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href="/www/command-line-options.html#print">‑print</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#process">‑process</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#profile">‑profile</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#quality">‑quality</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#quantize">‑quantize</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#quiet">‑quiet</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#radial-blur">‑radial‑blur</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#raise">‑raise</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#random-threshold">‑random‑threshold</a> <span class='bull'> • </span> <a href="/www/command-line-options.html#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="brightness-contrast" id="brightness-contrast"></a>-brightness-contrast <em class="arg">brightness</em><br />-brightness-contrast <em class="arg">brightness</em>{x<em class="arg">contrast</em>}{<em class="arg">%</em>}}</h4> 681</div> 682 683<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Adjust the brightness and/or contrast of the image.</td><td style='text-align:right;'></td></tr></table> 684 685<p>Brightness and Contrast values apply changes to the input image. They are not absolute settings. A brightness or contrast value of zero means no change. The range of values is -100 to +100 on each. Positive values increase the brightness or contrast and negative values decrease the brightness or contrast. To control only contrast, set the brightness=0. To control only brightness, set contrast=0 or just leave it off.</p> 686 687<p>You may also use <a href="#fill">-channel</a> to control which channels to apply the brightness and/or contrast change. The default is to apply the same transformation to all channels.</p> 688 689<p>Brightness and Contrast arguments are converted to offset and slope of a linear transform and applied using <a href="#fill">-function polynomial "slope,offset"</a>.</p> 690 691<p>The slope varies from 0 at contrast=-100 to almost vertical at contrast=+100. For brightness=0 and contrast=-100, the result will be totally midgray. For brightness=0 and contrast=+100, the result will approach but not quite reach a threshold at midgray; that is the linear transformation will be a a very steep vertical line at mid gray.</p> 692 693<p>Negative slopes, i.e. negating the image, are not possible with this function. All achievable slopes will be zero or positive.</p> 694 695<p>The offset varies from -0.5 at brightness=-100 to 0 at brightness=0 to +0.5 at brightness=+100. Thus, when contrast=0 and brightness=100, the result will be totally white. Similarly, when contrast=0 and brightness=-100, the result will be totally black.</p> 696 697<p>As the range of values for the arguments are -100 to +100, adding the '%' symbol will be no different than leaving it off.</p> 698 699<div style="margin: auto;"> 700 <h4><a name="cache" id="cache"></a>-cache <em class="arg">threshold</em></h4> 701</div> 702 703<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>(This option has been replaced by the <a href='#limit'>-limit</a> option.)</td><td style='text-align:right;'></td></tr></table> 704 705<div style="margin: auto;"> 706 <h4><a name="caption" id="caption"></a>-caption <em class="arg">string</em></h4> 707</div> 708 709<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Assign a caption to an image.</td><td style='text-align:right;'></td></tr></table> 710 711<div style="margin: auto;"> 712 <h4><a name="cdl" id="cdl"></a>-cdl <em class="arg">filename</em></h4> 713</div> 714 715<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>color correct with a color decision list.</td><td style='text-align:right;'></td></tr></table> 716 717<p>Here is an example color correction collection:</p> 718 719<pre class="text"> 720<?xml version="1.0" encoding="UTF-8"?> 721<ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2"> 722 <ColorCorrection id="cc06668"> 723 <SOPNode> 724 <Slope> 0.9 1.2 0.5 </Slope> 725 <Offset> 0.4 -0.5 0.6 </Offset> 726 <Power> 1.0 0.8 1.5 </Power> 727 </SOPNode> 728 <SATNode> 729 <Saturation> 0.85 </Saturation> 730 </SATNode> 731 </ColorCorrection> 732</ColorCorrectionCollection> 733</pre> 734 735<div style="margin: auto;"> 736 <h4><a name="channel" id="channel"></a>-channel <em class="arg">type</em></h4> 737</div> 738 739<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify those image color channels to which subsequent operators are limited.</td><td style='text-align:right;'></td></tr></table> 740 741<p>Choose from: <kbd>Red</kbd>, <kbd>Green</kbd>, <kbd>Blue</kbd>, <kbd>Alpha</kbd>, <kbd>Cyan</kbd>, <kbd>Magenta</kbd>, <kbd>Yellow</kbd>, <kbd>Black</kbd>, <kbd>Opacity</kbd>, <kbd>Index</kbd>, <kbd>RGB</kbd>, <kbd>RGBA</kbd>, <kbd>CMYK</kbd>, or <kbd>CMYKA</kbd>.</p> 742 743<p>To print a complete list of channel types, use <a href="#list">-list channel</a>.</p> 744 745<p>The channels above can be specified as a comma-separated list or can be 746abbreviated as a concatenation of the letters '<kbd>R</kbd>', '<kbd>G</kbd>', 747'<kbd>B</kbd>', '<kbd>A</kbd>', '<kbd>O</kbd>', '<kbd>C</kbd>', 748'<kbd>M</kbd>', '<kbd>Y</kbd>', '<kbd>K</kbd>'. 749 750For example, to negate only the alpha channel of an image, use</p> 751<p class="crtsnip"> 752 -channel Alpha -negate 753</p> 754 755Some operators also allow the use of a special channel flag 756'<code>sync</code>'. If present operators that understand this flag will 757apply the exact same image modification to all the image channels in the image 758so as to ensure that colors are kept 'in-sync'. Without this flag such 759operators will apply there function to each channel separately. See <a 760href="#auto-level">-auto-level</a> and <a href="#auto-gamma">-auto-gamma</a> 761for examples of such an operator. </p> 762 763 764<p>By default, ImageMagick sets <a href="#channel">-channel</a> to the value 765'<kbd>RGB,sync</kbd>', which specifies that operators act on all channels 766except the opacity channel, and that all the color channels are to be modified 767in exactly the same way. The 'plus' form <a href="#channel" >+channel</a> 768will reset the value back to this default. </p> 769 770<p>Options that are affected by the <a href="#channel" >-channel</a> setting 771include the following. 772 773<a href="#auto-gamma">-auto-gamma</a>, 774<a href="#auto-level">-auto-level</a>, 775<a href="#black-threshold">-black-threshold</a>, 776<a href="#blur">-blur</a>, 777<a href="#clamp">-clamp</a>, 778<a href="#clut">-clut</a>, 779<a href="#combine">-combine</a>, 780<a href="#contrast-stretch">-contrast-stretch</a>, 781<a href="#evaluate">-evaluate</a>, 782<a href="#function">-function</a>, 783<a href="#fx">-fx</a>, 784<a href="#gaussian-blur">-gaussian-blur</a>, 785<a href="#hald-clut">-hald-clut</a>, 786<a href="#motion-blur">-motion-blur</a>, 787<a href="#negate">-negate</a>, 788<a href="#normalize">-normalize</a>, 789<a href="#ordered-dither">-ordered-dither</a>, 790<a href="#radial-blur">-radial-blur</a>, 791<a href="#random-threshold">-random-threshold</a>, 792<a href="#separate">-separate</a>, and 793<a href="#threshold">-threshold</a>, and 794<a href="#white-threshold">-white-threshold</a>. 795</p> 796 797<p>Warning, some operators behave differentally when the <a href="#channel" 798>+channel</a> default setting is in effect, verses ANY user defined <a 799href="#channel" >-channel</a> setting (including the equivelent of the 800default). For example <a href="#threshold">-threshold</a> will by default 801gray-scale the image before thresholding, if no <a href="#channel" 802>-channel</a> setting has been defined. </p> 803 804<p>Also some operators such as <a href="#blur">-blur</a>, <a 805href="#gaussian-blur">-gaussian-blur</a>, will modify their handling of the 806color channels if the '<kbd>alpha</kbd>' channel is also enabled by <a 807href="#channel" >-channel</a>. Generally this done to ensure that 808fully-transparent colors are treated as being fully-transparent, and thus any 809underlying 'hidden' color has no effect on the final results. Typically 810resulting in 'halo' effects. </p> 811 812<p>As a alpha channel is optional within images some operators will read the 813color channels of an image as a greyscale alpha mask, when the image has no 814alpha channel present, but the <a href="#channel" >-channel</a> setting tells 815the operator to apply the alpha channel. The <a href="#clut">-clut</a> 816operator is a good example of this. </p> 817 818 819<div style="margin: auto;"> 820 <h4><a name="clamp" id="clamp"></a>-clamp</h4> 821</div> 822 823<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> 824 825<div style="margin: auto;"> 826 <h4><a name="charcoal" id="charcoal"></a>-charcoal <em class="arg">factor</em></h4> 827</div> 828 829<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> 830 831<div style="margin: auto;"> 832 <h4><a name="chop" id="chop"></a>-chop <em class="arg">geometry</em></h4> 833</div> 834 835<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> 836 837<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> 838 839<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> 840 841<div style="margin: auto;"> 842 <h4><a name="clip" id="clip"></a>-clip</h4> 843</div> 844 845<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> 846 847<p>If a clipping path is present, it is applied to subsequent operations.</p> 848 849<p>For example, in the command</p> 850 851<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -clip -negate cockatoo.tif negated.tif</span></p> 852<p>only the pixels within the clipping path are negated.</p> 853 854<p>The <a href="#clip">-clip</a> feature requires the XML library. If the XML library is not present, the option is ignored.</p> 855 856<div style="margin: auto;"> 857 <h4><a name="clip-mask" id="clip-mask"></a>-clip-mask</h4> 858</div> 859 860<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> 861 862<div style="margin: auto;"> 863 <h4><a name="clip-path" id="clip-path"></a>-clip-path <em class="arg">id</em></h4> 864</div> 865 866<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> 867 868<div style="margin: auto;"> 869 <h4><a name="clone" id="clone"></a>-clone <em class="arg">index(s)</em></h4> 870</div> 871 872<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> 873 874<p>Specify the image by its index in the sequence. The first image is index 8750. Negative indexes are relative to the end of the sequence; for example, −1 876represents the last image of the sequence. Specify a range of images with a 877dash (e.g. 0−4). Separate multiple indexes with commas but no spaces (e.g. 0,2,5). Use <a 878href="#clone">+clone</a> make a copy of the last image in the image 879sequence.</p> 880 881<div style="margin: auto;"> 882 <h4><a name="clut" id="clut"></a>-clut</h4> 883</div> 884 885<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 886corresponding channel in the second image as a <b>c</b>olor 887<b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style='text-align:right;'></td></tr></table> 888 889<p>The second (LUT) image is ordinarily a gradient image containing the 890histogram mapping of how each channel should be modified. Typically it is a 891either a single row or column image of replacement color values. If larger 892than a single row or column, values are taken from a diagonal line from 893top-left to bottom-right corners.</p> 894 895<p>The lookup is further controlled by the <a 896href="#interpolate">-interpolate</a> setting, which is especially handy for an 897LUT which is not the full length needed by the ImageMagick installed Quality 898(Q) level. Good settings for this are the '<kbd>bilinear</kbd>' and 899'<kbd>bicubic</kbd>' interpolation settings, which give smooth color 900gradients, and the '<kbd>integer</kbd>' setting for a direct, unsmoothed 901lookup of color values. </p> 902 903<p>This operator is especially suited to replacing a grayscale image with a 904specific color gradient from the CLUT image. </p> 905 906<p>Only the channel values defined by the <a href="#channel">-channel</a> 907setting will have their values replaced. In particular, since the default <a 908href="#channel">-channel</a> setting is <kbd>RGB</kbd>, this means that 909transparency (alpha/matte channel) is not affected, unless the <a 910href="#channel">-channel</a> setting is modified. When the alpha channel is 911set, it is treated by the <a href="#clut" >-clut</a> operator in the same way 912as the other channels, implying that alpha/matte values are replaced using the 913alpha/matte values of the original image. </p> 914 915<p>If either the image being modified, or the lookup image, conatins no 916transparency (i.e. <a href="#alpha" >-alpha</a> is turned 'off') but the <a 917href="#channel">-channel</a> setting includes alpha replacement, then it is 918assumed that image represents a gray-scale graident which will be used for the 919replacement alpha values. That is you can use a gray-scale CLUT image to 920adjust a existing images alpha channel, or you can color a gray-scale image 921using colors form CLUT containing the desired colors, including transparency. 922</p> 923 924<p>See also <a href="#hald-clut" >-hald-clut</a> which replaces colors according 925the lookup of the full color RGB value from a 2D representation of a 3D color 926cube. </p> 927 928 929<div style="margin: auto;"> 930 <h4><a name="coalesce" id="coalesce"></a>-coalesce</h4> 931</div> 932 933<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> 934 935<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> 936 937<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> 938 939 940<div style="margin: auto;"> 941 <h4><a name="colorize" id="colorize"></a>-colorize <em class="arg">value</em></h4> 942</div> 943 944<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> 945 946<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> 947 948<div style="margin: auto;"> 949 <h4><a name="colormap" id="colormap"></a>-colormap <em class="arg">type</em></h4> 950</div> 951 952<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> 953 954<p>The <em class="arg">type</em> can be <kbd>shared</kbd> or <kbd>private</kbd>.</p> 955 956<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> 957 958<div style="margin: auto;"> 959 <h4><a name="colors" id="colors"></a>-colors <em class="arg">value</em></h4> 960</div> 961 962<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> 963 964<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> 965 966<div style="margin: auto;"> 967 <h4><a name="colorspace" id="colorspace"></a>-colorspace <em class="arg">value</em></h4> 968</div> 969 970<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> 971 972<p>Choices are:</p> 973 974<pre class="text"> 975 CMY 976 CMYK 977 Gray 978 HSB 979 HSL 980 HWB 981 Lab 982 Log 983 OHTA 984 Rec601Luma 985 Rec601YCbCr 986 Rec709Luma 987 Rec709YCbCr 988 RGB 989 sRGB 990 Transparent 991 XYZ 992 YCbCr 993 YCC 994 YIQ 995 YPbPr 996 YUV 997</pre> 998 999<p>To print a complete list of colorspaces, use <a href="#list">-list colorspace</a>.</p> 1000 1001<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> 1002 1003<table class="doc"> 1004 <caption>Conversion Of RGB To Other Color Spaces</caption> 1005 <tr><th align="left" valign="middle">CMY</th></tr> 1006 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>−R</td></tr> 1007 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>−G</td></tr> 1008 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>−B</td></tr> 1009 <tr><th align="left" valign="middle">CMYK — starts with CMY from above</th></tr> 1010 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr> 1011 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1012 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1013 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 1014 1015 <tr><th align="left" valign="middle">Gray</th></tr> 1016 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 1017 1018 <tr><th align="left" valign="middle">HSB — Hue, Saturation, Brightness; like a cone peak downward</th></tr> 1019 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1020 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1021 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr> 1022 1023 <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> 1024 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 1025 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 1026 <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> 1027 1028 <tr><th align="left" valign="middle">HWB — Hue, Whiteness, Blackness</th></tr> 1029 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr> 1030 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr> 1031 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr> 1032 1033 <tr><th align="left" valign="middle">LAB</th></tr> 1034 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr> 1035 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr> 1036 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr> 1037 1038 <tr><th align="left" valign="middle">LOG</th></tr> 1039 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr> 1040 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr> 1041 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr> 1042 1043 <tr><th align="left" valign="middle">OHTA — approximates principal components transformation</th></tr> 1044 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr> 1045 <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> 1046 <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> 1047 1048 <tr><th align="left" valign="middle">Rec601Luma</th></tr> 1049 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 1050 1051 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr> 1052 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1053 <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> 1054 <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> 1055 1056 <tr><th align="left" valign="middle">Rec709Luma</th></tr> 1057 <tr><td align="left" valign="middle">Gray=0.21260*R+0.71520*G+0.07220*B</td></tr> 1058 1059 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr> 1060 <tr><td align="left" valign="middle">Y=0.212600*R+0.715200*G+0.072200*B; <em>intensity-like</em></td></tr> 1061 <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> 1062 <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> 1063 1064 <tr><th align="left" valign="middle">sRGB</th></tr> 1065 <tr><td align="left" valign="middle">if Rs ≤ .03928 then Rs=R/12.92 else Rs=((R+.055)/1.055)^2.4</td></tr> 1066 <tr><td align="left" valign="middle">if Gs ≤ .03928 then Gs=B/12.92 else Gs=((G+.055)/1.055)^2.4</td></tr> 1067 <tr><td align="left" valign="middle">if Bs ≤ .03928 then Bs=B/12.92 else Bs=((B+.055)/1.055)^2.4</td></tr> 1068 1069 <tr><th align="left" valign="middle">XYZ</th></tr> 1070 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr> 1071 <tr><td align="left" valign="middle">Y=0.2126560*R+0.7151580*G+0.0721856*B</td></tr> 1072 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr> 1073 1074 <tr><th align="left" valign="middle">YCC</th></tr> 1075 <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> 1076 <tr><td align="left" valign="middle">C1=(−0.29900*R−0.58700*G+0.88600*B) (with complicated scaling)</td></tr> 1077 <tr><td align="left" valign="middle">C2=(0.70100*R−0.58700*G−0.11400*B) (with complicated scaling)</td></tr> 1078 1079 <tr><th align="left" valign="middle">YCbCr</th></tr> 1080 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1081 <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> 1082 <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> 1083 1084 <tr><th align="left" valign="middle">YIQ</th></tr> 1085 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1086 <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> 1087 <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> 1088 1089 <tr><th align="left" valign="middle">YPbPr</th></tr> 1090 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 1091 <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> 1092 <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> 1093 1094 <tr><th align="left" valign="middle">YUV</th></tr> 1095 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 1096 <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> 1097 <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> 1098</table> 1099 1100<div style="margin: auto;"> 1101 <h4><a name="combine" id="combine"></a>-combine</h4> 1102</div> 1103 1104<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> 1105 1106<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> 1107 1108<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. 1109</p> 1110 1111<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert original.png -channel RGB -separate sepimage.png</span><span class='crtout'></span><span class="crtprompt"> $magick> </span><span class='crtin'>convert sepimage-0.png sepimage-1.png sepimage-2.png -channel RGB \ <br/> -combine imagecopy.png</span></p> 1112<div style="margin: auto;"> 1113 <h4><a name="comment" id="comment"></a>-comment <em class="arg">string</em></h4> 1114</div> 1115 1116<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> 1117 1118<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> 1119 1120<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> 1121 1122<p>For example,</p> 1123 1124<p class="crtsnip"> 1125 -comment "%m:%f %wx%h" 1126</p> 1127 1128<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> 1129 1130<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> 1131 1132<div style="margin: auto;"> 1133 <h4><a name="compose" id="compose"></a>-compose <em class="arg">operator</em></h4> 1134</div> 1135 1136<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> 1137 1138<p>The description of composition uses abstract terminology in order to allow 1139the description to be more precise, while avoiding constant values which are 1140specific to a particular build configuration. Each image pixel is represented 1141by red, green, and blue levels (which are equal for a gray pixel). The 1142build-dependent value <em class="QR">QuantumRange</em> is the maximum integral 1143value which may be stored, per pixel, in the red, green, or blue channels of 1144the image. Each image pixel may also optionally (if the image matte channel is 1145enabled) have an associated level of opacity, ranging from <em>opaque</em> to 1146<em>transparent</em>, which may be used to determine the influence of the pixel 1147color when compositing the pixel with another image pixel. If the image matte 1148channel is disabled, then all pixels in the image are treated as opaque. The 1149color of an opaque pixel is fully visible while the color of a transparent 1150pixel color is entirely absent (pixel color is ignored).</p> 1151 1152<p>By definition, raster images have a rectangular shape. All image rows are of 1153equal length, as are all image columns. By treating the alpha channel as a 1154visual "mask" the rectangular image may be given a "shape" by treating the 1155alpha channel as a cookie-cutter for the image. This is done by setting the 1156pixels within the shape to be opaque, with pixels outside the shape set as 1157transparent. Pixels on the boundary of the shape may be between opaque and 1158transparent in order to provide antialiasing (visually smooth edges). The 1159description of the composition operators use this concept of image "shape" in 1160order to make the description of the operators easier to understand. While it 1161is convenient to describe the operators in terms of "shapes" they are by no 1162means limited to mask-style operations since they are based on continuous 1163floating-point mathematics rather than simple boolean operations.</p> 1164 1165<p>The following alpha blending (Duff-Porter) compose methods are available:</p> 1166 1167<table class="doc"> 1168 <tbody> 1169 <tr valign="top"> 1170 <th align="left" style="width: 8%">Method</th> 1171 <th align="left">Description</th> 1172 </tr> 1173 1174 <tr valign="top"> 1175 <td valign="top">clear</td> 1176 <td valign="top">Both the color and the alpha of the destination are 1177 cleared. Neither the source nor the destination are used (except for 1178 destinations size and other meta-data which is always preserved.</td> 1179 </tr> 1180 1181 <tr valign="top"> 1182 <td valign="top">src</td> 1183 <td valign="top">The source is copied to the destination. The destination 1184 is not used as input, though it is cleared.</td> 1185 </tr> 1186 1187 <tr valign="top"> 1188 <td valign="top">dst</td> 1189 <td valign="top">The destination is left untouched. The source image is 1190 completely ignored.</td> 1191 </tr> 1192 1193 <tr valign="top"> 1194 <td valign="top">src-over</td> 1195 <td valign="top">The source is composited over the destination. this is 1196 the default alpha blending compose method, when neither the compose 1197 setting is set, nor is set in the image meta-data.</td> 1198 </tr> 1199 1200 <tr valign="top"> 1201 <td valign="top">dst-over</td> 1202 <td valign="top">The destination is composited over the source and the 1203 result replaces the destination.</td> 1204 </tr> 1205 1206 <tr valign="top"> 1207 <td valign="top">src-in</td> 1208 <td valign="top">The part of the source lying inside of the destination 1209 replaces the destination.</td> 1210 </tr> 1211 1212 <tr valign="top"> 1213 <td valign="top">dst-in</td> 1214 <td valign="top">The part of the destination lying inside of the source 1215 replaces the destination. Areas not overlaid are cleared.</td> 1216 </tr> 1217 1218 <tr valign="top"> 1219 <td valign="top">src-out</td> 1220 <td valign="top">The part of the source lying outside of the destination 1221 replaces the destination.</td> 1222 </tr> 1223 1224 <tr valign="top"> 1225 <td valign="top">dst-out</td> 1226 <td valign="top">The part of the destination lying outside of the source 1227 replaces the destination.</td> 1228 </tr> 1229 1230 <tr valign="top"> 1231 <td valign="top">src-atop</td> 1232 <td valign="top">The part of the source lying inside of the destination is 1233 composited onto the destination.</td> 1234 </tr> 1235 1236 <tr valign="top"> 1237 <td valign="top">dst-atop</td> 1238 <td valign="top">The part of the destination lying inside of the source is 1239 composited over the source and replaces the destination. Areas not 1240 overlaid are cleared. </td> 1241 </tr> 1242 1243 <tr valign="top"> 1244 <td valign="top">xor</td> 1245 <td valign="top">The part of the source that lies outside of the 1246 destination is combined with the part of the destination that lies 1247 outside of the source. Source or Destination, but not both. </td> 1248 </tr> 1249 1250 </tbody> 1251</table> 1252 1253<p>Any of the 'Src-*' methods can also be specified without the 'Src-' part. 1254For example the defaul compose method can be specified as just 'Over'.</p> 1255 1256 1257<p>The following mathemathical composition methods are also available. </p> 1258 1259<p>Typically these use the default 'Over' alpha blending when transparencies 1260are also involved, except for 'Plus', 'Minus', 'Add', and 'Subtract', which 1261also composes the alpha channel using the same process as the color channels. 1262This allows them to be used for special image masking techniques. </p> 1263 1264<table class="doc"> 1265 <tbody> 1266 <tr valign="top"> 1267 <th align="left" style="width: 8%">Method</th> 1268 <th align="left">Description</th> 1269 </tr> 1270 1271 <tr valign="top"> 1272 <td valign="top">multiply</td> 1273 <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> 1274 </tr> 1275 1276 <tr valign="top"> 1277 <td valign="top">screen</td> 1278 <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> 1279 </tr> 1280 1281 <tr valign="top"> 1282 <td valign="top">plus</td> 1283 <td valign="top">The source is added to the destination and replaces the 1284 destination. This operator is useful for averaging or a controled 1285 merger of two images, rather than a direct overlay.</td> 1286 </tr> 1287 1288 <tr valign="top"> 1289 <td valign="top">add</td> 1290 <td valign="top">As per 'plus' but transparency data is treated as matte 1291 values. As such any transparent areas in either image remain 1292 transparent. </td> 1293 </tr> 1294 1295 <tr valign="top"> 1296 <td valign="top">minus</td> 1297 <td valign="top">Subtract the colors in the source image from the 1298 destination image. When transparency is involved, opaque areas is 1299 subtracted from any destination opaque areas. </td> 1300 </tr> 1301 1302 <tr valign="top"> 1303 <td valign="top">subtract</td> 1304 <td valign="top">Subtract the colors in the source image from the 1305 destination image. When transparency is involved transparent areas are 1306 subtracted, so only the opaque areas in the source remain opaque in 1307 the destination image. </td> 1308 </tr> 1309 1310 <tr valign="top"> 1311 <td valign="top">difference</td> 1312 <td valign="top">Subtracts the darker of the two constituent colors from 1313 the lighter. Painting with white inverts the destination color. 1314 Painting with black produces no change.</td> 1315 </tr> 1316 1317 <tr valign="top"> 1318 <td valign="top">exclusion</td> 1319 <td valign="top">Produces an effect similar to that of 'difference', but 1320 appears as lower contrast. Painting with white inverts the 1321 destination color. Painting with black produces no change.</td> 1322 </tr> 1323 1324 <tr valign="top"> 1325 <td valign="top">darken</td> 1326 <td valign="top">Selects the darker of the destination and source colors. 1327 The destination is replaced with the source when the source is darker, 1328 otherwise it is left unchanged.</td> 1329 </tr> 1330 1331 <tr valign="top"> 1332 <td valign="top">lighten</td> 1333 <td valign="top">Selects the lighter of the destination and source colors. 1334 The destination is replaced with the source when the source is 1335 lighter, otherwise it is left unchanged. </td> 1336 </tr> 1337 1338 <tr valign="top"> 1339 <td valign="top">linear-dodge</td> 1340 <td valign="top">This is equivelent to 'Plus' in that the color channels 1341 are simply added, however it does not 'Plus' the alpha channel, but 1342 uses the normal 'Over' alpha blending, which transparencies are 1343 involved. Produces a sort of additive multiply-like result. Added 1344 ImageMagick version 6.5.4-3. </td> 1345 </tr> 1346 1347 <tr valign="top"> 1348 <td valign="top">linear-burn</td> 1349 <td valign="top">As 'Linear-Dodge', but also subtract one from the result. 1350 Sort of a additive 'Screen' of the images. Added ImageMagick version 1351 6.5.4-3. </td> 1352 </tr> 1353 1354 <tr valign="top"> 1355 <td valign="top">color-dodge</td> 1356 <td valign="top">Brightens the destination color to reflect the source 1357 color. Painting with black produces no change.</td> 1358 </tr> 1359 1360 <tr valign="top"> 1361 <td valign="top">color-burn</td> 1362 <td valign="top">Darkens the destination color to reflect the source 1363 color. Painting with white produces no change. Fixed in ImageMagick 1364 version 6.5.4-3. </td> 1365 </tr> 1366 1367 <tr valign="top"> 1368 <td valign="top">overlay</td> 1369 <td valign="top">Multiplies or screens the colors, dependent on the 1370 destination color. Source colors overlay the destination whilst 1371 preserving its highlights and shadows. The destination color is not 1372 replaced, but is mixed with the source color to reflect the lightness 1373 or darkness of the destination.</td> 1374 </tr> 1375 1376 <tr valign="top"> 1377 <td valign="top">hard-light</td> 1378 <td valign="top">Multiplies or screens the colors, dependent on the source 1379 color value. If the source color is lighter than 0.5, the destination 1380 is lightened as if it were screened. If the source color is darker 1381 than 0.5, the destination is darkened, as if it were multiplied. The 1382 degree of lightening or darkening is proportional to the difference 1383 between the source color and 0.5. If it is equal to 0.5 the 1384 destination is unchanged. Painting with pure black or white produces 1385 black or white.</td> 1386 </tr> 1387 1388 1389 <tr valign="top"> 1390 <td valign="top">linear-light</td> 1391 <td valign="top">Like 'Hard-Light' but using linear-dodge and linear-burn 1392 instead. Increases contrast slightly with an impact on the 1393 foreground's tonal values.</td> 1394 </tr> 1395 1396 <tr valign="top"> 1397 <td valign="top">soft-light</td> 1398 <td valign="top">Darkens or lightens the colors, dependent on the source 1399 color value. If the source color is lighter than 0.5, the destination 1400 is lightened. If the source color is darker than 0.5, the destination 1401 is darkened, as if it were burned in. The degree of darkening or 1402 lightening is proportional to the difference between the source color 1403 and 0.5. If it is equal to 0.5, the destination is unchanged. Painting 1404 with pure black or white produces a distinctly darker or lighter area, 1405 but does not result in pure black or white. Fixed in ImageMagick 1406 version 6.5.4-3. </td> 1407 </tr> 1408 1409 <tr valign="top"> 1410 <td valign="top">pegtop-light</td> 1411 <td valign="top">Almost equivelent to 'Soft-Light', but using a 1412 continuious mathematical formula rather than two conditionally 1413 selected formulae. Added ImageMagick version 6.5.4-3. </td> 1414 </tr> 1415 1416 <tr valign="top"> 1417 <td valign="top">vivid-light</td> 1418 <td valign="top">A modified 'Linear-Light' designed to preserve very stong 1419 primary and secondary colors in the image. Added ImageMagick version 1420 6.5.4-3. </td> 1421 </tr> 1422 1423 <tr valign="top"> 1424 <td valign="top">pin-light</td> 1425 <td valign="top">Similar to 'Hard-Light', but using sharp linear shadings, 1426 to similate the effects of a strong 'pinhole' light source. Added 1427 ImageMagick version 6.5.4-3. </td> 1428 </tr> 1429 1430 </tbody> 1431</table> 1432 1433 1434<p>Also included are these special purpose compose methods:</p> 1435 1436<table class="doc"> 1437 <tbody> 1438 <tr valign="top"> 1439 <th align="left" style="width: 8%">Method</th> 1440 <th align="left">Description</th> 1441 </tr> 1442 1443 <tr valign="top"> 1444 <td valign="top">copy-*</td> 1445 <td valign="top">Copy the specified channel (Red, Green, Blue, Cyan, 1446 Magenta, Yellow, Black, or Opacity) in the source image to the 1447 same channel in the destination image. If the channel specified 1448 does not exist in the source image, (which can only happen for methods, 1449 '<kbd>copy-opacity</kbd>' or '<kbd>copy-black</kbd>') then it is 1450 assumed that the source image is a special grayscale channel image 1451 of the values to be copied. </td> 1452 </tr> 1453 1454 <tr valign="top"> 1455 <td valign="top">change-mask</td> 1456 <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> 1457 </tr> 1458 </tbody> 1459</table> 1460 1461<p>On top of these composed methods are a few special ones that not only require 1462the two images that are being merged or overlaid, but have some extra numerical 1463arguments, which are tabled below. </p> 1464 1465<p>In the "<code>composite</code>" command these composition methods are 1466selected using special options with the arguments needed. They are usually, 1467but not always, the same name as the composte 'method' they use, and replaces 1468the normal use of the <a href="#compose" >-compose</a> setting in the 1469"<code>composite</code>" command. For example... </p> 1470 1471<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>composite ... -blend 50x50 ...</span></p> 1472<p>As of IM v6.5.3-4 the "<code>convert</code>" command can now also supply 1473these extra arguments to its <a href="#composite" >-composite</a> operator, 1474using the special <a href="#set">-set</a> attribute of '<kbd class="arg">option:compose:args</kbd>'. This means you can now make use of 1475these special argumented <a href="#compose" >-compose</a> methods, those the 1476argument and the method both need to be set separatally. For example... </p> 1477 1478<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert ... -compose blend -set option:compose:args 50x50 -composite ...</span></p> 1479<p>The following is a table of these special 'argumented' compose methods, 1480with a brief summary of what they do. For more details see the equivalent 1481"composite" command option name. </p> 1482 1483<table class="doc"> 1484 <tbody> 1485 <tr valign="top"> 1486 <th align="left" style="width: 8%">Method</th> 1487 <th align="left">Description</th> 1488 </tr> 1489 1490 <tr valign="top"> 1491 <td valign="top">dissolve</td> 1492 <td valign="top">Arguments: 1493 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>] 1494 <br>Equivalent to "<code>composite</code>" <a href="#dissolve">-dissolve</a> 1495 <br>Dissolve the 'source' image by the percentage given before overlaying 1496 'over' the 'destination' image. If <em class="arg">src_percent</em> is 1497 greater than 100, it starts dissolving the main image so it will 1498 become transparent at a value of '<kbd class="arg">200</kbd>'. If 1499 both percentages are given, each image are dissolved to the 1500 percentages given. 1501 </td> 1502 </tr> 1503 1504 <tr valign="top"> 1505 <td valign="top">blend</td> 1506 <td valign="top">Arguments: 1507 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>] 1508 <br>Equivalent to "<code>composite</code>" <a href="#blend">-blend</a> 1509 <br>Average the images together ('plus') according to the percentages 1510 given and each pixels transparency. If only a single percentage value 1511 is given it sets the weight of the composite or 'source' image, while 1512 the background image is weighted by the exact opposite amount. That is 1513 a <kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of 1514 the 'destination' image. Thus it is equivalent to <kbd>-blend 1515 30x70</kbd>. 1516 </td> 1517 </tr> 1518 1519 <tr valign="top"> 1520 <td valign="top">mathematics</td> 1521 <td valign="top">Arguments: <em class="arg">A, B, C, D</em> 1522 <br>Not available in "<code>composite</code>" at this time. 1523 <br>Merge the source and destination images according to the formula 1524 <br> <code>A*Sc*Dc + B*Sc + C*Dc + D</code> 1525 <br>Can be used to generate a custom composition method that would 1526 otherwise need to be implemented using the slow <a href="#fx">-fx</a> 1527 DIY image operator. Added to ImageMagick version 6.5.4-3. 1528 </td> 1529 </tr> 1530 1531 <tr valign="top"> 1532 <td valign="top">modulate</td> 1533 <td valign="top">Arguments: 1534 <em class="arg">brightness</em>[x<em class="arg">saturation</em>] 1535 <br>Equivalent to "<code>composite</code>" <a href="#watermark">-watermark</a> 1536 <br>Take a grayscale image (with alpha mask) and modify the destination 1537 image's brightness according to watermark image's grayscale value and 1538 the <em class="arg">brightness</em> percentage. The destinations 1539 color saturation attribute is just direct modified by the <em 1540 class="arg">saturation</em> percentage, which defaults to 100 percent 1541 (no color change). 1542 1543 </td> 1544 </tr> 1545 1546 <tr valign="top"> 1547 <td valign="top">displace</td> 1548 <td valign="top">Arguments: 1549 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em>][!][%] 1550 <br>Equivalent to "<code>composite</code>" <a href="#displace">-displace</a> 1551 <br>With this option, the 'overlay' image, and optionally the 'mask' 1552 image, is used as a relative displacement map, which is used to 1553 displace the lookup of what part of the destination image is seen at 1554 each point of the overlaid area. Much like the displacement map is a 1555 'lens' that distorts the original 'background' image behind it. 1556 <br><br> 1557 The X-scale is modilated by the 'red' channel of the overlay image 1558 while the Y-scale is modulated by the green channel, (the mask image 1559 if given is rolled into green channel of the overlay image. This 1560 separation allows you to modulate the X and Y lookup displacement 1561 separatally allowing you to di 2 dimentional displacements, rather 1562 than 1 dimentional verctored displacements (using grayscale image). 1563 <br><br> 1564 If the overlay image contains transparency this is used as a mask 1565 of the resulting image to remove 'invalid' pixels. 1566 <br><br> 1567 The '%' flag makes the displacement scale relative to the size of the 1568 overlay image (100% = half width/height of image). Using '!' switches 1569 percentage arguments to refer to the destination image size instead. 1570 <br><br> 1571 Special flags were added Added to ImageMagick version 6.5.3-5. 1572 </td> 1573 </tr> 1574 1575 <tr valign="top"> 1576 <td valign="top">distort</td> 1577 <td valign="top">Arguments: 1578 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em 1579 >[+<em class="arg">X-center</em>+<em class="arg">Y-center</em>]][!][%] 1580 <br>Not available in "<code>composite</code>" at this time. 1581 <br>Exactly as per 'Displace' (above), but using absolute coordinates, 1582 relative to the center of the overlay (or that given). Basically 1583 allows you to generate absolute distortion maps where 'black' will 1584 look up the left/top edge, and 'white' looks up the bottom/right 1585 edge of the destination image, according to the scale given. 1586 <br><br> 1587 The '!' flag not only switches percentage scaling, to use the 1588 destination image, but also the image the center offset of the lookup. 1589 This means the overlay can lookup a completely different region of the 1590 destination image. 1591 <br><br> 1592 Added to ImageMagick version 6.5.3-5. 1593 </td> 1594 </tr> 1595 1596 <tr valign="top"> 1597 <td valign="top">blur</td> 1598 <td valign="top">Arguments: 1599 <em class="arg">Width</em>[x<em class="arg">Height</em 1600 >[+<em class="arg">Angle</em>]] 1601 <br>Equivalent to "<code>composite</code>" 1602 <a href="#blur-composite">-blur</a> 1603 <br>A Variable Blur Mapping Composition method, where each pixel in the 1604 overlaid region is replaced with an Elliptical Weighted Average (EWA), 1605 with an ellipse (typically a circle) of the given sigma size, scaled 1606 according to overlay (source image) grayscale mapping. 1607 <br><br> 1608 As per 'Displace' and 'Distort', the red channel will modulate the 1609 width of the ellipse, while the green channel will modulate the height 1610 of the ellipse. However at this time the ellipse angle is not 1611 modulated though this may be a future posibility (perhaps with a 1612 special flag to enable use of blur channel for this purpose). 1613 <br><br> 1614 Added to ImageMagick version 6.5.4-0. 1615 </td> 1616 </tr> 1617 1618 </tbody> 1619</table> 1620 1621<p>To print a complete list of all the available compose operators, use <a href="#list">-list compose</a>.</p> 1622 1623 1624<div style="margin: auto;"> 1625 <h4><a name="composite" id="composite"></a>-composite</h4> 1626</div> 1627 1628<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> 1629 1630<p>Take the first image 'destination' and overlay the second 'source' image 1631according to the current <a href="#compose">-compose</a> setting. The location 1632of the 'source' or 'overlay' image is controlled according to <a 1633href="#geometry" >-geometry</a>, and <a href="#geometry" >-geometry</a> 1634settings. </p> 1635 1636<p>If a third image is given this is treated as a gray-scale 'mask' image 1637relative to the first 'destination' image. This mask will limit what parts of 1638the destination can be modified by the image composition. However for the 1639'<kbd>displace</kbd>' compose method, the mask is used to provide a separate 1640Y-displacement image instead. </p> 1641 1642<p>If a <a href="#compose">-compose</a> method requires extra numerical 1643arguments or flags these can be provided by setting the <a 1644href="#set">-set</a> '<kbd class="arg">option:compose:args</kbd>' 1645appropriatally for the compose method. </p> 1646 1647<p>Some <a href="#compose">-compose</a> methods can modify the 'destination' 1648image outside the overlay area. You can disable this by setting the special <a 1649href="#set">-set</a> '<kbd class="arg">option:compose:outside-overlay</kbd>' 1650to '<kbd>false</kbd>'. </p> 1651 1652 1653<div style="margin: auto;"> 1654 <h4><a name="compress" id="compress"></a>-compress <em class="arg">type</em></h4> 1655</div> 1656 1657<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> 1658 1659<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> 1660 1661<p>To print a complete list of compression types, use <a href="#list">-list compress</a>.</p> 1662 1663<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> 1664 1665<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> 1666 1667<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> 1668 1669<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> 1670 1671<div style="margin: auto;"> 1672 <h4><a name="contrast" id="contrast"></a>-contrast</h4> 1673</div> 1674 1675<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> 1676 1677<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> 1678 1679<p>For a more pronounced effect you can repeat the option:</p> 1680 1681<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -contrast -contrast rose_c2.png</span></p> 1682<div style="margin: auto;"> 1683 <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> 1684</div> 1685 1686<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> 1687 1688<p>While performing the stretch, black-out at most <em 1689class="arg" >black-point</em> pixels and white-out at most <em 1690class="arg" >white-point</em> pixels. Or, if percent is used, black-out at most 1691<em class="arg" >black-point %</em> pixels and white-out at most <em 1692class="arg" >white-point %</em> pixels.</p> 1693 1694<p>Prior to ImageMagick 6.4.7-0, <a href="#contrast-stretch" 1695>-contrast-stretch</a> will black-out at most <em class="arg" 1696>black-point</em> pixels and white-out at most <em class="arg" >total pixels 1697minus white-point</em> pixels. Or, if percent is used, black-out at most <em 1698class="arg">black-point %</em> pixels and white-out at most <em class="arg" 1699>100% minus white-point %</em> pixels.</p> 1700 1701<p>Note that <kbd>-contrast-stretch 0</kbd> will modify the image such that 1702the image's min and max values are stretched to 0 and <em class="QR" 1703>QuantumRange</em>, respectively, without any loss of data due to burn-out or 1704clipping at either end. This is not the same as <a href="#normalize" 1705>-normalize</a>, which is equivalent to <kbd>-contrast-stretch 2%x1%</kbd> (or 1706prior to ImageMagick 6.4.7-0, <kbd>-contrast-stretch 2%x99%</kbd>).</p> 1707 1708<p>Internally operator works by creating a histogram bin, and then uses that 1709bin to modify the image. As such some colors may be merged together when they 1710originally fell into the same 'bin'. </p> 1711 1712<p>All the channels are normalized in concert by the came amount so as to 1713preserve color integrity, when the default <a href="#channel" >+channel</a> 1714setting is in use. Specifing any other <a href="#channel" >-channel</a> 1715setting will normalize the RGB channels independently.</p> 1716 1717<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 1718normalization of mathematical images. </p> 1719 1720<p>This operator is under review for re-development. </p> 1721 1722 1723<div style="margin: auto;"> 1724 <h4><a name="convolve" id="convolve"></a>-convolve <em class="arg">kernel</em></h4> 1725</div> 1726 1727<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> 1728 1729<p>The <em class="arg">kernel</em> is a matrix specified as 1730a comma-separated list of integers (with no spaces), ordered left-to right, 1731starting with the top row. Presently, only odd-dimensioned kernels are 1732supported, and therefore the number of entries in the specified <em 1733class="arg">kernel</em> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25, 17347<sup>2</sup>=49, etc. </p> 1735 1736<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 1737positive and negative results are relative to a user-specified bias value. 1738This is important for non-HDRI compilations of ImageMagick when dealing with 1739convolutions that contain negative as well as positive values. This is 1740especially the case with convolutions involving high pass filters or edge 1741detection. Without an output bias, the negative values is clipped at zero. 1742</p> 1743 1744<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 1745negative results without clipping to the color value range (0..QuantumRange). 1746See the discussion on HDRI implementations of ImageMagick on the page <a 1747href="/www/high-dynamic-range.html">High 1748Dynamic-Range Images</a>. For more about HDRI go the ImageMagick <a 1749href="http://www.imagemagick.org/Usage/basics/#hdri">Usage</a> pages or this 1750<a href="http://en.wikipedia.org/wiki/High_dynamic_range_imaging">Wikipedia</a> 1751entry. </p> 1752 1753 1754<div style="margin: auto;"> 1755 <h4><a name="crop" id="crop"></a>-crop <em class="arg">geometry</em></h4> 1756</div> 1757 1758<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> 1759 1760<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> 1761 1762<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> 1763 1764<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> 1765 1766<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> 1767 1768<p>By adding a exclamation character flag to the geometry argument, the 1769cropped images virtual canvas page size and offset is set as if the 1770geometry argument was a viewport or window. This means the canvas page size 1771is set to exactly the same size you specified, the image offset set 1772relative top left corner of the region cropped. </p> 1773 1774<p>If the cropped image 'missed' the actual image on its virtual canvas, a 1775special single pixel transparent 'missed' image is returned, and a 'crop 1776missed' warning given. </p> 1777 1778<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> 1779 1780<div style="margin: auto;"> 1781 <h4><a name="cycle" id="cycle"></a>-cycle <em class="arg">amount</em></h4> 1782</div> 1783 1784<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> 1785 1786<p><em class="arg">Amount</em> defines the number of positions each 1787colormap entry is shifted.</p> 1788 1789 1790<div style="margin: auto;"> 1791 <h4><a name="debug" id="debug"></a>-debug <em class="arg">events</em></h4> 1792</div> 1793 1794<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> 1795 1796<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> 1797 1798 1799<p>For example, to log cache and blob events, use.</p> 1800 1801<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p> 1802<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p> 1803 1804<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p> 1805 1806<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p> 1807 1808<p>Use <a href="#debug">+debug</a> to turn off all logging.</p> 1809 1810<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> 1811 1812 1813<div style="margin: auto;"> 1814 <h4><a name="decipher" id="decipher"></a>-decipher <em class="arg">filename</em></h4> 1815</div> 1816 1817<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> 1818 1819<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 1820 1821<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 1822 1823 1824<div style="margin: auto;"> 1825 <h4><a name="deconstruct" id="deconstruct"></a>-deconstruct</h4> 1826</div> 1827 1828<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> 1829 1830<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> 1831 1832<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> 1833 1834<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p> 1835 1836 1837<div style="margin: auto;"> 1838 <h4><a name="define" id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4> 1839</div> 1840 1841<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> 1842 1843<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> 1844 1845<p>The following definitions may be created:</p> 1846 1847<ul> 1848<dt>dcm:display-range=reset</dt> 1849 <dd>Set the display range to the minimum and maximum pixel values for the DCM image format.</dd><br /> 1850<dt>dot:layout-engine=<em class="arg">value</em></dt> 1851 <dd>Set the specify the layout engine for the DOT image format (e.g. <kbd>neato</kbd>).</dd><br /> 1852<dt>jpeg:extent=<em class="arg">value</em></dt> 1853 <dd>Restrict the maximum JPEG file size, for example <kbd>-define jpeg:extent=400kb</kbd>.</dd><br /> 1854<dt>jpeg:size=<em class="arg">geometry</em></dt> 1855 <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 /> 1856<dt>jp2:rate=<em class="arg">value</em></dt> 1857 <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 /> 1858<dt>mng:need-cacheoff</dt> 1859 <dd>turn playback caching off for streaming MNG.</dd><br /> 1860<dt>png:bit-depth=<em class="arg">value</em></dt> 1861<dt>png:color-type=<em class="arg">value</em></dt> 1862 <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 /> 1863<dt>ps:imagemask</dt> 1864 <dd>If the ps:imagemask flag is defined, the PS3 and EPS3 coders will create Postscript files that render bilevel images with the Postscript imagemask operator instead of the image operator.</dd><br /> 1865<dt>quantum:format=<em class="arg">type</em></dt> 1866 <dd>Set the type to <kbd>floating-point</kbd> to specify a single precision floating-point format for raw files (e.g. GRAY:).</dd> 1867</ul> 1868 1869<p>For example, to create a postscript file that will render only the black pixels of a bilevel image, use:</p> 1870 1871<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p> 1872<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> 1873 1874<p class="crtsnip"> 1875-define registry:temporary-path=/data/tmp 1876</p> 1877 1878<div style="margin: auto;"> 1879 <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> 1880</div> 1881 1882<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> 1883 1884<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> 1885 1886<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> 1887 1888 1889<div style="margin: auto;"> 1890 <h4><a name="delete" id="delete"></a>-delete <em class="arg">index</em></h4> 1891</div> 1892 1893<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> 1894 1895<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> 1896 1897 1898<div style="margin: auto;"> 1899 <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> 1900</div> 1901 1902<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> 1903 1904<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> 1905 1906<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> 1907 1908<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> 1909 1910<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> 1911 1912<div style="margin: auto;"> 1913 <h4><a name="depth" id="depth"></a>-depth <em class="arg">value</em></h4> 1914</div> 1915 1916<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> 1917 1918<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> 1919 1920<div style="margin: auto;"> 1921 <h4><a name="descend" id="descend"></a>-descend</h4> 1922</div> 1923 1924<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> 1925 1926<div style="margin: auto;"> 1927 <h4><a name="deskew" id="deskew"></a>-deskew <em class="arg">threshold</em></h4> 1928</div> 1929 1930<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> 1931 1932<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> 1933 1934<div style="margin: auto;"> 1935 <h4><a name="despeckle" id="despeckle"></a>-despeckle</h4> 1936</div> 1937 1938<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> 1939 1940<div style="margin: auto;"> 1941 <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> 1942</div> 1943 1944<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> 1945 1946<p>With this option, the 'overlay' image, and optionally the 'mask' image, 1947will be used as a displacement map, which is used to displace the lookup of 1948what part of the 'background' image is seen at each point of the overlaid 1949area. Much like the displacement map is a 'lens' that redirects light shining 1950through it so as to present a distorted view the original 'background' image 1951behind it. </p> 1952 1953<p>Any perfect grey areas of the displacement map produce a zero 1954displacement of the image. Black areas produce the given maximum negative 1955displacement of the lookup point, while white produce a maximum positive 1956displacement of the lookup. </p> 1957 1958<p>Note that it is the lookup of the 'background' that is displaced, not a 1959displacement of the image itself. As such an area of the displacement map 1960containing 'white' will have the lookup point 'shifted' by a positive amount, 1961and thus generating a copy of the destination image to the right/downward from 1962the correct position. That is the image will look like it may have been 1963'shifted' in a negative left/upward direction. Understanding this is a very 1964important in understanding how displacement maps work. </p> 1965 1966<p>The given arguments define the maximum amount of displacement in pixels 1967that a particular map can produce. If the displacement scale is large enough 1968it is also posible to lookup parts of the 'background' image that lie well 1969outside the bounds of the displacement map itself. That is you could very 1970easilly copy a section of the original image from outside the overlay area 1971into the overlay area. </p> 1972 1973<p>The '%' flag makes the displacement scale relative to the size of the 1974overlay image (100% = half width/height of image). Using '!' switches 1975percentage arguments to refer to the destination image size instead. 1976these flags were added as of IM v6.5.3-5.</p> 1977 1978<p>Normally a single grayscale displacement map is provided, which with the 1979given scaling values will determine a single direction (vector) in which 1980displacements can occur (positivally or negativally). However, if you also 1981specify a third image which is normally used as a <em class="arg">mask</em>, 1982then the <em class="arg">composite image</em> will be used for horizontal X 1983displacement, while the <em class="arg">mask image</em> is used for vertical Y 1984displacement. This allows you to define completely different displacement 1985values for the X and Y directions, and allowing you to lookup any point within 1986the <em class="arg">scale</em> bounds. In other words each pixel can lookup 1987any other nearby pixel, producing complex 2 dimentional displacements, rather 1988than a simple 1 dimentional vector displacements. </p> 1989 1990<p>Alternativally rather than suppling two separate images, as of IM v6.4.4-0, 1991you can use the 'red' channel of the overlay image to specify the horizontal 1992or X displacement, and the 'green' channel for the vertical or Y displacement. 1993</p> 1994 1995<p>As of IM v6.5.3-5 any alpha channel in the overlay image will be used as a 1996mask the transparency of the destination image. However areas outside the 1997overlaid areas will not be effected. </p> 1998 1999 2000<div style="margin: auto;"> 2001 <h4><a name="display" id="display"></a>-display <em class="arg">host:display[.screen]</em></h4> 2002</div> 2003 2004<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> 2005 2006<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p> 2007 2008<div style="margin: auto;"> 2009 <h4><a name="dispose" id="dispose"></a>-dispose <em class="arg">method</em></h4> 2010</div> 2011 2012<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> 2013 2014<p>The layer disposal method defines the way each the displayed image is to be 2015modified after the current 'frame' of an animation has finished being 2016displayed (after its 'delay' period), but before the next frame on an 2017animation is to be overlaid onto the display. </p> 2018 2019<p>Here are the valid methods:</p> 2020 2021<pre class="text"> 2022Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>'). 2023None 1 Do not dispose, just overlay next frame image. 2024Background 2 Clear the frame area with the background color. 2025Previous 3 Clear to the image prior to this frames overlay. 2026</pre> 2027 2028<p>You can also use the numbers given above, which is what the GIF format 2029uses internally to represent the above settings. </p> 2030 2031<p>To print a complete list of dispose methods, use <a href="#list">-list dipose</a>.</p> 2032 2033<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent 2034resetting the layer disposal methods of images being read in. </p> 2035 2036<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image 2037disposal method for images already in memory.</p> 2038 2039<div style="margin: auto;"> 2040 <h4><a name="dissimilarity-threshold" id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4> 2041</div> 2042 2043<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> 2044 2045 2046<div style="margin: auto;"> 2047 <h4><a name="dissolve" id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4> 2048</div> 2049 2050<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> 2051 2052<p>The opacity of the composite image is multiplied by the given percent, then 2053it is composited 'over' the main image. If <em class="arg">src_percent</em> 2054is greater than 100, start dissolving the main image so it will become 2055transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages 2056are given, each image are dissolved to the percentages given. </p> 2057 2058<p>Note that dissolve percentages do not add, two opaque images dissolved 2059'50,50', produce a 75% transparency. For a 50% + 50% blending of the two 2060images, you would need to use dissolve values of '50,100'. </p> 2061 2062<div style="margin: auto;"> 2063 <h4><a name="distort" id="distort"></a>-distort <em class="arg">method arguments</em></h4> 2064</div> 2065 2066<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> 2067 2068<p>The <em class="arg">arguments</em> is a single string containing a list 2069of floating point numbers separated by commas or spaces. The number of 2070and meaning of the floating point values depends on the distortion <em 2071class="arg">method</em> being used. </p> 2072 2073<p>Choose from these distortion types:</p> 2074 2075<table class="doc"> 2076 <tr valign="top"> 2077 <th align="left" style="width: 8%">Method</th> 2078 <th align="left">Description</th> 2079 </tr> 2080 2081 <tr valign="top"> 2082 <td valign="top"><kbd>ScaleRotateTranslate</kbd> 2083 <br/>or <kbd>SRT</kbd></td> 2084 <td valign="top"> 2085 Distort image by first scaling and rotating about a given 'center', 2086 before translating that 'center' to the new location, in that order. It 2087 is an alternative method of specifying a '<kbd>Affine</kbd>' type of 2088 distortion, but without shearing effects. It also provides a good way 2089 of rotating and displacing a smaller image for tiling onto a larger 2090 background (IE 2-dimensional animations). <br/> 2091 2092 The number of arguments determine the specific meaning of each 2093 argument for the scales, rotation, and translation operations. <br/> 2094 2095 <table style="margin-left:auto; margin-right:auto;"> 2096 <tr><td># </td><td>arguments meaning</td></tr> 2097 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr> 2098 <tr><td>2:</td><td><em>Scale Angle</em></td></tr> 2099 <tr><td>3:</td><td><em>ScaleX,ScaleY Angle</em></td></tr> 2100 <tr><td>4:</td><td><em>X,Y Scale Angle</em></td></tr> 2101 <tr><td>5:</td> 2102 <td><em>X,Y ScaleX,ScaleY Angle</em></td></tr> 2103 <tr><td>6:</td> 2104 <td><em>X,Y Scale Angle NewX,NewY</em></td></tr> 2105 <tr><td>7:</td> 2106 <td><em>X,Y ScaleX,ScaleY Angle 2107 NewX,NewY</em></td></tr> 2108 </table> 2109 2110 This is actually an alternative way of specifing a 2 dimensional linear 2111 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr> 2112 2113 <tr valign="top"> 2114 <td valign="top"><kbd>Affine</kbd></td> 2115 <td valign="top"> 2116 Distort the image linearly by moving a list of at least 3 or more sets 2117 of control points (as defined below). Idealy 3 sets or 12 floating 2118 point values are given allowing the image to be linearly scaled, 2119 rotated, sheared, and translated, according to those three points. See 2120 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>' 2121 distortions. <br/> 2122 2123 More than 3 sets given control point pairs (12 numbers) is least 2124 squares fitted to best match a lineary affine distortion. If only 2 2125 control point pairs (8 numbers) are given a two point image translation 2126 rotation and scaling is performed, without any posible shearing, 2127 flipping or changes in aspect ratio to the resulting image. If only one 2128 control point pair is provides the image is only translated, (which may 2129 be a floating point non-integer translation). <br/> 2130 2131 This distortion does not include any form of perspective distortion. 2132 </td> 2133 2134 </tr> 2135 2136 <tr valign="top"> 2137 <td valign="top"><kbd>AffineProjection</kbd></td> 2138 <td valign="top"> 2139 Linearly distort an image using the given Affine Matrix of 6 2140 pre-calculated coefficients forming a set of Affine Equations to map 2141 the source image to the destination image. 2142 2143 <div style="text-align: center"><em> 2144 s<sub>x</sub>, r<sub>x</sub>, 2145 r<sub>y</sub>, s<sub>y</sub>, 2146 t<sub>x</sub>, t<sub>y</sub> 2147 </em></div> 2148 2149 See <a href="#affine" >-affine</a> setting for more detail, and 2150 meanings of these coefficients. <br/> 2151 2152 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide 2153 alternative methods of defining this distortion, with ImageMagick doing the 2154 calculations needed to generate the required coefficients. You can see 2155 the internally generated coefficients, by using a <a href="#verbose" 2156 >-verbose</a> setting. </td> 2157 2158 </tr> 2159 2160<!-- still under development, do not display - Anthony 2161 <tr valign="top"> 2162 <td valign="top"><kbd>Bilinear</kbd></td> 2163 <td valign="top"> 2164 Bilinear (reversed) Distortion, given a minimum of 4 sets of 2165 coordinate pairs, or 16 values (see below). Not that lines may not 2166 appear straight after distortion, though the distance between 2167 coordinates will remain consistant. </td> 2168 </tr> 2169--> 2170 2171 <tr valign="top"> 2172 <td valign="top"><kbd>Perspective</kbd></td> 2173 <td valign="top"> 2174 Perspective distort the images, using a list of 4 or more sets of 2175 control points (as defined below). More that 4 sets (16 numbers) of 2176 control points provide least squares fitting for more accurate 2177 distortions (for the purposes of image registration and panarama 2178 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>' 2179 linear distortion. <br/> 2180 2181 Perspective Distorted images ensures that straight lines remain 2182 straight, but the scale of the distorted image will vary. The horizon 2183 is anti-aliased, and the 'sky' color may be set using the 2184 <a href="#mattecolor" >-mattecolor</a> setting. </td> 2185 </tr> 2186 2187 <tr valign="top"> 2188 <td valign="top"><kbd>PerspectiveProjection</kbd> </td> 2189 <td valign="top"> 2190 Do a '<kbd>Perspective</kbd>' distortion basied on a set of 8 2191 pre-calculated coefficients. You can get these coefficients by looking 2192 at the <a href="#verbose" >-verbose</a> output of a 2193 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself. 2194 If the last two perspective scaling coefficients are zero, the 2195 remaining 6 represents a transposed 'Affine Matrix'. </td> 2196 2197 </tr> 2198 2199 <tr valign="top"> 2200 <td valign="top"><kbd>Arc</kbd></td> 2201 <td valign="top"> 2202 Arc the image (variation of polar mapping) over the angle given around 2203 a circle. <br/> 2204 <table width="90%" style = "margin-left: auto; margin-right: auto;"> 2205 <tr valign="top"><td>Argument</td> 2206 <td>Meaning</td></tr> 2207 <tr valign="top"><td><em>arc_angle</em></td> 2208 <td>The angle over which to arc the image side-to-side</td></tr> 2209 <tr valign="top"><td><em>rotate_angle</em></td> 2210 <td>Angle to rotate resulting image from vertical center</td></tr> 2211 <tr valign="top"><td><em>top_radius</em></td> 2212 <td>Set top edge of source image at this radius</td></tr> 2213 <tr valign="top"><td><em>bottom_radius</em> </td> 2214 <td>Set bottom edge to this radius (radial scaling)</td></tr> 2215 </table> 2216 2217 The resulting image is always resized to best fit the resulting image, 2218 (as if using <a href="#distort" >+distort</a>) while attempting to 2219 preserve scale and aspect ratio of the original image as much as 2220 possible with the arguments given by the user. All four arguments will 2221 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/> 2222 2223 This a variation of a polar distortion designed to try to preserve the 2224 aspect ratio of the image rather than direct Cartesian to Polar 2225 conversion. </td> 2226 </tr> 2227 2228 <tr valign="top"> 2229 <td valign="top"><kbd>Polar</kbd></td> 2230 <td valign="top"> 2231 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of 2232 the image. that is the height of the input image is mapped to the 2233 radius limits, while the width is wrapped around between the 2234 angle limits. <br/> 2235 2236 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/> 2237 2238 All arguments are optional. With <em>Rmin</em> defaulting to zero, the 2239 center to the center of the image, and the angles going from -180 (top) 2240 to +180 (top). If <em>Rmax</em> is given the special value of 2241 '<code>0</code>', the the distance from the center to the nearest edge 2242 is used for the radius of the output image, which will ensure the whole 2243 image is visible (though scaled smaller). However a special value of 2244 '<code>-1</code>' will use the distance from the center to the furthest 2245 corner, This may 'clip' the corners from the input rectangular image, 2246 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with 2247 the same arguments. <br/> 2248 2249 If the plus form of distort (<a href="#distort" >+distort</a>) is used 2250 output image center will default to <code>0,0</code> of the virtual 2251 canvas, and the image size adjusted to ensure the whole input image is 2252 made visible in the output image on the virtual canvas. </td> 2253 2254 </tr> 2255 2256 <tr valign="top"> 2257 <td valign="top"><kbd>DePolar</kbd></td> 2258 <td valign="top"> 2259 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion 2260 but generates the reverse Polar to Cartesian distortion. <br/> 2261 2262 The special <em>Rmax</em> setting of '<code>0</code>' may however clip 2263 the corners of the input image. However using the special 2264 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner 2265 distance) will ensure the whole distorted image is preserved in the 2266 generated result, so that the same argument to '<kbd>Polar</kbd>' will 2267 reverse the distortion re-producing the original. 2268 2269 Note that as this distortion requires the area resampling of a circular 2270 arc, which can not be handled by the builtin EWA resampling function. 2271 As such the normal EWA filters are turned off. It is recomended some 2272 form of 'super-sampling' image processing technique be used to produce 2273 a high quality result. </td> 2274 2275 </tr> 2276 2277 <tr valign="top"> 2278 <td valign="top"><kbd>Barrel</kbd></td> 2279 <td valign="top"> 2280 Given the four coefficients (A,B,C,D) as defined by <a 2281 href="http://www.all-in-one.ee/~dersch/barrel/barrel.html" >Helmut 2282 Dersch</a>, perform a barrell or pincussion distortion appropriate to 2283 correct radial lens distortions. That is in photographs, make straight 2284 lines straight again. <br/> 2285 2286 Arguments: <em>A B C</em> [ <em>D</em> [ 2287 <em>X</em> , <em>Y</em> ] ] <br/> 2288 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> 2289 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> 2290 [ <em>X</em> , <em>Y</em> ] <br/> 2291 So that it forms the function <br/> 2292 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2293 <em>C</em>*r + <em>D</em> )<br/> 2294 2295 Where <em>X</em>,<em>Y</em> is the optional center of the distortion 2296 (defaulting to the center of the image). <br/> 2297 The second form is typically used to distort images, rather than 2298 correct lens distortions. <br/> 2299 </td> 2300 2301 </tr> 2302 2303 <tr valign="top"> 2304 <td valign="top"><kbd>BarrelInverse</kbd></td> 2305 <td valign="top"> 2306 This is very simular to '<kbd>Barrel</kbd>' with the same set of 2307 arguments, and argument handling. However it uses the inverse 2308 of the radial polynomial, 2309 so that it forms the function <br/> 2310 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2311 <em>C</em>*r + <em>D</em> ) 2312 </td> 2313 </tr> 2314 2315 <tr valign="top"> 2316 <td valign="top"><kbd>Shepards</kbd></td> 2317 <td valign="top"> 2318 Distort the given list control points (any number) using an Inverse 2319 Squared Distance Interpolation Method (<a 2320 href="http://www.ems-i.com/smshelp/Data_Module/Interpolation/Inverse_Distance_Weighted.htm" 2321 >Shepards Method</a>). The control points in effect do 'localized' 2322 distortions of the image around the given control point. For best 2323 results extra control points should be added to 'lock' the positions of 2324 the corners and other unchanging parts of the image. <br/> 2325 2326 The distortion has been likened to 'taffy pulling' using nails, pins or 2327 sticks. It basically uses the <a href="#sparse-color" 2328 >-sparse-color</a> method of the same name to generate separate X and Y 2329 displacement maps (see <a href="#displace" >-displace</a>) for source 2330 image color look-up. </td> 2331 2332 </tr> 2333 2334</table> 2335 2336<p>To print a complete list of distortion methods, use <a href="#list">-list distort</a>.</p> 2337 2338<p>Many of the above distortion methods such as '<kbd>Affine</kbd>', 2339'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points 2340defining how these points in the given image should be distorted in the 2341destination image. Each set of four floating point values represent a source 2342image coordinate, followed immediately by the destination image coordinate. 2343This produces a list of values such as...</p> 2344<div style="text-align: center"><em> 2345 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> 2346 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> 2347 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> 2348 ... 2349 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> 2350</em></div> 2351<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the 2352destination image. </p> 2353 2354<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion, 2355needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the 2356perspective distortion of the built-in "rose:" image. Note how spaces were 2357used to group the 4 sets of coordinate pairs, to make it easier to read and 2358understand.</p> 2359 2360<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'> 2361 convert rose: -virtual-pixel black \ <br/> 2362 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \ <br/> 2363 rose_3d_rotated.gif</span></p> 2364<p>If more that the required number of coordinate pairs are given for a 2365distortion, the distortion method is 'least squares' fitted to 2366produce the best result for all the coordinate pairs given. If less than the 2367ideal number of points are given, the distort will generally fall back to a 2368simpler form of distortion that can handles the smaller number of coordinates 2369(usally a linear '<kbd>Affine</kbd>' distortion). </p> 2370 2371<p>By using more coodinates you can make use of image registration tool to 2372find matching coordinate pairs in overlaping images, so as to improve the 'fit' 2373of the distortion. Of course a bad coordinate pair can also make the 'fit' 2374worse. Caution is always advised. </p> 2375 2376<p>Colors are acquired from the source image according to the <a 2377href="#interpolate" >-interpolate</a> color lookup setting, when the image is 2378magnified. However if the viewed image is minified (image becomes smaller), a 2379special area resampling function (added ImageMagick v6.3.5-9), is used to 2380produce a higher quality image. For example you can use a 2381'<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all the 2382way to the horizon. </p> 2383 2384<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \ <br/> 2385 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \ <br/> 2386 checks_tiled.jpg</span></p> 2387<p>Note that a infinitely tiled perspective images involving the horizon can 2388be very slow to generate due to the use of the high quality 'area resampling' 2389function (added ImageMagick v6.3.5-9). You can turn off 'area resampling' 2390using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>' 2391(recommended if you plan to use super-sampling instead). </p> 2392 2393<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last 2394'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a> 2395will use the current <a href="#mattecolor" >-mattecolor</a> setting for these 2396pixels. If you do not what these pixels to be visible, set the color to match 2397the rest of the ground. </p> 2398 2399<p>The output image size will by default be the same as the input image. This 2400means that if the part of the distorted image falls outside the viewed area of 2401the 'distorted space', those parts is clipped and lost. However if you 2402use the plus form of the operator (<a href="#distort" >+distort</a>) the 2403operator will attempt (if posible) to show the whole of the distorted image, 2404while retaining a correct 'virtual canvas' offset, for image layering. This 2405offset may need to be removed using <a href="#repage" >+repage</a>, to remove 2406if it is unwanted. </p> 2407 2408<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a> 2409option:distort:viewport {geometry_string}</kbd>" setting which will specify 2410the size and the offset of the generated 'viewport' image of the distorted 2411image space.</p> 2412 2413<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale 2414{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by 2415that factor without changing the viewed contents of the distorted image. This 2416can be used either for 'super-sampling' the image for a higher quality result, 2417or for panning and zooming around the image (with appropriate viewport 2418changes, or post-distort cropping and resizing). </p> 2419 2420<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a 2421href="#distort" >-distort</a> to attempt to output the internal coefficients, 2422and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study, 2423and debugging purposes. This many not be available for all distorts. </p> 2424 2425<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to 2426produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a> 2427and/or <a href="#shear" >-shear</a> operation, with more control of due to the 2428above settings. It is algorithmically slower, though in ImageMagick it may be faster. 2429</p> 2430 2431 2432<div style="margin: auto;"> 2433 <h4><a name="dither" id="dither"></a>-dither <em class="arg">method</em></h4> 2434</div> 2435 2436<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> 2437 2438<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> 2439 2440<p>Dithering is turned on by default, to turn it off use the plus form of the 2441setting, <a href="#dither">+dither</a>. This will also also render PostScript 2442without text or graphic aliasing. Disabling dithering often (but not always) 2443leads to faster process, a smaller number of colors, but more cartoon like 2444image coloring. Generally resulting in 'color banding' effects in areas with 2445color gradients. </p> 2446 2447<p>The color reduction operators <a href="#colors">-colors</a>, <a 2448href="#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> 2449 2450<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> 2451 2452 2453<div style="margin: auto;"> 2454 <h4><a name="draw" id="draw"></a>-draw <em class="arg">string</em></h4> 2455</div> 2456 2457<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> 2458 2459<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> 2460 2461<p>The shape primitives:</p> 2462 2463<pre class="text"> 2464 point x,y 2465 line x0,y0 x1,y1 2466 rectangle x0,y0 x1,y1 2467 roundRectangle x0,y0 x1,y1 wc,hc 2468 arc x0,y0 x1,y1 a0,a1 2469 ellipse x0,y0 rx,ry a0,a1 2470 circle x0,y0 x1,y1 2471 polyline x0,y0 ... xn,yn 2472 polygon x0,y0 ... xn,yn 2473 bezier x0,y0 ... xn,yn 2474 path path specification 2475 image operator x0,y0 w,h filename 2476</pre> 2477 2478<p>The text primitive:</p> 2479 2480<pre class="text"> 2481 text x0,y0 string 2482</pre> 2483<p>The text gravity primitive:</p> 2484 2485<pre class="text"> 2486 gravity NorthWest, North, NorthEast, West, Center, 2487 East, SouthWest, South, or SouthEast 2488</pre> 2489 2490<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> 2491 2492<p>The transformation primitives:</p> 2493 2494<pre class="text"> 2495 rotate degrees 2496 translate dx,dy 2497 scale sx,sy 2498 skewX degrees 2499 skewY degrees 2500</pre> 2501 2502<p>The pixel operation primitives:</p> 2503 2504<pre class="text"> 2505 color x0,y0 method 2506 matte x0,y0 method 2507</pre> 2508 2509<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> 2510 2511<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> 2512 2513<p>A <kbd>line</kbd> primitive requires a start point and end point.</p> 2514 2515<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p> 2516 2517<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> 2518 2519<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p> 2520 2521<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> 2522 2523<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> 2524 2525<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>. 2526</p> 2527 2528<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p> 2529 2530<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p> 2531 2532<p class="crtsnip"> 2533 -draw 'circle 100,100 150,150' 2534</p> 2535 2536<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 2537draw 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> 2538 2539<p class="crtsnip"> 2540 -draw 'bezier 20,50 45,100 45,0 70,50' 2541</p> 2542<p class="crtsnip"> 2543 -draw 'bezier 70,50 95,100 95,0 120,50' 2544</p> 2545 2546 2547<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> 2548 2549<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> 2550 2551<p class="crtsnip"> 2552 -draw 'image SrcOver 100,100 225,225 image.jpg' 2553</p> 2554 2555<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> 2556 2557<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> 2558 2559<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p> 2560 2561<p class="crtsnip"> 2562 -draw 'text 100,100 "Works like magick!"' 2563</p> 2564 2565<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p> 2566 2567<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> 2568 2569<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p> 2570 2571<p>The <kbd>scale</kbd> primitive scales them.</p> 2572 2573<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> 2574 2575<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 2576matrix.</p> 2577 2578<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> 2579 2580<pre class="text"> 2581 point 2582 replace 2583 floodfill 2584 filltoborder 2585 reset 2586</pre> 2587 2588<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> 2589 2590<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> 2591 2592<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> 2593 2594<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p> 2595 2596<p>Drawing primitives conform to the <a href="/www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p> 2597 2598 2599<div style="margin: auto;"> 2600 <h4><a name="edge" id="edge"></a>-edge <em class="arg">radius</em></h4> 2601</div> 2602 2603<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> 2604 2605<div style="margin: auto;"> 2606 <h4><a name="emboss" id="emboss"></a>-emboss <em class="arg">radius</em></h4> 2607</div> 2608 2609<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> 2610 2611<div style="margin: auto;"> 2612 <h4><a name="encipher" id="encipher"></a>-encipher <em class="arg">filename</em></h4> 2613</div> 2614 2615<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> 2616 2617<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 2618 2619<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 2620 2621<div style="margin: auto;"> 2622 <h4><a name="encoding" id="encoding"></a>-encoding <em class="arg">type</em></h4> 2623</div> 2624 2625<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> 2626 2627<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> 2628 2629<div style="margin: auto;"> 2630 <h4><a name="endian" id="endian"></a>-endian <em class="arg">type</em></h4> 2631</div> 2632 2633<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> 2634 2635<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p> 2636 2637<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p> 2638 2639 2640<div style="margin: auto;"> 2641 <h4><a name="enhance" id="enhance"></a>-enhance</h4> 2642</div> 2643 2644<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> 2645 2646 2647<div style="margin: auto;"> 2648 <h4><a name="equalize" id="equalize"></a>-equalize</h4> 2649</div> 2650 2651<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> 2652 2653<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> 2654 2655<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p> 2656 2657<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> 2658 2659<div style="margin: auto;"> 2660 <h4><a name="evaluate" id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4> 2661</div> 2662 2663<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> 2664 2665<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> 2666 2667<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> 2668 2669<table class="doc"> 2670 <col width="25%" /> 2671 <col width="75%" /> 2672 <thead> 2673 <tr> 2674 <th><em class="arg">operator</em></th> 2675 <th>Summary (see further below for details)</th> 2676 </tr> 2677 </thead> 2678 <tbody> 2679 2680 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr> 2681 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr> 2682 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr> 2683 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2684 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr> 2685 <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> 2686 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr> 2687 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr> 2688 <tr><td>Mean </td> <td>Add the <em class="arg">value</em> and divide by 2.</td></tr> 2689 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr> 2690 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr> 2691 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr> 2692 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr> 2693 <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> 2694 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr> 2695 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2696 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr> 2697 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr> 2698 2699 <tr><td> </td></tr> 2700 2701 <tr><td>Gaussian-noise</td></tr> 2702 <tr><td>Impulse-noise</td></tr> 2703 <tr><td>Laplacian-noise</td></tr> 2704 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr> 2705 <tr><td>PoissonNoise</td></tr> 2706 <tr><td>Uniform-noise</td></tr> 2707 2708 <tr><td> </td></tr> 2709 2710 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr> 2711 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr> 2712 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr> 2713 </tbody> 2714 </table> 2715 2716<p>The specified functions are applied only to each previously set <a 2717href="#channel" >-channel</a> in the image. If necessary, the results of the 2718calculations are truncated (clipped) to fit in the interval [0, <em 2719class="QR">QuantumRange</em>]. The transparency channel of the image is 2720represented as a 'alpha' values (0 = fully transparent), so, for example, a 2721<kbd>Divide</kbd> by 2 of the alpha channel will make the image 2722semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value 2723as a percentage of the <em class="QR">QuantumRange</em>.</p> 2724 2725<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use 2726<a href="#list">-list evaluate</a>.</p> 2727 2728<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and 2729<kbd>Multiply</kbd> methods can also be achieved using either the <a 2730href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with 2731appropriate argument, to linearly modify the overall range of color values. 2732Please note, however, that <a href="#level" >-level</a> treats transparency as 2733'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with 2734'alpha' values.</p> 2735 2736<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> 2737 2738<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> 2739 2740 <div style="text-align:center;"> 2741 log(<em class="arg">value</em> × <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1) 2742 </div> 2743 2744<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on 2745normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a 2746href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent 2747to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used 2748with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used 2749with <kbd>Pow</kbd>.</p> 2750 2751<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and 2752converts the image values into a value according to a (co)sine wave function. 2753The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output 2754is biased 50% and normalized by 50% so as to fit in the respective color value 2755range. The <em class="arg">value</em> scaling of the <em>period</em> of the 2756function (its frequency), and thus determines the number of 'waves' that will 2757be generated over the input color range. For example, if the <em 2758class="arg">value</em> is 1, the effective period is simply the <em 2759class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is 2, 2760then the effective period is the <em>half</em> the <em 2761class="QR">QuantumRange</em>. 2762 2763 <div style="text-align:center;"> 2764 0.5 + 0.5 × cos(2 π <b><em>u</em></b> × <em class="arg">value</em>). 2765 </div> 2766 2767See also the <a href="#function" >-function</a> operator, which is a 2768multi-value version of evaluate. </P> 2769 2770<div style="margin: auto;"> 2771 <h4><a name="evaluate-sequence" id="evaluate-sequence"></a>-evaluate-sequence <em class="arg">operator</em></h4> 2772</div> 2773 2774<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Alter channel pixels by evaluating an arithmetic, relational, or logical expression over a sequence of images.</td><td style='text-align:right;'></td></tr></table> 2775 2776<div style="margin: auto;"> 2777 <h4><a name="extent" id="extent"></a>-extent <em class="arg">geometry</em></h4> 2778</div> 2779 2780<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> 2781 2782<p>If the image is enlarged, unfilled areas are set to the background color. To position the image, use offsets in the <em class="arg">geometry</em> specification or precede with a <a href="#gravity">-gravity</a> setting. To specify how to compose the image with the background, use <a href="#compose" >-compose</a>.</p> 2783 2784<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> 2785 2786<div style="margin: auto;"> 2787 <h4><a name="extract" id="extract"></a>-extract <em class="arg">geometry</em></h4> 2788</div> 2789 2790<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> 2791 2792<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p> 2793 2794<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480+1280+960 \ <br/> image.rgb image.png</span><span class='crtout'></span><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 'image.rgb[640x480+1280+960]' \ <br/> image.rgb image.png</span></p><p>If you omit the offsets, as in</p> 2795 2796<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480 \ <br/> image.rgb image.png</span></p> 2797<p>then the image will be <em>resized</em> to the specified dimensions instead, 2798equivalent to:</p> 2799 2800<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -resize 640x480 image.rgb image.png</span></p> 2801<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> 2802 2803<div style="margin: auto;"> 2804 <h4><a name="family" id="family"></a>-family <em class="arg">fontFamily</em></h4> 2805</div> 2806 2807<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> 2808 2809<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). 2810</p> 2811 2812<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>. 2813</p> 2814 2815<div style="margin: auto;"> 2816 <h4><a name="features" id="features"></a>-features <em class="arg">distance</em></h4> 2817</div> 2818 2819<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>display features for each channel in the image in each of four directions (horizontal, vertical, left and right diagonals) for the specified distance.</td><td style='text-align:right;'></td></tr></table> 2820 2821<div style="margin: auto;"> 2822 <h4><a name="fft" id="fft"></a>-fft</h4> 2823</div> 2824 2825<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> 2826 2827<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> 2828 2829<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> 2830 2831<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> 2832 2833<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p> 2834<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> 2835 2836<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.png</span></p> 2837<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> 2838 2839<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> 2840 2841<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> 2842 2843<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br /> 2844 -evaluate log 1000 fft_image_spectrum.png</span></p> 2845<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> 2846 2847<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>. 2848 2849<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> 2850 2851<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> 2852 2853<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> 2854 2855<p>See the discussion on HDRI implementations of ImageMagick on the page 2856<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. 2857</p> 2858 2859 2860<div style="margin: auto;"> 2861 <h4><a name="fill" id="fill"></a>-fill <em class="arg">color</em></h4> 2862</div> 2863 2864<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> 2865 2866<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> 2867 2868<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p> 2869 2870<p>For example,</p> 2871 2872<p class="crtsnip"> 2873 -fill blue 2874</p> 2875<p class="crtsnip"> 2876 -fill "#ddddff" 2877</p> 2878<p class="crtsnip"> 2879 -fill "rgb(255,255,255)" 2880</p> 2881 2882<p>See <a href="#draw">-draw</a> for further details.</p> 2883 2884<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p> 2885 2886<div style="margin: auto;"> 2887 <h4><a name="filter" id="filter"></a>-filter <em class="arg">type</em></h4> 2888</div> 2889 2890<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> 2891 2892<p>Use this option to affect the resizing operation of an image (see <a 2893href="#resize">-resize</a>). For example you can use a simple resize filter 2894such as:</p> 2895 2896<pre class="text"> 2897 Point Hermite Cubic 2898 Box Gaussian Catrom 2899 Triangle Quadratic Mitchell 2900</pre> 2901 2902<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided, but are 2903by default <kbd>blackman</kbd>-windowed. However these filters define a 2904windowing filter for the Sinc or Bessel filter function, as appropriate for 2905the scaling operator used (usally Sinc for orthogonal <a href="#resize" 2906>-resize</a>). Windowed filters include: </p> 2907 2908<pre class="text"> 2909 Lanczos Hamming Parzen 2910 Blackman Kaiser Welsh 2911 Hanning Bartlett Bohman 2912</pre> 2913 2914<p>Also one special self-windowing filter is also provided 2915<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending 2916on the current 'support' or 'lobes' expert settings (see below).</p> 2917 2918<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> 2919 2920<p>To print a complete list of resize filters, use the <a href="#list">-list filter</a> option.</p> 2921 2922<p>You can modify how the filter behaves as it scales your image through the 2923use of these expert settings:</p> 2924 2925<dl class="doc"> 2926<dt>-set filter:blur <em>factor</em></dt> 2927<dd>Scale the X axis of the filter (and its window). Use > 1.0 for 2928 blurry or < 1.0 for sharp.</dd> 2929 2930<dt>-set filter:support <em>radius</em></dt> 2931<dd>Set the filter support radius.</dd> 2932 2933<dt>-set filter:lobes <em>count</em></dt> 2934<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an 2935 alternative way of specifying the 'support' range of the filter.</dd> 2936 2937<dt>-set filter:b <em>b-spline_factor</em></dt> 2938<dt>-set filter:c <em>keys_alpha_factor</em></dt> 2939<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>, 2940 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as 2941 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values 2942 are defined, the other is set so as to generate a 'Keys' type cubic 2943 filter. 2944 2945<dt>-set filter:filter <em>filter</em></dt> 2946<dd>Use this function directly as the scaling filter. This will allow 2947 you to directly use a 'windowing filter' such as <kbd>blackman</kbd>, 2948 rather than as its normal usage as a windowing function for 'Sinc' or 2949 'Bessel'. If defined, no windowing function is used, unless the following 2950 expert setting is also defined.</dd> 2951 2952<dt>-set filter:window <em>filter</em></dt> 2953<dd>The IIR (infinite impulse response) filters <kbd>bessel</kbd> and 2954 <kbd>sinc</kbd> are windowed (brought down to zero over the defined 2955 support range) with the given filter. This allows you to use a filter that 2956 is not normally used as a windowing function, such as <kbd>box</kbd>, 2957 (which effectivally turns off the windowing function). </dd> 2958 2959</dl> 2960 2961<p>For example, to get a 8 lobe Lanczos-Bessel filter:</p> 2962 2963<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -filter bessel \ <br/> 2964 -set filter:window=bessel -set filter:lobes=8 \ <br/> 2965 -resize 150% image.jpg</span></p> 2966<p>Or a raw un-windowed Sinc filter with 4 lobes:</p> 2967 2968<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/> 2969 -resize 150% image.jpg</span></p> 2970<p>Note that the use of expert options (except for 'blur' with simple resize 2971filters), are provided for image processing experts who have studied and 2972understood how resize filters work. Without this knowledge, and an 2973understanding of the defination of the actual filters involved, using expert 2974settings are more likely to be detremental to your image resizing.</p> 2975 2976 2977<div style="margin: auto;"> 2978 <h4><a name="flatten" id="flatten"></a>-flatten</h4> 2979</div> 2980 2981<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> 2982 2983 2984<div style="margin: auto;"> 2985 <h4><a name="flip" id="flip"></a>-flip</h4> 2986</div> 2987 2988<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> 2989 2990<p>reflect the scanlines in the vertical direction.</p> 2991 2992<div style="margin: auto;"> 2993 <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> 2994</div> 2995 2996<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> 2997 2998<div style="margin: auto;"> 2999 <h4><a name="flop" id="flop"></a>-flop</h4> 3000</div> 3001 3002<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> 3003 3004<p>reflect the scanlines in the horizontal direction.</p> 3005 3006 3007<div style="margin: auto;"> 3008 <h4><a name="font" id="font"></a>-font <em class="arg">name</em></h4> 3009</div> 3010 3011<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> 3012 3013<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> 3014 3015<p>In addition to the fonts specified by the above pre-defined list, you can 3016also specify a font from a specific source. For example <kbd>Arial.ttf</kbd> 3017is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and 3018<kbd>x:fixed</kbd> is X11 font.</p> 3019 3020<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> 3021 3022 3023<div style="margin: auto;"> 3024 <h4><a name="foreground" id="foreground"></a>-foreground <em class="arg">color</em></h4> 3025</div> 3026 3027<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> 3028 3029<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 3030 3031<p>The default foreground color is black.</p> 3032 3033<div style="margin: auto;"> 3034 <h4><a name="format" id="format"></a>-format <em class="arg">type</em></h4> 3035</div> 3036 3037<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> 3038 3039<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> 3040 3041<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> 3042 3043<div style="margin: auto;"> 3044 <h4><a name="format_identify_" id="format_identify_"></a>-format <em class="arg">string</em></h4> 3045</div> 3046 3047<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> 3048 3049<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> 3050 3051<div style="margin: auto;"> 3052 <h4><a name="frame" id="frame"></a>-frame <em class="arg">geometry</em></h4> 3053</div> 3054 3055<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> 3056 3057<p>The color of the border is specified with the <a href="#mattecolor">-mattecolor</a> command line option. </p> 3058 3059<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> 3060 3061 3062<div style="margin: auto;"> 3063 <h4><a name="frame_import_" id="frame_import_"></a>-frame</h4> 3064</div> 3065 3066<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> 3067 3068<div style="margin: auto;"> 3069 <h4><a name="function" id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4> 3070</div> 3071 3072<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> 3073 3074<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> 3075 3076<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> 3077 3078<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> 3079 3080<pre class="text"> 3081 Polynomial 3082 Sinusoid 3083 Arcsin 3084 Arctan 3085</pre> 3086 3087<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p> 3088 3089<dl class="doc"> 3090<dt><kbd>Polynomial</kbd></dt> 3091<dd> 3092<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> 3093 3094<div style="text-align: center"> 3095 -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> 3096</div> 3097 3098<p>will invoke a polynomial function given by</p> 3099 3100<div style="text-align: center"> 3101 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> + 3102 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> + 3103 ··· <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>, 3104</div> 3105 3106<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p> 3107 3108<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> 3109 3110<table class="doc"> 3111 <col width="35%" /> 3112 <col width="35%" /> 3113 <col width="30%" /> 3114 <tr> 3115 <td>-evaluate Set <em class="arg">value</em> </td> 3116 <td>-function Polynomial <em class="arg">value</em></td> 3117 <td>(Constant functions; set <em class="arg">value</em>×100% gray when channels are RGB.)</td> 3118 </tr> 3119 <tr> 3120 <td>-evaluate Add <em class="arg">value</em> </td> 3121 <td>-function Polynomial 1,<em class="arg">value</em></td> 3122 </tr> 3123 <tr> 3124 <td>-evaluate Subtract <em class="arg">value</em> </td> 3125 <td>-function Polynomial 1,−<em class="arg">value</em></td> 3126 </tr> 3127 <tr> 3128 <td>-evaluate Multiply <em class="arg">value</em> </td> 3129 <td>-function Polynomial <em class="arg">value</em>,0</td> 3130 </tr> 3131 <tr> 3132 <td>+level black% x white%</td> 3133 <td>-function Polynomial A,B</td> 3134 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td> 3135 </tr> 3136</table> 3137 3138<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> 3139</dd> 3140 3141<dt><kbd>Sinusoid</kbd></dt> 3142<dd> 3143<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> 3144 3145<div style="text-align: center"> 3146 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]] 3147</div> 3148 3149<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> 3150 3151<div style="text-align: center"> 3152<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> 3153</div> 3154 3155<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> 3156 3157<p class="crtsnip"> 3158 -function Sinusoid 3,-90,.2,.7 3159</p> 3160 3161<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> 3162 3163<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> 3164 3165<table class="doc"> 3166 <tr> 3167 <td>-evaluate Sin <em class="arg">freq</em> </td> 3168 <td>-function Sinusoid <em class="arg">freq</em>,0 </td> 3169 </tr> 3170 <tr> 3171 <td>-evaluate Cos <em class="arg">freq</em> </td> 3172 <td>-function Sinusoid <em class="arg">freq</em>,90 </td> 3173 </tr> 3174</table> 3175</dd> 3176 3177<dt><kbd>ArcSin</kbd></dt> 3178<dd> 3179<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid, 3180and can be used to generate cylindrical distortion and displacement maps. 3181The curve can be adjusted relative to both the input values and output range 3182of values. 3183 3184<div style="text-align: center"> 3185 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3186</div> 3187 3188<p>with all values given in terms of noramlize color values (0.0 for black, 31891.0 for white). Defaulting to values covering the full range from 0.0 to 1.0 3190for bout input (<em class="arg">width</em>), and output (<em 3191class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p> 3192 3193<div style="text-align: center"> 3194<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> 3195</div> 3196 3197</dd> 3198 3199<dt><kbd>ArcTan</kbd></dt> 3200<dd> 3201<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from 3202limit values at infinities, though a center using the given slope value. 3203All these values can be adjusted via the arguments. 3204 3205<div style="text-align: center"> 3206 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3207</div> 3208 3209<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'. 3210</p> 3211 3212<div style="text-align: center"> 3213<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> 3214</div> 3215 3216</dd> 3217 3218</dl> 3219 3220 3221<div style="margin: auto;"> 3222 <h4><a name="fuzz" id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4> 3223</div> 3224 3225<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> 3226 3227<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> 3228 3229<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> 3230 3231 3232<div style="margin: auto;"> 3233 <h4><a name="fx" id="fx"></a>-fx <em class="arg">expression</em></h4> 3234</div> 3235 3236<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> 3237 3238<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> 3239 3240<p>See <a href="/www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p> 3241 3242 3243<div style="margin: auto;"> 3244 <h4><a name="gamma" id="gamma"></a>-gamma <em class="arg">value</em></h4> 3245</div> 3246 3247<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> 3248 3249<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> 3250 3251<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> 3252 3253<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> 3254 3255<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> 3256 3257<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p> 3258 3259<div style="margin: auto;"> 3260 <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> 3261</div> 3262 3263<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> 3264 3265<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p> 3266 3267<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 3268</div> 3269 3270<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> 3271 3272<p>This differs from the faster <a href="#blur">-blur</a> operator in that a 3273full 2-dimentional convolution is used to generate the weighted average of the 3274neighbouring pixels. </p> 3275 3276<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 3277pixels which are outside the image proper are blurred into the final result. 3278</p> 3279 3280 3281<div style="margin: auto;"> 3282 <h4><a name="geometry" id="geometry"></a>-geometry <em class="arg">geometry</em></h4> 3283</div> 3284 3285<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> 3286 3287<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> 3288 3289<div style="margin: auto;"> 3290 <h4><a name="gravity" id="gravity"></a>-gravity <em class="arg">type</em></h4> 3291</div> 3292 3293<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> 3294 3295<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>, 3296<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>, 3297<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete 3298list of <a href="#gravity">-gravity</a> settings available in your ImageMagick 3299installation.</p> 3300 3301<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> 3302 3303<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> 3304 3305<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> 3306 3307<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -gravity Center -region 10x10-40+20 \ <br/> -negate output.png</span></p> 3308<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> 3309 3310<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> 3311 3312 3313<div style="margin: auto;"> 3314 <h4><a name="green-primary" id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4> 3315</div> 3316 3317<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> 3318 3319 3320<div style="margin: auto;"> 3321 <h4><a name="hald-clut" id="hald-clut"></a>-hald-clut</h4> 3322</div> 3323 3324<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> 3325 3326<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2 3327dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You 3328can apply any color transformation to the Hald image and then use this option 3329to apply the transform to the image. </p> 3330 3331<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p> 3332<p>This option provides a convenient method for you to use Gimp or Photoshop 3333to make color corrections to the Hald CLUT image and subsequently apply them 3334to multiple images using an ImageMagick script. </p> 3335 3336<p>Note that the representation is only of the normal RGB color space and that 3337the whole color value triplet is used for the interpolated lookup of the 3338represented Hald color cube image. Because of this the operation is not <a 3339href="#channel" >-channel</a> setting effected, nor can it adjust or modify an 3340images transparency or alpha/matte channel.</p> 3341 3342<p>See also <a href="#clut" >-clut</a> which provides color value replacement 3343of the individual color channels, usally involving a simplier gray-scale 3344image. E.g: gray-scale to color replacement, or modification by a histogram 3345mapping. </p> 3346 3347 3348<div style="margin: auto;"> 3349 <h4><a name="help" id="help"></a>-help</h4> 3350</div> 3351 3352<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> 3353 3354<div style="margin: auto;"> 3355 <h4><a name="highlight-color" id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4> 3356</div> 3357 3358<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> 3359 3360<div style="margin: auto;"> 3361 <h4><a name="iconGeometry" id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4> 3362</div> 3363 3364<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> 3365 3366<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> 3367 3368<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> 3369 3370<div style="margin: auto;"> 3371 <h4><a name="iconic" id="iconic"></a>-iconic</h4> 3372</div> 3373 3374<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> 3375 3376<div style="margin: auto;"> 3377 <h4><a name="identify" id="identify"></a>-identify</h4> 3378</div> 3379 3380<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> 3381 3382<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> 3383 3384<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> 3385 3386<p>If <a href="#verbose">-verbose</a> preceds this option, copious 3387amounts of image properties are displayed including image statistics, profiles, 3388image histogram, and others.</p> 3389 3390<div style="margin: auto;"> 3391 <h4><a name="ift" id="ift"></a>-ift</h4> 3392</div> 3393 3394<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> 3395 3396<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> 3397 3398<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> 3399 3400<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p> 3401<p>or</p> 3402 3403<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> 3404 3405<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. 3406 3407<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>. 3408 3409<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. 3410 3411<div style="margin: auto;"> 3412 <h4><a name="immutable" id="immutable"></a>-immutable</h4> 3413</div> 3414 3415<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> 3416 3417<div style="margin: auto;"> 3418 <h4><a name="implode" id="implode"></a>-implode <em class="arg">factor</em></h4> 3419</div> 3420 3421<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> 3422 3423<div style="margin: auto;"> 3424 <h4><a name="insert" id="insert"></a>-insert <em class="arg">index</em></h4> 3425</div> 3426 3427<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> 3428 3429<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> 3430 3431<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> 3432 3433<div style="margin: auto;"> 3434 <h4><a name="intent" id="intent"></a>-intent <em class="arg">type</em></h4> 3435</div> 3436 3437<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> 3438 3439<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> 3440 3441<p>The default intent is undefined.</p> 3442 3443<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p> 3444 3445<div style="margin: auto;"> 3446 <h4><a name="interlace" id="interlace"></a>-interlace <em class="arg">type</em></h4> 3447</div> 3448 3449<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> 3450 3451<p>Choose from:</p> 3452 3453<pre class="text"> 3454 none 3455 line 3456 plane 3457 partition 3458 JPEG 3459 GIF 3460 PNG 3461</pre> 3462 3463<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> 3464 3465<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p> 3466 3467<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p> 3468 3469<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p> 3470 3471<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R, 3472image.G, and image.B).</p> 3473 3474<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> 3475image.</p> 3476 3477<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p> 3478 3479<div style="margin: auto;"> 3480 <h4><a name="interpolate" id="interpolate"></a>-interpolate <em class="arg">type</em></h4> 3481</div> 3482 3483<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> 3484 3485<p>When looking up the color of a pixel using a non-interger floating point 3486value, you typically fall in between the pixel colors defined by the source 3487image. This setting determines how the color is determined from the colors of 3488the pixels surrounding that point. That is how to determine the color of a 3489point that falls between two, or even four different colored pixels. </p> 3490 3491<pre class="text"> 3492 integer: The color of the top-left pixel (floor function) 3493 nearest-neighbor: The nearest pixel to the lookup point (rounded function) 3494 average: The average color of the surrounding four pixels 3495 bilinear A double linear interpolation of pixels (the default) 3496 mesh Divide area into two flat triangular interpolations 3497 bicubic Fitted bicubic-spines of surrounding 16 pixels 3498 spline Direct spline curves (colors are blurred) 3499 filter Use resize <a href="#filter">-filter</a> settings 3500</pre> 3501 3502<p>This most important for distortion operators such as <a href="#distort" 3503>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform" 3504>-transform</a> and <a href="#fx" >-fx</a>. </p> 3505 3506<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p> 3507 3508<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the 3509lookup for positions outside the boundaries of the image. </p> 3510 3511 3512<div style="margin: auto;"> 3513 <h4><a name="interline-spacing" id="interline-spacing"></a>-interline-spacing <em class="arg">value</em></h4> 3514</div> 3515 3516<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> 3517 3518<div style="margin: auto;"> 3519 <h4><a name="interword-spacing" id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4> 3520</div> 3521 3522<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> 3523 3524<div style="margin: auto;"> 3525 <h4><a name="kerning" id="kerning"></a>-kerning <em class="arg">value</em></h4> 3526</div> 3527 3528<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> 3529 3530<div style="margin: auto;"> 3531 <h4><a name="label" id="label"></a>-label <em class="arg">name</em></h4> 3532</div> 3533 3534<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> 3535 3536<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> 3537 3538<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> 3539 3540<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> 3541 3542<p>For example,</p> 3543 3544<p class="crtsnip"> 3545 -label "%m:%f %wx%h" bird.miff 3546</p> 3547 3548<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> 3549 3550<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> 3551 3552<p>The label font can be specified with <a href="#font">-font</a>, and the 3553other font attribute settings.</p> 3554 3555<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> 3556 3557 3558<div style="margin: auto;"> 3559 <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> 3560</div> 3561 3562<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> 3563 3564<p>Adaptively threshold each pixel based on the value of pixels in a 3565surrounding window. If the current pixel is lighter than this average plus 3566the optional <kbd>offset</kbd>, then it is made white, otherwise it is made 3567black. Small variations in pixel values such as found in scanned documents 3568can be ignored if offset is positive. A negative offset will make it more 3569sensitive to those small variations. </p> 3570 3571<p>This is commonly used to threshold images with an uneven background. It is 3572based on the assumption that average color of the small window is the 3573the local background color, from which to separate the forground color. </p> 3574 3575 3576<div style="margin: auto;"> 3577 <h4><a name="layers" id="layers"></a>-layers <em class="arg">method</em></h4> 3578</div> 3579 3580<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> 3581 3582<p>Perform various image operation methods to a ordered sequence of images 3583which may represent either a set of overlaid 'image layers', a GIF disposal 3584animation, or a fully-'coalesced' animation sequence. </p> 3585 3586<table class="doc"> 3587 <tbody> 3588 <tr valign="top"> 3589 <th align="left" style="width: 8%">Method</th> 3590 <th align="left">Description</th> 3591 </tr> 3592 3593 <tr valign="top"> 3594 <td valign="top">compare-any</td> 3595 <td valign="top">Crop the second and later frames to the smallest rectangle 3596 that contains all the differences between the two images. No GIF <a 3597 href="#dispose" >-dispose</a> methods are taken into account. </td> 3598 </tr> 3599 3600 <tr><td></td><td>This exactly the same as the <a href="#deconstruct" 3601 >-deconstruct</a> operator, and does not preserve animations normal 3602 working, especially when animation used layer disposal methods such as 3603 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td> 3604 </tr> 3605 3606 <tr valign="top"> 3607 <td valign="top">compare-clear</td> 3608 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any 3609 opaque pixels which become transparent in the second frame. That is the 3610 smallest image needed to mask or erase pixels for the next frame. </td> 3611 </tr> 3612 3613 <tr valign="top"> 3614 <td valign="top">compare-overlay</td> 3615 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add 3616 extra color to the next image, as a result of overlaying color pixels. 3617 That is the smallest single overlaid image to add or change colors. </td> 3618 </tr> 3619 3620 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha 3621 composition method '<kbd>change-mask</kbd>', to reduce the image to 3622 just the pixels that need to be overlaid. </td> 3623 </tr> 3624 3625 <tr valign="top"> 3626 <td valign="top">coalesce</td> 3627 <td valign="top">Equivalent to a call to the <a href="#coalesce" 3628 >-coalesce</a> operator. Apply the layer disposal methods set in the 3629 current image sequence to form a fully defined animation sequence, as 3630 it should be displayed. Effectively converting a GIF animation into a 3631 'film strip'-like animation. </td> 3632 </tr> 3633 3634 <tr valign="top"> 3635 <td valign="top">composite</td> 3636 <td valign="top">Alpha Composition of two image lists, separated by a 3637 "<kbd>null:</kbd>" image, with the destination image list first, and 3638 the source images last. An image from each list are composited 3639 together until one list is finished. The separator image and source 3640 image lists are removed. </td> 3641 </tr> 3642 3643 3644 <tr><td></td><td>The <a href="#geometry" >-geometry</a> offset is adjusted according to 3645 <a href="#gravity" >-gravity</a> in accordance of the virtual canvas 3646 size of the first image in each list. Unlike a normal <a 3647 href="#composite" >-composite</a> operation, the canvas offset is also 3648 added to the final composite positioning of each image. </td> 3649 </tr> 3650 3651 <tr><td></td><td>If one of the image lists only contains one image, that image is 3652 applied to all the images in the other image list, regardless of which 3653 list it is. In this case it is the image meta-data of the list which 3654 preserved. </td> 3655 </tr> 3656 3657 3658 <tr valign="top"> 3659 <td valign="top">dispose</td> 3660 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of 3661 the animation after the layer disposal method has been applied, before 3662 the next sub-frame image is overlaid. That is the 'dispose' image that 3663 results from the application of the GIF <a href="#dispose" 3664 >-dispose</a> method. This allows you to check what 3665 is going wrong with a particular animation you may be developing. 3666 </td> 3667 </tr> 3668 3669 <tr valign="top"> 3670 <td valign="top">flatten</td> 3671 <td valign="top">Create a canvas the size of the first images virtual 3672 canvas using the current <a href="#background" >-background</a> color, 3673 and <a href="#compose" >-compose</a> each image in turn onto that 3674 canvas. Images falling outside that canvas is clipped. Final 3675 image will have a zero virtual canvas offset. </td> 3676 </tr> 3677 3678 <tr><td></td><td>This usally used as one of the final 'image layering' operations 3679 overlaying all the prepared image layers into a final image. </td> 3680 </tr> 3681 3682 <tr><td></td><td>For a single image this method can also be used to fillout a virtual 3683 canvas with real pixels, or to underlay a opaque color to remove 3684 transparency from an image.</td> 3685 </tr> 3686 3687 3688 <tr valign="top"> 3689 <td valign="top">merge</td> 3690 <td valign="top">As 'flatten' method but merging all the given image 3691 layers into a new layer image just large enough to hold all the image 3692 without clipping or extra space. The new images virtual offset will 3693 prevere the position of the new layer, even if this offset is 3694 negative. the virtual canvas size of the first image is preserved. 3695 </td> 3696 </tr> 3697 3698 <tr><td></td><td>Caution is advised when handling image layers with negative offsets 3699 as few image file formats handle them correctly. </td> 3700 </tr> 3701 3702 <tr valign="top"> 3703 <td valign="top">mosaic</td> 3704 <td valign="top">As 'flatten' method but expanding the initial canvas size 3705 of the first image so as to hold all the image layers. However as a 3706 virtual canvas is 'locked' to the origin, by defination, image layers 3707 with a negative offsets will still be clipped by the top and left 3708 edges.</td> 3709 </tr> 3710 3711 <tr><td></td><td>This method is commonly used to layout individual image using various 3712 offset but without knowning the final canvas size. The resulting image 3713 will, like 'flatten' not have any virtual offset, so can be saved to 3714 any image file format. </td> 3715 </tr> 3716 3717 3718 <tr valign="top"> 3719 <td valign="top">optimize</td> 3720 <td valign="top">Optimize a coalesced animation, into GIF animation using 3721 a number of general techniques. This currently a short cut to 3722 apply both the '<kbd>optimize-frame</kbd>', and 3723 '<kbd>optimize-transparency</kbd>' methods but may be expanded to 3724 include other optimization methods as they are developed. </td> 3725 </tr> 3726 3727 <tr valign="top"> 3728 <td valign="top">optimize-frame</td> 3729 <td valign="top">Optimize a coalesced animation, into GIF animation by 3730 reducing the number of pixels per frame as much as possible by 3731 attempting to pick the best layer disposal method to use, while ensuring 3732 the result will continue to animate properly. </td> 3733 </tr> 3734 3735 <tr><td></td><td> There is no guarantee that the best optimization is found. But 3736 then no reasonably fast GIF optimization algorithm can do this. 3737 However this does seem to do better than most other GIF frame 3738 optimizers seen. </td> 3739 </tr> 3740 3741 <tr valign="top"> 3742 <td valign="top">optimize-plus</td> 3743 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the 3744 overall optimization by adding extra frames to the animation, without 3745 changing the final look or timing of the animation. The frames are 3746 added to attempt to separate the clearing of pixels from the 3747 overlaying of new additional pixels from one animation frame to the 3748 next. If this does not improve the optimization (for the next frame 3749 only), it will fall back to the results of the previous normal 3750 '<kbd>optimize-frame</kbd>' technique. </td> 3751 </tr> 3752 3753 <tr><td></td><td>There is the possibility that the change in the disposal style will 3754 result in a worsening in the optimization of later frames, though this 3755 is unlikely. In other words there no guarantee that it is better than 3756 the normal '<kbd>optimize-frame</kbd>' technique. For some animations 3757 however you can get a vast improvment in the final animation size. </td> 3758 </tr> 3759 3760 <tr valign="top"> 3761 <td valign="top">optimize-transparency</td> 3762 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame 3763 overlay images with transparency, if it does not change the resulting 3764 animation by more than the current <a href="#fuzz" >-fuzz</a> factor. 3765 </td> 3766 </tr> 3767 3768 <tr><td></td><td>This should allow a existing frame optimized GIF animation to compress 3769 into a smaller file size due to larger areas of one (transparent) 3770 color rather than a pattern of multiple colors repeating the current 3771 disposed image of the last frame. </td> 3772 </tr> 3773 3774 <tr valign="top"> 3775 <td valign="top">remove-dups</td> 3776 <td valign="top">Remove (and merge time delays) of duplicate consecutive 3777 images, so as to simplify layer overlays of coalesced animations. 3778 </td> 3779 </tr> 3780 3781 <tr><td></td><td>Usually this a result of using a constant time delay across the 3782 whole animation, or after a larger animation was split into smaller 3783 sub-animations. The duplicate frames could also have been used as 3784 part of some frame optimization methods. </td> 3785 </tr> 3786 3787 <tr valign="top"> 3788 <td valign="top">remove-zero</td> 3789 <td valign="top">Remove any image with a zero time delay, unless ALL the 3790 images have a zero time delay (and is not a proper timed animation, a 3791 warning is then issued). </td> 3792 </tr> 3793 3794 <tr><td></td><td>In a GIF animation, such images are usually frames which provide 3795 partial intermediary updates between the frames that are actually 3796 displayed to users. These frames are usally added for improved frame 3797 optimization in GIF animations. </td> 3798 </tr> 3799 3800 <tr valign="top"> 3801 <td valign="top">trim-bounds</td> 3802 <td valign="top">Find the bounds of all the images in the current 3803 image sequence, then adjust the offsets so all images are contained on 3804 a minimal positive canvas. None of the image data is modified, only 3805 there virtual canvas size and offset. The all the image is given 3806 the same canvas size, and and will have a positive offset, but will 3807 remain in the same position relative to each other. As a result of the 3808 minimal canvas size at least one image will touch every edge of that 3809 canvas. The image data however may be transparent. 3810 </td> 3811 </tr> 3812 3813 </tbody> 3814</table> 3815 3816<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p> 3817 3818<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct" 3819>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic" 3820>-mosaic</a> are only aliases for the above methods. Also see <a 3821href="#page" >-page</a>, <a href="#repage" >-repage</a> operators, the <a 3822href="#compose" >-compose</a> setting, and the GIF <a href="#dispose" 3823>-dispose</a> and <a href="#delay" >-delay</a> settings. </p> 3824 3825 3826<div style="margin: auto;"> 3827 <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> 3828</div> 3829 3830<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> 3831 3832<p>Given one, two or three values delimited with commas: black-point, 3833white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and 3834white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white 3835point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center 3836contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string, 3837both black and white points are percentages of the full color range. Gamma 3838will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is 3839omitted, the default of 1.0 (no gamma correction) is assumed.</p> 3840 3841<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that 3842the given '<kbd>black_point</kbd>' value in the original image is set to 3843zero (or black), while the given '<kbd>white_point</kbd>' value is set to 3844<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments 3845to the image. The '<kbd>gamma</kbd>' of the resulting image will then be 3846adjusted. </p> 3847 3848<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or 3849adding the special '!' flag anywhere in the argument list, will cause the 3850operator to do the reverse of the level adjustment. That is a zero, or 3851<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is 3852adjusted to the given level values, allowing you to de-contrast, or compress 3853the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p> 3854 3855<p>Only the channels defined by the current <a href="#channel">-channel</a> 3856setting are adjusted (defaults to RGB color channels only), allowing you to 3857limit the effect of this operator. </p> 3858 3859<p>Please note that the transparency channel is treated as 'matte' 3860values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 3861 3862 3863<div style="margin: auto;"> 3864 <h4><a name="level-colors" id="level-colors"></a>-level-colors {<em 3865 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4> 3866</div> 3867 3868<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> 3869 3870<p>This function is exactly like <a href="#level">-level</a>, except that the 3871value value for each color channel is determined by the 3872'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as 3873described under the <a href="#fill">-fill</a> option). </p> 3874 3875<p>This effectivally means the colors provided to <kbd>-level-colors</kbd> 3876is mapped to become 'black' and 'white' respectivally, with all the other 3877colors linearly adjusted (or clipped) to match that change. Each channel is 3878adjusted separatally using the channel values of the colors specified. </p> 3879 3880<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>) 3881will map the image color 'black' and 'white' to the given colors 3882respectivally, resulting in a gradient (de-contrasting) tint of the image to 3883those colors. This can also be used to convert a plain gray-scale image into a 3884one using the gradient of colors specified. </p> 3885 3886<p>By supplying a single color with a comma separator either before or after 3887that color, will just replace the respective 'black' or 'white' point 3888respectivally. But if no comma separator is provided, the given color is 3889used for both the black and white color points, making the operator either 3890threshold the images around that color (- form) or set all colors to that 3891color (+ form). </p> 3892 3893 3894<div style="margin: auto;"> 3895 <h4><a name="limit" id="limit"></a>-limit <em class="arg">type value</em></h4> 3896</div> 3897 3898<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> 3899 3900<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> 3901 3902<p>The value for <kbd>file</kbd> is in number of files. The other limits are in bytes. By default the limits are 768 files, 2GB of image area, 1.5GiB memory, 8GiB memory map, and 18.45EB of disk. These limits are adjusted relative to the available resources on your computer if this information is available. When any limit is reached, ImageMagick fails in some fashion but attempts to take compensating actions, if possible. For example, the following limits memory:</p> 3903 3904<p class="crtsnip"> 3905 -limit memory 32MiB -limit map 64MiB 3906</p> 3907 3908<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p> 3909 3910<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 3911------------------------------------------------------------------------------ 3912 768 12.404GB 8.6642GiB 23.104GiB 18.446744EB 8 unlimited</pre> 3913</span></p> 3914<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> 3915 3916<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> 3917 3918<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> 3919 3920<p class="crtsnip"> 3921-limit area 10mb 3922</p> 3923 3924<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> 3925 3926<p class="crtsnip"> 3927-limit area 10mb -limit disk 500mb 3928</p> 3929 3930<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p> 3931 3932<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> 3933 3934<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. 3935</p> 3936 3937<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. 3938</p> 3939 3940<div style="margin: auto;"> 3941 <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> 3942</div> 3943 3944<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> 3945 3946<p>This is very similar to <a href="#contrast-stretch" >-contrast-stretch</a>, 3947and uses a 'histogram bin' to determine the range of color values that needs to 3948be stretched. However it then stretchs those colors using the <a 3949href="#level" >-level</a> operator.</p> 3950 3951<p>As such while the initial determination may have 'binning' round off 3952effects, the image colors are stretched mathematically, rather than using the 3953histogram bins. This makes the operator more accurate. </p> 3954 3955<p>note however that a <a href="#linear-stretch" >-linear-stretch</a> of 3956'<kbd>0</kbd>' does nothing, while a value of '<kbd>1</kbd>' does a near 3957perfect stretch of the color range. </p> 3958 3959<p>See also <a href="#auto-level" >-auto-level</a> for a 'perfect' 3960normalization of mathematical images. </p> 3961 3962<p>This operator is under review for re-development. </p> 3963 3964 3965<div style="margin: auto;"> 3966 <h4><a name="linewidth" id="linewidth"></a>-linewidth</h4> 3967</div> 3968 3969<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> 3970 3971<div style="margin: auto;"> 3972 <h4><a name="liquid-rescale" id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4> 3973</div> 3974 3975<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> 3976 3977<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> 3978 3979<div style="margin: auto;"> 3980 <h4><a name="list" id="list"></a>-list <em class="arg">type</em></h4> 3981</div> 3982 3983<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> 3984 3985<pre class="text"> 3986 Layers 3987 LineCap 3988 LineJoin 3989 List 3990 Locale 3991 LogEvent 3992 Log 3993 Magic 3994 Method 3995 Metric 3996 Mime 3997 Mode 3998 Morphology 3999 Module 4000 Noise 4001 Orientation 4002 Policy 4003 PolicyDomain 4004 PolicyRights 4005 Preview 4006 Primitive 4007 QuantumFormat 4008 Resource 4009 SparseColor 4010 Storage 4011 Stretch 4012 Style 4013 Threshold 4014 Type 4015 Units 4016 Validate 4017 VirtualPixel 4018</pre> 4019 4020<p>These lists vary depending on your version of ImageMagick. Use "<kbd>-list list</kbd>" to get a complete listing of all the "<kbd>-list</kbd>" arguments available:</p> 4021 4022<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>identify -list list</span></p> 4023<div style="margin: auto;"> 4024 <h4><a name="log" id="log"></a>-log <em class="arg">string</em></h4> 4025</div> 4026 4027<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> 4028 4029<p>This option specifies the format for the log printed when the <a href="#debug">-debug</a> option is active.</p> 4030 4031<p>You can display the following components by embedding special format characters:</p> 4032 4033<pre class="text"> 4034 %d domain 4035 %e event 4036 %f function 4037 %l line 4038 %m module 4039 %p process ID 4040 %r real CPU time 4041 %t wall clock time 4042 %u user CPU time 4043 %% percent sign 4044 \n newline 4045 \r carriage return 4046</pre> 4047 4048<p>For example:</p> 4049 4050<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> 4051<p>The default behavior is to print all of the components.</p> 4052 4053<div style="margin: auto;"> 4054 <h4><a name="loop" id="loop"></a>-loop <em class="arg">iterations</em></h4> 4055</div> 4056 4057<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> 4058 4059<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> 4060 4061<div style="margin: auto;"> 4062 <h4><a name="lowlight-color" id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4> 4063</div> 4064 4065<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> 4066 4067<div style="margin: auto;"> 4068 <h4><a name="magnify" id="magnify"></a>-magnify <em class="arg">factor</em></h4> 4069</div> 4070 4071<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> 4072 4073 4074<div style="margin: auto;"> 4075 <h4><a name="map" id="map"></a>-map <em class="arg">type</em></h4> 4076</div> 4077 4078<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> 4079 4080<p>Choose from these <em class="arg">Standard Colormap</em> types:</p> 4081 4082<pre class="text"> 4083 best 4084 default 4085 gray 4086 red 4087 green 4088 blue 4089</pre> 4090 4091<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> 4092 4093 4094<div style="margin: auto;"> 4095 <h4><a name="map_stream_" id="map_stream_"></a>-map <em class="arg">components</em></h4> 4096</div> 4097 4098<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> 4099 4100<p>Here are the valid components of a map:</p> 4101 4102<pre class="text"> 4103 r red pixel component 4104 g green pixel component 4105 b blue pixel component 4106 a alpha pixel component (0 is transparent) 4107 o opacity pixel component (0 is opaque) 4108 i grayscale intensity pixel component 4109 c cyan pixel component 4110 m magenta pixel component 4111 y yellow pixel component 4112 k black pixel component 4113 p pad component (always 0) 4114</pre> 4115 4116<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> 4117 4118<div style="margin: auto;"> 4119 <h4><a name="mask" id="mask"></a>-mask 4120<em class="arg">filename</em></h4> 4121</div> 4122 4123<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> 4124 4125<p>Use <a href="#mask">+mask</a> to remove the image mask.</p> 4126 4127<div style="margin: auto;"> 4128 <h4><a name="mattecolor" id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4> 4129</div> 4130 4131<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> 4132 4133<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 4134 4135<p>The default matte color is <kbd>#BDBDBD</kbd>, <span style="background-color: #bdbdbd;">this shade of gray</span>.</p> 4136 4137<div style="margin: auto;"> 4138 <h4><a name="maximum" id="maximum"></a>-maximum</h4> 4139</div> 4140 4141<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>return the maximum intensity of an image sequence.</td><td style='text-align:right;'></td></tr></table> 4142 4143<div style="margin: auto;"> 4144 <h4><a name="median" id="median"></a>-median <em class="arg">radius</em></h4> 4145</div> 4146 4147<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> 4148 4149<div style="margin: auto;"> 4150 <h4><a name="metric" id="metric"></a>-metric <em class="arg">type</em></h4> 4151</div> 4152 4153<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> 4154 4155<p>Choose from:</p> 4156 4157<pre class="text"> 4158 AE absolute number of different pixels 4159 MAE mean absolute error (normalized), average channel error distance 4160 MEPP mean error per pixel (normalized mean error, normalized peak error) 4161 MSE mean error squared, average of the channel error squared 4162 PAE peak absolute (normalize peak absolute) 4163 PSNR peak signal to noise ratio 4164 RMSE root mean squared (normalized root mean squared) 4165</pre> 4166 4167<p>The '<kbd>AE</kbd>' or absolute count of pixels that are different, can be 4168controled using a <a href="#fuzz" >-fuzz</a> factor to ignore pixels which 4169only changed by a small amount. The '<kbd>PAE</kbd>' can be used to find the 4170size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels 4171'similar'. </p> 4172 4173<p>The '<kbd>MEPP</kbd>' metric returns three different metrics 4174('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>' 4175normalized) from the single comparision run. </p> 4176 4177<p>To print a complete list of metrics, use the <a href="#list">-list metrics</a> option.</p> 4178 4179<div style="margin: auto;"> 4180 <h4><a name="minimum" id="minimum"></a>-minimum</h4> 4181</div> 4182 4183<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>return the minimum intensity of an image sequence.</td><td style='text-align:right;'></td></tr></table> 4184 4185 4186<div style="margin: auto;"> 4187 <h4><a name="mode" id="mode"></a>-mode <em class="arg">value</em></h4> 4188</div> 4189 4190<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> 4191 4192<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame, Unframe, or Concatenate</kbd></p> 4193 4194<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>' 4195argument for a list of <a href="#mode" >-mode</a> arguments available 4196in your ImageMagick installation.</p> 4197 4198 4199<div style="margin: auto;"> 4200 <h4><a name="modulate" id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4> 4201</div> 4202 4203<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> 4204 4205<p>The arguments are given as a percentages of variation. A value of 100 means no change, and any 4206missing values are taken to mean 100.</p> 4207 4208<p>The <em class="arg">brightness</em> is a multiplier of the overall brightness of the image, so 0 4209means pure black, 50 is half as bright, 200 is twice as bright. To invert its 4210meaning <a href="#negate">-negate</a> the image before and after. </p> 4211 4212<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> 4213 4214<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 4215shades to purple, and so on. A value of either 0 or 200 results in a complete 4216180 degree rotation of the image. Using a value of 300 is a 360 degree 4217rotation resulting in no change to the original image. </p> 4218 4219<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> 4220 4221<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> 4222 4223<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> 4224<div style="margin: auto;"> 4225 <h4><a name="monitor" id="monitor"></a>-monitor</h4> 4226</div> 4227 4228<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> 4229 4230 4231<div style="margin: auto;"> 4232 <h4><a name="monochrome" id="monochrome"></a>-monochrome</h4> 4233</div> 4234 4235<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> 4236 4237 4238<div style="margin: auto;"> 4239 <h4><a name="morph" id="morph"></a>-morph <em class="arg">frames</em></h4> 4240</div> 4241 4242<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> 4243 4244<p>Both the image pixels and size are linearly interpolated to give the 4245appearance of a meta-morphosis from one image to the next, over all the images 4246in the current image list. The added images are the equivalent of a <a 4247href="#blend">-blend</a> composition. The <em class="arg">frames</em> 4248argument determine how many images to interpolate between each image. </p> 4249 4250 4251<div style="margin: auto;"> 4252 <h4><a name="morphology" id="morphology"></a>-morphology</h4> 4253 <h4><a name="morphology" id="morphology"></a>-morphology <em class="arg">method</em> <em class="arg">kernel</em></h4> 4254</div> 4255 4256<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>apply a morphology method to the image</td><td style='text-align:right;'></td></tr></table> 4257 4258<div style="margin: auto;"> 4259 <h4><a name="mosaic" id="mosaic"></a>-mosaic</h4> 4260</div> 4261 4262<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> 4263 4264 4265<div style="margin: auto;"> 4266 <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> 4267</div> 4268 4269<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> 4270 4271<p>Blur with the given radius, standard deviation (sigma), and angle. The 4272angle given is the angle toward which the image is blurred. That is the 4273direction people would consider the object is coming from. </p> 4274 4275<p>Note that the blur is not uniform distribution, giving the motion a 4276definate sense of direction of movement. </p> 4277 4278<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4279pixels which are outside the image proper are blurred into the final result. 4280</p> 4281 4282<div style="margin: auto;"> 4283 <h4><a name="name" id="name"></a>-name</h4> 4284</div> 4285 4286<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> 4287<div style="margin: auto;"> 4288 <h4><a name="negate" id="negate"></a>-negate</h4> 4289</div> 4290 4291<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>replace each pixel with its complementary color.</td><td style='text-align:right;'></td></tr></table> 4292 4293<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> 4294 4295<div style="margin: auto;"> 4296 <h4><a name="noise" id="noise"></a>-noise <em class="arg">radius</em><br/> 4297 +noise <em class="arg">type</em></h4> 4298</div> 4299 4300<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> 4301 4302<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> 4303 4304<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> 4305 4306<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> 4307 4308<pre class="text"> 4309Gaussian 4310Impulse 4311Laplacian 4312Multiplicative 4313Poisson 4314Random 4315Uniform 4316</pre> 4317 4318<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p> 4319 4320<p>Also see the <a href="#evaluate">-evaluate</a> noise functions that allos 4321the use of a controlling value to specify teh amount of noise that should be 4322added to an image. </p> 4323 4324 4325<div style="margin: auto;"> 4326 <h4><a name="normalize" id="normalize"></a>-normalize</h4> 4327</div> 4328 4329<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> 4330 4331<p>The intensity values are stretched to cover the entire range of possible 4332values. While doing so, black-out at most <em>2%</em> of the pixels and 4333white-out at most <em>1%</em> of the pixels.</p> 4334 4335<p>Note that as of ImageMagick 6.4.7-0, <a href="#normalize" >-normalize</a> 4336is equivalent to <a href="#contrast-stretch" >-contrast-stretch 2%x1%</a>. 4337(Before this version, it was equivalent to <a href="#contrast-stretch" 4338>-contrast-stretch 2%x99%</a>).</p> 4339 4340<p>All the channels are normalized in concert by the came amount so as to 4341preserve color integrity, when the default <a href="#channel" >+channel</a> 4342setting is in use. Specifing any other <a href="#channel" >-channel</a> 4343setting will normalize the RGB channels independently.</p> 4344 4345<p>See <a href="#contrast-stretch" >-contrast-stretch</A> for more details. 4346Also see <a href="#auto-level" >-auto-level</a> for a 'perfect' normalization 4347that is better suited to mathematically generated images. </p> 4348 4349<p>This operator is under review for re-development. </p> 4350 4351 4352<div style="margin: auto;"> 4353 <h4><a name="ordered-dither" id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4> 4354</div> 4355 4356<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 4357class="arg">threshold map</em> specified, and a uniform color map with the 4358given number of <em class="arg">levels</em> per color channel . </td><td style='text-align:right;'></td></tr></table> 4359 4360<p>You can choose from these standard threshold maps:</p> 4361 4362<pre class="text"> 4363 threshold 4364 checks 4365 o2x2 4366 o3x3 4367 o4x4 4368 o8x8 4369 h4x4a 4370 h6x6a 4371 h8x8a 4372 h4x4o 4373 h6x6o 4374 h8x8o 4375 h16x16o 4376</pre> 4377 4378<p>The '<kbd>o</kbd>' maps are ordered diffused pixel threshold maps, while the 4379'<kbd>h</kbd>' maps are halftone threshold maps which are either 'a' angled, or 4380'o' orthogonal. The '<kbd>checks</kbd>' produce a 3 level checkerbord dither 4381pattern. Or you can define your own <em class="arg" >threshold map</em> in a 4382personal or system "<kbd>thresholds.xml</kbd>" XML file. </p> 4383 4384<p>To print a complete list of threshold, use the <a href="#list" >-list 4385threshold</a> option.</p> 4386 4387<p>It is recommended that the <a href="#map" >+map</a> operator be used after 4388applying <a href="#ordered-dither" >-ordered-dither</a> to reduce the number of 4389colors an animated image sequence, to less that 256 colors. This ensures that 4390a common or global color table is used when saving the result to a color 4391limited file format such as GIF. </p> 4392 4393<p>Note that at this time the exact same threshold dithering map is used for 4394all color channels, no attempt is made to offset or rotate the map for 4395different channels is made, to create an offset printing effect. (possible 4396future expansion) </p> 4397 4398 4399<div style="margin: auto;"> 4400 <h4><a name="opaque" id="opaque"></a>-opaque <em class="arg">color</em></h4> 4401</div> 4402 4403<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> 4404 4405<p>The <em class="arg">color</em> argument is defined using the format 4406described under the <a href="#fill" >-fill</a> option. The <a href="#fuzz" 4407>-fuzz</a> setting can be used to match and replace colors similar to the one 4408given.</p> 4409 4410<p>The <a href="#transparent" >-transparent</a> operator is exactly the same 4411as <a href="#opaque" >-opaque</a> but makes the matching color transparent, 4412rather than the same as the current <a href="#fill">-fill</a> color. </p> 4413 4414<p>Use <a href="#opaque">+opaque</a> to paint any pixel that does not match the target color.</p> 4415 4416 4417 4418<div style="margin: auto;"> 4419 <h4><a name="orient" id="orient"></a>-orient <em class="arg">image orientation</em></h4> 4420</div> 4421 4422<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> 4423 4424<p>Choose from these orientations:</p> 4425 4426<pre class="text"> 4427 bottom-left 4428 bottom-right 4429 left-bottom 4430 left-top 4431 right-bottom 4432 right-top 4433 top-left 4434 top-right 4435 undefined 4436</pre> 4437 4438<p>To print a complete list of orientations, use the <a href="#list" >-list 4439orientation</a> option.</p> 4440 4441 4442<div style="margin: auto;"> 4443 <h4><a name="page" id="page"></a>-page <em class="arg">geometry</em><br/> 4444 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!<></em>}]<br/> 4445 +page 4446 </h4> 4447</div> 4448 4449<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> 4450 4451<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> 4452 4453<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> 4454 4455<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> 4456<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;"> 4457<thead> 4458 <tr valign="top"> 4459 <th align="center"><em class="arg">media</em></th> 4460 <th align="center"><em class="arg">width</em></th> 4461 <th align="center"><em class="arg">height</em></th> 4462 </tr> 4463</thead> 4464<tbody> 4465<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr> 4466<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr> 4467<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr> 4468<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4469<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4470<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr> 4471<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr> 4472<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr> 4473<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr> 4474<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr> 4475<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr> 4476<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr> 4477<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr> 4478<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr> 4479<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4480<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4481<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr> 4482<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr> 4483<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr> 4484<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr> 4485<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr> 4486<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr> 4487<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr> 4488<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr> 4489<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr> 4490<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr> 4491<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr> 4492<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr> 4493<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr> 4494<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr> 4495<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr> 4496<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr> 4497<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr> 4498<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr> 4499<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr> 4500<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4501<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4502<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr> 4503</tbody> 4504</table> 4505 4506 4507 4508 4509<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> 4510 4511<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> 4512 4513<p>The default page dimensions for a TEXT image is 612x792.</p> 4514 4515<p>This option is used in concert with <a href="#density">-density</a>.</p> 4516 4517<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p> 4518 4519<div style="margin: auto;"> 4520 <h4><a name="paint" id="paint"></a>-paint <em class="arg">radius</em></h4> 4521</div> 4522 4523<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> 4524 4525<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> 4526 4527<div style="margin: auto;"> 4528 <h4><a name="path" id="path"></a>-path <em class="arg">path</em></h4></div> 4529 4530<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> 4531 4532<div style="margin: auto;"> 4533 <h4><a name="pause_animate_" id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4> 4534</div> 4535 4536<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> 4537 4538<p>Pause for the specified number of seconds before repeating the animation.</p> 4539 4540<div style="margin: auto;"> 4541 <h4><a name="pause_import_" id="pause_import_"></a>-pause <em class="arg">seconds</em></h4> 4542</div> 4543 4544<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> 4545 4546<p>Pause for the specified number of seconds before taking the next snapshot.</p> 4547 4548<div style="margin: auto;"> 4549 <h4><a name="ping" id="ping"></a>-ping</h4> 4550</div> 4551 4552<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> 4553 4554<div style="margin: auto;"> 4555 <h4><a name="pointsize" id="pointsize"></a>-pointsize <em class="arg">value</em></h4> 4556</div> 4557 4558<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> 4559 4560<div style="margin: auto;"> 4561 <h4><a name="polaroid" id="polaroid"></a>-polaroid <em class="arg">angle</em></h4> 4562</div> 4563 4564<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> 4565 4566<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p> 4567 4568<div style="margin: auto;"> 4569 <h4><a name="posterize" id="posterize"></a>-posterize <em class="arg">levels</em></h4> 4570</div> 4571 4572<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> 4573 4574<div style="margin: auto;"> 4575 <h4><a name="precision" id="precision"></a>-precision <em class="arg">value</em></h4> 4576</div> 4577 4578<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the maximum number of significant digits to be printed.</td><td style='text-align:right;'></td></tr></table> 4579 4580<div style="margin: auto;"> 4581 <h4><a name="preview" id="preview"></a>-preview <em class="arg">type</em></h4> 4582</div> 4583 4584<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> 4585 4586<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> 4587 4588<pre class="text"> 4589 Rotate 4590 Shear 4591 Roll 4592 Hue 4593 Saturation 4594 Brightness 4595 Gamma 4596 Spiff 4597 Dull 4598 Grayscale 4599 Quantize 4600 Despeckle 4601 ReduceNoise 4602 Add Noise 4603 Sharpen 4604 Blur 4605 Threshold 4606 EdgeDetect 4607 Spread 4608 Shade 4609 Raise 4610 Segment 4611 Solarize 4612 Swirl 4613 Implode 4614 Wave 4615 OilPaint 4616 CharcoalDrawing 4617 JPEG 4618</pre> 4619 4620<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p> 4621 4622<p>The default preview is <kbd>JPEG</kbd>.</p> 4623 4624<div style="margin: auto;"> 4625 <h4><a name="print" id="print"></a>-print <em class="arg">string</em></h4> 4626</div> 4627 4628<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> 4629 4630<div style="margin: auto;"> 4631 <h4><a name="process" id="process"></a>-process <em class="arg">command</em></h4> 4632</div> 4633 4634<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> 4635 4636<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> 4637 4638<div style="margin: auto;"> 4639 <h4><a name="profile" id="profile"></a>-profile <em class="arg">filename</em><br/> 4640 +profile <em class="arg">profile_name</em></h4> 4641</div> 4642 4643<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> 4644 4645<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> 4646 4647<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> 4648 4649<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> 4650 4651<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> 4652 4653<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p> 4654 4655<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p> 4656<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> 4657 4658<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert CMYK.tif -profile "CMYK.icc" -profile "RGB.icc" RGB.tiff</span></p> 4659<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results. 4660CMYK profiles are often very asymmetric since they involve 3−>4 and 4−>3 channel mapping. 4661</p> 4662 4663<div style="margin: auto;"> 4664 <h4><a name="quality" id="quality"></a>-quality <em class="arg">value</em></h4> 4665</div> 4666 4667<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> 4668 4669<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> 4670 4671<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> 4672 4673<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> 4674 4675<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> 4676 4677<p>If filter-type is 4 or less, the specified filter-type is used for all scanlines:</p> 4678 4679<pre class="text"> 4680 0: none 4681 1: sub 4682 2: up 4683 3: average 4684 4: Paeth 4685</pre> 4686 4687<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> 4688 4689<p>If filter-type is 6, adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p> 4690 4691<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> 4692 4693<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> 4694 4695<p>For further information, see the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p> 4696 4697<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> 4698 4699<div style="margin: auto;"> 4700 <h4><a name="quantize" id="quantize"></a>-quantize <em class="arg">colorspace</em></h4> 4701</div> 4702 4703<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> 4704 4705<p>To print a complete list of colorspaces, use the <a href="#list">-list colorspace</a> option.</p> 4706 4707 4708<div style="margin: auto;"> 4709 <h4><a name="quiet" id="quiet"></a>-quiet</h4> 4710</div> 4711 4712<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> 4713 4714<div style="margin: auto;"> 4715 <h4><a name="radial-blur" id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4> 4716</div> 4717 4718<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> 4719 4720<p>Note that this is actually a rotational blur rather than a radial and as 4721such actually mis-named. </p> 4722 4723<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4724pixels which are outside the image proper are blurred into the final result. 4725</p> 4726 4727 4728<div style="margin: auto;"> 4729 <h4><a name="raise" id="raise"></a>-raise <em class="arg">thickness</em></h4> 4730</div> 4731 4732<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> 4733 4734<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>. 4735</p> 4736 4737<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p> 4738 4739<div style="margin: auto;"> 4740 <h4><a name="random-threshold" id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4> 4741</div> 4742 4743<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> 4744 4745<div style="margin: auto;"> 4746 <h4><a name="recolor" id="recolor"></a>-recolor <em class="arg">matrix</em></h4> 4747</div> 4748 4749<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> 4750 4751<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 4752Flash except that the offset is scaled to 1.0 (divide Flash offset by 255).</p> 4753 4754<div style="margin: auto;"> 4755 <h4><a name="red-primary" id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4> 4756</div> 4757 4758<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> 4759 4760<div style="margin: auto;"> 4761 <h4><a name="regard-warnings" id="regard-warnings"></a>-regard-warnings</h4> 4762</div> 4763 4764<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> 4765 4766<div style="margin: auto;"> 4767 <h4><a name="remap" id="remap"></a>-remap <em class="arg">filename</em></h4> 4768</div> 4769 4770<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> 4771 4772<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then 4773the given colors are dithered over the image as necessary, otherwise the closest 4774color (in RGB colorspace) is selected to replace that pixel in the image. </p> 4775 4776<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all 4777images in the current image sequence, all the images will have the same color 4778table. That means that when saved to a file format such as GIF, it will use 4779that color table as a single common or global color table, for all the images, 4780without requiring extra local color tables. </p> 4781 4782<p>Use <a href="#remap">+remap</a> to reduce all images in the current image 4783sequence to use a common color map over all the images. This equivalent to 4784appending all the images together (without extra background colors) and color 4785reducing those images using <a href="#colors">-colors</a> with a 256 color 4786limit, then <a href="#remap">-remap</a> those colors over the original list of 4787images. This ensures all the images follow a single color map. </p> 4788 4789<p>If the number of colors over all the images is less than 256, then <a 4790href="#remap">+remap</a> should not perform any color reduction or dithering, as 4791no color changes are needed. In that case, its only effect is to force the use 4792of a global color table. This recommended after using either <a 4793href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to 4794reduce the number of colors in an animated image sequence. </p> 4795 4796<div style="margin: auto;"> 4797 <h4><a name="region" id="region"></a>-region <em class="arg">geometry</em></h4> 4798</div> 4799 4800<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> 4801 4802<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> 4803 4804<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> 4805 4806<div style="margin: auto;"> 4807 <h4><a name="remote" id="remote"></a>-remote</h4> 4808</div> 4809 4810<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> 4811 4812<p>The only command recognized is the name of an image file to load.</p> 4813 4814<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> 4815 4816<div style="margin: auto;"> 4817 <h4><a name="render" id="render"></a>-render</h4> 4818</div> 4819 4820<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> 4821 4822<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> 4823 4824<div style="margin: auto;"> 4825<h4><a name="repage" id="repage"></a>-repage <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%'>Adjust the canvas and offset information of the image.</td><td style='text-align:right;'></td></tr></table> 4829 4830<p>This option is like <a href="#page">-page</a> but acts as an image operator 4831rather than a setting. You can separately set the canvas size or the offset 4832of the image on that canvas by only providing those components. </p> 4833 4834<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> 4835 4836<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing 4837offset to move the image relative to its previous position. This useful for 4838animation sequences. </p> 4839 4840<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to 4841recalculate the canvas size so the image (at its current offset) will appear 4842completely on that canvas (unless it has a negative offset).</p> 4843 4844<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual 4845canvas meta-data from the images. </p> 4846 4847<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to 4848directly assign virtual canvas meta-data. </p> 4849 4850 4851<div style="margin: auto;"> 4852 <h4><a name="resample" id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4> 4853</div> 4854 4855<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> 4856 4857<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> 4858 4859<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> 4860 4861<div style="margin: auto;"> 4862 <h4><a name="resize" id="resize"></a>-resize <em class="arg">geometry</em></h4> 4863</div> 4864 4865<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> 4866 4867<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> 4868 4869<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> 4870 4871<p>Many image processing algorithms assume your image is in a linear-light coding. If your image is gamma-corrected, you can remove the nonlinear gamma correction, apply the transform, then restore it like this:</p> 4872 4873<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert portrait.jpg -gamma .45455 -resize 25% -gamma 2.2 \ <br/> -quality 92 passport.jpg</span></p> 4874<div style="margin: auto;"> 4875 <h4><a name="respect-parentheses" id="respect-parentheses"></a>-respect-parentheses</h4> 4876</div> 4877 4878<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> 4879 4880<div style="margin: auto;"> 4881 <h4><a name="reverse" id="reverse"></a>-reverse</h4> 4882</div> 4883 4884<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> 4885 4886 4887<div style="margin: auto;"> 4888 <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> 4889</div> 4890 4891<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> 4892 4893<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> 4894 4895 4896<div style="margin: auto;"> 4897 <h4><a name="rotate" id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg"><</em>}{<em class="arg">></em>}</h4> 4898</div> 4899 4900<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> 4901 4902<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> 4903 4904<p>Empty triangles in the corners, left over from rotating the image, are 4905filled with the <kbd>background</kbd> color. </p> 4906 4907<p>See also the <a href="#distort">-distort</a> operator and specifically the 4908'<kbd>ScaleRotateTranslate</kbd>' distort method. </p> 4909 4910 4911<div style="margin: auto;"> 4912 <h4><a name="sample" id="sample"></a>-sample <em class="arg">geometry</em></h4> 4913</div> 4914 4915<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> 4916 4917<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> 4918 4919<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> 4920 4921 4922<div style="margin: auto;"> 4923 <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> 4924</div> 4925 4926<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> 4927 4928<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> 4929 4930<div style="margin: auto;"> 4931 <h4><a name="scale" id="scale"></a>-scale <em class="arg">geometry</em></h4> 4932</div> 4933 4934<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> 4935 4936<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> 4937 4938<div style="margin: auto;"> 4939 <h4><a name="scene" id="scene"></a>-scene <em class="arg">value</em></h4> 4940</div> 4941 4942<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> 4943 4944<p>This option sets the scene number of an image or the first image in an image sequence.</p> 4945 4946<div style="margin: auto;"> 4947 <h4><a name="screen" id="screen"></a>-screen</h4> 4948</div> 4949 4950<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> 4951 4952<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> 4953 4954<div style="margin: auto;"> 4955 <h4><a name="seed" id="seed"></a>-seed</h4> 4956</div> 4957 4958<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> 4959 4960<div style="margin: auto;"> 4961 <h4><a name="segment" id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4> 4962</div> 4963 4964<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> 4965 4966<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> 4967 4968<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> 4969 4970<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report 4971of the color clusters is returned.</p> 4972 4973 4974<div style="margin: auto;"> 4975 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">geometry</em></h4> 4976</div> 4977 4978<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> 4979 4980<div style="margin: auto;"> 4981 <h4><a name="separate" id="separate"></a>-separate</h4> 4982</div> 4983 4984<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> 4985 4986<div style="margin: auto;"> 4987 <h4><a name="sepia-tone" id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4> 4988</div> 4989 4990<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> 4991 4992<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p> 4993 4994<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> 4995 4996<div style="margin: auto;"> 4997 <h4><a name="set" id="set"></a>-set <em class="arg">attribute value</em></h4> 4998</div> 4999 5000<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> 5001 5002<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> 5003 5004<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -set comment 'Rose is a rose is a rose is a rose' \ <br/> rose.png</span><span class='crtout'></span><span class="crtprompt"> $magick> </span><span class='crtin'>identify -format %c rose.png</span><span class='crtout'>Rose is a rose is a rose is a rose</span></p> 5005<p>The <a href="#repage">-repage</a> operator will also set the 5006'<kbd>page</kbd>' attribute of images already in memory, but allows you to 5007separately set the virtual canvas's size and offset components, and also allows 5008relative offset changes, and automatic canvas size re-calculating. The above 5009<a href="#set">-set</a> option is purely a direct, unmodified assignment of the 5010virtual canvas (page) meta-data. </p> 5011 5012<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> 5013 5014<div style="margin: auto;"> 5015 <h4><a name="shade" id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4> 5016</div> 5017 5018<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> 5019 5020<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> 5021 5022<div style="margin: auto;"> 5023 <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> 5024</div> 5025 5026<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> 5027 5028<div style="margin: auto;"> 5029 <h4><a name="shared-memory" 5030id="shared-memory"></a>-shared-memory</h4> 5031</div> 5032 5033<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> 5034 5035<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> 5036 5037<div style="margin: auto;"> 5038 <h4><a name="sharpen" id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4> 5039</div> 5040 5041<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> 5042 5043<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p> 5044 5045<div style="margin: auto;"> 5046 <h4><a name="shave" id="shave"></a>-shave <em class="arg">geometry</em></h4> 5047</div> 5048 5049<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> 5050 5051<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> 5052 5053<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> 5054 5055<div style="margin: auto;"> 5056 <h4><a name="shear" id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4> 5057</div> 5058 5059<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> 5060 5061<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> 5062 5063<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> 5064 5065<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> 5066 5067<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> 5068 5069<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> 5070<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> 5071 5072<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p> 5073<div style="margin: auto;"> 5074 <h4><a name="sigmoidal" id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4> 5075</div> 5076 5077<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> 5078 5079<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> 5080 5081<div style="margin: auto;"> 5082 <h4><a name="silent" id="silent"></a>-silent</h4> 5083</div> 5084 5085<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> 5086 5087<div style="margin: auto;"> 5088 <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> 5089</div> 5090 5091<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> 5092 5093<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> 5094 5095<p>For Photo CD images, choose from these sizes:</p> 5096 5097<pre class="text"> 5098 192x128 5099 384x256 5100 768x512 5101 1536x1024 5102 3072x2048 5103</pre> 5104 5105<div style="margin: auto;"> 5106 <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> 5107</div> 5108 5109<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> 5110 5111<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> 5112 5113<div style="margin: auto;"> 5114 <h4><a name="snaps" id="snaps"></a>-snaps <em class="arg">value</em></h4> 5115</div> 5116 5117<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> 5118 5119<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p> 5120 5121<div style="margin: auto;"> 5122 <h4><a name="solarize" id="solarize"></a>-solarize <em class="arg">threshold</em></h4> 5123</div> 5124 5125<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>negate all pixels above the threshold level.</td><td style='text-align:right;'></td></tr></table> 5126 5127<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p> 5128 5129<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p> 5130 5131<div style="margin: auto;"> 5132 <h4><a name="sparse-color" id="sparse-color"></a>-sparse-color <em 5133 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4> 5134</div> 5135 5136<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> 5137 5138 5139<table class="doc"> 5140 <tbody> 5141 <tr valign="top"> 5142 <th align="left" style="width: 8%">Method</th> 5143 <th align="left">Description</th> 5144 </tr> 5145 5146 <tr valign="top"> 5147 <td valign="top">voronoi</td> 5148 <td valign="top">Simply map each pixel to the to nearest color point 5149 given. The result are polygonal 'cells' of solid color. </td> 5150 </tr> 5151 5152 <tr valign="top"> 5153 <td valign="top">shepards</td> 5154 <td valign="top">Colors points basied on the ratio of inverse distance 5155 squared. Generating spots of color in a sea of the average of 5156 colors. </td> 5157 </tr> 5158 5159 <tr valign="top"> 5160 <td valign="top">barycentric</td> 5161 <td valign="top">three point triangle of color given 3 points. 5162 Giving only 2 points will form a linear gradient between those points. 5163 Gradient is however not restricted to just the triangle or line. </td> 5164 </tr> 5165 5166 <tr valign="top"> 5167 <td valign="top">bilinear</td> 5168 <td valign="top">Like barycentric but for 4 points. Less than 4 points 5169 fall back to barycentric. </td> 5170 </tr> 5171 5172 </tbody> 5173</table> 5174 5175<p>The points are placed according to the images location on the virtual 5176canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a> 5177offset), and do not actually have to exist on the given image, but may be 5178some point beyond the edge of the image. All points are floating point values. 5179</p> 5180 5181<p>Only the color channels defined by the <a href="#channel" >-channel</a> are 5182modified, whcih means the matte/alpha transparency channel is not effected by 5183default. If enabled, the image also needs a the matte/alpha channel to be 5184enabled for this operator to effect an images transparency. This is typical 5185transparency handling for images. </p> 5186 5187<p>All the above methods when given a single point of color will replace all 5188the colors in the image with the color given, regardless of the point. This is 5189logical, and provides an alternative technique to recolor a image to some 5190default value. </p> 5191 5192 5193<div style="margin: auto;"> 5194 <h4><a name="splice" id="splice"></a>-splice <em class="arg">geometry</em></h4> 5195</div> 5196 5197<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> 5198 5199<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> 5200 5201<div style="margin: auto;"> 5202 <h4><a name="spread" id="spread"></a>-spread <em class="arg">amount</em></h4> 5203</div> 5204 5205<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> 5206 5207<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> 5208 5209<div style="margin: auto;"> 5210 <h4><a name="stegano" id="stegano"></a>-stegano <em class="arg">offset</em></h4> 5211</div> 5212 5213<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> 5214 5215<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> 5216 5217<div style="margin: auto;"> 5218 <h4><a name="stereo" id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4> 5219</div> 5220 5221<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> 5222 5223<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> 5224 5225<div style="margin: auto;"> 5226 <h4><a name="storage-type" id="storage-type"></a>-storage-type <em class="arg">type</em></h4> 5227</div> 5228 5229<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> 5230 5231<pre class="text"> 5232 char store pixels as unsigned characters 5233 double store pixels as doubles 5234 float store pixels as floats 5235 integer store pixels as integers 5236 long store pixels as longs 5237 quantum store pixels in the native depth of your ImageMagick distribution 5238 short store pixels as unsigned shorts 5239</pre> 5240 5241<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels 5242values range from 0 to the maximum value the storage type can support.</p> 5243 5244<div style="margin: auto;"> 5245 <h4><a name="stretch" id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4> 5246</div> 5247 5248<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> 5249 5250<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> 5251 5252<pre class="text"> 5253 Any 5254 Condensed 5255 Expanded 5256 ExtraCondensed 5257 ExtraExpanded 5258 Normal 5259 SemiCondensed 5260 SemiExpanded 5261 UltraCondensed 5262 UltraExpanded 5263</pre> 5264 5265<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p> 5266 5267<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> 5268 5269<div style="margin: auto;"> 5270 <h4><a name="strip" id="strip"></a>-strip</h4> 5271</div> 5272 5273<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> 5274 5275<div style="margin: auto;"> 5276 <h4><a name="stroke" id="stroke"></a>-stroke <em class="arg">color</em></h4> 5277</div> 5278 5279<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> 5280 5281<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5282 5283<p>See <a href="#draw">-draw</a> for further details.</p> 5284 5285<div style="margin: auto;"> 5286 <h4><a name="strokewidth" id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4> 5287</div> 5288 5289<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> 5290 5291<p>See <a href="#draw">-draw</a> for further details.</p> 5292 5293<div style="margin: auto;"> 5294 <h4><a name="style" id="style"></a>-style <em class="arg">fontStyle</em></h4> 5295</div> 5296 5297<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> 5298 5299<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> 5300 5301<pre class="text"> 5302 Any 5303 Italic 5304 Normal 5305 Oblique 5306</pre> 5307 5308<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> 5309 5310<div style="margin: auto;"> 5311 <h4><a name="swap" id="swap"></a>-swap <em class="arg">index,index</em></h4> 5312</div> 5313 5314<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> 5315 5316<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> 5317 5318<div style="margin: auto;"> 5319 <h4><a name="swirl" id="swirl"></a>-swirl <em class="arg">degrees</em></h4> 5320</div> 5321 5322<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> 5323 5324<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p> 5325 5326<div style="margin: auto;"> 5327 <h4><a name="taint" id="taint"></a>-taint</h4> 5328</div> 5329 5330<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> 5331 5332<div style="margin: auto;"> 5333 <h4><a name="text-font" id="text-font"></a>-text-font <em class="arg">name</em></h4> 5334</div> 5335 5336<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> 5337 5338<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> 5339 5340<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> 5341 5342<div style="margin: auto;"> 5343 <h4><a name="texture" id="texture"></a>-texture <em class="arg">filename</em></h4> 5344</div> 5345 5346<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> 5347 5348<div style="margin: auto;"> 5349 <h4><a name="threshold" id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 5350</div> 5351 5352<!-- {<em class="arg">green,blue,opacity</em>} 5353<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> 5354--> 5355 5356<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> 5357 5358<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> 5359 5360<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. 5361</p> 5362 5363<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> 5364 5365<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p> 5366<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> 5367 5368 5369<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> 5370<p>Note that the values of the transparency channel is treated as 'matte' 5371values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 5372 5373<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>. 5374</p> 5375 5376<div style="margin: auto;"> 5377 <h4><a name="thumbnail" id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4> 5378</div> 5379 5380<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> 5381 5382<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> 5383 5384<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> 5385 5386<div style="margin: auto;"> 5387 <h4><a name="tile" id="tile"></a>-tile <em class="arg">filename</em></h4> 5388</div> 5389 5390<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> 5391 5392<div style="margin: auto;"> 5393 <h4>-tile <em class="arg">geometry</em></h4> 5394</div> 5395 5396<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> 5397 5398<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> 5399 5400<div style="margin: auto;"> 5401 <h4>-tile</h4> 5402</div> 5403 5404<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> 5405 5406<div style="margin: auto;"> 5407 <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> 5408</div> 5409 5410<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> 5411 5412<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> 5413 5414<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> 5415 5416<div style="margin: auto;"> 5417 <h4><a name="tint" id="tint"></a>-tint <em class="arg">value</em></h4> 5418</div> 5419 5420<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> 5421 5422<p>Tint the image with the fill color.</p> 5423 5424<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> 5425 5426<div style="margin: auto;"> 5427 <h4><a name="title" id="title"></a>-title <em class="arg">string</em></h4> 5428</div> 5429 5430<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> 5431 5432<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> 5433 5434<p>For example,</p> 5435 5436<p class="crtsnip"> 5437 -title "%m:%f %wx%h" 5438</p> 5439 5440<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> 5441 5442 5443<div style="margin: auto;"> 5444 <h4><a name="transform" id="transform"></a>-transform</h4> 5445</div> 5446 5447<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> 5448 5449<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p> 5450 5451<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> 5452<div style="margin: auto;"> 5453 <h4><a name="transparent" id="transparent"></a>-transparent <em class="arg">color</em></h4> 5454</div> 5455 5456<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> 5457 5458<p>The <em class="arg">color</em> argument is defined using the format 5459described under the <a href="#fill">-fill</a> option. The <a href="#fuzz" 5460>-fuzz</a> setting can be used to match and replace colors similar to the one 5461given. </p> 5462 5463<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a 5464href="#transparent" >-transparent</a> but replaces the matching color same as 5465the current <a href="#fill">-fill</a> color setting. </p> 5466 5467<p>This does not define the 'transparency color' used for color-mapped image 5468formats, such as GIF. For that use <a href="#transparent-color" 5469>-transparent-color</a> </p> 5470 5471<p>Use <a href="#opaque">+opaque</a> to invert the pixels matched, that is 5472paint any pixel that does not match the target color, with the fill color.</p> 5473 5474 5475<div style="margin: auto;"> 5476 <h4><a name="transparent-color" id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4> 5477</div> 5478 5479<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Set the transparent color.</td><td style='text-align:right;'></td></tr></table> 5480 5481<p>Sometimes this is used for saving to image formats such as 5482GIF and PNG8 which uses this color to represent boolean transparency. This 5483does not make a color transparent, it only defines what color the transparent 5484color is in the color palette of the saved image. Use <a 5485href="#transparent">-transparent</a> to make an opaque color transparent.</p> 5486 5487<p>This option allows you to have both an opaque visible color, as well as a 5488transparent color of the same color value without conflict. That is, you can 5489use the same color for both the transparent and opaque color areas within an 5490image. This, in turn, frees to you to select a transparent color that is 5491appropriate when an image is displayed by an application that does not handle a 5492transparent color index, while allowing ImageMagick to correctly handle images of this 5493type. </p> 5494 5495<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p> 5496 5497<div style="margin: auto;"> 5498 <h4><a name="transpose" id="transpose"></a>-transpose</h4> 5499</div> 5500 5501<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> 5502 5503<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>. 5504</p> 5505 5506<div style="margin: auto;"> 5507 <h4><a name="transverse" id="transverse"></a>-transverse</h4> 5508</div> 5509 5510<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> 5511 5512 5513<div style="margin: auto;"> 5514 <h4><a name="treedepth" id="treedepth"></a>-treedepth <em class="arg">value</em></h4> 5515</div> 5516 5517<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> 5518 5519<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> 5520 5521<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> 5522 5523<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> 5524 5525<div style="margin: auto;"> 5526 <h4><a name="trim" id="trim"></a>-trim</h4> 5527</div> 5528 5529<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> 5530 5531<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> 5532 5533<p>The page or virtual canvas information of the image is preserved allowing 5534you to extract the result of the <a href="#trim">-trim</a> operation from the 5535image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page 5536information if it is unwanted.</p> 5537 5538<p>If the trimmed image 'disappears' an warning is produced, and a special 5539single pixel transparent 'missed' image is returned, in the same way as when a 5540<a href="#crop">-crop</a> operation 'misses' the image proper. </p> 5541 5542 5543<div style="margin: auto;"> 5544 <h4><a name="type" id="type"></a>-type <em class="arg">type</em></h4> 5545</div> 5546 5547<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> 5548 <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> 5549 5550<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> 5551 5552<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p> 5553<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> 5554 5555<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p> 5556 5557<div style="margin: auto;"> 5558 <h4><a name="undercolor" id="undercolor"></a>-undercolor <em class="arg">color</em></h4> 5559</div> 5560 5561<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> 5562 5563<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5564 5565<p>See <a href="#draw">-draw</a> for further details.</p> 5566 5567 5568<div style="margin: auto;"> 5569 <h4><a name="update" id="update"></a>-update <em class="arg">seconds</em></h4> 5570</div> 5571 5572<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> 5573 5574<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> 5575 5576 5577<div style="margin: auto;"> 5578 <h4><a name="unique-colors" id="unique-colors"></a>-unique-colors</h4> 5579</div> 5580 5581<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> 5582 5583 5584<div style="margin: auto;"> 5585 <h4><a name="units" id="units"></a>-units <em class="arg">type</em></h4> 5586</div> 5587 5588<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> 5589 5590<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> 5591 5592 5593<div style="margin: auto;"> 5594 <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> 5595</div> 5596 5597<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> 5598 5599<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> 5600 5601<p>The parameters are:</p> 5602 5603<pre class="text"> 5604 radius: The radius of the Gaussian, in pixels, not counting the center 5605 pixel (default 0). 5606 sigma: The standard deviation of the Gaussian, in pixels (default 1.0). 5607 amount: The fraction of the difference between the original and the blur 5608 image that is added back into the original (default 1.0). 5609 threshold: The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the 5610 difference amount (default 0.05). 5611</pre> 5612 5613 5614<div style="margin: auto;"> 5615 <h4><a name="verbose" id="verbose"></a>-verbose</h4> 5616</div> 5617 5618<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> 5619 5620 5621<div style="margin: auto;"> 5622 <h4><a name="version" id="version"></a>-version</h4> 5623</div> 5624 5625<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> 5626 5627 5628<div style="margin: auto;"> 5629 <h4><a name="view" id="view"></a>-view <em class="arg">string</em></h4> 5630</div> 5631 5632<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> 5633 5634 5635<div style="margin: auto;"> 5636 <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> 5637</div> 5638 5639<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> 5640 5641 5642<div style="margin: auto;"> 5643 <h4><a name="virtual-pixel" id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4> 5644</div> 5645 5646<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> 5647 5648<p>This option defines what color source should be used if and when a color 5649lookup completely 'misses' the source image. The color(s) that appear to 5650surround the source image. Generally this color is derived from the source 5651image, but could also be set to a specify background color. </p> 5652 5653<p>Choose from these methods:</p> 5654 5655<pre class="text"> 5656 background: the area surrounding the image is the background color 5657 black: the area surrounding the image is black 5658 checker-tile: alternate squares with image and background color 5659 dither: non-random 32x32 dithered pattern 5660 edge: extend the edge pixel toward infinity 5661 gray: the area surrounding the image is gray 5662 horizontal-tile: horizontally tile the image, background color above/below 5663 horizontal-tile-edge: horizontally tile the image and replicate the side edge pixels 5664 mirror: mirror tile the image 5665 random: choose a random pixel from the image 5666 tile: tile the image (default) 5667 transparent: the area surrounding the image is transparent blackness 5668 vertical-tile: vertically tile the image, sides are background color 5669 vertical-tile-edge: vertically tile the image and replicate the side edge pixels 5670 white: the area surrounding the image is white 5671</pre> 5672 5673<p>The default value is "edge".</p> 5674 5675<p>This most important for distortion operators such as <a href="#distort" 5676>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>. 5677However it also effects operations that may access pixels just outside the 5678image proper, such as <a href="#convolve">-convolve</a>, <a 5679href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p> 5680 5681<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p> 5682 5683 5684<div style="margin: auto;"> 5685 <h4><a name="visual" id="visual"></a>-visual <em class="arg">type</em></h4> 5686</div> 5687 5688<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>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> 5689 5690<p>Choose from these visual classes:</p> 5691 5692<pre class="text"> 5693 StaticGray 5694 GrayScale 5695 StaticColor 5696 PseudoColor 5697 TrueColor 5698 DirectColor 5699 default 5700 visual id 5701</pre> 5702 5703<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> 5704 5705 5706<div style="margin: auto;"> 5707 <h4><a name="watermark" id="watermark"></a>-watermark <em 5708 class="arg">brightness</em>x<em class="arg">saturation</em></h4> 5709</div> 5710 5711<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 5712saturation.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 5713 5714<p>Take a grayscale image (with alpha mask) and modify the destination image's 5715brightness according to watermark image's grayscale value and the <em 5716class="arg">brightness</em> percentage. The destinations color saturation 5717attribute is just direct modified by the <em class="arg">saturation</em> 5718percentage, which defaults to 100 percent (no color change). </p> 5719 5720 5721<div style="margin: auto;"> 5722 <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> 5723</div> 5724 5725<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> 5726 5727<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p> 5728 5729<div style="margin: auto;"> 5730 <h4><a name="weight" id="weight"></a>-weight <em class="arg">fontWeight</em></h4> 5731</div> 5732 5733<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> 5734 5735<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> 5736 5737<table class="doc"> 5738 <col width="25%" /> 5739 <col width="75%" /> 5740 <thead> 5741 <tr> 5742 <th><em class="arg">fontWeight</em></th> 5743 <th>Description</th> 5744 </tr> 5745 </thead> 5746 <tbody> 5747 <tr><td>All </td> <td>No effect. </td></tr> 5748 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr> 5749 <tr><td>Bolder </td> <td>Add 100 to font weight if currently ≤ 800.</td></tr> 5750 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently ≤ 100.</td></tr> 5751 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr> 5752 </tbody> 5753 </table> 5754 5755<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p> 5756 5757<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> 5758 5759<div style="margin: auto;"> 5760 <h4><a name="white-point" id="white-point"></a>-white-point <em class="arg">x,y</em></h4> 5761</div> 5762 5763<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> 5764 5765<div style="margin: auto;"> 5766 <h4><a name="white-threshold" id="white-threshold"></a>-white-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 5767</div> 5768 5769<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> 5770 5771<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. 5772</p> 5773 5774<div style="margin: auto;"> 5775 <h4><a name="window" id="window"></a>-window <em class="arg">id</em></h4> 5776</div> 5777 5778<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> 5779 5780<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> 5781 5782<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> 5783 5784<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> 5785 5786<div style="margin: auto;"> 5787 <h4><a name="window-group" id="window-group"></a>-window-group</h4> 5788</div> 5789 5790<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> 5791 5792<div style="margin: auto;"> 5793 <h4><a name="write" id="write"></a>-write <em class="arg">filename</em></h4> 5794</div> 5795 5796<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> 5797 <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> 5798 5799<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p> 5800 5801 5802</div> 5803 5804<div id="linkbar"> 5805 <!-- <span id="linkbar-west"> </span> --> 5806 <span id="linkbar-center"> 5807 <a href="http://www.imagemagick.org/discourse-server/">Discourse Server</a> • 5808 <a href="http://studio.webbyland.com/ImageMagick/MagickStudio/scripts/MagickStudio.cgi">Studio</a> 5809 </span> 5810 <span id="linkbar-east"> </span> 5811 </div> 5812 <div class="footer"> 5813 <span id="footer-west">© 1999-2010 ImageMagick Studio LLC</span> 5814 <span id="footer-east"> <a href="http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span> 5815 </div> 5816 <div style="clear: both; margin: 0; width: 100%; "></div> 5817</body> 5818</html> 5819
