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</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#recolor">‑recolor</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> 164 165<p>Below is list of command-line options recognized by the ImageMagick <a href="/www/command-line-tools.html">command-line tools</a>. If you want a description of a particular option, click on the option name in the navigation bar above and you will go right to it. Unless otherwise noted, each option is recognized by the commands 166<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> 173 174<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>Off</kbd> or 288 <kbd>Deactivate</kbd></td> 289 <td valign="top"> 290 Disables the image's transparency channel. Does not delete or change the 291 existing data, just turns off the use of that data. This is the same as 292 the older <a href="#matte" >+matte</a> operator. </td></tr> 293 294 <tr valign="top"> 295 <td valign="top"><kbd>On</kbd> or 296 <kbd>Activate</kbd></td> 297 <td valign="top"> 298 Enables the image's use of transparency. If transparency data does not 299 already exist, allocates the data and sets it to opaque. If the image has 300 transparency data, the channel is enabled and the transparency data is not changed or modified in any way. This is NOT 301 the same as the older <a href="#matte" >-matte</a> operator. </td></tr> 302 303 <tr valign="top"> 304 <td valign="top"><kbd>Set</kbd></td> 305 <td valign="top"> 306 Turns '<kbd>On</kbd>' the alpha/matte channel and if it was previously 307 turned off resets the channel to opaque. If the image already had the 308 alpha channel turned on, it will have no effect. This is the same as the older <a href="#matte">-matte</a> operator. </td></tr> 309 310 <tr valign="top"> 311 <td valign="top"><kbd>Opaque</kbd></td> 312 <td valign="top"> 313 Turns '<kbd>On</kbd>' the alpha/matte channel and forces it to be fully 314 opaque. </td></tr> 315 316 <tr valign="top"> 317 <td valign="top"><kbd>Transparent</kbd></td> 318 <td valign="top"> 319 Turns '<kbd>On</kbd>' the alpha/matte channel and forces it to be fully 320 transparent. This effectively creates a fully transparent image the same 321 size as the original and with all its original RGB data still intact. </td></tr> 322 323 <tr valign="top"> 324 <td valign="top"><kbd>Extract</kbd></td> 325 <td valign="top"> 326 Copies the alpha channel values into all the color channels and turns 327 '<kbd>Off</kbd>' the the image's transparency, so as to generate a 328 gray-scale mask of the image's shape. This is the inverse of 329 '<kbd>Copy</kbd>'. </td></tr> 330 331 <tr valign="top"> 332 <td valign="top"><kbd>Copy</kbd></td> 333 <td valign="top"> 334 Turns '<kbd>On</kbd>' the alpha/matte channel, then copies the 335 gray-scale intensity of the image, as an alpha mask, into the alpha 336 channel, converting a gray-scale mask into a transparent shaped image 337 ready to be colored appropriately. The color channels are not modified. 338 </td></tr> 339 340 <tr valign="top"> 341 <td valign="top"><kbd>Shape</kbd></td> 342 <td valign="top"> 343 As per '<kbd>Copy</kbd>' but also colors the resulting shape mask with 344 the current background color. 345 </td></tr> 346 347 <tr valign="top"> 348 <td valign="top"><kbd>Background</kbd></td> 349 <td valign="top"> 350 Set any fully-transparent pixel to the background color. 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> set</kbd>" and 358not "<kbd><a href="#alpha" >-alpha</a> on</kbd>". 359That is, "<kbd><a href="#alpha" >-alpha</a> set</kbd>" will ensure that the 360written image is opaque if the original image had no transparency 361channel enabled, regardless 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">percent</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 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="cache" id="cache"></a>-cache <em class="arg">threshold</em></h4> 681</div> 682 683<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> 684 685<div style="margin: auto;"> 686 <h4><a name="caption" id="caption"></a>-caption <em class="arg">string</em></h4> 687</div> 688 689<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> 690 691<div style="margin: auto;"> 692 <h4><a name="cdl" id="cdl"></a>-cdl <em class="arg">filename</em></h4> 693</div> 694 695<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> 696 697<p>Here is an example color correction collection:</p> 698 699<pre class="text"> 700<?xml version="1.0" encoding="UTF-8"?> 701<ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2"> 702 <ColorCorrection id="cc06668"> 703 <SOPNode> 704 <Slope> 0.9 1.2 0.5 </Slope> 705 <Offset> 0.4 -0.5 0.6 </Offset> 706 <Power> 1.0 0.8 1.5 </Power> 707 </SOPNode> 708 <SATNode> 709 <Saturation> 0.85 </Saturation> 710 </SATNode> 711 </ColorCorrection> 712</ColorCorrectionCollection> 713</pre> 714 715<div style="margin: auto;"> 716 <h4><a name="channel" id="channel"></a>-channel <em class="arg">type</em></h4> 717</div> 718 719<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> 720 721<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> 722 723<p>To print a complete list of channel types, use <a href="#list">-list channel</a>.</p> 724 725<p>The channels above can be specified as a comma-separated list or can be 726abbreviated as a concatenation of the letters '<kbd>R</kbd>', '<kbd>G</kbd>', 727'<kbd>B</kbd>', '<kbd>A</kbd>', '<kbd>O</kbd>', '<kbd>C</kbd>', 728'<kbd>M</kbd>', '<kbd>Y</kbd>', '<kbd>K</kbd>'. 729 730For example, to negate only the alpha channel of an image, use</p> 731<p class="crtsnip"> 732 -channel Alpha -negate 733</p> 734 735Some operators also allow the use of a special channel flag 736'<code>sync</code>'. If present operators that understand this flag will 737apply the exact same image modification to all the image channels in the image 738so as to ensure that colors are kept 'in-sync'. Without this flag such 739operators will apply there function to each channel separately. See <a 740href="#auto-level">-auto-level</a> and <a href="#auto-gamma">-auto-gamma</a> 741for examples of such an operator. </p> 742 743 744<p>By default, ImageMagick sets <a href="#channel">-channel</a> to the value 745'<kbd>RGB,sync</kbd>', which specifies that operators act on all channels 746except the opacity channel, and that all the color channels are to be modified 747in exactly the same way. The 'plus' form <a href="#channel" >+channel</a> 748will reset the value back to this default. </p> 749 750<p>Options that are affected by the <a href="#channel" >-channel</a> setting 751include the following. 752 753<a href="#auto-gamma">-auto-gamma</a>, 754<a href="#auto-level">-auto-level</a>, 755<a href="#black-threshold">-black-threshold</a>, 756<a href="#blur">-blur</a>, 757<a href="#clamp">-clamp</a>, 758<a href="#clut">-clut</a>, 759<a href="#combine">-combine</a>, 760<a href="#contrast-stretch">-contrast-stretch</a>, 761<a href="#evaluate">-evaluate</a>, 762<a href="#function">-function</a>, 763<a href="#fx">-fx</a>, 764<a href="#gaussian-blur">-gaussian-blur</a>, 765<a href="#hald-clut">-hald-clut</a>, 766<a href="#motion-blur">-motion-blur</a>, 767<a href="#negate">-negate</a>, 768<a href="#normalize">-normalize</a>, 769<a href="#ordered-dither">-ordered-dither</a>, 770<a href="#radial-blur">-radial-blur</a>, 771<a href="#random-threshold">-random-threshold</a>, 772<a href="#separate">-separate</a>, and 773<a href="#threshold">-threshold</a>, and 774<a href="#white-threshold">-white-threshold</a>. 775</p> 776 777<p>Warning, some operators behave differentally when the <a href="#channel" 778>+channel</a> default setting is in effect, verses ANY user defined <a 779href="#channel" >-channel</a> setting (including the equivelent of the 780default). For example <a href="#threshold">-threshold</a> will by default 781gray-scale the image before thresholding, if no <a href="#channel" 782>-channel</a> setting has been defined. </p> 783 784<p>Also some operators such as <a href="#blur">-blur</a>, <a 785href="#gaussian-blur">-gaussian-blur</a>, will modify their handling of the 786color channels if the '<kbd>alpha</kbd>' channel is also enabled by <a 787href="#channel" >-channel</a>. Generally this done to ensure that 788fully-transparent colors are treated as being fully-transparent, and thus any 789underlying 'hidden' color has no effect on the final results. Typically 790resulting in 'halo' effects. </p> 791 792<p>As a alpha channel is optional within images some operators will read the 793color channels of an image as a greyscale alpha mask, when the image has no 794alpha channel present, but the <a href="#channel" >-channel</a> setting tells 795the operator to apply the alpha channel. The <a href="#clut">-clut</a> 796operator is a good example of this. </p> 797 798 799<div style="margin: auto;"> 800 <h4><a name="clamp" id="clamp"></a>-clamp</h4> 801</div> 802 803<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> 804 805<div style="margin: auto;"> 806 <h4><a name="charcoal" id="charcoal"></a>-charcoal <em class="arg">factor</em></h4> 807</div> 808 809<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> 810 811<div style="margin: auto;"> 812 <h4><a name="chop" id="chop"></a>-chop <em class="arg">geometry</em></h4> 813</div> 814 815<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> 816 817<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> 818 819<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> 820 821<div style="margin: auto;"> 822 <h4><a name="clip" id="clip"></a>-clip</h4> 823</div> 824 825<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> 826 827<p>If a clipping path is present, it is applied to subsequent operations.</p> 828 829<p>For example, in the command</p> 830 831<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -clip -negate cockatoo.tif negated.tif</span></p> 832<p>only the pixels within the clipping path are negated.</p> 833 834<p>The <a href="#clip">-clip</a> feature requires the XML library. If the XML library is not present, the option is ignored.</p> 835 836<div style="margin: auto;"> 837 <h4><a name="clip-mask" id="clip-mask"></a>-clip-mask</h4> 838</div> 839 840<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> 841 842<div style="margin: auto;"> 843 <h4><a name="clip-path" id="clip-path"></a>-clip-path <em class="arg">id</em></h4> 844</div> 845 846<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> 847 848<div style="margin: auto;"> 849 <h4><a name="clone" id="clone"></a>-clone <em class="arg">index(s)</em></h4> 850</div> 851 852<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> 853 854<p>Specify the image by its index in the sequence. The first image is index 8550. Negative indexes are relative to the end of the sequence; for example, −1 856represents the last image of the sequence. Specify a range of images with a 857dash (e.g. 0−4). Separate multiple indexes with commas but no spaces (e.g. 0,2,5). Use <a 858href="#clone">+clone</a> make a copy of the last image in the image 859sequence.</p> 860 861<div style="margin: auto;"> 862 <h4><a name="clut" id="clut"></a>-clut</h4> 863</div> 864 865<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 866corresponding channel in the second image as a <b>c</b>olor 867<b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style='text-align:right;'></td></tr></table> 868 869<p>The second (LUT) image is ordinarily a gradient image containing the 870histogram mapping of how each channel should be modified. Typically it is a 871either a single row or column image of replacement color values. If larger 872than a single row or column, values are taken from a diagonal line from 873top-left to bottom-right corners.</p> 874 875<p>The lookup is further controlled by the <a 876href="#interpolate">-interpolate</a> setting, which is especially handy for an 877LUT which is not the full length needed by the ImageMagick installed Quality 878(Q) level. Good settings for this are the '<kbd>bilinear</kbd>' and 879'<kbd>bicubic</kbd>' interpolation settings, which give smooth color 880gradients, and the '<kbd>integer</kbd>' setting for a direct, unsmoothed 881lookup of color values. </p> 882 883<p>This operator is especially suited to replacing a grayscale image with a 884specific color gradient from the CLUT image. </p> 885 886<p>Only the channel values defined by the <a href="#channel">-channel</a> 887setting will have their values replaced. In particular, since the default <a 888href="#channel">-channel</a> setting is <kbd>RGB</kbd>, this means that 889transparency (alpha/matte channel) is not affected, unless the <a 890href="#channel">-channel</a> setting is modified. When the alpha channel is 891set, it is treated by the <a href="#clut" >-clut</a> operator in the same way 892as the other channels, implying that alpha/matte values are replaced using the 893alpha/matte values of the original image. </p> 894 895<p>If either the image being modified, or the lookup image, conatins no 896transparency (i.e. <a href="#alpha" >-alpha</a> is turned 'off') but the <a 897href="#channel">-channel</a> setting includes alpha replacement, then it is 898assumed that image represents a gray-scale graident which will be used for the 899replacement alpha values. That is you can use a gray-scale CLUT image to 900adjust a existing images alpha channel, or you can color a gray-scale image 901using colors form CLUT containing the desired colors, including transparency. 902</p> 903 904<p>See also <a href="#hald-clut" >-hald-clut</a> which replaces colors according 905the lookup of the full color RGB value from a 2D representation of a 3D color 906cube. </p> 907 908 909<div style="margin: auto;"> 910 <h4><a name="coalesce" id="coalesce"></a>-coalesce</h4> 911</div> 912 913<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> 914 915<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> 916 917<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> 918 919 920<div style="margin: auto;"> 921 <h4><a name="colorize" id="colorize"></a>-colorize <em class="arg">value</em></h4> 922</div> 923 924<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> 925 926<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> 927 928<div style="margin: auto;"> 929 <h4><a name="colormap" id="colormap"></a>-colormap <em class="arg">type</em></h4> 930</div> 931 932<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> 933 934<p>The <em class="arg">type</em> can be <kbd>shared</kbd> or <kbd>private</kbd>.</p> 935 936<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> 937 938<div style="margin: auto;"> 939 <h4><a name="colors" id="colors"></a>-colors <em class="arg">value</em></h4> 940</div> 941 942<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> 943 944<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> 945 946<div style="margin: auto;"> 947 <h4><a name="colorspace" id="colorspace"></a>-colorspace <em class="arg">value</em></h4> 948</div> 949 950<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> 951 952<p>Choices are:</p> 953 954<pre class="text"> 955 CMY 956 CMYK 957 Gray 958 HSB 959 HSL 960 HWB 961 Lab 962 Log 963 OHTA 964 Rec601Luma 965 Rec601YCbCr 966 Rec709Luma 967 Rec709YCbCr 968 RGB 969 sRGB 970 Transparent 971 XYZ 972 YCbCr 973 YCC 974 YIQ 975 YPbPr 976 YUV 977</pre> 978 979<p>To print a complete list of colorspaces, use <a href="#list">-list colorspace</a>.</p> 980 981<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> 982 983<table class="doc"> 984 <caption>Conversion Of RGB To Other Color Spaces</caption> 985 <tr><th align="left" valign="middle">CMY</th></tr> 986 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>−R</td></tr> 987 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>−G</td></tr> 988 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>−B</td></tr> 989 <tr><th align="left" valign="middle">CMYK — starts with CMY from above</th></tr> 990 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr> 991 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 992 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 993 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 994 995 <tr><th align="left" valign="middle">Gray</th></tr> 996 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 997 998 <tr><th align="left" valign="middle">HSB — Hue, Saturation, Brightness; like a cone peak downward</th></tr> 999 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1000 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1001 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr> 1002 1003 <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> 1004 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1005 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1006 <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> 1007 1008 <tr><th align="left" valign="middle">HWB — Hue, Whiteness, Blackness</th></tr> 1009 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr> 1010 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr> 1011 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr> 1012 1013 <tr><th align="left" valign="middle">LAB</th></tr> 1014 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr> 1015 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr> 1016 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr> 1017 1018 <tr><th align="left" valign="middle">LOG</th></tr> 1019 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr> 1020 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr> 1021 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr> 1022 1023 <tr><th align="left" valign="middle">OHTA — approximates principal components transformation</th></tr> 1024 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr> 1025 <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> 1026 <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> 1027 1028 <tr><th align="left" valign="middle">Rec601Luma</th></tr> 1029 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 1030 1031 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr> 1032 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1033 <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> 1034 <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> 1035 1036 <tr><th align="left" valign="middle">Rec709Luma</th></tr> 1037 <tr><td align="left" valign="middle">Gray=0.21260*R+0.71520*G+0.07220*B</td></tr> 1038 1039 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr> 1040 <tr><td align="left" valign="middle">Y=0.212600*R+0.715200*G+0.072200*B; <em>intensity-like</em></td></tr> 1041 <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> 1042 <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> 1043 1044 <tr><th align="left" valign="middle">sRGB</th></tr> 1045 <tr><td align="left" valign="middle">if Rs ≤ .03928 then Rs=R/12.92 else Rs=((R+.055)/1.055)^2.4</td></tr> 1046 <tr><td align="left" valign="middle">if Gs ≤ .03928 then Gs=B/12.92 else Gs=((G+.055)/1.055)^2.4</td></tr> 1047 <tr><td align="left" valign="middle">if Bs ≤ .03928 then Bs=B/12.92 else Bs=((B+.055)/1.055)^2.4</td></tr> 1048 1049 <tr><th align="left" valign="middle">XYZ</th></tr> 1050 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr> 1051 <tr><td align="left" valign="middle">Y=0.2126560*R+0.7151580*G+0.0721856*B</td></tr> 1052 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr> 1053 1054 <tr><th align="left" valign="middle">YCC</th></tr> 1055 <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> 1056 <tr><td align="left" valign="middle">C1=(−0.29900*R−0.58700*G+0.88600*B) (with complicated scaling)</td></tr> 1057 <tr><td align="left" valign="middle">C2=(0.70100*R−0.58700*G−0.11400*B) (with complicated scaling)</td></tr> 1058 1059 <tr><th align="left" valign="middle">YCbCr</th></tr> 1060 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1061 <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> 1062 <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> 1063 1064 <tr><th align="left" valign="middle">YIQ</th></tr> 1065 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1066 <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> 1067 <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> 1068 1069 <tr><th align="left" valign="middle">YPbPr</th></tr> 1070 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1071 <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> 1072 <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> 1073 1074 <tr><th align="left" valign="middle">YUV</th></tr> 1075 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1076 <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> 1077 <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> 1078</table> 1079 1080<div style="margin: auto;"> 1081 <h4><a name="combine" id="combine"></a>-combine</h4> 1082</div> 1083 1084<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> 1085 1086<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> 1087 1088<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. 1089</p> 1090 1091<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 -combine imagecopy.png</span></p> 1092<div style="margin: auto;"> 1093 <h4><a name="comment" id="comment"></a>-comment <em class="arg">string</em></h4> 1094</div> 1095 1096<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> 1097 1098<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> 1099 1100<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> 1101 1102<p>For example,</p> 1103 1104<p class="crtsnip"> 1105 -comment "%m:%f %wx%h" 1106</p> 1107 1108<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> 1109 1110<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> 1111 1112<div style="margin: auto;"> 1113 <h4><a name="compose" id="compose"></a>-compose <em class="arg">operator</em></h4> 1114</div> 1115 1116<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> 1117 1118<p>The description of composition uses abstract terminology in order to allow 1119the description to be more precise, while avoiding constant values which are 1120specific to a particular build configuration. Each image pixel is represented 1121by red, green, and blue levels (which are equal for a gray pixel). The 1122build-dependent value <em class="QR">QuantumRange</em> is the maximum integral 1123value which may be stored, per pixel, in the red, green, or blue channels of 1124the image. Each image pixel may also optionally (if the image matte channel is 1125enabled) have an associated level of opacity, ranging from <em>opaque</em> to 1126<em>transparent</em>, which may be used to determine the influence of the pixel 1127color when compositing the pixel with another image pixel. If the image matte 1128channel is disabled, then all pixels in the image are treated as opaque. The 1129color of an opaque pixel is fully visible while the color of a transparent 1130pixel color is entirely absent (pixel color is ignored).</p> 1131 1132<p>By definition, raster images have a rectangular shape. All image rows are of 1133equal length, as are all image columns. By treating the alpha channel as a 1134visual "mask" the rectangular image may be given a "shape" by treating the 1135alpha channel as a cookie-cutter for the image. This is done by setting the 1136pixels within the shape to be opaque, with pixels outside the shape set as 1137transparent. Pixels on the boundary of the shape may be between opaque and 1138transparent in order to provide antialiasing (visually smooth edges). The 1139description of the composition operators use this concept of image "shape" in 1140order to make the description of the operators easier to understand. While it 1141is convenient to describe the operators in terms of "shapes" they are by no 1142means limited to mask-style operations since they are based on continuous 1143floating-point mathematics rather than simple boolean operations.</p> 1144 1145<p>The following alpha blending (Duff-Porter) compose methods are available:</p> 1146 1147<table class="doc"> 1148 <tbody> 1149 <tr valign="top"> 1150 <th align="left" style="width: 8%">Method</th> 1151 <th align="left">Description</th> 1152 </tr> 1153 1154 <tr valign="top"> 1155 <td valign="top">clear</td> 1156 <td valign="top">Both the color and the alpha of the destination are 1157 cleared. Neither the source nor the destination are used (except for 1158 destinations size and other meta-data which is always preserved.</td> 1159 </tr> 1160 1161 <tr valign="top"> 1162 <td valign="top">src</td> 1163 <td valign="top">The source is copied to the destination. The destination 1164 is not used as input, though it is cleared.</td> 1165 </tr> 1166 1167 <tr valign="top"> 1168 <td valign="top">dst</td> 1169 <td valign="top">The destination is left untouched. The source image is 1170 completely ignored.</td> 1171 </tr> 1172 1173 <tr valign="top"> 1174 <td valign="top">src-over</td> 1175 <td valign="top">The source is composited over the destination. this is 1176 the default alpha blending compose method, when neither the compose 1177 setting is set, nor is set in the image meta-data.</td> 1178 </tr> 1179 1180 <tr valign="top"> 1181 <td valign="top">dst-over</td> 1182 <td valign="top">The destination is composited over the source and the 1183 result replaces the destination.</td> 1184 </tr> 1185 1186 <tr valign="top"> 1187 <td valign="top">src-in</td> 1188 <td valign="top">The part of the source lying inside of the destination 1189 replaces the destination.</td> 1190 </tr> 1191 1192 <tr valign="top"> 1193 <td valign="top">dst-in</td> 1194 <td valign="top">The part of the destination lying inside of the source 1195 replaces the destination. Areas not overlaid are cleared.</td> 1196 </tr> 1197 1198 <tr valign="top"> 1199 <td valign="top">src-out</td> 1200 <td valign="top">The part of the source lying outside of the destination 1201 replaces the destination.</td> 1202 </tr> 1203 1204 <tr valign="top"> 1205 <td valign="top">dst-out</td> 1206 <td valign="top">The part of the destination lying outside of the source 1207 replaces the destination.</td> 1208 </tr> 1209 1210 <tr valign="top"> 1211 <td valign="top">src-atop</td> 1212 <td valign="top">The part of the source lying inside of the destination is 1213 composited onto the destination.</td> 1214 </tr> 1215 1216 <tr valign="top"> 1217 <td valign="top">dst-atop</td> 1218 <td valign="top">The part of the destination lying inside of the source is 1219 composited over the source and replaces the destination. Areas not 1220 overlaid are cleared. </td> 1221 </tr> 1222 1223 <tr valign="top"> 1224 <td valign="top">xor</td> 1225 <td valign="top">The part of the source that lies outside of the 1226 destination is combined with the part of the destination that lies 1227 outside of the source. Source or Destination, but not both. </td> 1228 </tr> 1229 1230 </tbody> 1231</table> 1232 1233<p>Any of the 'Src-*' methods can also be specified without the 'Src-' part. 1234For example the defaul compose method can be specified as just 'Over'.</p> 1235 1236 1237<p>The following mathemathical composition methods are also available. </p> 1238 1239<p>Typically these use the default 'Over' alpha blending when transparencies 1240are also involved, except for 'Plus', 'Minus', 'Add', and 'Subtract', which 1241also composes the alpha channel using the same process as the color channels. 1242This allows them to be used for special image masking techniques. </p> 1243 1244<table class="doc"> 1245 <tbody> 1246 <tr valign="top"> 1247 <th align="left" style="width: 8%">Method</th> 1248 <th align="left">Description</th> 1249 </tr> 1250 1251 <tr valign="top"> 1252 <td valign="top">multiply</td> 1253 <td valign="top">The source is multiplied by the destination and replaces the destination. The resultant color is always at least as dark as either of the two constituent colors. Multiplying any color with black produces black. Multiplying any color with white leaves the original color unchanged.</td> 1254 </tr> 1255 1256 <tr valign="top"> 1257 <td valign="top">screen</td> 1258 <td valign="top">The source and destination are complemented and then multiplied and then replace the destination. The resultant color is always at least as light as either of the two constituent colors. Screening any color with white produces white. Screening any color with black leaves the original color unchanged.</td> 1259 </tr> 1260 1261 <tr valign="top"> 1262 <td valign="top">plus</td> 1263 <td valign="top">The source is added to the destination and replaces the 1264 destination. This operator is useful for averaging or a controled 1265 merger of two images, rather than a direct overlay.</td> 1266 </tr> 1267 1268 <tr valign="top"> 1269 <td valign="top">add</td> 1270 <td valign="top">As per 'plus' but transparency data is treated as matte 1271 values. As such any transparent areas in either image remain 1272 transparent. </td> 1273 </tr> 1274 1275 <tr valign="top"> 1276 <td valign="top">minus</td> 1277 <td valign="top">Subtract the colors in the source image from the 1278 destination image. When transparency is involved, opaque areas is 1279 subtracted from any destination opaque areas. </td> 1280 </tr> 1281 1282 <tr valign="top"> 1283 <td valign="top">subtract</td> 1284 <td valign="top">Subtract the colors in the source image from the 1285 destination image. When transparency is involved transparent areas are 1286 subtracted, so only the opaque areas in the source remain opaque in 1287 the destination image. </td> 1288 </tr> 1289 1290 <tr valign="top"> 1291 <td valign="top">difference</td> 1292 <td valign="top">Subtracts the darker of the two constituent colors from 1293 the lighter. Painting with white inverts the destination color. 1294 Painting with black produces no change.</td> 1295 </tr> 1296 1297 <tr valign="top"> 1298 <td valign="top">exclusion</td> 1299 <td valign="top">Produces an effect similar to that of 'difference', but 1300 appears as lower contrast. Painting with white inverts the 1301 destination color. Painting with black produces no change.</td> 1302 </tr> 1303 1304 <tr valign="top"> 1305 <td valign="top">darken</td> 1306 <td valign="top">Selects the darker of the destination and source colors. 1307 The destination is replaced with the source when the source is darker, 1308 otherwise it is left unchanged.</td> 1309 </tr> 1310 1311 <tr valign="top"> 1312 <td valign="top">lighten</td> 1313 <td valign="top">Selects the lighter of the destination and source colors. 1314 The destination is replaced with the source when the source is 1315 lighter, otherwise it is left unchanged. </td> 1316 </tr> 1317 1318 <tr valign="top"> 1319 <td valign="top">linear-dodge</td> 1320 <td valign="top">This is equivelent to 'Plus' in that the color channels 1321 are simply added, however it does not 'Plus' the alpha channel, but 1322 uses the normal 'Over' alpha blending, which transparencies are 1323 involved. Produces a sort of additive multiply-like result. Added 1324 ImageMagick version 6.5.4-3. </td> 1325 </tr> 1326 1327 <tr valign="top"> 1328 <td valign="top">linear-burn</td> 1329 <td valign="top">As 'Linear-Dodge', but also subtract one from the result. 1330 Sort of a additive 'Screen' of the images. Added ImageMagick version 1331 6.5.4-3. </td> 1332 </tr> 1333 1334 <tr valign="top"> 1335 <td valign="top">color-dodge</td> 1336 <td valign="top">Brightens the destination color to reflect the source 1337 color. Painting with black produces no change.</td> 1338 </tr> 1339 1340 <tr valign="top"> 1341 <td valign="top">color-burn</td> 1342 <td valign="top">Darkens the destination color to reflect the source 1343 color. Painting with white produces no change. Fixed in ImageMagick 1344 version 6.5.4-3. </td> 1345 </tr> 1346 1347 <tr valign="top"> 1348 <td valign="top">overlay</td> 1349 <td valign="top">Multiplies or screens the colors, dependent on the 1350 destination color. Source colors overlay the destination whilst 1351 preserving its highlights and shadows. The destination color is not 1352 replaced, but is mixed with the source color to reflect the lightness 1353 or darkness of the destination.</td> 1354 </tr> 1355 1356 <tr valign="top"> 1357 <td valign="top">hard-light</td> 1358 <td valign="top">Multiplies or screens the colors, dependent on the source 1359 color value. If the source color is lighter than 0.5, the destination 1360 is lightened as if it were screened. If the source color is darker 1361 than 0.5, the destination is darkened, as if it were multiplied. The 1362 degree of lightening or darkening is proportional to the difference 1363 between the source color and 0.5. If it is equal to 0.5 the 1364 destination is unchanged. Painting with pure black or white produces 1365 black or white.</td> 1366 </tr> 1367 1368 1369 <tr valign="top"> 1370 <td valign="top">linear-light</td> 1371 <td valign="top">Like 'Hard-Light' but using linear-dodge and linear-burn 1372 instead. Increases contrast slightly with an impact on the 1373 foreground's tonal values.</td> 1374 </tr> 1375 1376 <tr valign="top"> 1377 <td valign="top">soft-light</td> 1378 <td valign="top">Darkens or lightens the colors, dependent on the source 1379 color value. If the source color is lighter than 0.5, the destination 1380 is lightened. If the source color is darker than 0.5, the destination 1381 is darkened, as if it were burned in. The degree of darkening or 1382 lightening is proportional to the difference between the source color 1383 and 0.5. If it is equal to 0.5, the destination is unchanged. Painting 1384 with pure black or white produces a distinctly darker or lighter area, 1385 but does not result in pure black or white. Fixed in ImageMagick 1386 version 6.5.4-3. </td> 1387 </tr> 1388 1389 <tr valign="top"> 1390 <td valign="top">pegtop-light</td> 1391 <td valign="top">Almost equivelent to 'Soft-Light', but using a 1392 continuious mathematical formula rather than two conditionally 1393 selected formulae. Added ImageMagick version 6.5.4-3. </td> 1394 </tr> 1395 1396 <tr valign="top"> 1397 <td valign="top">vivid-light</td> 1398 <td valign="top">A modified 'Linear-Light' designed to preserve very stong 1399 primary and secondary colors in the image. Added ImageMagick version 1400 6.5.4-3. </td> 1401 </tr> 1402 1403 <tr valign="top"> 1404 <td valign="top">pin-light</td> 1405 <td valign="top">Similar to 'Hard-Light', but using sharp linear shadings, 1406 to similate the effects of a strong 'pinhole' light source. Added 1407 ImageMagick version 6.5.4-3. </td> 1408 </tr> 1409 1410 </tbody> 1411</table> 1412 1413 1414<p>Also included are these special purpose compose methods:</p> 1415 1416<table class="doc"> 1417 <tbody> 1418 <tr valign="top"> 1419 <th align="left" style="width: 8%">Method</th> 1420 <th align="left">Description</th> 1421 </tr> 1422 1423 <tr valign="top"> 1424 <td valign="top">copy-*</td> 1425 <td valign="top">Copy the specified channel (Red, Green, Blue, Cyan, 1426 Magenta, Yellow, Black, or Opacity) in the source image to the 1427 same channel in the destination image. If the channel specified 1428 does not exist in the source image, (which can only happen for methods, 1429 '<kbd>copy-opacity</kbd>' or '<kbd>copy-black</kbd>') then it is 1430 assumed that the source image is a special grayscale channel image 1431 of the values to be copied. </td> 1432 </tr> 1433 1434 <tr valign="top"> 1435 <td valign="top">change-mask</td> 1436 <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> 1437 </tr> 1438 </tbody> 1439</table> 1440 1441<p>On top of these composed methods are a few special ones that not only require 1442the two images that are being merged or overlaid, but have some extra numerical 1443arguments, which are tabled below. </p> 1444 1445<p>In the "<code>composite</code>" command these composition methods are 1446selected using special options with the arguments needed. They are usually, 1447but not always, the same name as the composte 'method' they use, and replaces 1448the normal use of the <a href="#compose" >-compose</a> setting in the 1449"<code>composite</code>" command. For example... </p> 1450 1451<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>composite ... -blend 50x50 ...</span></p> 1452<p>As of IM v6.5.3-4 the "<code>convert</code>" command can now also supply 1453these extra arguments to its <a href="#composite" >-composite</a> operator, 1454using the special <a href="#set">-set</a> attribute of '<kbd class="arg">option:compose:args</kbd>'. This means you can now make use of 1455these special argumented <a href="#compose" >-compose</a> methods, those the 1456argument and the method both need to be set separatally. For example... </p> 1457 1458<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert ... -compose blend -set option:compose:args 50x50 -composite ...</span></p> 1459<p>The following is a table of these special 'argumented' compose methods, 1460with a brief summary of what they do. For more details see the equivalent 1461"composite" command option name. </p> 1462 1463<table class="doc"> 1464 <tbody> 1465 <tr valign="top"> 1466 <th align="left" style="width: 8%">Method</th> 1467 <th align="left">Description</th> 1468 </tr> 1469 1470 <tr valign="top"> 1471 <td valign="top">dissolve</td> 1472 <td valign="top">Arguments: 1473 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>] 1474 <br>Equivalent to "<code>composite</code>" <a href="#dissolve">-dissolve</a> 1475 <br>Dissolve the 'source' image by the percentage given before overlaying 1476 'over' the 'destination' image. If <em class="arg">src_percent</em> is 1477 greater than 100, it starts dissolving the main image so it will 1478 become transparent at a value of '<kbd class="arg">200</kbd>'. If 1479 both percentages are given, each image are dissolved to the 1480 percentages given. 1481 </td> 1482 </tr> 1483 1484 <tr valign="top"> 1485 <td valign="top">blend</td> 1486 <td valign="top">Arguments: 1487 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>] 1488 <br>Equivalent to "<code>composite</code>" <a href="#blend">-blend</a> 1489 <br>Average the images together ('plus') according to the percentages 1490 given and each pixels transparency. If only a single percentage value 1491 is given it sets the weight of the composite or 'source' image, while 1492 the background image is weighted by the exact opposite amount. That is 1493 a <kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of 1494 the 'destination' image. Thus it is equivalent to <kbd>-blend 1495 30x70</kbd>. 1496 </td> 1497 </tr> 1498 1499 <tr valign="top"> 1500 <td valign="top">mathematics</td> 1501 <td valign="top">Arguments: <em class="arg">A, B, C, D</em> 1502 <br>Not available in "<code>composite</code>" at this time. 1503 <br>Merge the source and destination images according to the formula 1504 <br> <code>A*Sc*Dc + B*Sc + C*Dc + D</code> 1505 <br>Can be used to generate a custom composition method that would 1506 otherwise need to be implemented using the slow <a href="#fx">-fx</a> 1507 DIY image operator. Added to ImageMagick version 6.5.4-3. 1508 </td> 1509 </tr> 1510 1511 <tr valign="top"> 1512 <td valign="top">modulate</td> 1513 <td valign="top">Arguments: 1514 <em class="arg">brightness</em>[x<em class="arg">saturation</em>] 1515 <br>Equivalent to "<code>composite</code>" <a href="#watermark">-watermark</a> 1516 <br>Take a grayscale image (with alpha mask) and modify the destination 1517 image's brightness according to watermark image's grayscale value and 1518 the <em class="arg">brightness</em> percentage. The destinations 1519 color saturation attribute is just direct modified by the <em 1520 class="arg">saturation</em> percentage, which defaults to 100 percent 1521 (no color change). 1522 1523 </td> 1524 </tr> 1525 1526 <tr valign="top"> 1527 <td valign="top">displace</td> 1528 <td valign="top">Arguments: 1529 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em>][!][%] 1530 <br>Equivalent to "<code>composite</code>" <a href="#displace">-displace</a> 1531 <br>With this option, the 'overlay' image, and optionally the 'mask' 1532 image, is used as a relative displacement map, which is used to 1533 displace the lookup of what part of the destination image is seen at 1534 each point of the overlaid area. Much like the displacement map is a 1535 'lens' that distorts the original 'background' image behind it. 1536 <br><br> 1537 The X-scale is modilated by the 'red' channel of the overlay image 1538 while the Y-scale is modulated by the green channel, (the mask image 1539 if given is rolled into green channel of the overlay image. This 1540 separation allows you to modulate the X and Y lookup displacement 1541 separatally allowing you to di 2 dimentional displacements, rather 1542 than 1 dimentional verctored displacements (using grayscale image). 1543 <br><br> 1544 If the overlay image contains transparency this is used as a mask 1545 of the resulting image to remove 'invalid' pixels. 1546 <br><br> 1547 The '%' flag makes the displacement scale relative to the size of the 1548 overlay image (100% = half width/height of image). Using '!' switches 1549 percentage arguments to refer to the destination image size instead. 1550 <br><br> 1551 Special flags were added Added to ImageMagick version 6.5.3-5. 1552 </td> 1553 </tr> 1554 1555 <tr valign="top"> 1556 <td valign="top">distort</td> 1557 <td valign="top">Arguments: 1558 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em 1559 >[+<em class="arg">X-center</em>+<em class="arg">Y-center</em>]][!][%] 1560 <br>Not available in "<code>composite</code>" at this time. 1561 <br>Exactly as per 'Displace' (above), but using absolute coordinates, 1562 relative to the center of the overlay (or that given). Basically 1563 allows you to generate absolute distortion maps where 'black' will 1564 look up the left/top edge, and 'white' looks up the bottom/right 1565 edge of the destination image, according to the scale given. 1566 <br><br> 1567 The '!' flag not only switches percentage scaling, to use the 1568 destination image, but also the image the center offset of the lookup. 1569 This means the overlay can lookup a completely different region of the 1570 destination image. 1571 <br><br> 1572 Added to ImageMagick version 6.5.3-5. 1573 </td> 1574 </tr> 1575 1576 <tr valign="top"> 1577 <td valign="top">blur</td> 1578 <td valign="top">Arguments: 1579 <em class="arg">Width</em>[x<em class="arg">Height</em 1580 >[+<em class="arg">Angle</em>]] 1581 <br>Equivalent to "<code>composite</code>" 1582 <a href="#blur-composite">-blur</a> 1583 <br>A Variable Blur Mapping Composition method, where each pixel in the 1584 overlaid region is replaced with an Elliptical Weighted Average (EWA), 1585 with an ellipse (typically a circle) of the given sigma size, scaled 1586 according to overlay (source image) grayscale mapping. 1587 <br><br> 1588 As per 'Displace' and 'Distort', the red channel will modulate the 1589 width of the ellipse, while the green channel will modulate the height 1590 of the ellipse. However at this time the ellipse angle is not 1591 modulated though this may be a future posibility (perhaps with a 1592 special flag to enable use of blur channel for this purpose). 1593 <br><br> 1594 Added to ImageMagick version 6.5.4-0. 1595 </td> 1596 </tr> 1597 1598 </tbody> 1599</table> 1600 1601<p>To print a complete list of all the available compose operators, use <a href="#list">-list compose</a>.</p> 1602 1603 1604<div style="margin: auto;"> 1605 <h4><a name="composite" id="composite"></a>-composite</h4> 1606</div> 1607 1608<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> 1609 1610<p>Take the first image 'destination' and overlay the second 'source' image 1611according to the current <a href="#compose">-compose</a> setting. The location 1612of the 'source' or 'overlay' image is controlled according to <a 1613href="#geometry" >-geometry</a>, and <a href="#geometry" >-geometry</a> 1614settings. </p> 1615 1616<p>If a third image is given this is treated as a gray-scale 'mask' image 1617relative to the first 'destination' image. This mask will limit what parts of 1618the destination can be modified by the image composition. However for the 1619'<kbd>displace</kbd>' compose method, the mask is used to provide a separate 1620Y-displacement image instead. </p> 1621 1622<p>If a <a href="#compose">-compose</a> method requires extra numerical 1623arguments or flags these can be provided by setting the <a 1624href="#set">-set</a> '<kbd class="arg">option:compose:args</kbd>' 1625appropriatally for the compose method. </p> 1626 1627<p>Some <a href="#compose">-compose</a> methods can modify the 'destination' 1628image outside the overlay area. You can disable this by setting the special <a 1629href="#set">-set</a> '<kbd class="arg">option:compose:outside-overlay</kbd>' 1630to '<kbd>false</kbd>'. </p> 1631 1632 1633<div style="margin: auto;"> 1634 <h4><a name="compress" id="compress"></a>-compress <em class="arg">type</em></h4> 1635</div> 1636 1637<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> 1638 1639<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> 1640 1641<p>To print a complete list of compression types, use <a href="#list">-list compress</a>.</p> 1642 1643<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> 1644 1645<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> 1646 1647<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> 1648 1649<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> 1650 1651<div style="margin: auto;"> 1652 <h4><a name="contrast" id="contrast"></a>-contrast</h4> 1653</div> 1654 1655<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> 1656 1657<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> 1658 1659<p>For a more pronounced effect you can repeat the option:</p> 1660 1661<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -contrast -contrast rose_c2.png</span></p> 1662<div style="margin: auto;"> 1663 <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> 1664</div> 1665 1666<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> 1667 1668<p>While performing the stretch, black-out at most <em 1669class="arg" >black-point</em> pixels and white-out at most <em 1670class="arg" >white-point</em> pixels. Or, if percent is used, black-out at most 1671<em class="arg" >black-point %</em> pixels and white-out at most <em 1672class="arg" >white-point %</em> pixels.</p> 1673 1674<p>Prior to ImageMagick 6.4.7-0, <a href="#contrast-stretch" 1675>-contrast-stretch</a> will black-out at most <em class="arg" 1676>black-point</em> pixels and white-out at most <em class="arg" >total pixels 1677minus white-point</em> pixels. Or, if percent is used, black-out at most <em 1678class="arg">black-point %</em> pixels and white-out at most <em class="arg" 1679>100% minus white-point %</em> pixels.</p> 1680 1681<p>Note that <kbd>-contrast-stretch 0</kbd> will modify the image such that 1682the image's min and max values are stretched to 0 and <em class="QR" 1683>QuantumRange</em>, respectively, without any loss of data due to burn-out or 1684clipping at either end. This is not the same as <a href="#normalize" 1685>-normalize</a>, which is equivalent to <kbd>-contrast-stretch 2%x1%</kbd> (or 1686prior to ImageMagick 6.4.7-0, <kbd>-contrast-stretch 2%x99%</kbd>).</p> 1687 1688<p>Internally operator works by creating a histogram bin, and then uses that 1689bin to modify the image. As such some colors may be merged together when they 1690originally fell into the same 'bin'. </p> 1691 1692<p>All the channels are normalized in concert by the came amount so as to 1693preserve color integrity, when the default <a href="#channel" >+channel</a> 1694setting is in use. Specifing any other <a href="#channel" >-channel</a> 1695setting will normalize the RGB channels independently.</p> 1696 1697<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 1698normalization of mathematical images. </p> 1699 1700<p>This operator is under review for re-development. </p> 1701 1702 1703<div style="margin: auto;"> 1704 <h4><a name="convolve" id="convolve"></a>-convolve <em class="arg">kernel</em></h4> 1705</div> 1706 1707<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> 1708 1709<p>The <em class="arg">kernel</em> is a square matrix specified as 1710a comma-separated list of integers (with no spaces), ordered left-to right, 1711starting with the top row. Presently, only odd-dimensioned kernels are 1712supported, and therefore the number of entries in the specified <em 1713class="arg">kernel</em> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25, 17147<sup>2</sup>=49, etc. </p> 1715 1716<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 1717positive and negative results are relative to a user-specified bias value. 1718This is important for non-HDRI compilations of ImageMagick when dealing with 1719convolutions that contain negative as well as positive values. This is 1720especially the case with convolutions involving high pass filters or edge 1721detection. Without an output bias, the negative values is clipped at zero. 1722</p> 1723 1724<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 1725negative results without clipping to the color value range (0..QuantumRange). 1726See the discussion on HDRI implementations of ImageMagick on the page <a 1727href="/www/high-dynamic-range.html">High 1728Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a 1729href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this 1730<a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> 1731entry. </p> 1732 1733 1734<div style="margin: auto;"> 1735 <h4><a name="crop" id="crop"></a>-crop <em class="arg">geometry</em></h4> 1736</div> 1737 1738<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> 1739 1740<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> 1741 1742<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> 1743 1744<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> 1745 1746<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> 1747 1748<p>By adding a exclamation character flag to the geometry argument, the 1749cropped images virtual canvas page size and offset is set as if the 1750geometry argument was a viewport or window. This means the canvas page size 1751is set to exactly the same size you specified, the image offset set 1752relative top left corner of the region cropped. </p> 1753 1754<p>If the cropped image 'missed' the actual image on its virtual canvas, a 1755special single pixel transparent 'missed' image is returned, and a 'crop 1756missed' warning given. </p> 1757 1758<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> 1759 1760<div style="margin: auto;"> 1761 <h4><a name="cycle" id="cycle"></a>-cycle <em class="arg">amount</em></h4> 1762</div> 1763 1764<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> 1765 1766<p><em class="arg">Amount</em> defines the number of positions each 1767colormap entry is shifted.</p> 1768 1769 1770<div style="margin: auto;"> 1771 <h4><a name="debug" id="debug"></a>-debug <em class="arg">events</em></h4> 1772</div> 1773 1774<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> 1775 1776<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> 1777 1778 1779<p>For example, to log cache and blob events, use.</p> 1780 1781<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p> 1782<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p> 1783 1784<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p> 1785 1786<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p> 1787 1788<p>Use <a href="#debug">+debug</a> to turn off all logging.</p> 1789 1790<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> 1791 1792 1793<div style="margin: auto;"> 1794 <h4><a name="decipher" id="decipher"></a>-decipher <em class="arg">filename</em></h4> 1795</div> 1796 1797<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> 1798 1799<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 1800 1801<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 1802 1803 1804<div style="margin: auto;"> 1805 <h4><a name="deconstruct" id="deconstruct"></a>-deconstruct</h4> 1806</div> 1807 1808<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> 1809 1810<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> 1811 1812<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> 1813 1814<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p> 1815 1816 1817<div style="margin: auto;"> 1818 <h4><a name="define" id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4> 1819</div> 1820 1821<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> 1822 1823<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> 1824 1825<p>The following definitions may be created:</p> 1826 1827<ul> 1828<dt>jpeg:size=geometry</dt> 1829 <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 /> 1830<dt>jp2:rate=value</dt> 1831 <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 /> 1832<dt>mng:need-cacheoff</dt> 1833 <dd>turn playback caching off for streaming MNG.</dd><br /> 1834<dt>png:bit-depth=value</dt> 1835<dt>png:color-type=value</dt> 1836 <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 /> 1837<dt>ps:imagemask</dt> 1838 <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> 1839</ul> 1840 1841<p>For example, to create a postscript file that will render only the black pixels of a bilevel image, use:</p> 1842 1843<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p> 1844<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> 1845 1846<p class="crtsnip"> 1847-define registry:temporary-path=/data/tmp 1848</p> 1849 1850<div style="margin: auto;"> 1851 <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> 1852</div> 1853 1854<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> 1855 1856<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> 1857 1858<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> 1859 1860 1861<div style="margin: auto;"> 1862 <h4><a name="delete" id="delete"></a>-delete <em class="arg">index</em></h4> 1863</div> 1864 1865<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> 1866 1867<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> 1868 1869 1870<div style="margin: auto;"> 1871 <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> 1872</div> 1873 1874<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> 1875 1876<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> 1877 1878<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> 1879 1880<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> 1881 1882<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> 1883 1884<div style="margin: auto;"> 1885 <h4><a name="depth" id="depth"></a>-depth <em class="arg">value</em></h4> 1886</div> 1887 1888<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> 1889 1890<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> 1891 1892<div style="margin: auto;"> 1893 <h4><a name="descend" id="descend"></a>-descend</h4> 1894</div> 1895 1896<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> 1897 1898<div style="margin: auto;"> 1899 <h4><a name="deskew" id="deskew"></a>-deskew <em class="arg">threshold</em></h4> 1900</div> 1901 1902<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> 1903 1904<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> 1905 1906<div style="margin: auto;"> 1907 <h4><a name="despeckle" id="despeckle"></a>-despeckle</h4> 1908</div> 1909 1910<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> 1911 1912<div style="margin: auto;"> 1913 <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> 1914</div> 1915 1916<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> 1917 1918<p>With this option, the 'overlay' image, and optionally the 'mask' image, 1919will be used as a displacement map, which is used to displace the lookup of 1920what part of the 'background' image is seen at each point of the overlaid 1921area. Much like the displacement map is a 'lens' that redirects light shining 1922through it so as to present a distorted view the original 'background' image 1923behind it. </p> 1924 1925<p>Any perfect grey areas of the displacement map produce a zero 1926displacement of the image. Black areas produce the given maximum negative 1927displacement of the lookup point, while white produce a maximum positive 1928displacement of the lookup. </p> 1929 1930<p>Note that it is the lookup of the 'background' that is displaced, not a 1931displacement of the image itself. As such an area of the displacement map 1932containing 'white' will have the lookup point 'shifted' by a positive amount, 1933and thus generating a copy of the destination image to the right/downward from 1934the correct position. That is the image will look like it may have been 1935'shifted' in a negative left/upward direction. Understanding this is a very 1936important in understanding how displacement maps work. </p> 1937 1938<p>The given arguments define the maximum amount of displacement in pixels 1939that a particular map can produce. If the displacement scale is large enough 1940it is also posible to lookup parts of the 'background' image that lie well 1941outside the bounds of the displacement map itself. That is you could very 1942easilly copy a section of the original image from outside the overlay area 1943into the overlay area. </p> 1944 1945<p>The '%' flag makes the displacement scale relative to the size of the 1946overlay image (100% = half width/height of image). Using '!' switches 1947percentage arguments to refer to the destination image size instead. 1948these flags were added as of IM v6.5.3-5.</p> 1949 1950<p>Normally a single grayscale displacement map is provided, which with the 1951given scaling values will determine a single direction (vector) in which 1952displacements can occur (positivally or negativally). However, if you also 1953specify a third image which is normally used as a <em class="arg">mask</em>, 1954then the <em class="arg">composite image</em> will be used for horizontal X 1955displacement, while the <em class="arg">mask image</em> is used for vertical Y 1956displacement. This allows you to define completely different displacement 1957values for the X and Y directions, and allowing you to lookup any point within 1958the <em class="arg">scale</em> bounds. In other words each pixel can lookup 1959any other nearby pixel, producing complex 2 dimentional displacements, rather 1960than a simple 1 dimentional vector displacements. </p> 1961 1962<p>Alternativally rather than suppling two separate images, as of IM v6.4.4-0, 1963you can use the 'red' channel of the overlay image to specify the horizontal 1964or X displacement, and the 'green' channel for the vertical or Y displacement. 1965</p> 1966 1967<p>As of IM v6.5.3-5 any alpha channel in the overlay image will be used as a 1968mask the transparency of the destination image. However areas outside the 1969overlaid areas will not be effected. </p> 1970 1971 1972<div style="margin: auto;"> 1973 <h4><a name="display" id="display"></a>-display <em class="arg">host:display[.screen]</em></h4> 1974</div> 1975 1976<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> 1977 1978<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p> 1979 1980<div style="margin: auto;"> 1981 <h4><a name="dispose" id="dispose"></a>-dispose <em class="arg">method</em></h4> 1982</div> 1983 1984<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> 1985 1986<p>The layer disposal method defines the way each the displayed image is to be 1987modified after the current 'frame' of an animation has finished being 1988displayed (after its 'delay' period), but before the next frame on an 1989animation is to be overlaid onto the display. </p> 1990 1991<p>Here are the valid methods:</p> 1992 1993<pre class="text"> 1994Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>'). 1995None 1 Do not dispose, just overlay next frame image. 1996Background 2 Clear the frame area with the background color. 1997Previous 3 Clear to the image prior to this frames overlay. 1998</pre> 1999 2000<p>You can also use the numbers given above, which is what the GIF format 2001uses internally to represent the above settings. </p> 2002 2003<p>To print a complete list of dispose methods, use <a href="#list">-list dipose</a>.</p> 2004 2005<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent 2006resetting the layer disposal methods of images being read in. </p> 2007 2008<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image 2009disposal method for images already in memory.</p> 2010 2011<div style="margin: auto;"> 2012 <h4><a name="dissimilarity-threshold" id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4> 2013</div> 2014 2015<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> 2016 2017 2018<div style="margin: auto;"> 2019 <h4><a name="dissolve" id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4> 2020</div> 2021 2022<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> 2023 2024<p>The opacity of the composite image is multiplied by the given percent, then 2025it is composited 'over' the main image. If <em class="arg">src_percent</em> 2026is greater than 100, start dissolving the main image so it will become 2027transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages 2028are given, each image are dissolved to the percentages given. </p> 2029 2030<p>Note that dissolve percentages do not add, two opaque images dissolved 2031'50,50', produce a 75% transparency. For a 50% + 50% blending of the two 2032images, you would need to use dissolve values of '50,100'. </p> 2033 2034<div style="margin: auto;"> 2035 <h4><a name="distort" id="distort"></a>-distort <em class="arg">method arguments</em></h4> 2036</div> 2037 2038<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> 2039 2040<p>The <em class="arg">arguments</em> is a single string containing a list 2041of floating point numbers separated by commas or spaces. The number of 2042and meaning of the floating point values depends on the distortion <em 2043class="arg">method</em> being used. </p> 2044 2045<p>Choose from these distortion types:</p> 2046 2047<table class="doc"> 2048 <tr valign="top"> 2049 <th align="left" style="width: 8%">Method</th> 2050 <th align="left">Description</th> 2051 </tr> 2052 2053 <tr valign="top"> 2054 <td valign="top"><kbd>ScaleRotateTranslate</kbd> 2055 <br/>or <kbd>SRT</kbd></td> 2056 <td valign="top"> 2057 Distort image by first scaling and rotating about a given 'center', 2058 before translating that 'center' to the new location, in that order. It 2059 is an alternative method of specifying a '<kbd>Affine</kbd>' type of 2060 distortion, but without shearing effects. It also provides a good way 2061 of rotating and displacing a smaller image for tiling onto a larger 2062 background (IE 2-dimensional animations). <br/> 2063 2064 The number of arguments determine the specific meaning of each 2065 argument for the scales, rotation, and translation operations. <br/> 2066 2067 <table style="margin-left:auto; margin-right:auto;"> 2068 <tr><td># </td><td>arguments meaning</td></tr> 2069 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr> 2070 <tr><td>2:</td><td><em>Scale Angle</em></td></tr> 2071 <tr><td>3:</td><td><em>ScaleX,ScaleY Angle</em></td></tr> 2072 <tr><td>4:</td><td><em>X,Y Scale Angle</em></td></tr> 2073 <tr><td>5:</td> 2074 <td><em>X,Y ScaleX,ScaleY Angle</em></td></tr> 2075 <tr><td>6:</td> 2076 <td><em>X,Y Scale Angle NewX,NewY</em></td></tr> 2077 <tr><td>7:</td> 2078 <td><em>X,Y ScaleX,ScaleY Angle 2079 NewX,NewY</em></td></tr> 2080 </table> 2081 2082 This is actually an alternative way of specifing a 2 dimensional linear 2083 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr> 2084 2085 <tr valign="top"> 2086 <td valign="top"><kbd>Affine</kbd></td> 2087 <td valign="top"> 2088 Distort the image linearly by moving a list of at least 3 or more sets 2089 of control points (as defined below). Idealy 3 sets or 12 floating 2090 point values are given allowing the image to be linearly scaled, 2091 rotated, sheared, and translated, according to those three points. See 2092 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>' 2093 distortions. <br/> 2094 2095 More than 3 sets given control point pairs (12 numbers) is least 2096 squares fitted to best match a lineary affine distortion. If only 2 2097 control point pairs (8 numbers) are given a two point image translation 2098 rotation and scaling is performed, without any posible shearing, 2099 flipping or changes in aspect ratio to the resulting image. If only one 2100 control point pair is provides the image is only translated, (which may 2101 be a floating point non-integer translation). <br/> 2102 2103 This distortion does not include any form of perspective distortion. 2104 </td> 2105 2106 </tr> 2107 2108 <tr valign="top"> 2109 <td valign="top"><kbd>AffineProjection</kbd></td> 2110 <td valign="top"> 2111 Linearly distort an image using the given Affine Matrix of 6 2112 pre-calculated coefficients forming a set of Affine Equations to map 2113 the source image to the destination image. 2114 2115 <div style="text-align: center"><em> 2116 s<sub>x</sub>, r<sub>x</sub>, 2117 r<sub>y</sub>, s<sub>y</sub>, 2118 t<sub>x</sub>, t<sub>y</sub> 2119 </em></div> 2120 2121 See <a href="#affine" >-affine</a> setting for more detail, and 2122 meanings of these coefficients. <br/> 2123 2124 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide 2125 alternative methods of defining this distortion, with ImageMagick doing the 2126 calculations needed to generate the required coefficients. You can see 2127 the internally generated coefficients, by using a <a href="#verbose" 2128 >-verbose</a> setting. </td> 2129 2130 </tr> 2131 2132<!-- still under development, do not display - Anthony 2133 <tr valign="top"> 2134 <td valign="top"><kbd>Bilinear</kbd></td> 2135 <td valign="top"> 2136 Bilinear (reversed) Distortion, given a minimum of 4 sets of 2137 coordinate pairs, or 16 values (see below). Not that lines may not 2138 appear straight after distortion, though the distance between 2139 coordinates will remain consistant. </td> 2140 </tr> 2141--> 2142 2143 <tr valign="top"> 2144 <td valign="top"><kbd>Perspective</kbd></td> 2145 <td valign="top"> 2146 Perspective distort the images, using a list of 4 or more sets of 2147 control points (as defined below). More that 4 sets (16 numbers) of 2148 control points provide least squares fitting for more accurate 2149 distortions (for the purposes of image registration and panarama 2150 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>' 2151 linear distortion. <br/> 2152 2153 Perspective Distorted images ensures that straight lines remain 2154 straight, but the scale of the distorted image will vary. The horizon 2155 is anti-aliased, and the 'sky' color may be set using the 2156 <a href="#mattecolor" >-mattecolor</a> setting. </td> 2157 </tr> 2158 2159 <tr valign="top"> 2160 <td valign="top"><kbd>PerspectiveProjection</kbd> </td> 2161 <td valign="top"> 2162 Do a '<kbd>Perspective</kbd>' distortion basied on a set of 8 2163 pre-calculated coefficients. You can get these coefficients by looking 2164 at the <a href="#verbose" >-verbose</a> output of a 2165 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself. 2166 If the last two perspective scaling coefficients are zero, the 2167 remaining 6 represents a transposed 'Affine Matrix'. </td> 2168 2169 </tr> 2170 2171 <tr valign="top"> 2172 <td valign="top"><kbd>Arc</kbd></td> 2173 <td valign="top"> 2174 Arc the image (variation of polar mapping) over the angle given around 2175 a circle. <br/> 2176 <table width="90%" style = "margin-left: auto; margin-right: auto;"> 2177 <tr valign="top"><td>Argument</td> 2178 <td>Meaning</td></tr> 2179 <tr valign="top"><td><em>arc_angle</em></td> 2180 <td>The angle over which to arc the image side-to-side</td></tr> 2181 <tr valign="top"><td><em>rotate_angle</em></td> 2182 <td>Angle to rotate resulting image from vertical center</td></tr> 2183 <tr valign="top"><td><em>top_radius</em></td> 2184 <td>Set top edge of source image at this radius</td></tr> 2185 <tr valign="top"><td><em>bottom_radius</em> </td> 2186 <td>Set bottom edge to this radius (radial scaling)</td></tr> 2187 </table> 2188 2189 The resulting image is always resized to best fit the resulting image, 2190 (as if using <a href="#distort" >+distort</a>) while attempting to 2191 preserve scale and aspect ratio of the original image as much as 2192 possible with the arguments given by the user. All four arguments will 2193 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/> 2194 2195 This a variation of a polar distortion designed to try to preserve the 2196 aspect ratio of the image rather than direct Cartesian to Polar 2197 conversion. </td> 2198 </tr> 2199 2200 <tr valign="top"> 2201 <td valign="top"><kbd>Polar</kbd></td> 2202 <td valign="top"> 2203 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of 2204 the image. that is the height of the input image is mapped to the 2205 radius limits, while the width is wrapped around between the 2206 angle limits. <br/> 2207 2208 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/> 2209 2210 All arguments are optional. With <em>Rmin</em> defaulting to zero, the 2211 center to the center of the image, and the angles going from -180 (top) 2212 to +180 (top). If <em>Rmax</em> is given the special value of 2213 '<code>0</code>', the the distance from the center to the nearest edge 2214 is used for the radius of the output image, which will ensure the whole 2215 image is visible (though scaled smaller). However a special value of 2216 '<code>-1</code>' will use the distance from the center to the furthest 2217 corner, This may 'clip' the corners from the input rectangular image, 2218 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with 2219 the same arguments. <br/> 2220 2221 If the plus form of distort (<a href="#distort" >+distort</a>) is used 2222 output image center will default to <code>0,0</code> of the virtual 2223 canvas, and the image size adjusted to ensure the whole input image is 2224 made visible in the output image on the virtual canvas. </td> 2225 2226 </tr> 2227 2228 <tr valign="top"> 2229 <td valign="top"><kbd>DePolar</kbd></td> 2230 <td valign="top"> 2231 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion 2232 but generates the reverse Polar to Cartesian distortion. <br/> 2233 2234 The special <em>Rmax</em> setting of '<code>0</code>' may however clip 2235 the corners of the input image. However using the special 2236 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner 2237 distance) will ensure the whole distorted image is preserved in the 2238 generated result, so that the same argument to '<kbd>Polar</kbd>' will 2239 reverse the distortion re-producing the original. 2240 2241 Note that as this distortion requires the area resampling of a circular 2242 arc, which can not be handled by the builtin EWA resampling function. 2243 As such the normal EWA filters are turned off. It is recomended some 2244 form of 'super-sampling' image processing technique be used to produce 2245 a high quality result. </td> 2246 2247 </tr> 2248 2249 <tr valign="top"> 2250 <td valign="top"><kbd>Barrel</kbd></td> 2251 <td valign="top"> 2252 Given the four coefficients (A,B,C,D) as defined by <a 2253 href="http://www.all-in-one.ee/~dersch/barrel/barrel.html" >Helmut 2254 Dersch</a>, perform a barrell or pincussion distortion appropriate to 2255 correct radial lens distortions. That is in photographs, make straight 2256 lines straight again. <br/> 2257 2258 Arguments: <em>A B C</em> [ <em>D</em> [ 2259 <em>X</em> , <em>Y</em> ] ] <br/> 2260 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> 2261 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> 2262 [ <em>X</em> , <em>Y</em> ] <br/> 2263 So that it forms the function <br/> 2264 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2265 <em>C</em>*r + <em>D</em> )<br/> 2266 2267 Where <em>X</em>,<em>Y</em> is the optional center of the distortion 2268 (defaulting to the center of the image). <br/> 2269 The second form is typically used to distort images, rather than 2270 correct lens distortions. <br/> 2271 </td> 2272 2273 </tr> 2274 2275 <tr valign="top"> 2276 <td valign="top"><kbd>BarrelInverse</kbd></td> 2277 <td valign="top"> 2278 This is very simular to '<kbd>Barrel</kbd>' with the same set of 2279 arguments, and argument handling. However it uses the inverse 2280 of the radial polynomial, 2281 so that it forms the function <br/> 2282 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2283 <em>C</em>*r + <em>D</em> ) 2284 </td> 2285 </tr> 2286 2287 <tr valign="top"> 2288 <td valign="top"><kbd>Shepards</kbd></td> 2289 <td valign="top"> 2290 Distort the given list control points (any number) using an Inverse 2291 Squared Distance Interpolation Method (<a 2292 href="http://www.ems-i.com/smshelp/Data_Module/Interpolation/Inverse_Distance_Weighted.htm" 2293 >Shepards Method</a>). The control points in effect do 'localized' 2294 distortions of the image around the given control point. For best 2295 results extra control points should be added to 'lock' the positions of 2296 the corners and other unchanging parts of the image. <br/> 2297 2298 The distortion has been likened to 'taffy pulling' using nails, pins or 2299 sticks. It basically uses the <a href="#sparse-color" 2300 >-sparse-color</a> method of the same name to generate separate X and Y 2301 displacement maps (see <a href="#displace" >-displace</a>) for source 2302 image color look-up. </td> 2303 2304 </tr> 2305 2306</table> 2307 2308<p>To print a complete list of distortion methods, use <a href="#list">-list distort</a>.</p> 2309 2310<p>Many of the above distortion methods such as '<kbd>Affine</kbd>', 2311'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points 2312defining how these points in the given image should be distorted in the 2313destination image. Each set of four floating point values represent a source 2314image coordinate, followed immediately by the destination image coordinate. 2315This produces a list of values such as...</p> 2316<div style="text-align: center"><em> 2317 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> 2318 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> 2319 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> 2320 ... 2321 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> 2322</em></div> 2323<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the 2324destination image. </p> 2325 2326<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion, 2327needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the 2328perspective distortion of the built-in "rose:" image. Note how spaces were 2329used to group the 4 sets of coordinate pairs, to make it easier to read and 2330understand.</p> 2331 2332<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'> 2333 convert rose: -virtual-pixel black \ <br/> 2334 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \ <br/> 2335 rose_3d_rotated.gif</span></p> 2336<p>If more that the required number of coordinate pairs are given for a 2337distortion, the distortion method is 'least squares' fitted to 2338produce the best result for all the coordinate pairs given. If less than the 2339ideal number of points are given, the distort will generally fall back to a 2340simpler form of distortion that can handles the smaller number of coordinates 2341(usally a linear '<kbd>Affine</kbd>' distortion). </p> 2342 2343<p>By using more coodinates you can make use of image registration tool to 2344find matching coordinate pairs in overlaping images, so as to improve the 'fit' 2345of the distortion. Of course a bad coordinate pair can also make the 'fit' 2346worse. Caution is always advised. </p> 2347 2348<p>Colors are acquired from the source image according to the <a 2349href="#interpolate" >-interpolate</a> color lookup setting, when the image is 2350magnified. However if the viewed image is minified (image becomes smaller), a 2351special area resampling function (added ImageMagick v6.3.5-9), is used to 2352produce a higher quality image. For example you can use a 2353'<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all the 2354way to the horizon. </p> 2355 2356<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \ <br/> 2357 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \ <br/> 2358 checks_tiled.jpg</span></p> 2359<p>Note that a infinitely tiled perspective images involving the horizon can 2360be very slow to generate due to the use of the high quality 'area resampling' 2361function (added ImageMagick v6.3.5-9). You can turn off 'area resampling' 2362using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>' 2363(recommended if you plan to use super-sampling instead). </p> 2364 2365<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last 2366'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a> 2367will use the current <a href="#mattecolor" >-mattecolor</a> setting for these 2368pixels. If you do not what these pixels to be visible, set the color to match 2369the rest of the ground. </p> 2370 2371<p>The output image size will by default be the same as the input image. This 2372means that if the part of the distorted image falls outside the viewed area of 2373the 'distorted space', those parts is clipped and lost. However if you 2374use the plus form of the operator (<a href="#distort" >+distort</a>) the 2375operator will attempt (if posible) to show the whole of the distorted image, 2376while retaining a correct 'virtual canvas' offset, for image layering. This 2377offset may need to be removed using <a href="#repage" >+repage</a>, to remove 2378if it is unwanted. </p> 2379 2380<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a> 2381option:distort:viewport {geometry_string}</kbd>" setting which will specify 2382the size and the offset of the generated 'viewport' image of the distorted 2383image space.</p> 2384 2385<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale 2386{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by 2387that factor without changing the viewed contents of the distorted image. This 2388can be used either for 'super-sampling' the image for a higher quality result, 2389or for panning and zooming around the image (with appropriate viewport 2390changes, or post-distort cropping and resizing). </p> 2391 2392<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a 2393href="#distort" >-distort</a> to attempt to output the internal coefficients, 2394and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study, 2395and debugging purposes. This many not be available for all distorts. </p> 2396 2397<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to 2398produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a> 2399and/or <a href="#shear" >-shear</a> operation, with more control of due to the 2400above settings. It is algorithmically slower, though in ImageMagick it may be faster. 2401</p> 2402 2403 2404<div style="margin: auto;"> 2405 <h4><a name="dither" id="dither"></a>-dither <em class="arg">method</em></h4> 2406</div> 2407 2408<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> 2409 2410<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> 2411 2412<p>Dithering is turned on by default, to turn it off use the plus form of the 2413setting, <a href="#dither">+dither</a>. This will also also render PostScript 2414without text or graphic aliasing. Disabling dithering often (but not always) 2415leads to faster process, a smaller number of colors, but more cartoon like 2416image coloring. Generally resulting in 'color banding' effects in areas with 2417color gradients. </p> 2418 2419<p>The color reduction operators <a href="#colors">-colors</a>, <a 2420href="#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> 2421 2422<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> 2423 2424 2425<div style="margin: auto;"> 2426 <h4><a name="draw" id="draw"></a>-draw <em class="arg">string</em></h4> 2427</div> 2428 2429<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> 2430 2431<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> 2432 2433<p>The shape primitives:</p> 2434 2435<pre class="text"> 2436 point x,y 2437 line x0,y0 x1,y1 2438 rectangle x0,y0 x1,y1 2439 roundRectangle x0,y0 x1,y1 wc,hc 2440 arc x0,y0 x1,y1 a0,a1 2441 ellipse x0,y0 rx,ry a0,a1 2442 circle x0,y0 x1,y1 2443 polyline x0,y0 ... xn,yn 2444 polygon x0,y0 ... xn,yn 2445 bezier x0,y0 ... xn,yn 2446 path path specification 2447 image operator x0,y0 w,h filename 2448</pre> 2449 2450<p>The text primitive:</p> 2451 2452<pre class="text"> 2453 text x0,y0 string 2454</pre> 2455<p>The text gravity primitive:</p> 2456 2457<pre class="text"> 2458 gravity NorthWest, North, NorthEast, West, Center, 2459 East, SouthWest, South, or SouthEast 2460</pre> 2461 2462<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> 2463 2464<p>The transformation primitives:</p> 2465 2466<pre class="text"> 2467 rotate degrees 2468 translate dx,dy 2469 scale sx,sy 2470 skewX degrees 2471 skewY degrees 2472</pre> 2473 2474<p>The pixel operation primitives:</p> 2475 2476<pre class="text"> 2477 color x0,y0 method 2478 matte x0,y0 method 2479</pre> 2480 2481<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> 2482 2483<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> 2484 2485<p>A <kbd>line</kbd> primitive requires a start point and end point.</p> 2486 2487<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p> 2488 2489<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> 2490 2491<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p> 2492 2493<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> 2494 2495<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> 2496 2497<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>. 2498</p> 2499 2500<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p> 2501 2502<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p> 2503 2504<p class="crtsnip"> 2505 -draw 'circle 100,100 150,150' 2506</p> 2507 2508<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 2509draw 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> 2510 2511<p class="crtsnip"> 2512 -draw 'bezier 20,50 45,100 45,0 70,50' 2513</p> 2514<p class="crtsnip"> 2515 -draw 'bezier 70,50 95,100 95,0 120,50' 2516</p> 2517 2518 2519<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> 2520 2521<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> 2522 2523<p class="crtsnip"> 2524 -draw 'image SrcOver 100,100 225,225 image.jpg' 2525</p> 2526 2527<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> 2528 2529<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> 2530 2531<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p> 2532 2533<p class="crtsnip"> 2534 -draw 'text 100,100 "Works like magick!"' 2535</p> 2536 2537<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p> 2538 2539<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> 2540 2541<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p> 2542 2543<p>The <kbd>scale</kbd> primitive scales them.</p> 2544 2545<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> 2546 2547<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 2548matrix.</p> 2549 2550<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> 2551 2552<pre class="text"> 2553 point 2554 replace 2555 floodfill 2556 filltoborder 2557 reset 2558</pre> 2559 2560<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> 2561 2562<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> 2563 2564<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> 2565 2566<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p> 2567 2568<p>Drawing primitives conform to the <a href="/www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p> 2569 2570 2571<div style="margin: auto;"> 2572 <h4><a name="edge" id="edge"></a>-edge <em class="arg">radius</em></h4> 2573</div> 2574 2575<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> 2576 2577<div style="margin: auto;"> 2578 <h4><a name="emboss" id="emboss"></a>-emboss <em class="arg">radius</em></h4> 2579</div> 2580 2581<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> 2582 2583<div style="margin: auto;"> 2584 <h4><a name="encipher" id="encipher"></a>-encipher <em class="arg">filename</em></h4> 2585</div> 2586 2587<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> 2588 2589<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 2590 2591<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 2592 2593<div style="margin: auto;"> 2594 <h4><a name="encoding" id="encoding"></a>-encoding <em class="arg">type</em></h4> 2595</div> 2596 2597<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> 2598 2599<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> 2600 2601<div style="margin: auto;"> 2602 <h4><a name="endian" id="endian"></a>-endian <em class="arg">type</em></h4> 2603</div> 2604 2605<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> 2606 2607<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p> 2608 2609<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p> 2610 2611 2612<div style="margin: auto;"> 2613 <h4><a name="enhance" id="enhance"></a>-enhance</h4> 2614</div> 2615 2616<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> 2617 2618 2619<div style="margin: auto;"> 2620 <h4><a name="equalize" id="equalize"></a>-equalize</h4> 2621</div> 2622 2623<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> 2624 2625<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> 2626 2627<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p> 2628 2629<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> 2630 2631<div style="margin: auto;"> 2632 <h4><a name="evaluate" id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4> 2633</div> 2634 2635<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> 2636 2637<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> 2638 2639<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> 2640 2641<table class="doc"> 2642 <col width="25%" /> 2643 <col width="75%" /> 2644 <thead> 2645 <tr> 2646 <th><em class="arg">operator</em></th> 2647 <th>Summary (see further below for details)</th> 2648 </tr> 2649 </thead> 2650 <tbody> 2651 2652 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr> 2653 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr> 2654 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr> 2655 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2656 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr> 2657 <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> 2658 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr> 2659 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr> 2660 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr> 2661 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr> 2662 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr> 2663 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr> 2664 <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> 2665 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr> 2666 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2667 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr> 2668 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr> 2669 2670 <tr><td> </td></tr> 2671 2672 <tr><td>Gaussian-noise</td></tr> 2673 <tr><td>Impulse-noise</td></tr> 2674 <tr><td>Laplacian-noise</td></tr> 2675 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr> 2676 <tr><td>PoissonNoise</td></tr> 2677 <tr><td>Uniform-noise</td></tr> 2678 2679 <tr><td> </td></tr> 2680 2681 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr> 2682 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr> 2683 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr> 2684 </tbody> 2685 </table> 2686 2687<p>The specified functions are applied only to each previously set <a 2688href="#channel" >-channel</a> in the image. If necessary, the results of the 2689calculations are truncated (clipped) to fit in the interval [0, <em 2690class="QR">QuantumRange</em>]. The transparency channel of the image is 2691represented as a 'alpha' values (0 = fully transparent), so, for example, a 2692<kbd>Divide</kbd> by 2 of the alpha channel will make the image 2693semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value 2694as a percentage of the <em class="QR">QuantumRange</em>.</p> 2695 2696<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use 2697<a href="#list">-list evaluate</a>.</p> 2698 2699<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and 2700<kbd>Multiply</kbd> methods can also be achieved using either the <a 2701href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with 2702appropriate argument, to linearly modify the overall range of color values. 2703Please note, however, that <a href="#level" >-level</a> treats transparency as 2704'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with 2705'alpha' values.</p> 2706 2707<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> 2708 2709<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> 2710 2711 <div style="text-align:center;"> 2712 log(<em class="arg">value</em> × <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1) 2713 </div> 2714 2715<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on 2716normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a 2717href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent 2718to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used 2719with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used 2720with <kbd>Pow</kbd>.</p> 2721 2722<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and 2723converts the image values into a value according to a (co)sine wave function. 2724The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output 2725is biased 50% and normalized by 50% so as to fit in the respective color value 2726range. The <em class="arg">value</em> scaling of the <em>period</em> of the 2727function (its frequency), and thus determines the number of 'waves' that will 2728be generated over the input color range. For example, if the <em 2729class="arg">value</em> is 1, the effective period is simply the <em 2730class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is 2, 2731then the effective period is the <em>half</em> the <em 2732class="QR">QuantumRange</em>. 2733 2734 <div style="text-align:center;"> 2735 0.5 + 0.5 × cos(2 π <b><em>u</em></b> × <em class="arg">value</em>). 2736 </div> 2737 2738See also the <a href="#function" >-function</a> operator, which is a 2739multi-value version of evaluate. </P> 2740 2741 2742<div style="margin: auto;"> 2743 <h4><a name="extent" id="extent"></a>-extent <em class="arg">geometry</em></h4> 2744</div> 2745 2746<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> 2747 2748<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.</p> 2749 2750<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> 2751 2752<div style="margin: auto;"> 2753 <h4><a name="extract" id="extract"></a>-extract <em class="arg">geometry</em></h4> 2754</div> 2755 2756<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> 2757 2758<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p> 2759 2760<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480+1280+960 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]' image.rgb image.png</span></p><p>If you omit the offsets, as in</p> 2761 2762<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480 image.rgb image.png</span></p> 2763<p>then the image will be <em>resized</em> to the specified dimensions instead, 2764equivalent to:</p> 2765 2766<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -resize 640x480 image.rgb image.png</span></p> 2767<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> 2768 2769<div style="margin: auto;"> 2770 <h4><a name="family" id="family"></a>-family <em class="arg">fontFamily</em></h4> 2771</div> 2772 2773<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> 2774 2775<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). 2776</p> 2777 2778<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>. 2779</p> 2780 2781<div style="margin: auto;"> 2782 <h4><a name="fft" id="fft"></a>-fft</h4> 2783</div> 2784 2785<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> 2786 2787<p>This option is new as of ImageMagick 6.5.4-3 and 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> 2788 2789<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> 2790 2791<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> 2792 2793<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p> 2794<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> 2795 2796<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.png</span></p> 2797<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> 2798 2799<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> 2800 2801<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> 2802 2803<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br /> 2804 -evaluate log 1000 fft_image_spectrum.png</span></p> 2805<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> 2806 2807<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>. 2808 2809<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> 2810 2811<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> 2812 2813<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> 2814 2815<p>See the discussion on HDRI implementations of ImageMagick on the page 2816<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. 2817</p> 2818 2819 2820<div style="margin: auto;"> 2821 <h4><a name="fill" id="fill"></a>-fill <em class="arg">color</em></h4> 2822</div> 2823 2824<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> 2825 2826<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> 2827 2828<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p> 2829 2830<p>For example,</p> 2831 2832<p class="crtsnip"> 2833 -fill blue 2834</p> 2835<p class="crtsnip"> 2836 -fill "#ddddff" 2837</p> 2838<p class="crtsnip"> 2839 -fill "rgb(255,255,255)" 2840</p> 2841 2842<p>See <a href="#draw">-draw</a> for further details.</p> 2843 2844<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p> 2845 2846<div style="margin: auto;"> 2847 <h4><a name="filter" id="filter"></a>-filter <em class="arg">type</em></h4> 2848</div> 2849 2850<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> 2851 2852<p>Use this option to affect the resizing operation of an image (see <a 2853href="#resize">-resize</a>). For example you can use a simple resize filter 2854such as:</p> 2855 2856<pre class="text"> 2857 Point Hermite Cubic 2858 Box Gaussian Catrom 2859 Triangle Quadratic Mitchell 2860</pre> 2861 2862<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided, but are 2863by default <kbd>blackman</kbd>-windowed. However these filters define a 2864windowing filter for the Sinc or Bessel filter function, as appropriate for 2865the scaling operator used (usally Sinc for orthogonal <a href="#resize" 2866>-resize</a>). Windowed filters include: </p> 2867 2868<pre class="text"> 2869 Lanczos Hamming Parzen 2870 Blackman Kaiser Welsh 2871 Hanning Bartlett Bohman 2872</pre> 2873 2874<p>Also one special self-windowing filter is also provided 2875<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending 2876on the current 'support' or 'lobes' expert settings (see below).</p> 2877 2878<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> 2879 2880<p>To print a complete list of resize filters, use the <a href="#list">-list filter</a> option.</p> 2881 2882<p>You can modify how the filter behaves as it scales your image through the 2883use of these expert settings:</p> 2884 2885<dl class="doc"> 2886<dt>-set filter:blur <em>factor</em></dt> 2887<dd>Scale the X axis of the filter (and its window). Use > 1.0 for 2888 blurry or < 1.0 for sharp.</dd> 2889 2890<dt>-set filter:support <em>radius</em></dt> 2891<dd>Set the filter support radius.</dd> 2892 2893<dt>-set filter:lobes <em>count</em></dt> 2894<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an 2895 alternative way of specifying the 'support' range of the filter.</dd> 2896 2897<dt>-set filter:b <em>b-spline_factor</em></dt> 2898<dt>-set filter:c <em>keys_alpha_factor</em></dt> 2899<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>, 2900 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as 2901 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values 2902 are defined, the other is set so as to generate a 'Keys' type cubic 2903 filter. 2904 2905<dt>-set filter:filter <em>filter</em></dt> 2906<dd>Use this function directly as the scaling filter. This will allow 2907 you to directly use a 'windowing filter' such as <kbd>blackman</kbd>, 2908 rather than as its normal usage as a windowing function for 'Sinc' or 2909 'Bessel'. If defined, no windowing function is used, unless the following 2910 expert setting is also defined.</dd> 2911 2912<dt>-set filter:window <em>filter</em></dt> 2913<dd>The IIR (infinite impulse response) filters <kbd>bessel</kbd> and 2914 <kbd>sinc</kbd> are windowed (brought down to zero over the defined 2915 support range) with the given filter. This allows you to use a filter that 2916 is not normally used as a windowing function, such as <kbd>box</kbd>, 2917 (which effectivally turns off the windowing function). </dd> 2918 2919</dl> 2920 2921<p>For example, to get a 8 lobe Lanczos-Bessel filter:</p> 2922 2923<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -filter bessel \ <br/> 2924 -set filter:window=bessel -set filter:lobes=8 \ <br/> 2925 -resize 150% image.jpg</span></p> 2926<p>Or a raw un-windowed Sinc filter with 4 lobes:</p> 2927 2928<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/> 2929 -resize 150% image.jpg</span></p> 2930<p>Note that the use of expert options (except for 'blur' with simple resize 2931filters), are provided for image processing experts who have studied and 2932understood how resize filters work. Without this knowledge, and an 2933understanding of the defination of the actual filters involved, using expert 2934settings are more likely to be detremental to your image resizing.</p> 2935 2936 2937<div style="margin: auto;"> 2938 <h4><a name="flatten" id="flatten"></a>-flatten</h4> 2939</div> 2940 2941<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> 2942 2943 2944<div style="margin: auto;"> 2945 <h4><a name="flip" id="flip"></a>-flip</h4> 2946</div> 2947 2948<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> 2949 2950<p>reflect the scanlines in the vertical direction.</p> 2951 2952<div style="margin: auto;"> 2953 <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> 2954</div> 2955 2956<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> 2957 2958<div style="margin: auto;"> 2959 <h4><a name="flop" id="flop"></a>-flop</h4> 2960</div> 2961 2962<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> 2963 2964<p>reflect the scanlines in the horizontal direction.</p> 2965 2966 2967<div style="margin: auto;"> 2968 <h4><a name="font" id="font"></a>-font <em class="arg">name</em></h4> 2969</div> 2970 2971<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> 2972 2973<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> 2974 2975<p>In addition to the fonts specified by the above pre-defined list, you can 2976also specify a font from a specific source. For example <kbd>Arial.ttf</kbd> 2977is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and 2978<kbd>x:fixed</kbd> is X11 font.</p> 2979 2980<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> 2981 2982 2983<div style="margin: auto;"> 2984 <h4><a name="foreground" id="foreground"></a>-foreground <em class="arg">color</em></h4> 2985</div> 2986 2987<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> 2988 2989<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 2990 2991<p>The default foreground color is black.</p> 2992 2993<div style="margin: auto;"> 2994 <h4><a name="format" id="format"></a>-format <em class="arg">type</em></h4> 2995</div> 2996 2997<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> 2998 2999<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> 3000 3001<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> 3002 3003<div style="margin: auto;"> 3004 <h4><a name="format_identify_" id="format_identify_"></a>-format <em class="arg">string</em></h4> 3005</div> 3006 3007<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> 3008 3009<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> 3010 3011<div style="margin: auto;"> 3012 <h4><a name="frame" id="frame"></a>-frame <em class="arg">geometry</em></h4> 3013</div> 3014 3015<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> 3016 3017<p>The color of the border is specified with the <a href="#mattecolor">-mattecolor</a> command line option. </p> 3018 3019<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> 3020 3021 3022<div style="margin: auto;"> 3023 <h4><a name="frame_import_" id="frame_import_"></a>-frame</h4> 3024</div> 3025 3026<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> 3027 3028<div style="margin: auto;"> 3029 <h4><a name="function" id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4> 3030</div> 3031 3032<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> 3033 3034<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> 3035 3036<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> 3037 3038<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> 3039 3040<pre class="text"> 3041 Polynomial 3042 Sinusoid 3043 Arcsin 3044 Arctan 3045</pre> 3046 3047<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p> 3048 3049<dl class="doc"> 3050<dt><kbd>Polynomial</kbd></dt> 3051<dd> 3052<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> 3053 3054<div style="text-align: center"> 3055 -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> 3056</div> 3057 3058<p>will invoke a polynomial function given by</p> 3059 3060<div style="text-align: center"> 3061 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> + 3062 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> + 3063 ··· <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>, 3064</div> 3065 3066<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p> 3067 3068<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> 3069 3070<table class="doc"> 3071 <col width="35%" /> 3072 <col width="35%" /> 3073 <col width="30%" /> 3074 <tr> 3075 <td>-evaluate Set <em class="arg">value</em> </td> 3076 <td>-function Polynomial <em class="arg">value</em></td> 3077 <td>(Constant functions; set <em class="arg">value</em>×100% gray when channels are RGB.)</td> 3078 </tr> 3079 <tr> 3080 <td>-evaluate Add <em class="arg">value</em> </td> 3081 <td>-function Polynomial 1,<em class="arg">value</em></td> 3082 </tr> 3083 <tr> 3084 <td>-evaluate Subtract <em class="arg">value</em> </td> 3085 <td>-function Polynomial 1,−<em class="arg">value</em></td> 3086 </tr> 3087 <tr> 3088 <td>-evaluate Multiply <em class="arg">value</em> </td> 3089 <td>-function Polynomial <em class="arg">value</em>,0</td> 3090 </tr> 3091 <tr> 3092 <td>+level black% x white%</td> 3093 <td>-function Polynomial A,B</td> 3094 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td> 3095 </tr> 3096</table> 3097 3098<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> 3099</dd> 3100 3101<dt><kbd>Sinusoid</kbd></dt> 3102<dd> 3103<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> 3104 3105<div style="text-align: center"> 3106 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]] 3107</div> 3108 3109<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> 3110 3111<div style="text-align: center"> 3112<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> 3113</div> 3114 3115<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> 3116 3117<p class="crtsnip"> 3118 -function Sinusoid 3,-90,.2,.7 3119</p> 3120 3121<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> 3122 3123<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> 3124 3125<table class="doc"> 3126 <tr> 3127 <td>-evaluate Sin <em class="arg">freq</em> </td> 3128 <td>-function Sinusoid <em class="arg">freq</em>,0 </td> 3129 </tr> 3130 <tr> 3131 <td>-evaluate Cos <em class="arg">freq</em> </td> 3132 <td>-function Sinusoid <em class="arg">freq</em>,90 </td> 3133 </tr> 3134</table> 3135</dd> 3136 3137<dt><kbd>ArcSin</kbd></dt> 3138<dd> 3139<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid, 3140and can be used to generate cylindrical distortion and displacement maps. 3141The curve can be adjusted relative to both the input values and output range 3142of values. 3143 3144<div style="text-align: center"> 3145 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3146</div> 3147 3148<p>with all values given in terms of noramlize color values (0.0 for black, 31491.0 for white). Defaulting to values covering the full range from 0.0 to 1.0 3150for bout input (<em class="arg">width</em>), and output (<em 3151class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p> 3152 3153<div style="text-align: center"> 3154<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> 3155</div> 3156 3157</dd> 3158 3159<dt><kbd>ArcTan</kbd></dt> 3160<dd> 3161<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from 3162limit values at infinities, though a center using the given slope value. 3163All these values can be adjusted via the arguments. 3164 3165<div style="text-align: center"> 3166 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3167</div> 3168 3169<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'. 3170</p> 3171 3172<div style="text-align: center"> 3173<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> 3174</div> 3175 3176</dd> 3177 3178</dl> 3179 3180 3181<div style="margin: auto;"> 3182 <h4><a name="fuzz" id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4> 3183</div> 3184 3185<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> 3186 3187<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> 3188 3189<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> 3190 3191 3192<div style="margin: auto;"> 3193 <h4><a name="fx" id="fx"></a>-fx <em class="arg">expression</em></h4> 3194</div> 3195 3196<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> 3197 3198<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> 3199 3200<p>See <a href="/www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p> 3201 3202 3203<div style="margin: auto;"> 3204 <h4><a name="gamma" id="gamma"></a>-gamma <em class="arg">value</em></h4> 3205</div> 3206 3207<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> 3208 3209<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> 3210 3211<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> 3212 3213<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> 3214 3215<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> 3216 3217<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p> 3218 3219<div style="margin: auto;"> 3220 <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> 3221</div> 3222 3223<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> 3224 3225<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p> 3226 3227<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 3228</div> 3229 3230<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> 3231 3232<p>This differs from the faster <a href="#blur">-blur</a> operator in that a 3233full 2-dimentional convolution is used to generate the weighted average of the 3234neighbouring pixels. </p> 3235 3236<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 3237pixels which are outside the image proper are blurred into the final result. 3238</p> 3239 3240 3241<div style="margin: auto;"> 3242 <h4><a name="geometry" id="geometry"></a>-geometry <em class="arg">geometry</em></h4> 3243</div> 3244 3245<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> 3246 3247<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> 3248 3249<div style="margin: auto;"> 3250 <h4><a name="gravity" id="gravity"></a>-gravity <em class="arg">type</em></h4> 3251</div> 3252 3253<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> 3254 3255<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>, 3256<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>, 3257<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete 3258list of <a href="#gravity">-gravity</a> settings available in your ImageMagick 3259installation.</p> 3260 3261<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> 3262 3263<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> 3264 3265<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> 3266 3267<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -gravity Center -region 10x10-40+20 -negate output.png</span></p> 3268<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> 3269 3270<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> 3271 3272 3273<div style="margin: auto;"> 3274 <h4><a name="green-primary" id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4> 3275</div> 3276 3277<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> 3278 3279 3280<div style="margin: auto;"> 3281 <h4><a name="hald-clut" id="hald-clut"></a>-hald-clut</h4> 3282</div> 3283 3284<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> 3285 3286<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2 3287dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You 3288can apply any color transformation to the Hald image and then use this option 3289to apply the transform to the image. </p> 3290 3291<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p> 3292<p>This option provides a convenient method for you to use Gimp or Photoshop 3293to make color corrections to the Hald CLUT image and subsequently apply them 3294to multiple images using an ImageMagick script. </p> 3295 3296<p>Note that the representation is only of the normal RGB color space and that 3297the whole color value triplet is used for the interpolated lookup of the 3298represented Hald color cube image. Because of this the operation is not <a 3299href="#channel" >-channel</a> setting effected, nor can it adjust or modify an 3300images transparency or alpha/matte channel.</p> 3301 3302<p>See also <a href="#clut" >-clut</a> which provides color value replacement 3303of the individual color channels, usally involving a simplier gray-scale 3304image. E.g: gray-scale to color replacement, or modification by a histogram 3305mapping. </p> 3306 3307 3308<div style="margin: auto;"> 3309 <h4><a name="help" id="help"></a>-help</h4> 3310</div> 3311 3312<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> 3313 3314<div style="margin: auto;"> 3315 <h4><a name="highlight-color" id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4> 3316</div> 3317 3318<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> 3319 3320<div style="margin: auto;"> 3321 <h4><a name="iconGeometry" id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4> 3322</div> 3323 3324<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> 3325 3326<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> 3327 3328<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> 3329 3330<div style="margin: auto;"> 3331 <h4><a name="iconic" id="iconic"></a>-iconic</h4> 3332</div> 3333 3334<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> 3335 3336<div style="margin: auto;"> 3337 <h4><a name="identify" id="identify"></a>-identify</h4> 3338</div> 3339 3340<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> 3341 3342<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> 3343 3344<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> 3345 3346<p>If <a href="#verbose">-verbose</a> preceds this option, copious 3347amounts of image properties are displayed including image statistics, profiles, 3348image histogram, and others.</p> 3349 3350<div style="margin: auto;"> 3351 <h4><a name="ift" id="ift"></a>-ift</h4> 3352</div> 3353 3354<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> 3355 3356<p>This option is new as of ImageMagick 6.5.4-3 and 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> 3357 3358<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> 3359 3360<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p> 3361<p>or</p> 3362 3363<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> 3364 3365<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. 3366 3367<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>. 3368 3369<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. 3370 3371<div style="margin: auto;"> 3372 <h4><a name="immutable" id="immutable"></a>-immutable</h4> 3373</div> 3374 3375<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> 3376 3377<div style="margin: auto;"> 3378 <h4><a name="implode" id="implode"></a>-implode <em class="arg">factor</em></h4> 3379</div> 3380 3381<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> 3382 3383<div style="margin: auto;"> 3384 <h4><a name="insert" id="insert"></a>-insert <em class="arg">index</em></h4> 3385</div> 3386 3387<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> 3388 3389<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> 3390 3391<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> 3392 3393<div style="margin: auto;"> 3394 <h4><a name="intent" id="intent"></a>-intent <em class="arg">type</em></h4> 3395</div> 3396 3397<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> 3398 3399<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> 3400 3401<p>The default intent is undefined.</p> 3402 3403<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p> 3404 3405<div style="margin: auto;"> 3406 <h4><a name="interlace" id="interlace"></a>-interlace <em class="arg">type</em></h4> 3407</div> 3408 3409<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> 3410 3411<p>Choose from:</p> 3412 3413<pre class="text"> 3414 none 3415 line 3416 plane 3417 partition 3418 JPEG 3419 GIF 3420 PNG 3421</pre> 3422 3423<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> 3424 3425<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p> 3426 3427<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p> 3428 3429<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p> 3430 3431<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R, 3432image.G, and image.B).</p> 3433 3434<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> 3435image.</p> 3436 3437<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p> 3438 3439<div style="margin: auto;"> 3440 <h4><a name="interpolate" id="interpolate"></a>-interpolate <em class="arg">type</em></h4> 3441</div> 3442 3443<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> 3444 3445<p>When looking up the color of a pixel using a non-interger floating point 3446value, you typically fall in between the pixel colors defined by the source 3447image. This setting determines how the color is determined from the colors of 3448the pixels surrounding that point. That is how to determine the color of a 3449point that falls between two, or even four different colored pixels. </p> 3450 3451<pre class="text"> 3452 integer: The color of the top-left pixel (floor function) 3453 nearest-neighbor: The nearest pixel to the lookup point (rounded function) 3454 average: The average color of the surrounding four pixels 3455 bilinear A double linear interpolation of pixels (the default) 3456 mesh Divide area into two flat triangular interpolations 3457 bicubic Fitted bicubic-spines of surrounding 16 pixels 3458 spline Direct spline curves (colors are blurred) 3459 filter Use resize <a href="#filter">-filter</a> settings 3460</pre> 3461 3462<p>This most important for distortion operators such as <a href="#distort" 3463>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform" 3464>-transform</a> and <a href="#fx" >-fx</a>. </p> 3465 3466<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p> 3467 3468<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the 3469lookup for positions outside the boundaries of the image. </p> 3470 3471 3472<div style="margin: auto;"> 3473 <h4><a name="interline-spacing" id="interline-spacing"></a>-interline-spacing <em class="arg">value</em></h4> 3474</div> 3475 3476<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> 3477 3478<div style="margin: auto;"> 3479 <h4><a name="interword-spacing" id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4> 3480</div> 3481 3482<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> 3483 3484<div style="margin: auto;"> 3485 <h4><a name="kerning" id="kerning"></a>-kerning <em class="arg">value</em></h4> 3486</div> 3487 3488<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> 3489 3490<div style="margin: auto;"> 3491 <h4><a name="label" id="label"></a>-label <em class="arg">name</em></h4> 3492</div> 3493 3494<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> 3495 3496<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> 3497 3498<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> 3499 3500<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> 3501 3502<p>For example,</p> 3503 3504<p class="crtsnip"> 3505 -label "%m:%f %wx%h" bird.miff 3506</p> 3507 3508<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> 3509 3510<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> 3511 3512<p>The label font can be specified with <a href="#font">-font</a>, and the 3513other font attribute settings.</p> 3514 3515<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> 3516 3517 3518<div style="margin: auto;"> 3519 <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> 3520</div> 3521 3522<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> 3523 3524<p>Adaptively threshold each pixel based on the value of pixels in a 3525surrounding window. If the current pixel is lighter than this average plus 3526the optional <kbd>offset</kbd>, then it is made white, otherwise it is made 3527black. Small variations in pixel values such as found in scanned documents 3528can be ignored if offset is positive. A negative offset will make it more 3529sensitive to those small variations. </p> 3530 3531<p>This is commonly used to threshold images with an uneven background. It is 3532based on the assumption that average color of the small window is the 3533the local background color, from which to separate the forground color. </p> 3534 3535 3536<div style="margin: auto;"> 3537 <h4><a name="layers" id="layers"></a>-layers <em class="arg">method</em></h4> 3538</div> 3539 3540<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> 3541 3542<p>Perform various image operation methods to a ordered sequence of images 3543which may represent either a set of overlaid 'image layers', a GIF disposal 3544animation, or a fully-'coalesced' animation sequence. </p> 3545 3546<table class="doc"> 3547 <tbody> 3548 <tr valign="top"> 3549 <th align="left" style="width: 8%">Method</th> 3550 <th align="left">Description</th> 3551 </tr> 3552 3553 <tr valign="top"> 3554 <td valign="top">compare-any</td> 3555 <td valign="top">Crop the second and later frames to the smallest rectangle 3556 that contains all the differences between the two images. No GIF <a 3557 href="#dispose" >-dispose</a> methods are taken into account. </td> 3558 </tr> 3559 3560 <tr><td></td><td>This exactly the same as the <a href="#deconstruct" 3561 >-deconstruct</a> operator, and does not preserve animations normal 3562 working, especially when animation used layer disposal methods such as 3563 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td> 3564 </tr> 3565 3566 <tr valign="top"> 3567 <td valign="top">compare-clear</td> 3568 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any 3569 opaque pixels which become transparent in the second frame. That is the 3570 smallest image needed to mask or erase pixels for the next frame. </td> 3571 </tr> 3572 3573 <tr valign="top"> 3574 <td valign="top">compare-overlay</td> 3575 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add 3576 extra color to the next image, as a result of overlaying color pixels. 3577 That is the smallest single overlaid image to add or change colors. </td> 3578 </tr> 3579 3580 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha 3581 composition method '<kbd>change-mask</kbd>', to reduce the image to 3582 just the pixels that need to be overlaid. </td> 3583 </tr> 3584 3585 <tr valign="top"> 3586 <td valign="top">coalesce</td> 3587 <td valign="top">Equivalent to a call to the <a href="#coalesce" 3588 >-coalesce</a> operator. Apply the layer disposal methods set in the 3589 current image sequence to form a fully defined animation sequence, as 3590 it should be displayed. Effectively converting a GIF animation into a 3591 'film strip'-like animation. </td> 3592 </tr> 3593 3594 <tr valign="top"> 3595 <td valign="top">composite</td> 3596 <td valign="top">Alpha Composition of two image lists, separated by a 3597 "<kbd>null:</kbd>" image, with the destination image list first, and 3598 the source images last. An image from each list are composited 3599 together until one list is finished. The separator image and source 3600 image lists are removed. </td> 3601 </tr> 3602 3603 3604 <tr><td></td><td>The <a href="#geometry" >-geometry</a> offset is adjusted according to 3605 <a href="#gravity" >-gravity</a> in accordance of the virtual canvas 3606 size of the first image in each list. Unlike a normal <a 3607 href="#composite" >-composite</a> operation, the canvas offset is also 3608 added to the final composite positioning of each image. </td> 3609 </tr> 3610 3611 <tr><td></td><td>If one of the image lists only contains one image, that image is 3612 applied to all the images in the other image list, regardless of which 3613 list it is. In this case it is the image meta-data of the list which 3614 preserved. </td> 3615 </tr> 3616 3617 3618 <tr valign="top"> 3619 <td valign="top">dispose</td> 3620 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of 3621 the animation after the layer disposal method has been applied, before 3622 the next sub-frame image is overlaid. That is the 'dispose' image that 3623 results from the application of the GIF <a href="#dispose" 3624 >-dispose</a> method. This allows you to check what 3625 is going wrong with a particular animation you may be developing. 3626 </td> 3627 </tr> 3628 3629 <tr valign="top"> 3630 <td valign="top">flatten</td> 3631 <td valign="top">Create a canvas the size of the first images virtual 3632 canvas using the current <a href="#background" >-background</a> color, 3633 and <a href="#compose" >-compose</a> each image in turn onto that 3634 canvas. Images falling outside that canvas is clipped. Final 3635 image will have a zero virtual canvas offset. </td> 3636 </tr> 3637 3638 <tr><td></td><td>This usally used as one of the final 'image layering' operations 3639 overlaying all the prepared image layers into a final image. </td> 3640 </tr> 3641 3642 <tr><td></td><td>For a single image this method can also be used to fillout a virtual 3643 canvas with real pixels, or to underlay a opaque color to remove 3644 transparency from an image.</td> 3645 </tr> 3646 3647 3648 <tr valign="top"> 3649 <td valign="top">merge</td> 3650 <td valign="top">As 'flatten' method but merging all the given image 3651 layers into a new layer image just large enough to hold all the image 3652 without clipping or extra space. The new images virtual offset will 3653 prevere the position of the new layer, even if this offset is 3654 negative. the virtual canvas size of the first image is preserved. 3655 </td> 3656 </tr> 3657 3658 <tr><td></td><td>Caution is advised when handling image layers with negative offsets 3659 as few image file formats handle them correctly. </td> 3660 </tr> 3661 3662 <tr valign="top"> 3663 <td valign="top">mosaic</td> 3664 <td valign="top">As 'flatten' method but expanding the initial canvas size 3665 of the first image so as to hold all the image layers. However as a 3666 virtual canvas is 'locked' to the origin, by defination, image layers 3667 with a negative offsets will still be clipped by the top and left 3668 edges.</td> 3669 </tr> 3670 3671 <tr><td></td><td>This method is commonly used to layout individual image using various 3672 offset but without knowning the final canvas size. The resulting image 3673 will, like 'flatten' not have any virtual offset, so can be saved to 3674 any image file format. </td> 3675 </tr> 3676 3677 3678 <tr valign="top"> 3679 <td valign="top">optimize</td> 3680 <td valign="top">Optimize a coalesced animation, into GIF animation using 3681 a number of general techniques. This currently a short cut to 3682 apply both the '<kbd>optimize-frame</kbd>', and 3683 '<kbd>optimize-transparency</kbd>' methods but may be expanded to 3684 include other optimization methods as they are developed. </td> 3685 </tr> 3686 3687 <tr valign="top"> 3688 <td valign="top">optimize-frame</td> 3689 <td valign="top">Optimize a coalesced animation, into GIF animation by 3690 reducing the number of pixels per frame as much as possible by 3691 attempting to pick the best layer disposal method to use, while ensuring 3692 the result will continue to animate properly. </td> 3693 </tr> 3694 3695 <tr><td></td><td> There is no guarantee that the best optimization is found. But 3696 then no reasonably fast GIF optimization algorithm can do this. 3697 However this does seem to do better than most other GIF frame 3698 optimizers seen. </td> 3699 </tr> 3700 3701 <tr valign="top"> 3702 <td valign="top">optimize-plus</td> 3703 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the 3704 overall optimization by adding extra frames to the animation, without 3705 changing the final look or timing of the animation. The frames are 3706 added to attempt to separate the clearing of pixels from the 3707 overlaying of new additional pixels from one animation frame to the 3708 next. If this does not improve the optimization (for the next frame 3709 only), it will fall back to the results of the previous normal 3710 '<kbd>optimize-frame</kbd>' technique. </td> 3711 </tr> 3712 3713 <tr><td></td><td>There is the possibility that the change in the disposal style will 3714 result in a worsening in the optimization of later frames, though this 3715 is unlikely. In other words there no guarantee that it is better than 3716 the normal '<kbd>optimize-frame</kbd>' technique. For some animations 3717 however you can get a vast improvment in the final animation size. </td> 3718 </tr> 3719 3720 <tr valign="top"> 3721 <td valign="top">optimize-transparency</td> 3722 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame 3723 overlay images with transparency, if it does not change the resulting 3724 animation by more than the current <a href="#fuzz" >-fuzz</a> factor. 3725 </td> 3726 </tr> 3727 3728 <tr><td></td><td>This should allow a existing frame optimized GIF animation to compress 3729 into a smaller file size due to larger areas of one (transparent) 3730 color rather than a pattern of multiple colors repeating the current 3731 disposed image of the last frame. </td> 3732 </tr> 3733 3734 <tr valign="top"> 3735 <td valign="top">remove-dups</td> 3736 <td valign="top">Remove (and merge time delays) of duplicate consecutive 3737 images, so as to simplify layer overlays of coalesced animations. 3738 </td> 3739 </tr> 3740 3741 <tr><td></td><td>Usually this a result of using a constant time delay across the 3742 whole animation, or after a larger animation was split into smaller 3743 sub-animations. The duplicate frames could also have been used as 3744 part of some frame optimization methods. </td> 3745 </tr> 3746 3747 <tr valign="top"> 3748 <td valign="top">remove-zero</td> 3749 <td valign="top">Remove any image with a zero time delay, unless ALL the 3750 images have a zero time delay (and is not a proper timed animation, a 3751 warning is then issued). </td> 3752 </tr> 3753 3754 <tr><td></td><td>In a GIF animation, such images are usually frames which provide 3755 partial intermediary updates between the frames that are actually 3756 displayed to users. These frames are usally added for improved frame 3757 optimization in GIF animations. </td> 3758 </tr> 3759 3760 <tr valign="top"> 3761 <td valign="top">trim-bounds</td> 3762 <td valign="top">Find the bounds of all the images in the current 3763 image sequence, then adjust the offsets so all images are contained on 3764 a minimal positive canvas. None of the image data is modified, only 3765 there virtual canvas size and offset. The all the image is given 3766 the same canvas size, and and will have a positive offset, but will 3767 remain in the same position relative to each other. As a result of the 3768 minimal canvas size at least one image will touch every edge of that 3769 canvas. The image data however may be transparent. 3770 </td> 3771 </tr> 3772 3773 </tbody> 3774</table> 3775 3776<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p> 3777 3778<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct" 3779>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic" 3780>-mosaic</a> are only aliases for the above methods. Also see <a 3781href="#page" >-page</a>, <a href="#repage" >-repage</a> operators, the <a 3782href="#compose" >-compose</a> setting, and the GIF <a href="#dispose" 3783>-dispose</a> and <a href="#delay" >-delay</a> settings. </p> 3784 3785 3786<div style="margin: auto;"> 3787 <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> 3788</div> 3789 3790<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> 3791 3792<p>Given one, two or three values delimited with commas: black-point, 3793white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and 3794white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white 3795point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center 3796contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string, 3797both black and white points are percentages of the full color range. Gamma 3798will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is 3799omitted, the default of 1.0 (no gamma correction) is assumed.</p> 3800 3801<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that 3802the given '<kbd>black_point</kbd>' value in the original image is set to 3803zero (or black), while the given '<kbd>white_point</kbd>' value is set to 3804<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments 3805to the image. The '<kbd>gamma</kbd>' of the resulting image will then be 3806adjusted. </p> 3807 3808<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or 3809adding the special '!' flag anywhere in the argument list, will cause the 3810operator to do the reverse of the level adjustment. That is a zero, or 3811<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is 3812adjusted to the given level values, allowing you to de-contrast, or compress 3813the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p> 3814 3815<p>Only the channels defined by the current <a href="#channel">-channel</a> 3816setting are adjusted (defaults to RGB color channels only), allowing you to 3817limit the effect of this operator. </p> 3818 3819<p>Please note that the transparency channel is treated as 'matte' 3820values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 3821 3822 3823<div style="margin: auto;"> 3824 <h4><a name="level-colors" id="level-colors"></a>-level-colors {<em 3825 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4> 3826</div> 3827 3828<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> 3829 3830<p>This function is exactly like <a href="#level">-level</a>, except that the 3831value value for each color channel is determined by the 3832'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as 3833described under the <a href="#fill">-fill</a> option). </p> 3834 3835<p>This effectivally means the colors provided to <kbd>-level-colors</kbd> 3836is mapped to become 'black' and 'white' respectivally, with all the other 3837colors linearly adjusted (or clipped) to match that change. Each channel is 3838adjusted separatally using the channel values of the colors specified. </p> 3839 3840<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>) 3841will map the image color 'black' and 'white' to the given colors 3842respectivally, resulting in a gradient (de-contrasting) tint of the image to 3843those colors. This can also be used to convert a plain gray-scale image into a 3844one using the gradient of colors specified. </p> 3845 3846<p>By supplying a single color with a comma separator either before or after 3847that color, will just replace the respective 'black' or 'white' point 3848respectivally. But if no comma separator is provided, the given color is 3849used for both the black and white color points, making the operator either 3850threshold the images around that color (- form) or set all colors to that 3851color (+ form). </p> 3852 3853 3854<div style="margin: auto;"> 3855 <h4><a name="limit" id="limit"></a>-limit <em class="arg">type value</em></h4> 3856</div> 3857 3858<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> 3859 3860<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> 3861 3862<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, 1.5gb memory, 8gb memory map, and 16tb 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> 3863 3864<p class="crtsnip"> 3865 -limit memory 32MiB -limit map 64MiB 3866</p> 3867 3868<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p> 3869 3870<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 3871----------------------------------------------------------------------- 3872 768 3.8187GiB 2.864GiB 7.6375GiB 16EiB 2 unlimited</pre> 3873</span></p> 3874<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> 3875 3876<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> 3877 3878<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> 3879 3880<p class="crtsnip"> 3881-limit area 10mb 3882</p> 3883 3884<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> 3885 3886<p class="crtsnip"> 3887-limit area 10mb -limit disk 500mb 3888</p> 3889 3890<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p> 3891 3892<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> 3893 3894<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. 3895</p> 3896 3897<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. 3898</p> 3899 3900<div style="margin: auto;"> 3901 <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> 3902</div> 3903 3904<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> 3905 3906<p>This is very similar to <a href="#contrast-stretch" >-contrast-stretch</a>, 3907and uses a 'histogram bin' to determine the range of color values that needs to 3908be stretched. However it then stretchs those colors using the <a 3909href="#level" >-level</a> operator.</p> 3910 3911<p>As such while the initial determination may have 'binning' round off 3912effects, the image colors are stretched mathematically, rather than using the 3913histogram bins. This makes the operator more accurate. </p> 3914 3915<p>note however that a <a href="#linear-stretch" >-linear-stretch</a> of 3916'<kbd>0</kbd>' does nothing, while a value of '<kbd>1</kbd>' does a near 3917perfect stretch of the color range. </p> 3918 3919<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 3920normalization of mathematical images. </p> 3921 3922<p>This operator is under review for re-development. </p> 3923 3924 3925<div style="margin: auto;"> 3926 <h4><a name="linewidth" id="linewidth"></a>-linewidth</h4> 3927</div> 3928 3929<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> 3930 3931<div style="margin: auto;"> 3932 <h4><a name="liquid-rescale" id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4> 3933</div> 3934 3935<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> 3936 3937<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> 3938 3939<div style="margin: auto;"> 3940 <h4><a name="list" id="list"></a>-list <em class="arg">type</em></h4> 3941</div> 3942 3943<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> 3944 3945<pre class="text"> 3946 coder 3947 color 3948 configure 3949 delegate 3950 font 3951 format 3952 list 3953 log 3954 magic 3955 module 3956 resource 3957 threshold 3958</pre> 3959 3960<p>The above lists are only some of the many lists available. These lists vary depending on your version of ImageMagick. For example use "<kbd>-list list</kbd>" to get a complete listing of all the "<kbd>-list</kbd>" arguments available:</p> 3961 3962<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>identify -list list</span></p> 3963<div style="margin: auto;"> 3964 <h4><a name="log" id="log"></a>-log <em class="arg">string</em></h4> 3965</div> 3966 3967<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> 3968 3969<p>This option specifies the format for the log printed when the <a href="#debug">-debug</a> option is active.</p> 3970 3971<p>You can display the following components by embedding special format characters:</p> 3972 3973<pre class="text"> 3974 %d domain 3975 %e event 3976 %f function 3977 %l line 3978 %m module 3979 %p process ID 3980 %r real CPU time 3981 %t wall clock time 3982 %u user CPU time 3983 %% percent sign 3984 \n newline 3985 \r carriage return 3986</pre> 3987 3988<p>For example:</p> 3989 3990<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> 3991<p>The default behavior is to print all of the components.</p> 3992 3993<div style="margin: auto;"> 3994 <h4><a name="loop" id="loop"></a>-loop <em class="arg">iterations</em></h4> 3995</div> 3996 3997<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> 3998 3999<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> 4000 4001<div style="margin: auto;"> 4002 <h4><a name="lowlight-color" id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4> 4003</div> 4004 4005<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> 4006 4007<div style="margin: auto;"> 4008 <h4><a name="magnify" id="magnify"></a>-magnify <em class="arg">factor</em></h4> 4009</div> 4010 4011<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> 4012 4013 4014<div style="margin: auto;"> 4015 <h4><a name="map" id="map"></a>-map <em class="arg">type</em></h4> 4016</div> 4017 4018<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> 4019 4020<p>Choose from these <em class="arg">Standard Colormap</em> types:</p> 4021 4022<pre class="text"> 4023 best 4024 default 4025 gray 4026 red 4027 green 4028 blue 4029</pre> 4030 4031<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> 4032 4033 4034<div style="margin: auto;"> 4035 <h4><a name="map_stream_" id="map_stream_"></a>-map <em class="arg">components</em></h4> 4036</div> 4037 4038<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> 4039 4040<p>Here are the valid components of a map:</p> 4041 4042<pre class="text"> 4043 r red pixel component 4044 g green pixel component 4045 b blue pixel component 4046 a alpha pixel component (0 is transparent) 4047 o opacity pixel component (0 is opaque) 4048 i grayscale intensity pixel component 4049 c cyan pixel component 4050 m magenta pixel component 4051 y yellow pixel component 4052 k black pixel component 4053 p pad component (always 0) 4054</pre> 4055 4056<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> 4057 4058<div style="margin: auto;"> 4059 <h4><a name="mask" id="mask"></a>-mask 4060<em class="arg">filename</em></h4> 4061</div> 4062 4063<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> 4064 4065<p>Use <a href="#mask">+mask</a> to remove the image mask.</p> 4066 4067<div style="margin: auto;"> 4068 <h4><a name="mattecolor" id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4> 4069</div> 4070 4071<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> 4072 4073<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 4074 4075<p>The default matte color is <kbd>#BDBDBD</kbd>, <span style="background-color: #bdbdbd;">this shade of gray</span>.</p> 4076 4077<div style="margin: auto;"> 4078 <h4><a name="median" id="median"></a>-median <em class="arg">radius</em></h4> 4079</div> 4080 4081<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> 4082 4083<div style="margin: auto;"> 4084 <h4><a name="metric" id="metric"></a>-metric <em class="arg">type</em></h4> 4085</div> 4086 4087<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> 4088 4089<p>Choose from:</p> 4090 4091<pre class="text"> 4092 AE absolute number of differnet pixels 4093 MAE mean absolute error (normalized), average channel error distance 4094 MEPP mean error per pixel (normalized mean error, normalized peak error) 4095 MSE mean error squared, average of the channel error squared 4096 PAE peak absolute (normalize peak absolute) 4097 PSNR peak signal to noise ratio 4098 RMSE root mean squared (normalized root mean squared) 4099</pre> 4100 4101<p>The '<kbd>AE</kbd>' or absolute count of pixels that are different, can be 4102controled using a <a href="#fuzz" >-fuzz</a> factor to ignore pixels which 4103only changed by a small amount. The '<kbd>PAE</kbd>' can be used to find the 4104size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels 4105'similar'. </p> 4106 4107<p>The '<kbd>MEPP</kbd>' metric returns three different metrics 4108('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>' 4109normalized) from the single comparision run. </p> 4110 4111<p>To print a complete list of metrics, use the <a href="#list">-list metrics</a> option.</p> 4112 4113 4114<div style="margin: auto;"> 4115 <h4><a name="mode" id="mode"></a>-mode <em class="arg">value</em></h4> 4116</div> 4117 4118<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> 4119 4120<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame, Unframe, or Concatenate</kbd></p> 4121 4122<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>' 4123argument for a list of <a href="#mode" >-mode</a> arguments available 4124in your ImageMagick installation.</p> 4125 4126 4127<div style="margin: auto;"> 4128 <h4><a name="modulate" id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4> 4129</div> 4130 4131<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> 4132 4133<p>The arguments are given as a percentages of variation. A value of 100 means no change, and any 4134missing values are taken to mean 100.</p> 4135 4136<p>The <em class="arg">brightness</em> is a multiplier of the overall brightness of the image, so 0 4137means pure black, 50 is half as bright, 200 is twice as bright. To invert its 4138meaning <a href="#negate">-negate</a> the image before and after. </p> 4139 4140<p>The <em class="arg">saturation</em> controls the amount of color in an image. For example, 0 produce a grayscale image, while a large value such as 200 produce a very colorful, 'cartoonish' color.</p> 4141 4142<p>The <em class="arg">hue</em> argument causes a "rotation" of the colors within the image by the amount specified. For example, 50 results in a counter-clockwise rotation of 90, mapping red 4143shades to purple, and so on. A value of either 0 or 200 results in a complete 4144180 degree rotation of the image. Using a value of 300 is a 360 degree 4145rotation resulting in no change to the original image. </p> 4146 4147<p>For example, to increase the color brightness by 20% and decrease the color saturation by 10% and leave the hue unchanged, use <a href="#modulate">-modulate 120,90</a>.</p> 4148 4149<p>Use <a href="#set">-set</a> attribute of '<kbd class="arg">option:modulate:colorspace</kbd>' to specify which colorspace to modulate. Choose from <kbd>HSB</kbd>, <kbd>HSL</kbd> (the default), or <kbd>HWB</kbd>. For example,</p> 4150 4151<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> 4152<div style="margin: auto;"> 4153 <h4><a name="monitor" id="monitor"></a>-monitor</h4> 4154</div> 4155 4156<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> 4157 4158 4159<div style="margin: auto;"> 4160 <h4><a name="monochrome" id="monochrome"></a>-monochrome</h4> 4161</div> 4162 4163<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> 4164 4165 4166<div style="margin: auto;"> 4167 <h4><a name="morph" id="morph"></a>-morph <em class="arg">frames</em></h4> 4168</div> 4169 4170<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> 4171 4172<p>Both the image pixels and size are linearly interpolated to give the 4173appearance of a meta-morphosis from one image to the next, over all the images 4174in the current image list. The added images are the equivalent of a <a 4175href="#blend">-blend</a> composition. The <em class="arg">frames</em> 4176argument determine how many images to interpolate between each image. </p> 4177 4178 4179<div style="margin: auto;"> 4180 <h4><a name="mosaic" id="mosaic"></a>-mosaic</h4> 4181</div> 4182 4183<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> 4184 4185 4186<div style="margin: auto;"> 4187 <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> 4188</div> 4189 4190<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> 4191 4192<p>Blur with the given radius, standard deviation (sigma), and angle. The 4193angle given is the angle toward which the image is blurred. That is the 4194direction people would consider the object is coming from. </p> 4195 4196<p>Note that the blur is not uniform distribution, giving the motion a 4197definate sense of direction of movement. </p> 4198 4199<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4200pixels which are outside the image proper are blurred into the final result. 4201</p> 4202 4203<div style="margin: auto;"> 4204 <h4><a name="name" id="name"></a>-name</h4> 4205</div> 4206 4207<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> 4208<div style="margin: auto;"> 4209 <h4><a name="negate" id="negate"></a>-negate</h4> 4210</div> 4211 4212<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>replace every pixel with its complementary color.</td><td style='text-align:right;'></td></tr></table> 4213 4214<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> 4215 4216<div style="margin: auto;"> 4217 <h4><a name="noise" id="noise"></a>-noise <em class="arg">radius</em><br/> 4218 +noise <em class="arg">type</em></h4> 4219</div> 4220 4221<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> 4222 4223<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> 4224 4225<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> 4226 4227<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> 4228 4229<pre class="text"> 4230Gaussian 4231Impulse 4232Laplacian 4233Multiplicative 4234Poisson 4235Random 4236Uniform 4237</pre> 4238 4239<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p> 4240 4241<p>Also see the <a href="#evaluate">-evaluate</a> noise functions that allos 4242the use of a controlling value to specify teh amount of noise that should be 4243added to an image. </p> 4244 4245 4246<div style="margin: auto;"> 4247 <h4><a name="normalize" id="normalize"></a>-normalize</h4> 4248</div> 4249 4250<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> 4251 4252<p>The intensity values are stretched to cover the entire range of possible 4253values. While doing so, black-out at most <em>2%</em> of the pixels and 4254white-out at most <em>1%</em> of the pixels.</p> 4255 4256<p>Note that as of ImageMagick 6.4.7-0, <a href="#normalize" >-normalize</a> 4257is equivalent to <a href="#contrast-stretch" >-contrast-stretch 2%x1%</a>. 4258(Before this version, it was equivalent to <a href="#contrast-stretch" 4259>-contrast-stretch 2%x99%</a>).</p> 4260 4261<p>All the channels are normalized in concert by the came amount so as to 4262preserve color integrity, when the default <a href="#channel" >+channel</a> 4263setting is in use. Specifing any other <a href="#channel" >-channel</a> 4264setting will normalize the RGB channels independently.</p> 4265 4266<p>See <a href="#contrast-stretch" >-contrast-stretch</A> for more details. 4267Also see <a href="#auto-level" >-auto-level</a> for a 'perfect' normalization 4268that is better suited to mathematically generated images. </p> 4269 4270<p>This operator is under review for re-development. </p> 4271 4272 4273<div style="margin: auto;"> 4274 <h4><a name="ordered-dither" id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4> 4275</div> 4276 4277<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 4278class="arg">threshold map</em> specified, and a uniform color map with the 4279given number of <em class="arg">levels</em> per color channel . </td><td style='text-align:right;'></td></tr></table> 4280 4281<p>You can choose from these standard threshold maps:</p> 4282 4283<pre class="text"> 4284 threshold 4285 checks 4286 o2x2 4287 o3x3 4288 o4x4 4289 o8x8 4290 h4x4a 4291 h6x6a 4292 h8x8a 4293 h4x4o 4294 h6x6o 4295 h8x8o 4296 h16x16o 4297</pre> 4298 4299<p>The '<kbd>o</kbd>' maps are ordered diffused pixel threshold maps, while the 4300'<kbd>h</kbd>' maps are halftone threshold maps which are either 'a' angled, or 4301'o' orthogonal. The '<kbd>checks</kbd>' produce a 3 level checkerbord dither 4302pattern. Or you can define your own <em class="arg" >threshold map</em> in a 4303personal or system "<kbd>thresholds.xml</kbd>" XML file. </p> 4304 4305<p>To print a complete list of threshold, use the <a href="#list" >-list 4306threshold</a> option.</p> 4307 4308<p>It is recommended that the <a href="#map" >+map</a> operator be used after 4309applying <a href="#ordered-dither" >-ordered-dither</a> to reduce the number of 4310colors an animated image sequence, to less that 256 colors. This ensures that 4311a common or global color table is used when saving the result to a color 4312limited file format such as GIF. </p> 4313 4314<p>Note that at this time the exact same threshold dithering map is used for 4315all color channels, no attempt is made to offset or rotate the map for 4316different channels is made, to create an offset printing effect. (possible 4317future expansion) </p> 4318 4319 4320<div style="margin: auto;"> 4321 <h4><a name="opaque" id="opaque"></a>-opaque <em class="arg">color</em></h4> 4322</div> 4323 4324<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> 4325 4326<p>The <em class="arg" >color</em> argument is defined using the format 4327described under the <a href="#fill" >-fill</a> option. The <a href="#fuzz" 4328>-fuzz</a> setting can be used to match and replace colors similar to the one 4329given.</p> 4330 4331<p>The <a href="#transparent" >-transparent</a> operator is exactly the same 4332as <a href="#opaque" >-opaque</a> but makes the matching color transparent, 4333rather than the same as the current <a href="#fill">-fill</a> color. </p> 4334 4335<p>Use <em class="arg" >+opaque</em> to paint any pixel that does not match 4336the target color.</p> 4337 4338 4339 4340<div style="margin: auto;"> 4341 <h4><a name="orient" id="orient"></a>-orient <em class="arg">image orientation</em></h4> 4342</div> 4343 4344<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> 4345 4346<p>Choose from these orientations:</p> 4347 4348<pre class="text"> 4349 bottom-left 4350 bottom-right 4351 left-bottom 4352 left-top 4353 right-bottom 4354 right-top 4355 top-left 4356 top-right 4357 undefined 4358</pre> 4359 4360<p>To print a complete list of orientations, use the <a href="#list" >-list 4361orientation</a> option.</p> 4362 4363 4364<div style="margin: auto;"> 4365 <h4><a name="page" id="page"></a>-page <em class="arg">geometry</em><br/> 4366 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!<></em>}]<br/> 4367 +page 4368 </h4> 4369</div> 4370 4371<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> 4372 4373<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> 4374 4375<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> 4376 4377<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> 4378<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;"> 4379<thead> 4380 <tr valign="top"> 4381 <th align="center"><em class="arg">media</em></th> 4382 <th align="center"><em class="arg">width</em></th> 4383 <th align="center"><em class="arg">height</em></th> 4384 </tr> 4385</thead> 4386<tbody> 4387<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr> 4388<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr> 4389<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr> 4390<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4391<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4392<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr> 4393<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr> 4394<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr> 4395<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr> 4396<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr> 4397<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr> 4398<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr> 4399<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr> 4400<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr> 4401<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4402<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4403<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr> 4404<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr> 4405<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr> 4406<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr> 4407<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr> 4408<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr> 4409<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr> 4410<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr> 4411<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr> 4412<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr> 4413<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr> 4414<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr> 4415<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr> 4416<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr> 4417<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr> 4418<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr> 4419<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr> 4420<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr> 4421<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr> 4422<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4423<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4424<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr> 4425</tbody> 4426</table> 4427 4428 4429 4430 4431<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> 4432 4433<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> 4434 4435<p>The default page dimensions for a TEXT image is 612x792.</p> 4436 4437<p>This option is used in concert with <a href="#density">-density</a>.</p> 4438 4439<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p> 4440 4441<div style="margin: auto;"> 4442 <h4><a name="paint" id="paint"></a>-paint <em class="arg">radius</em></h4> 4443</div> 4444 4445<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> 4446 4447<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> 4448 4449<div style="margin: auto;"> 4450 <h4><a name="path" id="path"></a>-path <em class="arg">path</em></h4></div> 4451 4452<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> 4453 4454<div style="margin: auto;"> 4455 <h4><a name="pause_animate_" id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4> 4456</div> 4457 4458<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> 4459 4460<p>Pause for the specified number of seconds before repeating the animation.</p> 4461 4462<div style="margin: auto;"> 4463 <h4><a name="pause_import_" id="pause_import_"></a>-pause <em class="arg">seconds</em></h4> 4464</div> 4465 4466<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> 4467 4468<p>Pause for the specified number of seconds before taking the next snapshot.</p> 4469 4470<div style="margin: auto;"> 4471 <h4><a name="ping" id="ping"></a>-ping</h4> 4472</div> 4473 4474<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> 4475 4476<div style="margin: auto;"> 4477 <h4><a name="pointsize" id="pointsize"></a>-pointsize <em class="arg">value</em></h4> 4478</div> 4479 4480<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> 4481 4482<div style="margin: auto;"> 4483 <h4><a name="polaroid" id="polaroid"></a>-polaroid <em class="arg">angle</em></h4> 4484</div> 4485 4486<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> 4487 4488<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p> 4489 4490<div style="margin: auto;"> 4491 <h4><a name="posterize" id="posterize"></a>-posterize <em class="arg">levels</em></h4> 4492</div> 4493 4494<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> 4495 4496<div style="margin: auto;"> 4497 <h4><a name="preview" id="preview"></a>-preview <em class="arg">type</em></h4> 4498</div> 4499 4500<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> 4501 4502<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> 4503 4504<pre class="text"> 4505 Rotate 4506 Shear 4507 Roll 4508 Hue 4509 Saturation 4510 Brightness 4511 Gamma 4512 Spiff 4513 Dull 4514 Grayscale 4515 Quantize 4516 Despeckle 4517 ReduceNoise 4518 Add Noise 4519 Sharpen 4520 Blur 4521 Threshold 4522 EdgeDetect 4523 Spread 4524 Shade 4525 Raise 4526 Segment 4527 Solarize 4528 Swirl 4529 Implode 4530 Wave 4531 OilPaint 4532 CharcoalDrawing 4533 JPEG 4534</pre> 4535 4536<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p> 4537 4538<p>The default preview is <kbd>JPEG</kbd>.</p> 4539 4540<div style="margin: auto;"> 4541 <h4><a name="print" id="print"></a>-print <em class="arg">string</em></h4> 4542</div> 4543 4544<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> 4545 4546<div style="margin: auto;"> 4547 <h4><a name="process" id="process"></a>-process <em class="arg">command</em></h4> 4548</div> 4549 4550<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> 4551 4552<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> 4553 4554<div style="margin: auto;"> 4555 <h4><a name="profile" id="profile"></a>-profile <em class="arg">filename</em><br/> 4556 +profile <em class="arg">profile_name</em></h4> 4557</div> 4558 4559<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> 4560 4561<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> 4562 4563<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> 4564 4565<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> 4566 4567<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> 4568 4569<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p> 4570 4571<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p> 4572<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> 4573 4574<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert CMYK.tif -profile "CMYK.icc" -profile "RGB.icc" RGB.tiff</span></p> 4575<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results. 4576CMYK profiles are often very asymmetric since they involve 3−>4 and 4−>3 channel mapping. 4577</p> 4578 4579<div style="margin: auto;"> 4580 <h4><a name="quality" id="quality"></a>-quality <em class="arg">value</em></h4> 4581</div> 4582 4583<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> 4584 4585<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> 4586 4587<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> 4588 4589<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> 4590 4591<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> 4592 4593<p>If filter-type is 4 or less, the specified filter-type is used for all scanlines:</p> 4594 4595<pre class="text"> 4596 0: none 4597 1: sub 4598 2: up 4599 3: average 4600 4: Paeth 4601</pre> 4602 4603<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> 4604 4605<p>If filter-type is 6, adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p> 4606 4607<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> 4608 4609<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> 4610 4611<p>For further information, see the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p> 4612 4613<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> 4614 4615<div style="margin: auto;"> 4616 <h4><a name="quantize" id="quantize"></a>-quantize <em class="arg">colorspace</em></h4> 4617</div> 4618 4619<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> 4620 4621<p>To print a complete list of colorspaces, use the <a href="#list">-list colorspace</a> option.</p> 4622 4623 4624<div style="margin: auto;"> 4625 <h4><a name="quiet" id="quiet"></a>-quiet</h4> 4626</div> 4627 4628<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> 4629 4630<div style="margin: auto;"> 4631 <h4><a name="radial-blur" id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4> 4632</div> 4633 4634<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> 4635 4636<p>Note that this is actually a rotational blur rather than a radial and as 4637such actually mis-named. </p> 4638 4639<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4640pixels which are outside the image proper are blurred into the final result. 4641</p> 4642 4643 4644<div style="margin: auto;"> 4645 <h4><a name="raise" id="raise"></a>-raise <em class="arg">thickness</em></h4> 4646</div> 4647 4648<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> 4649 4650<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>. 4651</p> 4652 4653<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p> 4654 4655<div style="margin: auto;"> 4656 <h4><a name="random-threshold" id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4> 4657</div> 4658 4659<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> 4660 4661<div style="margin: auto;"> 4662 <h4><a name="recolor" id="recolor"></a>-recolor <em class="arg">matrix</em></h4> 4663</div> 4664 4665<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Translate, scale, shear, or rotate image colors.</td><td style='text-align:right;'></td></tr></table> 4666 4667<p>Although variable-sized matrices can be used, typically one uses a 5x5 matrix for an RGBA image and a 6x6 for CMYKA. Populate the last row with normalized values to translate. The translation matrix is similar to that used by Adobe 4668Flash except that the offset is scaled to 1.0 (divide Flash offset by 255).</p> 4669 4670<div style="margin: auto;"> 4671 <h4><a name="red-primary" id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4> 4672</div> 4673 4674<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> 4675 4676<div style="margin: auto;"> 4677 <h4><a name="regard-warnings" id="regard-warnings"></a>-regard-warnings</h4> 4678</div> 4679 4680<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> 4681 4682<div style="margin: auto;"> 4683 <h4><a name="remap" id="remap"></a>-remap <em class="arg">filename</em></h4> 4684</div> 4685 4686<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> 4687 4688<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then 4689the given colors are dithered over the image as necessary, otherwise the closest 4690color (in RGB colorspace) is selected to replace that pixel in the image. </p> 4691 4692<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all 4693images in the current image sequence, all the images will have the same color 4694table. That means that when saved to a file format such as GIF, it will use 4695that color table as a single common or global color table, for all the images, 4696without requiring extra local color tables. </p> 4697 4698<p>Use <a href="#remap">+remap</a> to reduce all images in the current image 4699sequence to use a common color map over all the images. This equivalent to 4700appending all the images together (without extra background colors) and color 4701reducing those images using <a href="#colors">-colors</a> with a 256 color 4702limit, then <a href="#remap">-remap</a> those colors over the original list of 4703images. This ensures all the images follow a single color map. </p> 4704 4705<p>If the number of colors over all the images is less than 256, then <a 4706href="#remap">+remap</a> should not perform any color reduction or dithering, as 4707no color changes are needed. In that case, its only effect is to force the use 4708of a global color table. This recommended after using either <a 4709href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to 4710reduce the number of colors in an animated image sequence. </p> 4711 4712<div style="margin: auto;"> 4713 <h4><a name="region" id="region"></a>-region <em class="arg">geometry</em></h4> 4714</div> 4715 4716<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> 4717 4718<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> 4719 4720<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> 4721 4722<div style="margin: auto;"> 4723 <h4><a name="remote" id="remote"></a>-remote</h4> 4724</div> 4725 4726<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> 4727 4728<p>The only command recognized is the name of an image file to load.</p> 4729 4730<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> 4731 4732<div style="margin: auto;"> 4733 <h4><a name="render" id="render"></a>-render</h4> 4734</div> 4735 4736<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> 4737 4738<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> 4739 4740<div style="margin: auto;"> 4741<h4><a name="repage" id="repage"></a>-repage <em class="arg">geometry</em></h4> 4742</div> 4743 4744<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> 4745 4746<p>This option is like <a href="#page">-page</a> but acts as an image operator 4747rather than a setting. You can separately set the canvas size or the offset 4748of the image on that canvas by only providing those components. </p> 4749 4750<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> 4751 4752<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing 4753offset to move the image relative to its previous position. This useful for 4754animation sequences. </p> 4755 4756<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to 4757recalculate the canvas size so the image (at its current offset) will appear 4758completely on that canvas (unless it has a negative offset).</p> 4759 4760<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual 4761canvas meta-data from the images. </p> 4762 4763<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to 4764directly assign virtual canvas meta-data. </p> 4765 4766 4767<div style="margin: auto;"> 4768 <h4><a name="resample" id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4> 4769</div> 4770 4771<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> 4772 4773<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> 4774 4775<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> 4776 4777<div style="margin: auto;"> 4778 <h4><a name="resize" id="resize"></a>-resize <em class="arg">geometry</em></h4> 4779</div> 4780 4781<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> 4782 4783<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> 4784 4785<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> 4786 4787<div style="margin: auto;"> 4788 <h4><a name="respect-parentheses" id="respect-parentheses"></a>-respect-parentheses</h4> 4789</div> 4790 4791<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> 4792 4793<div style="margin: auto;"> 4794 <h4><a name="reverse" id="reverse"></a>-reverse</h4> 4795</div> 4796 4797<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> 4798 4799 4800<div style="margin: auto;"> 4801 <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> 4802</div> 4803 4804<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> 4805 4806<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> 4807 4808 4809<div style="margin: auto;"> 4810 <h4><a name="rotate" id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg"><</em>}{<em class="arg">></em>}</h4> 4811</div> 4812 4813<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> 4814 4815<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> 4816 4817<p>Empty triangles in the corners, left over from rotating the image, are 4818filled with the <kbd>background</kbd> color. </p> 4819 4820<p>See also the <a href="#distort">-distort</a> operator and specifically the 4821'<kbd>ScaleRotateTranslate</kbd>' distort method. </p> 4822 4823 4824<div style="margin: auto;"> 4825 <h4><a name="sample" id="sample"></a>-sample <em class="arg">geometry</em></h4> 4826</div> 4827 4828<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> 4829 4830<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> 4831 4832<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> 4833 4834 4835<div style="margin: auto;"> 4836 <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> 4837</div> 4838 4839<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> 4840 4841<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> 4842 4843<div style="margin: auto;"> 4844 <h4><a name="scale" id="scale"></a>-scale <em class="arg">geometry</em></h4> 4845</div> 4846 4847<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> 4848 4849<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> 4850 4851<div style="margin: auto;"> 4852 <h4><a name="scene" id="scene"></a>-scene <em class="arg">value</em></h4> 4853</div> 4854 4855<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> 4856 4857<p>This option sets the scene number of an image or the first image in an image sequence.</p> 4858 4859<div style="margin: auto;"> 4860 <h4><a name="screen" id="screen"></a>-screen</h4> 4861</div> 4862 4863<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> 4864 4865<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> 4866 4867<div style="margin: auto;"> 4868 <h4><a name="seed" id="seed"></a>-seed</h4> 4869</div> 4870 4871<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> 4872 4873<div style="margin: auto;"> 4874 <h4><a name="segment" id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4> 4875</div> 4876 4877<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> 4878 4879<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> 4880 4881<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> 4882 4883<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report 4884of the color clusters is returned.</p> 4885 4886 4887<div style="margin: auto;"> 4888 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">geometry</em></h4> 4889</div> 4890 4891<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> 4892 4893<div style="margin: auto;"> 4894 <h4><a name="separate" id="separate"></a>-separate</h4> 4895</div> 4896 4897<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> 4898 4899<div style="margin: auto;"> 4900 <h4><a name="sepia-tone" id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4> 4901</div> 4902 4903<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> 4904 4905<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p> 4906 4907<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> 4908 4909<div style="margin: auto;"> 4910 <h4><a name="set" id="set"></a>-set <em class="arg">attribute value</em></h4> 4911</div> 4912 4913<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> 4914 4915<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> 4916 4917<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -set comment 'Rose is a rose is a rose is a rose' rose.png</span><span class='crtout'></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> 4918<p>The <a href="#repage">-repage</a> operator will also set the 4919'<kbd>page</kbd>' attribute of images already in memory, but allows you to 4920separately set the virtual canvas's size and offset components, and also allows 4921relative offset changes, and automatic canvas size re-calculating. The above 4922<a href="#set">-set</a> option is purely a direct, unmodified assignment of the 4923virtual canvas (page) meta-data. </p> 4924 4925<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> 4926 4927<div style="margin: auto;"> 4928 <h4><a name="shade" id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4> 4929</div> 4930 4931<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> 4932 4933<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> 4934 4935<div style="margin: auto;"> 4936 <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> 4937</div> 4938 4939<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> 4940 4941<div style="margin: auto;"> 4942 <h4><a name="shared-memory" 4943id="shared-memory"></a>-shared-memory</h4> 4944</div> 4945 4946<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> 4947 4948<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> 4949 4950<div style="margin: auto;"> 4951 <h4><a name="sharpen" id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4> 4952</div> 4953 4954<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> 4955 4956<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p> 4957 4958<div style="margin: auto;"> 4959 <h4><a name="shave" id="shave"></a>-shave <em class="arg">geometry</em></h4> 4960</div> 4961 4962<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> 4963 4964<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> 4965 4966<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> 4967 4968<div style="margin: auto;"> 4969 <h4><a name="shear" id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4> 4970</div> 4971 4972<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> 4973 4974<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> 4975 4976<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> 4977 4978<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> 4979 4980<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> 4981 4982<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> 4983<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> 4984 4985<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p> 4986<div style="margin: auto;"> 4987 <h4><a name="sigmoidal" id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4> 4988</div> 4989 4990<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> 4991 4992<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> 4993 4994<div style="margin: auto;"> 4995 <h4><a name="silent" id="silent"></a>-silent</h4> 4996</div> 4997 4998<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> 4999 5000<div style="margin: auto;"> 5001 <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> 5002</div> 5003 5004<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> 5005 5006<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> 5007 5008<p>For Photo CD images, choose from these sizes:</p> 5009 5010<pre class="text"> 5011 192x128 5012 384x256 5013 768x512 5014 1536x1024 5015 3072x2048 5016</pre> 5017 5018<div style="margin: auto;"> 5019 <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> 5020</div> 5021 5022<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> 5023 5024<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> 5025 5026<div style="margin: auto;"> 5027 <h4><a name="snaps" id="snaps"></a>-snaps <em class="arg">value</em></h4> 5028</div> 5029 5030<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> 5031 5032<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p> 5033 5034<div style="margin: auto;"> 5035 <h4><a name="solarize" id="solarize"></a>-solarize <em class="arg">threshold</em></h4> 5036</div> 5037 5038<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> 5039 5040<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p> 5041 5042<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p> 5043 5044<div style="margin: auto;"> 5045 <h4><a name="sparse-color" id="sparse-color"></a>-sparse-color <em 5046 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4> 5047</div> 5048 5049<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> 5050 5051 5052<table class="doc"> 5053 <tbody> 5054 <tr valign="top"> 5055 <th align="left" style="width: 8%">Method</th> 5056 <th align="left">Description</th> 5057 </tr> 5058 5059 <tr valign="top"> 5060 <td valign="top">voronoi</td> 5061 <td valign="top">Simply map each pixel to the to nearest color point 5062 given. The result are polygonal 'cells' of solid color. </td> 5063 </tr> 5064 5065 <tr valign="top"> 5066 <td valign="top">shepards</td> 5067 <td valign="top">Colors points basied on the ratio of inverse distance 5068 squared. Generating spots of color in a sea of the average of 5069 colors. </td> 5070 </tr> 5071 5072 <tr valign="top"> 5073 <td valign="top">barycentric</td> 5074 <td valign="top">three point triangle of color given 3 points. 5075 Giving only 2 points will form a linear gradient between those points. 5076 Gradient is however not restricted to just the triangle or line. </td> 5077 </tr> 5078 5079 <tr valign="top"> 5080 <td valign="top">bilinear</td> 5081 <td valign="top">Like barycentric but for 4 points. Less than 4 points 5082 fall back to barycentric. </td> 5083 </tr> 5084 5085 </tbody> 5086</table> 5087 5088<p>The points are placed according to the images location on the virtual 5089canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a> 5090offset), and do not actually have to exist on the given image, but may be 5091some point beyond the edge of the image. All points are floating point values. 5092</p> 5093 5094<p>Only the color channels defined by the <a href="#channel" >-channel</a> are 5095modified, whcih means the matte/alpha transparency channel is not effected by 5096default. If enabled, the image also needs a the matte/alpha channel to be 5097enabled for this operator to effect an images transparency. This is typical 5098transparency handling for images. </p> 5099 5100<p>All the above methods when given a single point of color will replace all 5101the colors in the image with the color given, regardless of the point. This is 5102logical, and provides an alternative technique to recolor a image to some 5103default value. </p> 5104 5105 5106<div style="margin: auto;"> 5107 <h4><a name="splice" id="splice"></a>-splice <em class="arg">geometry</em></h4> 5108</div> 5109 5110<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> 5111 5112<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> 5113 5114<div style="margin: auto;"> 5115 <h4><a name="spread" id="spread"></a>-spread <em class="arg">amount</em></h4> 5116</div> 5117 5118<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> 5119 5120<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> 5121 5122<div style="margin: auto;"> 5123 <h4><a name="stegano" id="stegano"></a>-stegano <em class="arg">offset</em></h4> 5124</div> 5125 5126<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> 5127 5128<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> 5129 5130<div style="margin: auto;"> 5131 <h4><a name="stereo" id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4> 5132</div> 5133 5134<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> 5135 5136<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> 5137 5138<div style="margin: auto;"> 5139 <h4><a name="storage-type" id="storage-type"></a>-storage-type <em class="arg">type</em></h4> 5140</div> 5141 5142<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> 5143 5144<pre class="text"> 5145 char store pixels as unsigned characters 5146 double store pixels as doubles 5147 float store pixels as floats 5148 integer store pixels as integers 5149 long store pixels as longs 5150 quantum store pixels in the native depth of your ImageMagick distribution 5151 short store pixels as unsigned shorts 5152</pre> 5153 5154<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels 5155values range from 0 to the maximum value the storage type can support.</p> 5156 5157<div style="margin: auto;"> 5158 <h4><a name="stretch" id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4> 5159</div> 5160 5161<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> 5162 5163<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> 5164 5165<pre class="text"> 5166 Any 5167 Condensed 5168 Expanded 5169 ExtraCondensed 5170 ExtraExpanded 5171 Normal 5172 SemiCondensed 5173 SemiExpanded 5174 UltraCondensed 5175 UltraExpanded 5176</pre> 5177 5178<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p> 5179 5180<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> 5181 5182<div style="margin: auto;"> 5183 <h4><a name="strip" id="strip"></a>-strip</h4> 5184</div> 5185 5186<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> 5187 5188<div style="margin: auto;"> 5189 <h4><a name="stroke" id="stroke"></a>-stroke <em class="arg">color</em></h4> 5190</div> 5191 5192<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> 5193 5194<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5195 5196<p>See <a href="#draw">-draw</a> for further details.</p> 5197 5198<div style="margin: auto;"> 5199 <h4><a name="strokewidth" id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4> 5200</div> 5201 5202<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> 5203 5204<p>See <a href="#draw">-draw</a> for further details.</p> 5205 5206<div style="margin: auto;"> 5207 <h4><a name="style" id="style"></a>-style <em class="arg">fontStyle</em></h4> 5208</div> 5209 5210<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> 5211 5212<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> 5213 5214<pre class="text"> 5215 Any 5216 Italic 5217 Normal 5218 Oblique 5219</pre> 5220 5221<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> 5222 5223<div style="margin: auto;"> 5224 <h4><a name="swap" id="swap"></a>-swap <em class="arg">index,index</em></h4> 5225</div> 5226 5227<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> 5228 5229<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> 5230 5231<div style="margin: auto;"> 5232 <h4><a name="swirl" id="swirl"></a>-swirl <em class="arg">degrees</em></h4> 5233</div> 5234 5235<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> 5236 5237<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p> 5238 5239<div style="margin: auto;"> 5240 <h4><a name="taint" id="taint"></a>-taint</h4> 5241</div> 5242 5243<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> 5244 5245<div style="margin: auto;"> 5246 <h4><a name="text-font" id="text-font"></a>-text-font <em class="arg">name</em></h4> 5247</div> 5248 5249<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> 5250 5251<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> 5252 5253<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> 5254 5255<div style="margin: auto;"> 5256 <h4><a name="texture" id="texture"></a>-texture <em class="arg">filename</em></h4> 5257</div> 5258 5259<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> 5260 5261<div style="margin: auto;"> 5262 <h4><a name="threshold" id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 5263</div> 5264 5265<!-- {<em class="arg">green,blue,opacity</em>} 5266<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> 5267--> 5268 5269<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> 5270 5271<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> 5272 5273<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. 5274</p> 5275 5276<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> 5277 5278<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p> 5279<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> 5280 5281 5282<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> 5283<p>Note that the values of the transparency channel is treated as 'matte' 5284values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 5285 5286<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>. 5287</p> 5288 5289<div style="margin: auto;"> 5290 <h4><a name="thumbnail" id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4> 5291</div> 5292 5293<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> 5294 5295<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> 5296 5297<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> 5298 5299<div style="margin: auto;"> 5300 <h4><a name="tile" id="tile"></a>-tile <em class="arg">filename</em></h4> 5301</div> 5302 5303<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> 5304 5305<div style="margin: auto;"> 5306 <h4>-tile <em class="arg">geometry</em></h4> 5307</div> 5308 5309<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> 5310 5311<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> 5312 5313<div style="margin: auto;"> 5314 <h4>-tile</h4> 5315</div> 5316 5317<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> 5318 5319<div style="margin: auto;"> 5320 <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> 5321</div> 5322 5323<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> 5324 5325<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> 5326 5327<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> 5328 5329<div style="margin: auto;"> 5330 <h4><a name="tint" id="tint"></a>-tint <em class="arg">value</em></h4> 5331</div> 5332 5333<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> 5334 5335<p>Tint the image with the fill color.</p> 5336 5337<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> 5338 5339<div style="margin: auto;"> 5340 <h4><a name="title" id="title"></a>-title <em class="arg">string</em></h4> 5341</div> 5342 5343<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> 5344 5345<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> 5346 5347<p>For example,</p> 5348 5349<p class="crtsnip"> 5350 -title "%m:%f %wx%h" 5351</p> 5352 5353<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> 5354 5355 5356<div style="margin: auto;"> 5357 <h4><a name="transform" id="transform"></a>-transform</h4> 5358</div> 5359 5360<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> 5361 5362<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p> 5363 5364<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> 5365<div style="margin: auto;"> 5366 <h4><a name="transparent" id="transparent"></a>-transparent <em class="arg">color</em></h4> 5367</div> 5368 5369<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> 5370 5371<p>The <em class="arg">color</em> argument is defined using the format 5372described under the <a href="#fill">-fill</a> option. The <a href="#fuzz" 5373>-fuzz</a> setting can be used to match and replace colors similar to the one 5374given. </p> 5375 5376<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a 5377href="#transparent" >-transparent</a> but replaces the matching color same as 5378the current <a href="#fill">-fill</a> color setting. </p> 5379 5380<p>This does not define the 'transparency color' used for color-mapped image 5381formats, such as GIF. For that use <a href="#transparent-color" 5382>-transparent-color</a> </p> 5383 5384<p>Use <a href="#opaque">+opaque</a> to invered the pixels matched, that is 5385paint any pixel that does not match the target color, with the fill color.</p> 5386 5387 5388<div style="margin: auto;"> 5389 <h4><a name="transparent-color" id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4> 5390</div> 5391 5392<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> 5393 5394<p>Sometimes this is used for saving to image formats such as 5395GIF and PNG8 which uses this color to represent boolean transparency. This 5396does not make a color transparent, it only defines what color the transparent 5397color is in the color palette of the saved image. Use <a 5398href="#transparent">-transparent</a> to make an opaque color transparent.</p> 5399 5400<p>This option allows you to have both an opaque visible color, as well as a 5401transparent color of the same color value without conflict. That is, you can 5402use the same color for both the transparent and opaque color areas within an 5403image. This, in turn, frees to you to select a transparent color that is 5404appropriate when an image is displayed by an application that does not handle a 5405transparent color index, while allowing ImageMagick to correctly handle images of this 5406type. </p> 5407 5408<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p> 5409 5410<div style="margin: auto;"> 5411 <h4><a name="transpose" id="transpose"></a>-transpose</h4> 5412</div> 5413 5414<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> 5415 5416<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>. 5417</p> 5418 5419<div style="margin: auto;"> 5420 <h4><a name="transverse" id="transverse"></a>-transverse</h4> 5421</div> 5422 5423<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> 5424 5425 5426<div style="margin: auto;"> 5427 <h4><a name="treedepth" id="treedepth"></a>-treedepth <em class="arg">value</em></h4> 5428</div> 5429 5430<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> 5431 5432<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> 5433 5434<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> 5435 5436<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> 5437 5438<div style="margin: auto;"> 5439 <h4><a name="trim" id="trim"></a>-trim</h4> 5440</div> 5441 5442<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> 5443 5444<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> 5445 5446<p>The page or virtual canvas information of the image is preserved allowing 5447you to extract the result of the <a href="#trim">-trim</a> operation from the 5448image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page 5449information if it is unwanted.</p> 5450 5451<p>If the trimmed image 'disappears' an warning is produced, and a special 5452single pixel transparent 'missed' image is returned, in the same way as when a 5453<a href="#crop">-crop</a> operation 'misses' the image proper. </p> 5454 5455 5456<div style="margin: auto;"> 5457 <h4><a name="type" id="type"></a>-type <em class="arg">type</em></h4> 5458</div> 5459 5460<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the image type.</td><td style='text-align:right;'></td></tr></table> 5461 <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> 5462 5463<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> 5464 5465<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p> 5466<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> 5467 5468<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p> 5469 5470<div style="margin: auto;"> 5471 <h4><a name="undercolor" id="undercolor"></a>-undercolor <em class="arg">color</em></h4> 5472</div> 5473 5474<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> 5475 5476<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5477 5478<p>See <a href="#draw">-draw</a> for further details.</p> 5479 5480 5481<div style="margin: auto;"> 5482 <h4><a name="update" id="update"></a>-update <em class="arg">seconds</em></h4> 5483</div> 5484 5485<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> 5486 5487<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> 5488 5489 5490<div style="margin: auto;"> 5491 <h4><a name="unique-colors" id="unique-colors"></a>-unique-colors</h4> 5492</div> 5493 5494<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> 5495 5496 5497<div style="margin: auto;"> 5498 <h4><a name="units" id="units"></a>-units <em class="arg">type</em></h4> 5499</div> 5500 5501<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> 5502 5503<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> 5504 5505 5506<div style="margin: auto;"> 5507 <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> 5508</div> 5509 5510<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> 5511 5512<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> 5513 5514<p>The parameters are:</p> 5515 5516<pre class="text"> 5517 radius: The radius of the Gaussian, in pixels, not counting the center 5518 pixel (default 0). 5519 sigma: The standard deviation of the Gaussian, in pixels (default 1.0). 5520 amount: The fraction of the difference between the original and the blur 5521 image that is added back into the original (default 1.0). 5522 threshold: The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the 5523 difference amount (default 0.05). 5524</pre> 5525 5526 5527<div style="margin: auto;"> 5528 <h4><a name="verbose" id="verbose"></a>-verbose</h4> 5529</div> 5530 5531<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> 5532 5533 5534<div style="margin: auto;"> 5535 <h4><a name="version" id="version"></a>-version</h4> 5536</div> 5537 5538<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> 5539 5540 5541<div style="margin: auto;"> 5542 <h4><a name="view" id="view"></a>-view <em class="arg">string</em></h4> 5543</div> 5544 5545<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> 5546 5547 5548<div style="margin: auto;"> 5549 <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> 5550</div> 5551 5552<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> 5553 5554 5555<div style="margin: auto;"> 5556 <h4><a name="virtual-pixel" id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4> 5557</div> 5558 5559<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> 5560 5561<p>This option defines what color source should be used if and when a color 5562lookup completely 'misses' the source image. The color(s) that appear to 5563surround the source image. Generally this color is derived from the source 5564image, but could also be set to a specify background color. </p> 5565 5566<p>Choose from these methods:</p> 5567 5568<pre class="text"> 5569 background: the area surrounding the image is the background color 5570 black: the area surrounding the image is black 5571 checker-tile: alternate squares with image and background color 5572 dither: non-random 32x32 dithered pattern 5573 edge: extend the edge pixel toward infinity 5574 gray: the area surrounding the image is gray 5575 horizontal-tile: horizontally tile the image, background color above/below 5576 horizontal-tile-edge: horizontally tile the image and replicate the side edge pixels 5577 mirror: mirror tile the image 5578 random: choose a random pixel from the image 5579 tile: tile the image (default) 5580 transparent: the area surrounding the image is transparent blackness 5581 vertical-tile: vertically tile the image, sides are background color 5582 vertical-tile-edge: vertically tile the image and replicate the side edge pixels 5583 white: the area surrounding the image is white 5584</pre> 5585 5586<p>The default value is "edge".</p> 5587 5588<p>This most important for distortion operators such as <a href="#distort" 5589>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>. 5590However it also effects operations that may access pixels just outside the 5591image proper, such as <a href="#convolve">-convolve</a>, <a 5592href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p> 5593 5594<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p> 5595 5596 5597<div style="margin: auto;"> 5598 <h4><a name="visual" id="visual"></a>-visual <em class="arg">type</em></h4> 5599</div> 5600 5601<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> 5602 5603<p>Choose from these visual classes:</p> 5604 5605<pre class="text"> 5606 StaticGray 5607 GrayScale 5608 StaticColor 5609 PseudoColor 5610 TrueColor 5611 DirectColor 5612 default 5613 visual id 5614</pre> 5615 5616<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> 5617 5618 5619<div style="margin: auto;"> 5620 <h4><a name="watermark" id="watermark"></a>-watermark <em 5621 class="arg">brightness</em>x<em class="arg">saturation</em></h4> 5622</div> 5623 5624<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 5625saturation.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 5626 5627<p>Take a grayscale image (with alpha mask) and modify the destination image's 5628brightness according to watermark image's grayscale value and the <em 5629class="arg">brightness</em> percentage. The destinations color saturation 5630attribute is just direct modified by the <em class="arg">saturation</em> 5631percentage, which defaults to 100 percent (no color change). </p> 5632 5633 5634<div style="margin: auto;"> 5635 <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> 5636</div> 5637 5638<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> 5639 5640<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p> 5641 5642<div style="margin: auto;"> 5643 <h4><a name="weight" id="weight"></a>-weight <em class="arg">fontWeight</em></h4> 5644</div> 5645 5646<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> 5647 5648<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> 5649 5650<table class="doc"> 5651 <col width="25%" /> 5652 <col width="75%" /> 5653 <thead> 5654 <tr> 5655 <th><em class="arg">fontWeight</em></th> 5656 <th>Description</th> 5657 </tr> 5658 </thead> 5659 <tbody> 5660 <tr><td>All </td> <td>No effect. </td></tr> 5661 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr> 5662 <tr><td>Bolder </td> <td>Add 100 to font weight if currently ≤ 800.</td></tr> 5663 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently ≤ 100.</td></tr> 5664 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr> 5665 </tbody> 5666 </table> 5667 5668<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p> 5669 5670<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> 5671 5672<div style="margin: auto;"> 5673 <h4><a name="white-point" id="white-point"></a>-white-point <em class="arg">x,y</em></h4> 5674</div> 5675 5676<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> 5677 5678<div style="margin: auto;"> 5679 <h4><a name="white-threshold" id="white-threshold"></a>-white-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 5680</div> 5681 5682<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> 5683 5684<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. 5685</p> 5686 5687<div style="margin: auto;"> 5688 <h4><a name="window" id="window"></a>-window <em class="arg">id</em></h4> 5689</div> 5690 5691<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> 5692 5693<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> 5694 5695<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> 5696 5697<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> 5698 5699<div style="margin: auto;"> 5700 <h4><a name="window-group" id="window-group"></a>-window-group</h4> 5701</div> 5702 5703<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> 5704 5705<div style="margin: auto;"> 5706 <h4><a name="write" id="write"></a>-write <em class="arg">filename</em></h4> 5707</div> 5708 5709<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> 5710 <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> 5711 5712<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p> 5713 5714 5715</div> 5716 5717<div id="linkbar"> 5718 <!-- <span id="linkbar-west"> </span> --> 5719 <span id="linkbar-center"> 5720 <a href="http://www.imagemagick.org/discourse-server/">Discourse Server</a> • 5721 <a href="/www/mailing-list.html">Mailing Lists</a> • 5722 <a href="http://studio.webbyland.com/ImageMagick/MagickStudio/scripts/MagickStudio.cgi">Studio</a> 5723 </span> 5724 <span id="linkbar-east"> </span> 5725 </div> 5726 <div class="footer"> 5727 <span id="footer-west">© 1999-2009 ImageMagick Studio LLC</span> 5728 <span id="footer-east"> <a href="http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span> 5729 </div> 5730 <div style="clear: both; margin: 0; width: 100%; "></div> 5731</body> 5732</html> 5733
