" id="format"></a>-format <em class="arg">type</em></h4> 3120</div> 3121 3122<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> 3123 3124<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> 3125 3126<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> 3127 3128<div style="margin: auto;"> 3129 <h4><a name="format_identify_" id="format_identify_"></a>-format <em class="arg">string</em></h4> 3130</div> 3131 3132<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> 3133 3134<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> 3135 3136<div style="margin: auto;"> 3137 <h4><a name="frame" id="frame"></a>-frame <em class="arg">geometry</em></h4> 3138</div> 3139 3140<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> 3141 3142<p>The color of the border is specified with the <a href="#mattecolor">-mattecolor</a> command line option. </p> 3143 3144<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 class="arg">geometry</em> argument indicates the amount of extra width and height that is added to the dimensions of the image. If no offsets are given in the <em class="arg">geometry</em> argument, then the border added is a solid color. Offsets <em>x</em> and <em>y</em>, if present, specify that the width and height of the border is partitioned to form an outer bevel of thickness <em>x</em> pixels and an inner bevel of thickness <em>y</em> pixels. (Negative offsets make no sense here.) The <a href="#frame">-frame</a> option is not affected by the <a href="#gravity">-gravity</a> option.</p> 3145 3146 3147<div style="margin: auto;"> 3148 <h4><a name="frame_import_" id="frame_import_"></a>-frame</h4> 3149</div> 3150 3151<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> 3152 3153<div style="margin: auto;"> 3154 <h4><a name="function" id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4> 3155</div> 3156 3157<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> 3158 3159<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> 3160 3161<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> 3162 3163<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> 3164 3165<pre class="text"> 3166 Polynomial 3167 Sinusoid 3168 Arcsin 3169 Arctan 3170</pre> 3171 3172<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p> 3173 3174<dl class="doc"> 3175<dt><kbd>Polynomial</kbd></dt> 3176<dd> 3177<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> 3178 3179<div style="text-align: center"> 3180 -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> 3181</div> 3182 3183<p>will invoke a polynomial function given by</p> 3184 3185<div style="text-align: center"> 3186 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> + 3187 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> + 3188 ··· <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>, 3189</div> 3190 3191<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p> 3192 3193<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> 3194 3195<table class="doc"> 3196 <col width="35%" /> 3197 <col width="35%" /> 3198 <col width="30%" /> 3199 <tr> 3200 <td>-evaluate Set <em class="arg">value</em> </td> 3201 <td>-function Polynomial <em class="arg">value</em></td> 3202 <td>(Constant functions; set <em class="arg">value</em>×100% gray when channels are RGB.)</td> 3203 </tr> 3204 <tr> 3205 <td>-evaluate Add <em class="arg">value</em> </td> 3206 <td>-function Polynomial 1,<em class="arg">value</em></td> 3207 </tr> 3208 <tr> 3209 <td>-evaluate Subtract <em class="arg">value</em> </td> 3210 <td>-function Polynomial 1,−<em class="arg">value</em></td> 3211 </tr> 3212 <tr> 3213 <td>-evaluate Multiply <em class="arg">value</em> </td> 3214 <td>-function Polynomial <em class="arg">value</em>,0</td> 3215 </tr> 3216 <tr> 3217 <td>+level black% x white%</td> 3218 <td>-function Polynomial A,B</td> 3219 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td> 3220 </tr> 3221</table> 3222 3223<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> 3224</dd> 3225 3226<dt><kbd>Sinusoid</kbd></dt> 3227<dd> 3228<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> 3229 3230<div style="text-align: center"> 3231 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]] 3232</div> 3233 3234<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> 3235 3236<div style="text-align: center"> 3237<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> 3238</div> 3239 3240<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> 3241 3242<p class="crtsnip"> 3243 -function Sinusoid 3,-90,.2,.7 3244</p> 3245 3246<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> 3247 3248<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> 3249 3250<table class="doc"> 3251 <tr> 3252 <td>-evaluate Sin <em class="arg">freq</em> </td> 3253 <td>-function Sinusoid <em class="arg">freq</em>,0 </td> 3254 </tr> 3255 <tr> 3256 <td>-evaluate Cos <em class="arg">freq</em> </td> 3257 <td>-function Sinusoid <em class="arg">freq</em>,90 </td> 3258 </tr> 3259</table> 3260</dd> 3261 3262<dt><kbd>ArcSin</kbd></dt> 3263<dd> 3264<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid, 3265and can be used to generate cylindrical distortion and displacement maps. 3266The curve can be adjusted relative to both the input values and output range 3267of values. 3268 3269<div style="text-align: center"> 3270 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3271</div> 3272 3273<p>with all values given in terms of noramlize color values (0.0 for black, 32741.0 for white). Defaulting to values covering the full range from 0.0 to 1.0 3275for bout input (<em class="arg">width</em>), and output (<em 3276class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p> 3277 3278<div style="text-align: center"> 3279<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> 3280</div> 3281 3282</dd> 3283 3284<dt><kbd>ArcTan</kbd></dt> 3285<dd> 3286<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from 3287limit values at infinities, though a center using the given slope value. 3288All these values can be adjusted via the arguments. 3289 3290<div style="text-align: center"> 3291 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3292</div> 3293 3294<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'. 3295</p> 3296 3297<div style="text-align: center"> 3298<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> 3299</div> 3300 3301</dd> 3302 3303</dl> 3304 3305 3306<div style="margin: auto;"> 3307 <h4><a name="fuzz" id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4> 3308</div> 3309 3310<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> 3311 3312<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> 3313 3314<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> 3315 3316 3317<div style="margin: auto;"> 3318 <h4><a name="fx" id="fx"></a>-fx <em class="arg">expression</em></h4> 3319</div> 3320 3321<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> 3322 3323<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> 3324 3325<p>See <a href="/www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p> 3326 3327 3328<div style="margin: auto;"> 3329 <h4><a name="gamma" id="gamma"></a>-gamma <em class="arg">value</em></h4> 3330</div> 3331 3332<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> 3333 3334<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> 3335 3336<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> 3337 3338<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> 3339 3340<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> 3341 3342<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p> 3343 3344<div style="margin: auto;"> 3345 <h4><a name="gaussian-blur" 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> 3346</div> 3347 3348<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> 3349 3350<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p> 3351 3352<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 3353</div> 3354 3355<p>where <i>r</i> is the blur radius (<i>r</i><sup>2</sup> = <i>u</i><sup>2</sup> + <i>v</i><sup>2</sup>), and σ is the standard deviation of the Gaussian distribution. As a guideline, set <i>r</i> to approximately 3σ. Specify a radius of 0 and ImageMagick selects a suitable radius for you.</p> 3356 3357<p>This differs from the faster <a href="#blur">-blur</a> operator in that a 3358full 2-dimentional convolution is used to generate the weighted average of the 3359neighbouring pixels. </p> 3360 3361<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 3362pixels which are outside the image proper are blurred into the final result. 3363</p> 3364 3365 3366<div style="margin: auto;"> 3367 <h4><a name="geometry" id="geometry"></a>-geometry <em class="arg">geometry</em></h4> 3368</div> 3369 3370<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> 3371 3372<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> 3373 3374<div style="margin: auto;"> 3375 <h4><a name="gravity" id="gravity"></a>-gravity <em class="arg">type</em></h4> 3376</div> 3377 3378<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> 3379 3380<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>, 3381<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>, 3382<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete 3383list of <a href="#gravity">-gravity</a> settings available in your ImageMagick 3384installation.</p> 3385 3386<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> 3387 3388<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> 3389 3390<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> 3391 3392<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> 3393<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> 3394 3395<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> 3396 3397 3398<div style="margin: auto;"> 3399 <h4><a name="green-primary" id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4> 3400</div> 3401 3402<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> 3403 3404 3405<div style="margin: auto;"> 3406 <h4><a name="hald-clut" id="hald-clut"></a>-hald-clut</h4> 3407</div> 3408 3409<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> 3410 3411<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2 3412dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You 3413can apply any color transformation to the Hald image and then use this option 3414to apply the transform to the image. </p> 3415 3416<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p> 3417<p>This option provides a convenient method for you to use Gimp or Photoshop 3418to make color corrections to the Hald CLUT image and subsequently apply them 3419to multiple images using an ImageMagick script. </p> 3420 3421<p>Note that the representation is only of the normal RGB color space and that 3422the whole color value triplet is used for the interpolated lookup of the 3423represented Hald color cube image. Because of this the operation is not <a 3424href="#channel" >-channel</a> setting effected, nor can it adjust or modify an 3425images transparency or alpha/matte channel.</p> 3426 3427<p>See also <a href="#clut" >-clut</a> which provides color value replacement 3428of the individual color channels, usally involving a simplier gray-scale 3429image. E.g: gray-scale to color replacement, or modification by a histogram 3430mapping. </p> 3431 3432 3433<div style="margin: auto;"> 3434 <h4><a name="help" id="help"></a>-help</h4> 3435</div> 3436 3437<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> 3438 3439<div style="margin: auto;"> 3440 <h4><a name="highlight-color" id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4> 3441</div> 3442 3443<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> 3444 3445<div style="margin: auto;"> 3446 <h4><a name="iconGeometry" id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4> 3447</div> 3448 3449<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> 3450 3451<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> 3452 3453<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> 3454 3455<div style="margin: auto;"> 3456 <h4><a name="iconic" id="iconic"></a>-iconic</h4> 3457</div> 3458 3459<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> 3460 3461<div style="margin: auto;"> 3462 <h4><a name="identify" id="identify"></a>-identify</h4> 3463</div> 3464 3465<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> 3466 3467<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> 3468 3469<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> 3470 3471<p>If <a href="#verbose">-verbose</a> preceds this option, copious 3472amounts of image properties are displayed including image statistics, profiles, 3473image histogram, and others.</p> 3474 3475<div style="margin: auto;"> 3476 <h4><a name="ift" id="ift"></a>-ift</h4> 3477</div> 3478 3479<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> 3480 3481<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" target="_blank">Fourier Transform</a>, <a href="http://en.wikipedia.org/wiki/DFT" target="_blank">Discrete Fourier Transform</a> and <a href="http://en.wikipedia.org/wiki/FFT" target="_blank">Fast Fourier Transform</a>.</p> 3482 3483<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> 3484 3485<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p> 3486<p>or</p> 3487 3488<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> 3489 3490<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 will be at the right and/or bottom sides of the image. 3491 3492<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>. 3493 3494<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. 3495 3496<div style="margin: auto;"> 3497 <h4><a name="immutable" id="immutable"></a>-immutable</h4> 3498</div> 3499 3500<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> 3501 3502<div style="margin: auto;"> 3503 <h4><a name="implode" id="implode"></a>-implode <em class="arg">factor</em></h4> 3504</div> 3505 3506<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> 3507 3508<div style="margin: auto;"> 3509 <h4><a name="insert" id="insert"></a>-insert <em class="arg">index</em></h4> 3510</div> 3511 3512<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> 3513 3514<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> 3515 3516<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> 3517 3518<div style="margin: auto;"> 3519 <h4><a name="intent" id="intent"></a>-intent <em class="arg">type</em></h4> 3520</div> 3521 3522<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> 3523 3524<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> 3525 3526<p>The default intent is undefined.</p> 3527 3528<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p> 3529 3530<div style="margin: auto;"> 3531 <h4><a name="interlace" id="interlace"></a>-interlace <em class="arg">type</em></h4> 3532</div> 3533 3534<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> 3535 3536<p>Choose from:</p> 3537 3538<pre class="text"> 3539 none 3540 line 3541 plane 3542 partition 3543 JPEG 3544 GIF 3545 PNG 3546</pre> 3547 3548<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> 3549 3550<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p> 3551 3552<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p> 3553 3554<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p> 3555 3556<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R, 3557image.G, and image.B).</p> 3558 3559<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> 3560image.</p> 3561 3562<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p> 3563 3564<div style="margin: auto;"> 3565 <h4><a name="interpolate" id="interpolate"></a>-interpolate <em class="arg">type</em></h4> 3566</div> 3567 3568<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> 3569 3570<p>When looking up the color of a pixel using a non-interger floating point 3571value, you typically fall in between the pixel colors defined by the source 3572image. This setting determines how the color is determined from the colors of 3573the pixels surrounding that point. That is how to determine the color of a 3574point that falls between two, or even four different colored pixels. </p> 3575 3576<pre class="text"> 3577 integer: The color of the top-left pixel (floor function) 3578 nearest-neighbor: The nearest pixel to the lookup point (rounded function) 3579 average: The average color of the surrounding four pixels 3580 bilinear A double linear interpolation of pixels (the default) 3581 mesh Divide area into two flat triangular interpolations 3582 bicubic Fitted bicubic-spines of surrounding 16 pixels 3583 spline Direct spline curves (colors are blurred) 3584 filter Use resize <a href="#filter">-filter</a> settings 3585</pre> 3586 3587<p>This most important for distortion operators such as <a href="#distort" 3588>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform" 3589>-transform</a> and <a href="#fx" >-fx</a>. </p> 3590 3591<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p> 3592 3593<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the 3594lookup for positions outside the boundaries of the image. </p> 3595 3596 3597<div style="margin: auto;"> 3598 <h4><a name="interline-spacing" id="interline-spacing"></a>-interline-spacing <em class="arg">value</em></h4> 3599</div> 3600 3601<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> 3602 3603<div style="margin: auto;"> 3604 <h4><a name="interword-spacing" id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4> 3605</div> 3606 3607<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> 3608 3609<div style="margin: auto;"> 3610 <h4><a name="kerning" id="kerning"></a>-kerning <em class="arg">value</em></h4> 3611</div> 3612 3613<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> 3614 3615<div style="margin: auto;"> 3616 <h4><a name="label" id="label"></a>-label <em class="arg">name</em></h4> 3617</div> 3618 3619<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> 3620 3621<p>Use this option to assign a specific label to the image, as it is read in or created. You can use the <a href="#set" >-set</a> operation to re-assign a the labels of images already read in. Image formats such as TIFF, PNG, MIFF, supports saving the label information with the image.</p> 3622 3623<p>When saving an image to a <em class="arg">PostScript</em> file, any label assigned to an image is used as a header string to print above the postscript image. </p> 3624 3625<p>You can include the image filename, type, width, height, or other image attribute by embedding special format character. See <a href="#format">-format</a> for details of the percent escape codes.</p> 3626 3627<p>For example,</p> 3628 3629<p class="crtsnip"> 3630 -label "%m:%f %wx%h" bird.miff 3631</p> 3632 3633<p>assigns an image label of <kbd>MIFF:bird.miff 512x480</kbd> to the "<kbd>bird.miff</kbd>" image and whose width is 512 and height is 480, as it is read in. If a <a href="#label">+label</a> option was used instead, any existing label present in the image would be used. You can remove all labels from an image by assigning the empty string. </p> 3634 3635<p>A label is not drawn on the image, but is embedded in the image datastream via <em>Label</em> tag or similar mechanism. If you want the label to be visible on the image itself, use the <a href="#draw">-draw</a> option, or during the final processing in the creation of a image montage.</p> 3636 3637<p>The label font can be specified with <a href="#font">-font</a>, and the 3638other font attribute settings.</p> 3639 3640<p>If the first character of <em class="arg">string</em> is <em class="arg">@</em>, the image label is read from a file titled by the remaining characters in the string. Labels in a file are literal, no embedded formatting characters are recognized.</p> 3641 3642 3643<div style="margin: auto;"> 3644 <h4><a name="lat" 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> 3645</div> 3646 3647<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> 3648 3649<p>Adaptively threshold each pixel based on the value of pixels in a 3650surrounding window. If the current pixel is lighter than this average plus 3651the optional <kbd>offset</kbd>, then it is made white, otherwise it is made 3652black. Small variations in pixel values such as found in scanned documents 3653can be ignored if offset is positive. A negative offset will make it more 3654sensitive to those small variations. </p> 3655 3656<p>This is commonly used to threshold images with an uneven background. It is 3657based on the assumption that average color of the small window is the 3658the local background color, from which to separate the forground color. </p> 3659 3660 3661<div style="margin: auto;"> 3662 <h4><a name="layers" id="layers"></a>-layers <em class="arg">method</em></h4> 3663</div> 3664 3665<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> 3666 3667<p>Perform various image operation methods to a ordered sequence of images 3668which may represent either a set of overlaid 'image layers', a GIF disposal 3669animation, or a fully-'coalesced' animation sequence. </p> 3670 3671<table class="doc"> 3672 <tbody> 3673 <tr valign="top"> 3674 <th align="left" style="width: 8%">Method</th> 3675 <th align="left">Description</th> 3676 </tr> 3677 3678 <tr valign="top"> 3679 <td valign="top">compare-any</td> 3680 <td valign="top">Crop the second and later frames to the smallest rectangle 3681 that contains all the differences between the two images. No GIF <a 3682 href="#dispose" >-dispose</a> methods are taken into account. </td> 3683 </tr> 3684 3685 <tr><td></td><td>This exactly the same as the <a href="#deconstruct" 3686 >-deconstruct</a> operator, and does not preserve animations normal 3687 working, especially when animation used layer disposal methods such as 3688 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td> 3689 </tr> 3690 3691 <tr valign="top"> 3692 <td valign="top">compare-clear</td> 3693 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any 3694 opaque pixels which become transparent in the second frame. That is the 3695 smallest image needed to mask or erase pixels for the next frame. </td> 3696 </tr> 3697 3698 <tr valign="top"> 3699 <td valign="top">compare-overlay</td> 3700 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add 3701 extra color to the next image, as a result of overlaying color pixels. 3702 That is the smallest single overlaid image to add or change colors. </td> 3703 </tr> 3704 3705 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha 3706 composition method '<kbd>change-mask</kbd>', to reduce the image to 3707 just the pixels that need to be overlaid. </td> 3708 </tr> 3709 3710 <tr valign="top"> 3711 <td valign="top">coalesce</td> 3712 <td valign="top">Equivalent to a call to the <a href="#coalesce" 3713 >-coalesce</a> operator. Apply the layer disposal methods set in the 3714 current image sequence to form a fully defined animation sequence, as 3715 it should be displayed. Effectively converting a GIF animation into a 3716 'film strip'-like animation. </td> 3717 </tr> 3718 3719 <tr valign="top"> 3720 <td valign="top">composite</td> 3721 <td valign="top">Alpha Composition of two image lists, separated by a 3722 "<kbd>null:</kbd>" image, with the destination image list first, and 3723 the source images last. An image from each list are composited 3724 together until one list is finished. The separator image and source 3725 image lists are removed. </td> 3726 </tr> 3727 3728 3729 <tr><td></td><td>The <a href="#geometry" >-geometry</a> offset is adjusted according to 3730 <a href="#gravity" >-gravity</a> in accordance of the virtual canvas 3731 size of the first image in each list. Unlike a normal <a 3732 href="#composite" >-composite</a> operation, the canvas offset is also 3733 added to the final composite positioning of each image. </td> 3734 </tr> 3735 3736 <tr><td></td><td>If one of the image lists only contains one image, that image is 3737 applied to all the images in the other image list, regardless of which 3738 list it is. In this case it is the image meta-data of the list which 3739 preserved. </td> 3740 </tr> 3741 3742 3743 <tr valign="top"> 3744 <td valign="top">dispose</td> 3745 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of 3746 the animation after the layer disposal method has been applied, before 3747 the next sub-frame image is overlaid. That is the 'dispose' image that 3748 results from the application of the GIF <a href="#dispose" 3749 >-dispose</a> method. This allows you to check what 3750 is going wrong with a particular animation you may be developing. 3751 </td> 3752 </tr> 3753 3754 <tr valign="top"> 3755 <td valign="top">flatten</td> 3756 <td valign="top">Create a canvas the size of the first images virtual 3757 canvas using the current <a href="#background" >-background</a> color, 3758 and <a href="#compose" >-compose</a> each image in turn onto that 3759 canvas. Images falling outside that canvas is clipped. Final 3760 image will have a zero virtual canvas offset. </td> 3761 </tr> 3762 3763 <tr><td></td><td>This usally used as one of the final 'image layering' operations 3764 overlaying all the prepared image layers into a final image. </td> 3765 </tr> 3766 3767 <tr><td></td><td>For a single image this method can also be used to fillout a virtual 3768 canvas with real pixels, or to underlay a opaque color to remove 3769 transparency from an image.</td> 3770 </tr> 3771 3772 3773 <tr valign="top"> 3774 <td valign="top">merge</td> 3775 <td valign="top">As 'flatten' method but merging all the given image 3776 layers into a new layer image just large enough to hold all the image 3777 without clipping or extra space. The new images virtual offset will 3778 prevere the position of the new layer, even if this offset is 3779 negative. the virtual canvas size of the first image is preserved. 3780 </td> 3781 </tr> 3782 3783 <tr><td></td><td>Caution is advised when handling image layers with negative offsets 3784 as few image file formats handle them correctly. </td> 3785 </tr> 3786 3787 <tr valign="top"> 3788 <td valign="top">mosaic</td> 3789 <td valign="top">As 'flatten' method but expanding the initial canvas size 3790 of the first image so as to hold all the image layers. However as a 3791 virtual canvas is 'locked' to the origin, by defination, image layers 3792 with a negative offsets will still be clipped by the top and left 3793 edges.</td> 3794 </tr> 3795 3796 <tr><td></td><td>This method is commonly used to layout individual image using various 3797 offset but without knowning the final canvas size. The resulting image 3798 will, like 'flatten' not have any virtual offset, so can be saved to 3799 any image file format. </td> 3800 </tr> 3801 3802 3803 <tr valign="top"> 3804 <td valign="top">optimize</td> 3805 <td valign="top">Optimize a coalesced animation, into GIF animation using 3806 a number of general techniques. This currently a short cut to 3807 apply both the '<kbd>optimize-frame</kbd>', and 3808 '<kbd>optimize-transparency</kbd>' methods but may be expanded to 3809 include other optimization methods as they are developed. </td> 3810 </tr> 3811 3812 <tr valign="top"> 3813 <td valign="top">optimize-frame</td> 3814 <td valign="top">Optimize a coalesced animation, into GIF animation by 3815 reducing the number of pixels per frame as much as possible by 3816 attempting to pick the best layer disposal method to use, while ensuring 3817 the result will continue to animate properly. </td> 3818 </tr> 3819 3820 <tr><td></td><td> There is no guarantee that the best optimization is found. But 3821 then no reasonably fast GIF optimization algorithm can do this. 3822 However this does seem to do better than most other GIF frame 3823 optimizers seen. </td> 3824 </tr> 3825 3826 <tr valign="top"> 3827 <td valign="top">optimize-plus</td> 3828 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the 3829 overall optimization by adding extra frames to the animation, without 3830 changing the final look or timing of the animation. The frames are 3831 added to attempt to separate the clearing of pixels from the 3832 overlaying of new additional pixels from one animation frame to the 3833 next. If this does not improve the optimization (for the next frame 3834 only), it will fall back to the results of the previous normal 3835 '<kbd>optimize-frame</kbd>' technique. </td> 3836 </tr> 3837 3838 <tr><td></td><td>There is the possibility that the change in the disposal style will 3839 result in a worsening in the optimization of later frames, though this 3840 is unlikely. In other words there no guarantee that it is better than 3841 the normal '<kbd>optimize-frame</kbd>' technique. For some animations 3842 however you can get a vast improvment in the final animation size. </td> 3843 </tr> 3844 3845 <tr valign="top"> 3846 <td valign="top">optimize-transparency</td> 3847 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame 3848 overlay images with transparency, if it does not change the resulting 3849 animation by more than the current <a href="#fuzz" >-fuzz</a> factor. 3850 </td> 3851 </tr> 3852 3853 <tr><td></td><td>This should allow a existing frame optimized GIF animation to compress 3854 into a smaller file size due to larger areas of one (transparent) 3855 color rather than a pattern of multiple colors repeating the current 3856 disposed image of the last frame. </td> 3857 </tr> 3858 3859 <tr valign="top"> 3860 <td valign="top">remove-dups</td> 3861 <td valign="top">Remove (and merge time delays) of duplicate consecutive 3862 images, so as to simplify layer overlays of coalesced animations. 3863 </td> 3864 </tr> 3865 3866 <tr><td></td><td>Usually this a result of using a constant time delay across the 3867 whole animation, or after a larger animation was split into smaller 3868 sub-animations. The duplicate frames could also have been used as 3869 part of some frame optimization methods. </td> 3870 </tr> 3871 3872 <tr valign="top"> 3873 <td valign="top">remove-zero</td> 3874 <td valign="top">Remove any image with a zero time delay, unless ALL the 3875 images have a zero time delay (and is not a proper timed animation, a 3876 warning is then issued). </td> 3877 </tr> 3878 3879 <tr><td></td><td>In a GIF animation, such images are usually frames which provide 3880 partial intermediary updates between the frames that are actually 3881 displayed to users. These frames are usally added for improved frame 3882 optimization in GIF animations. </td> 3883 </tr> 3884 3885 <tr valign="top"> 3886 <td valign="top">trim-bounds</td> 3887 <td valign="top">Find the bounds of all the images in the current 3888 image sequence, then adjust the offsets so all images are contained on 3889 a minimal positive canvas. None of the image data is modified, only 3890 there virtual canvas size and offset. The all the image is given 3891 the same canvas size, and and will have a positive offset, but will 3892 remain in the same position relative to each other. As a result of the 3893 minimal canvas size at least one image will touch every edge of that 3894 canvas. The image data however may be transparent. 3895 </td> 3896 </tr> 3897 3898 </tbody> 3899</table> 3900 3901<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p> 3902 3903<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct" 3904>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic" 3905>-mosaic</a> are only aliases for the above methods. Also see <a 3906href="#page" >-page</a>, <a href="#repage" >-repage</a> operators, the <a 3907href="#compose" >-compose</a> setting, and the GIF <a href="#dispose" 3908>-dispose</a> and <a href="#delay" >-delay</a> settings. </p> 3909 3910 3911<div style="margin: auto;"> 3912 <h4><a name="level" 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> 3913</div> 3914 3915<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> 3916 3917<p>Given one, two or three values delimited with commas: black-point, 3918white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and 3919white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white 3920point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center 3921contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string, 3922both black and white points are percentages of the full color range. Gamma 3923will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is 3924omitted, the default of 1.0 (no gamma correction) is assumed.</p> 3925 3926<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that 3927the given '<kbd>black_point</kbd>' value in the original image is set to 3928zero (or black), while the given '<kbd>white_point</kbd>' value is set to 3929<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments 3930to the image. The '<kbd>gamma</kbd>' of the resulting image will then be 3931adjusted. </p> 3932 3933<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or 3934adding the special '!' flag anywhere in the argument list, will cause the 3935operator to do the reverse of the level adjustment. That is a zero, or 3936<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is 3937adjusted to the given level values, allowing you to de-contrast, or compress 3938the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p> 3939 3940<p>Only the channels defined by the current <a href="#channel">-channel</a> 3941setting are adjusted (defaults to RGB color channels only), allowing you to 3942limit the effect of this operator. </p> 3943 3944<p>Please note that the transparency channel is treated as 'matte' 3945values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 3946 3947 3948<div style="margin: auto;"> 3949 <h4><a name="level-colors" id="level-colors"></a>-level-colors {<em 3950 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4> 3951</div> 3952 3953<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 seperated colors.</td><td style='text-align:right;'></td></tr></table> 3954 3955<p>This function is exactly like <a href="#level">-level</a>, except that the 3956value value for each color channel is determined by the 3957'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as 3958described under the <a href="#fill">-fill</a> option). </p> 3959 3960<p>This effectivally means the colors provided to <kbd>-level-colors</kbd> 3961is mapped to become 'black' and 'white' respectivally, with all the other 3962colors linearly adjusted (or clipped) to match that change. Each channel is 3963adjusted separatally using the channel values of the colors specified. </p> 3964 3965<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>) 3966will map the image color 'black' and 'white' to the given colors 3967respectivally, resulting in a gradient (de-contrasting) tint of the image to 3968those colors. This can also be used to convert a plain gray-scale image into a 3969one using the gradient of colors specified. </p> 3970 3971<p>By supplying a single color with a comma separator either before or after 3972that color, will just replace the respective 'black' or 'white' point 3973respectivally. But if no comma separator is provided, the given color is 3974used for both the black and white color points, making the operator either 3975threshold the images around that color (- form) or set all colors to that 3976color (+ form). </p> 3977 3978 3979<div style="margin: auto;"> 3980 <h4><a name="limit" id="limit"></a>-limit <em class="arg">type value</em></h4> 3981</div> 3982 3983<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> 3984 3985<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> 3986 3987<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> 3988 3989<p class="crtsnip"> 3990 -limit memory 32MiB -limit map 64MiB 3991</p> 3992 3993<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p> 3994 3995<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>identify -list resource</span><span class='crtout'><pre>File Area Memory Map Disk Thread Time 3996------------------------------------------------------------------------------ 3997 768 12.404GB 8.6642GiB 23.104GiB 18.446744EB 8 unlimited</pre> 3998</span></p> 3999<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> 4000 4001<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> 4002 4003<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> 4004 4005<p class="crtsnip"> 4006-limit area 10mb 4007</p> 4008 4009<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 inadvertedly upload a huge image to process, you should set a disk limit as well:</p> 4010 4011<p class="crtsnip"> 4012-limit area 10mb -limit disk 500mb 4013</p> 4014 4015<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p> 4016 4017<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> 4018 4019<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. 4020</p> 4021 4022<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. 4023</p> 4024 4025<div style="margin: auto;"> 4026 <h4><a name="linear-stretch" 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> 4027</div> 4028 4029<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> 4030 4031<p>This is very similar to <a href="#contrast-stretch" >-contrast-stretch</a>, 4032and uses a 'histogram bin' to determine the range of color values that needs to 4033be stretched. However it then stretchs those colors using the <a 4034href="#level" >-level</a> operator.</p> 4035 4036<p>As such while the initial determination may have 'binning' round off 4037effects, the image colors are stretched mathematically, rather than using the 4038histogram bins. This makes the operator more accurate. </p> 4039 4040<p>note however that a <a href="#linear-stretch" >-linear-stretch</a> of 4041'<kbd>0</kbd>' does nothing, while a value of '<kbd>1</kbd>' does a near 4042perfect stretch of the color range. </p> 4043 4044<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 4045normalization of mathematical images. </p> 4046 4047<p>This operator is under review for re-development. </p> 4048 4049 4050<div style="margin: auto;"> 4051 <h4><a name="linewidth" id="linewidth"></a>-linewidth</h4> 4052</div> 4053 4054<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> 4055 4056<div style="margin: auto;"> 4057 <h4><a name="liquid-rescale" id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4> 4058</div> 4059 4060<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> 4061 4062<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> 4063 4064<div style="margin: auto;"> 4065 <h4><a name="list" id="list"></a>-list <em class="arg">type</em></h4> 4066</div> 4067 4068<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> 4069 4070<pre class="text"> 4071 Align 4072 Alpha 4073 Boolean 4074 Channel 4075 Class 4076 ClipPath 4077 Coder 4078 Color 4079 Colorspace 4080 Command 4081 Compose 4082 Compress 4083 Configure 4084 DataType 4085 Debug 4086 Decoration 4087 Delegate 4088 Direction 4089 Dispose 4090 Distort 4091 Dither 4092 Endian 4093 Evaluate 4094 FillRule 4095 Filter 4096 Font 4097 Format 4098 Function 4099 Gravity 4100 ImageList 4101 Intent 4102 Interlace 4103 Interpolate 4104 Kernel 4105 Layers 4106 LineCap 4107 LineJoin 4108 List 4109 Locale 4110 LogEvent 4111 Log 4112 Magic 4113 Method 4114 Metric 4115 Mime 4116 Mode 4117 Morphology 4118 Module 4119 Noise 4120 Orientation 4121 Policy 4122 PolicyDomain 4123 PolicyRights 4124 Preview 4125 Primitive 4126 QuantumFormat 4127 Resource 4128 SparseColor 4129 Storage 4130 Stretch 4131 Style 4132 Threshold 4133 Type 4134 Units 4135 Validate 4136 VirtualPixel 4137</pre> 4138 4139<p>These lists vary depending on your version of ImageMagick. Use "<kbd>-list list</kbd>" to get a complete listing of all the "<kbd>-list</kbd>" arguments available:</p> 4140 4141<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>identify -list list</span></p> 4142<div style="margin: auto;"> 4143 <h4><a name="log" id="log"></a>-log <em class="arg">string</em></h4> 4144</div> 4145 4146<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> 4147 4148<p>This option specifies the format for the log printed when the <a href="#debug">-debug</a> option is active.</p> 4149 4150<p>You can display the following components by embedding special format characters:</p> 4151 4152<pre class="text"> 4153 %d domain 4154 %e event 4155 %f function 4156 %l line 4157 %m module 4158 %p process ID 4159 %r real CPU time 4160 %t wall clock time 4161 %u user CPU time 4162 %% percent sign 4163 \n newline 4164 \r carriage return 4165</pre> 4166 4167<p>For example:</p> 4168 4169<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> 4170<p>The default behavior is to print all of the components.</p> 4171 4172<div style="margin: auto;"> 4173 <h4><a name="loop" id="loop"></a>-loop <em class="arg">iterations</em></h4> 4174</div> 4175 4176<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> 4177 4178<p>Set iterations to zero to repeat the animation an infinite number of times, otherwise the animation repeats itself up to <em class="arg">iterations</em> times.</p> 4179 4180<div style="margin: auto;"> 4181 <h4><a name="lowlight-color" id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4> 4182</div> 4183 4184<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> 4185 4186<div style="margin: auto;"> 4187 <h4><a name="magnify" id="magnify"></a>-magnify <em class="arg">factor</em></h4> 4188</div> 4189 4190<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> 4191 4192 4193<div style="margin: auto;"> 4194 <h4><a name="map" id="map"></a>-map <em class="arg">type</em></h4> 4195</div> 4196 4197<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> 4198 4199<p>Choose from these <em class="arg">Standard Colormap</em> types:</p> 4200 4201<pre class="text"> 4202 best 4203 default 4204 gray 4205 red 4206 green 4207 blue 4208</pre> 4209 4210<p>The <em class="arg">X server</em> must support the <em class="arg">Standard Colormap</em> you choose, otherwise an error occurs. Use <kbd>list</kbd> as the type and <kbd>display</kbd> searches the list of colormap types in <kbd>top-to-bottom</kbd> order until one is located. See <em class="arg">xstdcmap(1)</em> for one way of creating Standard Colormaps.</p> 4211 4212 4213<div style="margin: auto;"> 4214 <h4><a name="map_stream_" id="map_stream_"></a>-map <em class="arg">components</em></h4> 4215</div> 4216 4217<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> 4218 4219<p>Here are the valid components of a map:</p> 4220 4221<pre class="text"> 4222 r red pixel component 4223 g green pixel component 4224 b blue pixel component 4225 a alpha pixel component (0 is transparent) 4226 o opacity pixel component (0 is opaque) 4227 i grayscale intensity pixel component 4228 c cyan pixel component 4229 m magenta pixel component 4230 y yellow pixel component 4231 k black pixel component 4232 p pad component (always 0) 4233</pre> 4234 4235<p>You can specify as many of these components as needed in any order (e.g. bgr). The components can repeat as well (e.g. rgbr).</p> 4236 4237<div style="margin: auto;"> 4238 <h4><a name="mask" id="mask"></a>-mask 4239<em class="arg">filename</em></h4> 4240</div> 4241 4242<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> 4243 4244<p>Use <a href="#mask">+mask</a> to remove the image mask.</p> 4245 4246<div style="margin: auto;"> 4247 <h4><a name="mattecolor" id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4> 4248</div> 4249 4250<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> 4251 4252<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 4253 4254<p>The default matte color is <kbd>#BDBDBD</kbd>, <span style="background-color: #bdbdbd;">this shade of gray</span>.</p> 4255 4256<div style="margin: auto;"> 4257 <h4><a name="maximum" id="maximum"></a>-maximum</h4> 4258</div> 4259 4260<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> 4261 4262<div style="margin: auto;"> 4263 <h4><a name="median" id="median"></a>-median <em class="arg">radius</em></h4> 4264</div> 4265 4266<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> 4267 4268<div style="margin: auto;"> 4269 <h4><a name="metric" id="metric"></a>-metric <em class="arg">type</em></h4> 4270</div> 4271 4272<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> 4273 4274<p>Choose from:</p> 4275 4276<pre class="text"> 4277 AE absolute number of different pixels 4278 MAE mean absolute error (normalized), average channel error distance 4279 MEPP mean error per pixel (normalized mean error, normalized peak error) 4280 MSE mean error squared, average of the channel error squared 4281 PAE peak absolute (normalize peak absolute) 4282 PSNR peak signal to noise ratio 4283 RMSE root mean squared (normalized root mean squared) 4284</pre> 4285 4286<p>The '<kbd>AE</kbd>' or absolute count of pixels that are different, can be 4287controled using a <a href="#fuzz" >-fuzz</a> factor to ignore pixels which 4288only changed by a small amount. The '<kbd>PAE</kbd>' can be used to find the 4289size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels 4290'similar'. </p> 4291 4292<p>The '<kbd>MEPP</kbd>' metric returns three different metrics 4293('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>' 4294normalized) from the single comparision run. </p> 4295 4296<p>To print a complete list of metrics, use the <a href="#list">-list metrics</a> option.</p> 4297 4298<div style="margin: auto;"> 4299 <h4><a name="minimum" id="minimum"></a>-minimum</h4> 4300</div> 4301 4302<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> 4303 4304 4305<div style="margin: auto;"> 4306 <h4><a name="mode" id="mode"></a>-mode <em class="arg">value</em></h4> 4307</div> 4308 4309<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> 4310 4311<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame, Unframe, or Concatenate</kbd></p> 4312 4313<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>' 4314argument for a list of <a href="#mode" >-mode</a> arguments available 4315in your ImageMagick installation.</p> 4316 4317 4318<div style="margin: auto;"> 4319 <h4><a name="modulate" id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4> 4320</div> 4321 4322<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 class="arg">saturation</em>, and <em class="arg">hue</em> of an image.</td><td style='text-align:right;'></td></tr></table> 4323 4324<p>The arguments are given as a percentages of variation. A value of 100 means 4325no change, and any missing values are taken to mean 100.</p> 4326 4327<p>The <em class="arg">brightness</em> is a multiplier of the overall 4328brightness of the image, so 0 means pure black, 50 is half as bright, 200 is 4329twice as bright. To invert its meaning <a href="#negate">-negate</a> the image 4330before and after. </p> 4331 4332<p>The <em class="arg">saturation</em> controls the amount of color in an 4333image. For example, 0 produce a grayscale image, while a large value such as 4334200 produce a very colorful, 'cartoonish' color.</p> 4335 4336<p>The <em class="arg">hue</em> argument causes a "rotation" of the colors 4337within the image by the amount specified. For example, 50 results in 4338a counter-clockwise rotation of 90, mapping red shades to purple, and so on. 4339A value of either 0 or 200 results in a complete 180 degree rotation of the 4340image. Using a value of 300 is a 360 degree rotation resulting in no change to 4341the original image. </p> 4342 4343<p>For example, to increase the color brightness by 20% and decrease the color 4344saturation by 10% and leave the hue unchanged, use <a 4345href="#modulate">-modulate 120,90</a>.</p> 4346 4347<p>Use <a href="#set">-set</a> attribute of '<kbd 4348class="arg">option:modulate:colorspace</kbd>' to specify which colorspace to 4349modulate. Choose from <kbd>HSB</kbd>, <kbd>HSL</kbd> (the default), or 4350<kbd>HWB</kbd>. For example,</p> 4351 4352<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> 4353 4354<div style="margin: auto;"> 4355 <h4><a name="monitor" id="monitor"></a>-monitor</h4> 4356</div> 4357 4358<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> 4359 4360 4361<div style="margin: auto;"> 4362 <h4><a name="monochrome" id="monochrome"></a>-monochrome</h4> 4363</div> 4364 4365<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> 4366 4367 4368<div style="margin: auto;"> 4369 <h4><a name="morph" id="morph"></a>-morph <em class="arg">frames</em></h4> 4370</div> 4371 4372<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> 4373 4374<p>Both the image pixels and size are linearly interpolated to give the 4375appearance of a meta-morphosis from one image to the next, over all the images 4376in the current image list. The added images are the equivalent of a <a 4377href="#blend">-blend</a> composition. The <em class="arg">frames</em> 4378argument determine how many images to interpolate between each image. </p> 4379 4380 4381<div style="margin: auto;"> 4382 <h4><a name="morphology" id="morphology"></a>-morphology</h4> 4383 <h4><a name="morphology" id="morphology"></a>-morphology <em class="arg">method</em> <em class="arg">kernel</em></h4> 4384</div> 4385 4386<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> 4387 4388Until I get around to writing a option summary for this, see <A 4389HREF="http://www.imagemagick.org/Usage/morphology/" >IM Usage Examples, 4390Morphology</A>. </P> 4391 4392 4393<div style="margin: auto;"> 4394 <h4><a name="mosaic" id="mosaic"></a>-mosaic</h4> 4395</div> 4396 4397<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> 4398 4399 4400<div style="margin: auto;"> 4401 <h4><a name="motion-blur" 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> 4402</div> 4403 4404<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> 4405 4406<p>Blur with the given radius, standard deviation (sigma), and angle. The 4407angle given is the angle toward which the image is blurred. That is the 4408direction people would consider the object is coming from. </p> 4409 4410<p>Note that the blur is not uniform distribution, giving the motion a 4411definate sense of direction of movement. </p> 4412 4413<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4414pixels which are outside the image proper are blurred into the final result. 4415</p> 4416 4417<div style="margin: auto;"> 4418 <h4><a name="name" id="name"></a>-name</h4> 4419</div> 4420 4421<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> 4422<div style="margin: auto;"> 4423 <h4><a name="negate" id="negate"></a>-negate</h4> 4424</div> 4425 4426<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> 4427 4428<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> 4429 4430<div style="margin: auto;"> 4431 <h4><a name="noise" id="noise"></a>-noise <em class="arg">radius</em><br/> 4432 +noise <em class="arg">type</em></h4> 4433</div> 4434 4435<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> 4436 4437<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> 4438 4439<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> 4440 4441<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> 4442 4443<pre class="text"> 4444Gaussian 4445Impulse 4446Laplacian 4447Multiplicative 4448Poisson 4449Random 4450Uniform 4451</pre> 4452 4453<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p> 4454 4455<p>Also see the <a href="#evaluate">-evaluate</a> noise functions that allos 4456the use of a controlling value to specify teh amount of noise that should be 4457added to an image. </p> 4458 4459 4460<div style="margin: auto;"> 4461 <h4><a name="normalize" id="normalize"></a>-normalize</h4> 4462</div> 4463 4464<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> 4465 4466<p>The intensity values are stretched to cover the entire range of possible 4467values. While doing so, black-out at most <em>2%</em> of the pixels and 4468white-out at most <em>1%</em> of the pixels.</p> 4469 4470<p>Note that as of ImageMagick 6.4.7-0, <a href="#normalize" >-normalize</a> 4471is equivalent to <a href="#contrast-stretch" >-contrast-stretch 2%x1%</a>. 4472(Before this version, it was equivalent to <a href="#contrast-stretch" 4473>-contrast-stretch 2%x99%</a>).</p> 4474 4475<p>All the channels are normalized in concert by the came amount so as to 4476preserve color integrity, when the default <a href="#channel" >+channel</a> 4477setting is in use. Specifing any other <a href="#channel" >-channel</a> 4478setting will normalize the RGB channels independently.</p> 4479 4480<p>See <a href="#contrast-stretch" >-contrast-stretch</A> for more details. 4481Also see <a href="#auto-level" >-auto-level</a> for a 'perfect' normalization 4482that is better suited to mathematically generated images. </p> 4483 4484<p>This operator is under review for re-development. </p> 4485 4486 4487<div style="margin: auto;"> 4488 <h4><a name="ordered-dither" id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4> 4489</div> 4490 4491<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 4492class="arg">threshold map</em> specified, and a uniform color map with the 4493given number of <em class="arg">levels</em> per color channel . </td><td style='text-align:right;'></td></tr></table> 4494 4495<p>You can choose from these standard threshold maps:</p> 4496 4497<pre class="text"> 4498 threshold 4499 checks 4500 o2x2 4501 o3x3 4502 o4x4 4503 o8x8 4504 h4x4a 4505 h6x6a 4506 h8x8a 4507 h4x4o 4508 h6x6o 4509 h8x8o 4510 h16x16o 4511</pre> 4512 4513<p>The '<kbd>o</kbd>' maps are ordered diffused pixel threshold maps, while the 4514'<kbd>h</kbd>' maps are halftone threshold maps which are either 'a' angled, or 4515'o' orthogonal. The '<kbd>checks</kbd>' produce a 3 level checkerbord dither 4516pattern. Or you can define your own <em class="arg" >threshold map</em> in a 4517personal or system "<kbd>thresholds.xml</kbd>" XML file. </p> 4518 4519<p>To print a complete list of threshold, use the <a href="#list" >-list 4520threshold</a> option.</p> 4521 4522<p>It is recommended that the <a href="#map" >+map</a> operator be used after 4523applying <a href="#ordered-dither" >-ordered-dither</a> to reduce the number of 4524colors an animated image sequence, to less that 256 colors. This ensures that 4525a common or global color table is used when saving the result to a color 4526limited file format such as GIF. </p> 4527 4528<p>Note that at this time the exact same threshold dithering map is used for 4529all color channels, no attempt is made to offset or rotate the map for 4530different channels is made, to create an offset printing effect. (possible 4531future expansion) </p> 4532 4533 4534<div style="margin: auto;"> 4535 <h4><a name="opaque" id="opaque"></a>-opaque <em class="arg">color</em></h4> 4536</div> 4537 4538<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> 4539 4540<p>The <em class="arg">color</em> argument is defined using the format 4541described under the <a href="#fill" >-fill</a> option. The <a href="#fuzz" 4542>-fuzz</a> setting can be used to match and replace colors similar to the one 4543given.</p> 4544 4545<p>Use <a href="#opaque">+opaque</a> to paint any pixel that does not match 4546the target color. </p> 4547 4548<p>The <a href="#transparent">-transparent</a> operator is exactly the same 4549as <a href="#opaque" >-opaque</a> but replaces the matching color with 4550transparency rather than the current <a href="#fill">-fill</a> color setting. 4551To ensure that it can do this it also ensures that the image has an alpha 4552channel enabled, as per "<kbd><a href="#alpha" >-alpha</a> set</kbd>", for 4553the new transparent colors, and does not require you to modify the <a 4554href="#channel">-channel</a> to enable alpha channel handling. </p> 4555 4556 4557<div style="margin: auto;"> 4558 <h4><a name="orient" id="orient"></a>-orient <em class="arg">image orientation</em></h4> 4559</div> 4560 4561<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> 4562 4563<p>Choose from these orientations:</p> 4564 4565<pre class="text"> 4566 bottom-left 4567 bottom-right 4568 left-bottom 4569 left-top 4570 right-bottom 4571 right-top 4572 top-left 4573 top-right 4574 undefined 4575</pre> 4576 4577<p>To print a complete list of orientations, use the <a href="#list" >-list 4578orientation</a> option.</p> 4579 4580 4581<div style="margin: auto;"> 4582 <h4><a name="page" id="page"></a>-page <em class="arg">geometry</em><br/> 4583 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!<></em>}]<br/> 4584 +page 4585 </h4> 4586</div> 4587 4588<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> 4589 4590<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> 4591 4592<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> 4593 4594<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> 4595<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;"> 4596<thead> 4597 <tr valign="top"> 4598 <th align="center"><em class="arg">media</em></th> 4599 <th align="center"><em class="arg">width</em></th> 4600 <th align="center"><em class="arg">height</em></th> 4601 </tr> 4602</thead> 4603<tbody> 4604<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr> 4605<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr> 4606<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr> 4607<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4608<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4609<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr> 4610<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr> 4611<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr> 4612<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr> 4613<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr> 4614<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr> 4615<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr> 4616<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr> 4617<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr> 4618<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4619<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4620<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr> 4621<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr> 4622<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr> 4623<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr> 4624<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr> 4625<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr> 4626<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr> 4627<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr> 4628<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr> 4629<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr> 4630<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr> 4631<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr> 4632<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr> 4633<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr> 4634<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr> 4635<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr> 4636<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr> 4637<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr> 4638<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr> 4639<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4640<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4641<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr> 4642</tbody> 4643</table> 4644 4645 4646 4647 4648<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> 4649 4650<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> 4651 4652<p>The default page dimensions for a TEXT image is 612x792.</p> 4653 4654<p>This option is used in concert with <a href="#density">-density</a>.</p> 4655 4656<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p> 4657 4658<div style="margin: auto;"> 4659 <h4><a name="paint" id="paint"></a>-paint <em class="arg">radius</em></h4> 4660</div> 4661 4662<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> 4663 4664<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> 4665 4666<div style="margin: auto;"> 4667 <h4><a name="path" id="path"></a>-path <em class="arg">path</em></h4></div> 4668 4669<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> 4670 4671<div style="margin: auto;"> 4672 <h4><a name="pause_animate_" id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4> 4673</div> 4674 4675<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> 4676 4677<p>Pause for the specified number of seconds before repeating the animation.</p> 4678 4679<div style="margin: auto;"> 4680 <h4><a name="pause_import_" id="pause_import_"></a>-pause <em class="arg">seconds</em></h4> 4681</div> 4682 4683<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> 4684 4685<p>Pause for the specified number of seconds before taking the next snapshot.</p> 4686 4687<div style="margin: auto;"> 4688 <h4><a name="ping" id="ping"></a>-ping</h4> 4689</div> 4690 4691<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> 4692 4693<div style="margin: auto;"> 4694 <h4><a name="pointsize" id="pointsize"></a>-pointsize <em class="arg">value</em></h4> 4695</div> 4696 4697<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> 4698 4699<div style="margin: auto;"> 4700 <h4><a name="polaroid" id="polaroid"></a>-polaroid <em class="arg">angle</em></h4> 4701</div> 4702 4703<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> 4704 4705<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p> 4706 4707<div style="margin: auto;"> 4708 <h4><a name="posterize" id="posterize"></a>-posterize <em class="arg">levels</em></h4> 4709</div> 4710 4711<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> 4712 4713<div style="margin: auto;"> 4714 <h4><a name="precision" id="precision"></a>-precision <em class="arg">value</em></h4> 4715</div> 4716 4717<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> 4718 4719<div style="margin: auto;"> 4720 <h4><a name="preview" id="preview"></a>-preview <em class="arg">type</em></h4> 4721</div> 4722 4723<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> 4724 4725<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> 4726 4727<pre class="text"> 4728 Rotate 4729 Shear 4730 Roll 4731 Hue 4732 Saturation 4733 Brightness 4734 Gamma 4735 Spiff 4736 Dull 4737 Grayscale 4738 Quantize 4739 Despeckle 4740 ReduceNoise 4741 Add Noise 4742 Sharpen 4743 Blur 4744 Threshold 4745 EdgeDetect 4746 Spread 4747 Shade 4748 Raise 4749 Segment 4750 Solarize 4751 Swirl 4752 Implode 4753 Wave 4754 OilPaint 4755 CharcoalDrawing 4756 JPEG 4757</pre> 4758 4759<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p> 4760 4761<p>The default preview is <kbd>JPEG</kbd>.</p> 4762 4763<div style="margin: auto;"> 4764 <h4><a name="print" id="print"></a>-print <em class="arg">string</em></h4> 4765</div> 4766 4767<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> 4768 4769<div style="margin: auto;"> 4770 <h4><a name="process" id="process"></a>-process <em class="arg">command</em></h4> 4771</div> 4772 4773<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> 4774 4775<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> 4776 4777<div style="margin: auto;"> 4778 <h4><a name="profile" id="profile"></a>-profile <em class="arg">filename</em><br/> 4779 +profile <em class="arg">profile_name</em></h4> 4780</div> 4781 4782<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> 4783 4784<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> 4785 4786<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> 4787 4788<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> 4789 4790<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> 4791 4792<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p> 4793 4794<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p> 4795<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> 4796 4797<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert CMYK.tif -profile "CMYK.icc" -profile "RGB.icc" RGB.tiff</span></p> 4798<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results. 4799CMYK profiles are often very asymmetric since they involve 3−>4 and 4−>3 channel mapping. 4800</p> 4801 4802<div style="margin: auto;"> 4803 <h4><a name="quality" id="quality"></a>-quality <em class="arg">value</em></h4> 4804</div> 4805 4806<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> 4807 4808<p>For the JPEG and MPEG image formats, quality is 0 (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 85. Use the <a href="#sampling-factor">-sampling-factor</a> option to specify the factors for chroma downsampling.</p> 4809 4810<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> 4811 4812<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 85 results in a request for 16:1 compression. The quality value 100 results in a request for non-lossy compression.</p> 4813 4814<p>For the MNG and PNG image formats, the quality value sets the zlib compression level (quality / 10) and filter-type (quality % 10). Compression levels range from 0 (fastest compression) to 100 (best but slowest). For compression level 0, the Huffman-only strategy is used, which is fastest but not necessarily the worst compression.</p> 4815 4816<p>If filter-type is 4 or less, the specified filter-type is used for all scanlines:</p> 4817 4818<pre class="text"> 4819 0: none 4820 1: sub 4821 2: up 4822 3: average 4823 4: Paeth 4824</pre> 4825 4826<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> 4827 4828<p>If filter-type is 6, adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p> 4829 4830<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> 4831 4832<p>The default is quality is 85, which means nearly the best compression with adaptive filtering. The quality setting has no effect on the appearance of PNG and MNG images, since the compression is always lossless.</p> 4833 4834<p>For further information, see the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p> 4835 4836<p>When writing a JNG image with transparency, two quality values are required, one for the main image and one for the grayscale image that conveys the alpha channel. These are written as a single integer equal to the main image quality plus 1000 times the opacity quality. For example, if you want to use quality 85 for the main image and quality 90 to compress the opacity data, use <a href="#quality">-quality 90085</a>.</p> 4837 4838<div style="margin: auto;"> 4839 <h4><a name="quantize" id="quantize"></a>-quantize <em class="arg">colorspace</em></h4> 4840</div> 4841 4842<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>reduce colors in this colorspace.</td><td style='text-align:right;'></td></tr></table> 4843 4844<p>To print a complete list of colorspaces, use the <a href="#list">-list colorspace</a> option.</p> 4845 4846 4847<div style="margin: auto;"> 4848 <h4><a name="quiet" id="quiet"></a>-quiet</h4> 4849</div> 4850 4851<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> 4852 4853<div style="margin: auto;"> 4854 <h4><a name="radial-blur" id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4> 4855</div> 4856 4857<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> 4858 4859<p>Note that this is actually a rotational blur rather than a radial and as 4860such actually mis-named. </p> 4861 4862<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4863pixels which are outside the image proper are blurred into the final result. 4864</p> 4865 4866 4867<div style="margin: auto;"> 4868 <h4><a name="raise" id="raise"></a>-raise <em class="arg">thickness</em></h4> 4869</div> 4870 4871<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> 4872 4873<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>. 4874</p> 4875 4876<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p> 4877 4878<div style="margin: auto;"> 4879 <h4><a name="random-threshold" id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4> 4880</div> 4881 4882<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> 4883 4884<div style="margin: auto;"> 4885 <h4><a name="red-primary" id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4> 4886</div> 4887 4888<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> 4889 4890<div style="margin: auto;"> 4891 <h4><a name="regard-warnings" id="regard-warnings"></a>-regard-warnings</h4> 4892</div> 4893 4894<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> 4895 4896<div style="margin: auto;"> 4897 <h4><a name="remap" id="remap"></a>-remap <em class="arg">filename</em></h4> 4898</div> 4899 4900<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> 4901 4902<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then 4903the given colors are dithered over the image as necessary, otherwise the closest 4904color (in RGB colorspace) is selected to replace that pixel in the image. </p> 4905 4906<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all 4907images in the current image sequence, all the images will have the same color 4908table. That means that when saved to a file format such as GIF, it will use 4909that color table as a single common or global color table, for all the images, 4910without requiring extra local color tables. </p> 4911 4912<p>Use <a href="#remap">+remap</a> to reduce all images in the current image 4913sequence to use a common color map over all the images. This equivalent to 4914appending all the images together (without extra background colors) and color 4915reducing those images using <a href="#colors">-colors</a> with a 256 color 4916limit, then <a href="#remap">-remap</a> those colors over the original list of 4917images. This ensures all the images follow a single color map. </p> 4918 4919<p>If the number of colors over all the images is less than 256, then <a 4920href="#remap">+remap</a> should not perform any color reduction or dithering, as 4921no color changes are needed. In that case, its only effect is to force the use 4922of a global color table. This recommended after using either <a 4923href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to 4924reduce the number of colors in an animated image sequence. </p> 4925 4926<div style="margin: auto;"> 4927 <h4><a name="region" id="region"></a>-region <em class="arg">geometry</em></h4> 4928</div> 4929 4930<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> 4931 4932<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> 4933 4934<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> 4935 4936<div style="margin: auto;"> 4937 <h4><a name="remote" id="remote"></a>-remote</h4> 4938</div> 4939 4940<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> 4941 4942<p>The only command recognized is the name of an image file to load.</p> 4943 4944<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> 4945 4946<div style="margin: auto;"> 4947 <h4><a name="render" id="render"></a>-render</h4> 4948</div> 4949 4950<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> 4951 4952<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> 4953 4954<div style="margin: auto;"> 4955<h4><a name="repage" id="repage"></a>-repage <em class="arg">geometry</em></h4> 4956</div> 4957 4958<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> 4959 4960<p>This option is like <a href="#page">-page</a> but acts as an image operator 4961rather than a setting. You can separately set the canvas size or the offset 4962of the image on that canvas by only providing those components. </p> 4963 4964<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> 4965 4966<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing 4967offset to move the image relative to its previous position. This useful for 4968animation sequences. </p> 4969 4970<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to 4971recalculate the canvas size so the image (at its current offset) will appear 4972completely on that canvas (unless it has a negative offset).</p> 4973 4974<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual 4975canvas meta-data from the images. </p> 4976 4977<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to 4978directly assign virtual canvas meta-data. </p> 4979 4980 4981<div style="margin: auto;"> 4982 <h4><a name="resample" id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4> 4983</div> 4984 4985<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> 4986 4987<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> 4988 4989<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> 4990 4991<div style="margin: auto;"> 4992 <h4><a name="resize" id="resize"></a>-resize <em class="arg">geometry</em></h4> 4993</div> 4994 4995<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> 4996 4997<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> 4998 4999<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> 5000 5001<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> 5002 5003<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> 5004<div style="margin: auto;"> 5005 <h4><a name="respect-parentheses" id="respect-parentheses"></a>-respect-parentheses</h4> 5006</div> 5007 5008<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> 5009 5010<div style="margin: auto;"> 5011 <h4><a name="reverse" id="reverse"></a>-reverse</h4> 5012</div> 5013 5014<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> 5015 5016 5017<div style="margin: auto;"> 5018 <h4><a name="roll" id="roll"></a>-roll {<em class="arg">+-</em>}<em class="arg">x</em>{<em class="arg">+-</em>}<em class="arg">y</em></h4> 5019</div> 5020 5021<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> 5022 5023<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> 5024 5025 5026<div style="margin: auto;"> 5027 <h4><a name="rotate" id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg"><</em>}{<em class="arg">></em>}</h4> 5028</div> 5029 5030<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> 5031 5032<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> 5033 5034<p>Empty triangles in the corners, left over from rotating the image, are 5035filled with the <kbd>background</kbd> color. </p> 5036 5037<p>See also the <a href="#distort">-distort</a> operator and specifically the 5038'<kbd>ScaleRotateTranslate</kbd>' distort method. </p> 5039 5040 5041<div style="margin: auto;"> 5042 <h4><a name="sample" id="sample"></a>-sample <em class="arg">geometry</em></h4> 5043</div> 5044 5045<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>scale image using pixel sampling.</td><td style='text-align:right;'></td></tr></table> 5046 5047<p><a href="#sample">-sample</a> ignores the current <a href="#resize">-resize</a> <a href="#filter">-filter</a> setting. The results are equivalent to using <a href="#resize">-resize</a> with a <a href="#filter">-filter</a> setting of <kbd>point</kbd>, though <a href="#sample">-sample</a> is a lot faster. </p> 5048 5049<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> 5050 5051 5052<div style="margin: auto;"> 5053 <h4><a name="sampling-factor" id="sampling-factor"></a>-sampling-factor <em class="arg">horizontal-factor</em>x<em class="arg">vertical-factor</em></h4> 5054</div> 5055 5056<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> 5057 5058<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> 5059 5060<div style="margin: auto;"> 5061 <h4><a name="scale" id="scale"></a>-scale <em class="arg">geometry</em></h4> 5062</div> 5063 5064<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>scale the image.</td><td style='text-align:right;'></td></tr></table> 5065 5066<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="#scale">-scale</a> option uses a simpler, faster algorithm than <a href="#resize">-resize</a>, and it ignores the <a href="#filter">-filter</a> setting if one is present. Offsets, if present in the <em class="arg">geometry</em> string, are ignored, and the <a href="#gravity">-gravity</a> option has no effect.</p> 5067 5068<div style="margin: auto;"> 5069 <h4><a name="scene" id="scene"></a>-scene <em class="arg">value</em></h4> 5070</div> 5071 5072<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> 5073 5074<p>This option sets the scene number of an image or the first image in an image sequence.</p> 5075 5076<div style="margin: auto;"> 5077 <h4><a name="screen" id="screen"></a>-screen</h4> 5078</div> 5079 5080<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> 5081 5082<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> 5083 5084<div style="margin: auto;"> 5085 <h4><a name="seed" id="seed"></a>-seed</h4> 5086</div> 5087 5088<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> 5089 5090<div style="margin: auto;"> 5091 <h4><a name="segment" id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4> 5092</div> 5093 5094<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> 5095 5096<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> 5097 5098<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> 5099 5100<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report 5101of the color clusters is returned.</p> 5102 5103 5104<div style="margin: auto;"> 5105 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">geometry</em></h4> 5106</div> 5107 5108<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> 5109 5110<div style="margin: auto;"> 5111 <h4><a name="separate" id="separate"></a>-separate</h4> 5112</div> 5113 5114<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> 5115 5116<div style="margin: auto;"> 5117 <h4><a name="sepia-tone" id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4> 5118</div> 5119 5120<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> 5121 5122<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p> 5123 5124<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> 5125 5126<div style="margin: auto;"> 5127 <h4><a name="set" id="set"></a>-set <em class="arg">attribute value</em></h4> 5128</div> 5129 5130<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set an image attribute for all images in the current image sequence, after they have been created or read in. </td><td style='text-align:right;'></td></tr></table> 5131 5132<p>Attributes of interest include <a href="#comment">-comment</a>, <a href="#delay">-delay</a>, <a href="#dispose">-dispose</a>, and <a href="#page">-page</a>. For example:</p> 5133 5134<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' \ <br/> rose.png</span><span class='crtout'></span><span class="crtprompt"> $magick> </span><span class='crtin'>identify -format %c rose.png</span><span class='crtout'>Rose is a rose is a rose is a rose</span></p> 5135<p>The <a href="#repage">-repage</a> operator will also set the 5136'<kbd>page</kbd>' attribute of images already in memory, but allows you to 5137separately set the virtual canvas's size and offset components, and also allows 5138relative offset changes, and automatic canvas size re-calculating. The above 5139<a href="#set">-set</a> option is purely a direct, unmodified assignment of the 5140virtual canvas (page) meta-data. </p> 5141 5142<p>Use this option to associate a colorspace or profile with your image. For example,</p> 5143<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> 5144<p>Set image options by prefixing the value with <kbd>option:</kbd>. Set attributes of the image registry by prefixing the value with <kbd>registry:</kbd>.</p> 5145 5146<div style="margin: auto;"> 5147 <h4><a name="shade" id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4> 5148</div> 5149 5150<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> 5151 5152<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> 5153 5154<div style="margin: auto;"> 5155 <h4><a name="shadow" 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> 5156</div> 5157 5158<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> 5159 5160<div style="margin: auto;"> 5161 <h4><a name="shared-memory" 5162id="shared-memory"></a>-shared-memory</h4> 5163</div> 5164 5165<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> 5166 5167<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> 5168 5169<div style="margin: auto;"> 5170 <h4><a name="sharpen" id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4> 5171</div> 5172 5173<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> 5174 5175<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p> 5176 5177<div style="margin: auto;"> 5178 <h4><a name="shave" id="shave"></a>-shave <em class="arg">geometry</em></h4> 5179</div> 5180 5181<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> 5182 5183<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> 5184 5185<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> 5186 5187<div style="margin: auto;"> 5188 <h4><a name="shear" id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4> 5189</div> 5190 5191<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> 5192 5193<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> 5194 5195<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> 5196 5197<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> 5198 5199<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> 5200 5201<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> 5202<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> 5203 5204<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p> 5205<div style="margin: auto;"> 5206 <h4><a name="sigmoidal" id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4> 5207</div> 5208 5209<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> 5210 5211<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> 5212 5213<div style="margin: auto;"> 5214 <h4><a name="silent" id="silent"></a>-silent</h4> 5215</div> 5216 5217<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> 5218 5219<div style="margin: auto;"> 5220 <h4><a name="size" id="size"></a>-size <em class="arg">width</em>[x<em class="arg">height</em>][<em class="arg">+offset</em>]</h4> 5221</div> 5222 5223<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> 5224 5225<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> 5226 5227<p>For Photo CD images, choose from these sizes:</p> 5228 5229<pre class="text"> 5230 192x128 5231 384x256 5232 768x512 5233 1536x1024 5234 3072x2048 5235</pre> 5236 5237<div style="margin: auto;"> 5238 <h4><a name="sketch" 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> 5239</div> 5240 5241<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> 5242 5243<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> 5244 5245<div style="margin: auto;"> 5246 <h4><a name="snaps" id="snaps"></a>-snaps <em class="arg">value</em></h4> 5247</div> 5248 5249<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> 5250 5251<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p> 5252 5253<div style="margin: auto;"> 5254 <h4><a name="solarize" id="solarize"></a>-solarize <em class="arg">threshold</em></h4> 5255</div> 5256 5257<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> 5258 5259<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p> 5260 5261<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p> 5262 5263<div style="margin: auto;"> 5264 <h4><a name="sparse-color" id="sparse-color"></a>-sparse-color <em 5265 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4> 5266</div> 5267 5268<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> 5269 5270 5271<table class="doc"> 5272 <tbody> 5273 <tr valign="top"> 5274 <th align="left" style="width: 8%">Method</th> 5275 <th align="left">Description</th> 5276 </tr> 5277 5278 <tr valign="top"> 5279 <td valign="top">voronoi</td> 5280 <td valign="top">Simply map each pixel to the to nearest color point 5281 given. The result are polygonal 'cells' of solid color. </td> 5282 </tr> 5283 5284 <tr valign="top"> 5285 <td valign="top">shepards</td> 5286 <td valign="top">Colors points basied on the ratio of inverse distance 5287 squared. Generating spots of color in a sea of the average of 5288 colors. </td> 5289 </tr> 5290 5291 <tr valign="top"> 5292 <td valign="top">barycentric</td> 5293 <td valign="top">three point triangle of color given 3 points. 5294 Giving only 2 points will form a linear gradient between those points. 5295 Gradient is however not restricted to just the triangle or line. </td> 5296 </tr> 5297 5298 <tr valign="top"> 5299 <td valign="top">bilinear</td> 5300 <td valign="top">Like barycentric but for 4 points. Less than 4 points 5301 fall back to barycentric. </td> 5302 </tr> 5303 5304 </tbody> 5305</table> 5306 5307<p>The points are placed according to the images location on the virtual 5308canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a> 5309offset), and do not actually have to exist on the given image, but may be 5310some point beyond the edge of the image. All points are floating point values. 5311</p> 5312 5313<p>Only the color channels defined by the <a href="#channel" >-channel</a> are 5314modified, whcih means the matte/alpha transparency channel is not effected by 5315default. If enabled, the image also needs a the matte/alpha channel to be 5316enabled for this operator to effect an images transparency. This is typical 5317transparency handling for images. </p> 5318 5319<p>All the above methods when given a single point of color will replace all 5320the colors in the image with the color given, regardless of the point. This is 5321logical, and provides an alternative technique to recolor a image to some 5322default value. </p> 5323 5324 5325<div style="margin: auto;"> 5326 <h4><a name="splice" id="splice"></a>-splice <em class="arg">geometry</em></h4> 5327</div> 5328 5329<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> 5330 5331<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> 5332 5333<div style="margin: auto;"> 5334 <h4><a name="spread" id="spread"></a>-spread <em class="arg">amount</em></h4> 5335</div> 5336 5337<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> 5338 5339<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> 5340 5341<div style="margin: auto;"> 5342 <h4><a name="stegano" id="stegano"></a>-stegano <em class="arg">offset</em></h4> 5343</div> 5344 5345<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> 5346 5347<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> 5348 5349<div style="margin: auto;"> 5350 <h4><a name="stereo" id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4> 5351</div> 5352 5353<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> 5354 5355<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> 5356 5357<div style="margin: auto;"> 5358 <h4><a name="storage-type" id="storage-type"></a>-storage-type <em class="arg">type</em></h4> 5359</div> 5360 5361<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> 5362 5363<pre class="text"> 5364 char store pixels as unsigned characters 5365 double store pixels as doubles 5366 float store pixels as floats 5367 integer store pixels as integers 5368 long store pixels as longs 5369 quantum store pixels in the native depth of your ImageMagick distribution 5370 short store pixels as unsigned shorts 5371</pre> 5372 5373<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels 5374values range from 0 to the maximum value the storage type can support.</p> 5375 5376<div style="margin: auto;"> 5377 <h4><a name="stretch" id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4> 5378</div> 5379 5380<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> 5381 5382<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> 5383 5384<pre class="text"> 5385 Any 5386 Condensed 5387 Expanded 5388 ExtraCondensed 5389 ExtraExpanded 5390 Normal 5391 SemiCondensed 5392 SemiExpanded 5393 UltraCondensed 5394 UltraExpanded 5395</pre> 5396 5397<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p> 5398 5399<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> 5400 5401<div style="margin: auto;"> 5402 <h4><a name="strip" id="strip"></a>-strip</h4> 5403</div> 5404 5405<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> 5406 5407<div style="margin: auto;"> 5408 <h4><a name="stroke" id="stroke"></a>-stroke <em class="arg">color</em></h4> 5409</div> 5410 5411<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> 5412 5413<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5414 5415<p>See <a href="#draw">-draw</a> for further details.</p> 5416 5417<div style="margin: auto;"> 5418 <h4><a name="strokewidth" id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4> 5419</div> 5420 5421<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> 5422 5423<p>See <a href="#draw">-draw</a> for further details.</p> 5424 5425<div style="margin: auto;"> 5426 <h4><a name="style" id="style"></a>-style <em class="arg">fontStyle</em></h4> 5427</div> 5428 5429<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> 5430 5431<p>This setting suggests a font style that ImageMagick should try to apply to the currently selected font family. Select <em class="arg">fontStyle</em> from the following.</p> 5432 5433<pre class="text"> 5434 Any 5435 Italic 5436 Normal 5437 Oblique 5438</pre> 5439 5440<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> 5441 5442<div style="margin: auto;"> 5443 <h4><a name="swap" id="swap"></a>-swap <em class="arg">index,index</em></h4> 5444</div> 5445 5446<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> 5447 5448<p>For example, <a href="#swap">-swap 0,2</a> swaps the first and the third images in the current image sequence. Use <a href="#swap">+swap</a> to switch the last two images in the sequence.</p> 5449 5450<div style="margin: auto;"> 5451 <h4><a name="swirl" id="swirl"></a>-swirl <em class="arg">degrees</em></h4> 5452</div> 5453 5454<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> 5455 5456<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p> 5457 5458<div style="margin: auto;"> 5459 <h4><a name="taint" id="taint"></a>-taint</h4> 5460</div> 5461 5462<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Mark the image as modified even if it isn't.</td><td style='text-align:right;'></td></tr></table> 5463 5464<div style="margin: auto;"> 5465 <h4><a name="text-font" id="text-font"></a>-text-font <em class="arg">name</em></h4> 5466</div> 5467 5468<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> 5469 5470<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> 5471 5472<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> 5473 5474<div style="margin: auto;"> 5475 <h4><a name="texture" id="texture"></a>-texture <em class="arg">filename</em></h4> 5476</div> 5477 5478<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> 5479 5480<div style="margin: auto;"> 5481 <h4><a name="threshold" id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 5482</div> 5483 5484<!-- {<em class="arg">green,blue,opacity</em>} 5485<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> 5486--> 5487 5488<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> 5489 5490<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> 5491 5492<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. 5493</p> 5494 5495<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> 5496 5497<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p> 5498<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> 5499 5500 5501<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> 5502<p>Note that the values of the transparency channel is treated as 'matte' 5503values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 5504 5505<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>. 5506</p> 5507 5508<div style="margin: auto;"> 5509 <h4><a name="thumbnail" id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4> 5510</div> 5511 5512<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> 5513 5514<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> 5515 5516<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> 5517 5518<div style="margin: auto;"> 5519 <h4><a name="tile" id="tile"></a>-tile <em class="arg">filename</em></h4> 5520</div> 5521 5522<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> 5523 5524<div style="margin: auto;"> 5525 <h4>-tile <em class="arg">geometry</em></h4> 5526</div> 5527 5528<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> 5529 5530<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> 5531 5532<div style="margin: auto;"> 5533 <h4>-tile</h4> 5534</div> 5535 5536<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> 5537 5538<div style="margin: auto;"> 5539 <h4><a name="tile-offset" 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> 5540</div> 5541 5542<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> 5543 5544<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> 5545 5546<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> 5547 5548<div style="margin: auto;"> 5549 <h4><a name="tint" id="tint"></a>-tint <em class="arg">value</em></h4> 5550</div> 5551 5552<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> 5553 5554<p>Tint the image with the fill color.</p> 5555 5556<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> 5557 5558<div style="margin: auto;"> 5559 <h4><a name="title" id="title"></a>-title <em class="arg">string</em></h4> 5560</div> 5561 5562<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> 5563 5564<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> 5565 5566<p>For example,</p> 5567 5568<p class="crtsnip"> 5569 -title "%m:%f %wx%h" 5570</p> 5571 5572<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> 5573 5574 5575<div style="margin: auto;"> 5576 <h4><a name="transform" id="transform"></a>-transform</h4> 5577</div> 5578 5579<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> 5580 5581<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p> 5582 5583<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> 5584 5585<p>This operator has been now been superseded by the <a 5586href="#distort">-distort</a> '<kbd>AffineProjection</kbd>' method. </p> 5587 5588 5589<div style="margin: auto;"> 5590 <h4><a name="transparent" id="transparent"></a>-transparent <em class="arg">color</em></h4> 5591</div> 5592 5593<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> 5594 5595<p>The <em class="arg">color</em> argument is defined using the format 5596described under the <a href="#fill">-fill</a> option. The <a href="#fuzz" 5597>-fuzz</a> setting can be used to match and replace colors similar to the one 5598given. </p> 5599 5600<p>Use <a href="#transparent" >+transparent</a> to invert the pixels matched. 5601that is make all non-matching colors transparent. </p> 5602 5603<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a 5604href="#transparent" >-transparent</a> but replaces the matching color with the 5605current <a href="#fill">-fill</a> color setting, rather than transparent. 5606However the <a href="#transparent" >-transparent</a> operator also ensures 5607that the image has an alpha channel enabled, as per "<kbd><a href="#alpha" 5608>-alpha</a> set</kbd>", and does not require you to modify the <a 5609href="#channel">-channel</a> to enable alpha channel handling. </p> 5610 5611<p>Note that this does not define the color as being the 'transparency color' 5612used for color-mapped image formats, such as GIF. For that use <a 5613href="#transparent-color" >-transparent-color</a> </p> 5614 5615 5616<div style="margin: auto;"> 5617 <h4><a name="transparent-color" id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4> 5618</div> 5619 5620<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> 5621 5622<p>Sometimes this is used for saving to image formats such as 5623GIF and PNG8 which uses this color to represent boolean transparency. This 5624does not make a color transparent, it only defines what color the transparent 5625color is in the color palette of the saved image. Use <a 5626href="#transparent">-transparent</a> to make an opaque color transparent.</p> 5627 5628<p>This option allows you to have both an opaque visible color, as well as a 5629transparent color of the same color value without conflict. That is, you can 5630use the same color for both the transparent and opaque color areas within an 5631image. This, in turn, frees to you to select a transparent color that is 5632appropriate when an image is displayed by an application that does not handle a 5633transparent color index, while allowing ImageMagick to correctly handle images of this 5634type. </p> 5635 5636<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p> 5637 5638<div style="margin: auto;"> 5639 <h4><a name="transpose" id="transpose"></a>-transpose</h4> 5640</div> 5641 5642<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> 5643 5644<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>. 5645</p> 5646 5647<div style="margin: auto;"> 5648 <h4><a name="transverse" id="transverse"></a>-transverse</h4> 5649</div> 5650 5651<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> 5652 5653 5654<div style="margin: auto;"> 5655 <h4><a name="treedepth" id="treedepth"></a>-treedepth <em class="arg">value</em></h4> 5656</div> 5657 5658<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> 5659 5660<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> 5661 5662<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> 5663 5664<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> 5665 5666<div style="margin: auto;"> 5667 <h4><a name="trim" id="trim"></a>-trim</h4> 5668</div> 5669 5670<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> 5671 5672<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> 5673 5674<p>The page or virtual canvas information of the image is preserved allowing 5675you to extract the result of the <a href="#trim">-trim</a> operation from the 5676image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page 5677information if it is unwanted.</p> 5678 5679<p>If the trimmed image 'disappears' an warning is produced, and a special 5680single pixel transparent 'missed' image is returned, in the same way as when a 5681<a href="#crop">-crop</a> operation 'misses' the image proper. </p> 5682 5683 5684<div style="margin: auto;"> 5685 <h4><a name="type" id="type"></a>-type <em class="arg">type</em></h4> 5686</div> 5687 5688<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> 5689 <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>, <kbd>ColorSeparationMatte</kbd>, or <kbd>Optimize</kbd>.</p> 5690 5691<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> 5692 5693<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p> 5694<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> 5695 5696<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p> 5697 5698<div style="margin: auto;"> 5699 <h4><a name="undercolor" id="undercolor"></a>-undercolor <em class="arg">color</em></h4> 5700</div> 5701 5702<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> 5703 5704<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5705 5706<p>See <a href="#draw">-draw</a> for further details.</p> 5707 5708 5709<div style="margin: auto;"> 5710 <h4><a name="update" id="update"></a>-update <em class="arg">seconds</em></h4> 5711</div> 5712 5713<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> 5714 5715<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> 5716 5717 5718<div style="margin: auto;"> 5719 <h4><a name="unique-colors" id="unique-colors"></a>-unique-colors</h4> 5720</div> 5721 5722<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> 5723 5724 5725<div style="margin: auto;"> 5726 <h4><a name="units" id="units"></a>-units <em class="arg">type</em></h4> 5727</div> 5728 5729<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> 5730 5731<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> 5732 5733 5734<div style="margin: auto;"> 5735 <h4><a name="unsharp" 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> 5736</div> 5737 5738<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> 5739 5740<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> 5741 5742<p>The parameters are:</p> 5743 5744<pre class="text"> 5745 radius: The radius of the Gaussian, in pixels, not counting the center 5746 pixel (default 0). 5747 sigma: The standard deviation of the Gaussian, in pixels (default 1.0). 5748 amount: The fraction of the difference between the original and the blur 5749 image that is added back into the original (default 1.0). 5750 threshold: The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the 5751 difference amount (default 0.05). 5752</pre> 5753 5754 5755<div style="margin: auto;"> 5756 <h4><a name="verbose" id="verbose"></a>-verbose</h4> 5757</div> 5758 5759<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 preceds the <a href="#identify">-identify</a> option or <kbd>info:</kbd>.</td><td style='text-align:right;'></td></tr></table> 5760 5761 5762<div style="margin: auto;"> 5763 <h4><a name="version" id="version"></a>-version</h4> 5764</div> 5765 5766<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> 5767 5768 5769<div style="margin: auto;"> 5770 <h4><a name="view" id="view"></a>-view <em class="arg">string</em></h4> 5771</div> 5772 5773<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> 5774 5775 5776<div style="margin: auto;"> 5777 <h4><a name="vignette" 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> 5778</div> 5779 5780<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> 5781 5782 5783<div style="margin: auto;"> 5784 <h4><a name="virtual-pixel" id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4> 5785</div> 5786 5787<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> 5788 5789<p>This option defines what color source should be used if and when a color 5790lookup completely 'misses' the source image. The color(s) that appear to 5791surround the source image. Generally this color is derived from the source 5792image, but could also be set to a specify background color. </p> 5793 5794<p>Choose from these methods:</p> 5795 5796<pre class="text"> 5797 background: the area surrounding the image is the background color 5798 black: the area surrounding the image is black 5799 checker-tile: alternate squares with image and background color 5800 dither: non-random 32x32 dithered pattern 5801 edge: extend the edge pixel toward infinity 5802 gray: the area surrounding the image is gray 5803 horizontal-tile: horizontally tile the image, background color above/below 5804 horizontal-tile-edge: horizontally tile the image and replicate the side edge pixels 5805 mirror: mirror tile the image 5806 random: choose a random pixel from the image 5807 tile: tile the image (default) 5808 transparent: the area surrounding the image is transparent blackness 5809 vertical-tile: vertically tile the image, sides are background color 5810 vertical-tile-edge: vertically tile the image and replicate the side edge pixels 5811 white: the area surrounding the image is white 5812</pre> 5813 5814<p>The default value is "edge".</p> 5815 5816<p>This most important for distortion operators such as <a href="#distort" 5817>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>. 5818However it also effects operations that may access pixels just outside the 5819image proper, such as <a href="#convolve">-convolve</a>, <a 5820href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p> 5821 5822<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p> 5823 5824 5825<div style="margin: auto;"> 5826 <h4><a name="visual" id="visual"></a>-visual <em class="arg">type</em></h4> 5827</div> 5828 5829<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> 5830 5831<p>Choose from these visual classes:</p> 5832 5833<pre class="text"> 5834 StaticGray 5835 GrayScale 5836 StaticColor 5837 PseudoColor 5838 TrueColor 5839 DirectColor 5840 default 5841 visual id 5842</pre> 5843 5844<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> 5845 5846 5847<div style="margin: auto;"> 5848 <h4><a name="watermark" id="watermark"></a>-watermark <em 5849 class="arg">brightness</em>x<em class="arg">saturation</em></h4> 5850</div> 5851 5852<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 5853saturation.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 5854 5855<p>Take a grayscale image (with alpha mask) and modify the destination image's 5856brightness according to watermark image's grayscale value and the <em 5857class="arg">brightness</em> percentage. The destinations color saturation 5858attribute is just direct modified by the <em class="arg">saturation</em> 5859percentage, which defaults to 100 percent (no color change). </p> 5860 5861 5862<div style="margin: auto;"> 5863 <h4><a name="wave" id="wave"></a>-wave <em class="arg">amplitude</em><br />-wave <em class="arg">amplitude</em>x<em class="arg">wavelength</em></h4> 5864</div> 5865 5866<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> 5867 5868<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p> 5869 5870<div style="margin: auto;"> 5871 <h4><a name="weight" id="weight"></a>-weight <em class="arg">fontWeight</em></h4> 5872</div> 5873 5874<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> 5875 5876<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> 5877 5878<table class="doc"> 5879 <col width="25%" /> 5880 <col width="75%" /> 5881 <thead> 5882 <tr> 5883 <th><em class="arg">fontWeight</em></th> 5884 <th>Description</th> 5885 </tr> 5886 </thead> 5887 <tbody> 5888 <tr><td>All </td> <td>No effect. </td></tr> 5889 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr> 5890 <tr><td>Bolder </td> <td>Add 100 to font weight if currently ≤ 800.</td></tr> 5891 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently ≤ 100.</td></tr> 5892 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr> 5893 </tbody> 5894 </table> 5895 5896<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p> 5897 5898<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> 5899 5900<div style="margin: auto;"> 5901 <h4><a name="white-point" id="white-point"></a>-white-point <em class="arg">x,y</em></h4> 5902</div> 5903 5904<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> 5905 5906<div style="margin: auto;"> 5907 <h4><a name="white-threshold" id="white-threshold"></a>-white-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 5908</div> 5909 5910<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> 5911 5912<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. 5913</p> 5914 5915<div style="margin: auto;"> 5916 <h4><a name="window" id="window"></a>-window <em class="arg">id</em></h4> 5917</div> 5918 5919<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> 5920 5921<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> 5922 5923<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> 5924 5925<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> 5926 5927<div style="margin: auto;"> 5928 <h4><a name="window-group" id="window-group"></a>-window-group</h4> 5929</div> 5930 5931<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> 5932 5933<div style="margin: auto;"> 5934 <h4><a name="write" id="write"></a>-write <em class="arg">filename</em></h4> 5935</div> 5936 5937<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> 5938 <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> 5939 5940<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p> 5941 5942 5943</div> 5944 5945<div id="linkbar"> 5946 <!-- <span id="linkbar-west"> </span> --> 5947 <span id="linkbar-center"> 5948 <a href="http://www.imagemagick.org/discourse-server/">Discourse Server</a> • 5949 <a href="http://www.imagemagick.org/MagickStudio/scripts/MagickStudio.cgi">Studio</a> 5950 </span> 5951 <span id="linkbar-east"> </span> 5952 </div> 5953 <div class="footer"> 5954 <span id="footer-west">© 1999-2010 ImageMagick Studio LLC</span> 5955 <span id="footer-east"> <a href="http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span> 5956 </div> 5957 <div style="clear: both; margin: 0; width: 100%; "></div> 5958</body> 5959</html> 5960
