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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> 160 161<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 162<a href="/www/convert.html">convert</a>, <a href="/www/mogrify.html">mogrify</a>, and .... </p> 163 164<div style="margin: auto;"> 165 <h4><a name="adaptive-blur" id="adaptive-blur"></a>-adaptive-blur <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4> 166</div> 167 168<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> 169 170<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> 171 172<div style="margin: auto;"> 173 <h4><a name="adaptive-resize" id="adaptive-resize"></a>-adaptive-resize <em class="arg">geometry</em></h4> 174</div> 175 176<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> 177 178<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> 179 180<div style="margin: auto;"> 181 <h4><a name="adaptive-sharpen" id="adaptive-sharpen"></a>-adaptive-sharpen <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4> 182</div> 183 184<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> 185 186<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> 187 188<div style="margin: auto;"> 189 <h4><a name="adjoin" id="adjoin"></a>-adjoin</h4> 190</div> 191 192<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> 193 194<p>This option is enabled by default. An attempt is made to save all 195images of an image sequence into the given output file. 196However, some formats, such as JPEG and PNG, do not support more than one 197image per file, and in that case ImageMagick is forced to write each image as a separate file. As 198such, if more than one image needs to be written, the filename given is 199modified by adding a <a href="#scene">-scene</a> number before the 200suffix, in order to make distinct names for each image. </p> 201 202<p>Use <a href="#adjoin">+adjoin</a> to force each image to be written 203to separate files, whether or not the file format allows multiple images 204per file (for example, GIF, MIFF, and TIFF). </p> 205 206<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> 207 208<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: rose: -morph 15 my%02dmorph.jpg</span></p> 209<p>will create a sequence of 17 images named my00morph.jpg, my01morph.jpg, my02morph.jpg, ..., my16morph.jpg. 210</p> 211 212<p>In summary, ImageMagick tries to write all images to one file, but will use 213multiple files if either (1) the output image's file format does not allow multi-image files, 214(2) the <a href="#adjoin">+adjoin</a> option is given, or (3) a C-style integer format string is 215present in the output filename. </p> 216 217 218<div style="margin: auto;"> 219 <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/> 220 -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> 221</div> 222 223<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> 224 225<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> 226 227<p>The matrix entries are entered as comma-separated numeric values <i>with no spaces</i>. </p> 228 229<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> 230 231<div class="eqn"> 232<img alt="affine transformation" src="/images/affine.png"/> 233</div> 234 235<p> 236The 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> 237 238<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> 239 240<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> 241 242<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> 243 244<p class="crtsnip"> 245 -affine <em class="arg">s<sub>x</sub></em>,0,0,<em class="arg">s<sub>y</sub></em> 246</p> 247 248<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> 249 250<p class="crtsnip"> 251 -affine 1,0,0,1,<em class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em> 252</p> 253 254<p>Rotate clockwise about the origin (the upper left-hand corner) by an angle <em>a</em> by letting 255<em>c</em> = cos(<em>a</em>), <em>s</em> = sin(<em>a</em>), and using the following.</p> 256 257<p class="crtsnip"> 258 -affine <em>c</em>,<em>s</em>,-<em>s</em>,<em>c</em> 259</p> 260 261<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> 262 263<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> 264 265<div style="margin: auto;"> 266 <h4><a name="alpha" id="alpha"></a>-alpha <em class="arg">type</em></h4> 267</div> 268 269<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> 270 271<p>Used to set a flag on an image indicating whether or not to use existing alpha 272channel 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> 273 274 275<table class="doc"> 276 <tbody> 277 <tr valign="top"> 278 <th align="left" style="width: 8%">type</th> 279 <th align="left">Description</th> 280 </tr> 281 282 <tr valign="top"> 283 <td valign="top"><kbd>Off</kbd> or 284 <kbd>Deactivate</kbd></td> 285 <td valign="top"> 286 Disables the image's transparency channel. Does not delete or change the 287 existing data, just turns off the use of that data. This is the same as 288 the older <a href="#matte" >+matte</a> operator. </td></tr> 289 290 <tr valign="top"> 291 <td valign="top"><kbd>On</kbd> or 292 <kbd>Activate</kbd></td> 293 <td valign="top"> 294 Enables the image's use of transparency. If transparency data does not 295 already exist, allocates the data and sets it to opaque. If the image has 296 transparency data, the channel is enabled and the transparency data is not changed or modified in any way. This is NOT 297 the same as the older <a href="#matte" >-matte</a> operator. </td></tr> 298 299 <tr valign="top"> 300 <td valign="top"><kbd>Set</kbd></td> 301 <td valign="top"> 302 Turns '<kbd>On</kbd>' the alpha/matte channel and if it was previously 303 turned off resets the channel to opaque. If the image already had the 304 alpha channel turned on, it will have no effect. This is the same as the older <a href="#matte">-matte</a> operator. </td></tr> 305 306 <tr valign="top"> 307 <td valign="top"><kbd>Opaque</kbd></td> 308 <td valign="top"> 309 Turns '<kbd>On</kbd>' the alpha/matte channel and forces it to be fully 310 opaque. </td></tr> 311 312 <tr valign="top"> 313 <td valign="top"><kbd>Transparent</kbd></td> 314 <td valign="top"> 315 Turns '<kbd>On</kbd>' the alpha/matte channel and forces it to be fully 316 transparent. This effectively creates a fully transparent image the same 317 size as the original and with all its original RGB data still intact. </td></tr> 318 319 <tr valign="top"> 320 <td valign="top"><kbd>Extract</kbd></td> 321 <td valign="top"> 322 Copies the alpha channel values into all the color channels and turns 323 '<kbd>Off</kbd>' the the image's transparency, so as to generate a 324 gray-scale mask of the image's shape. This is the inverse of 325 '<kbd>Copy</kbd>'. </td></tr> 326 327 <tr valign="top"> 328 <td valign="top"><kbd>Copy</kbd></td> 329 <td valign="top"> 330 Turns '<kbd>On</kbd>' the alpha/matte channel, then copies the 331 gray-scale intensity of the image, as an alpha mask, into the alpha 332 channel, converting a gray-scale mask into a transparent shaped image 333 ready to be colored appropriately. The color channels are not modified. 334 </td></tr> 335 336 <tr valign="top"> 337 <td valign="top"><kbd>Shape</kbd></td> 338 <td valign="top"> 339 As per '<kbd>Copy</kbd>' but also colors the resulting shape mask with 340 the current background color. 341 </td></tr> 342 343 <tr valign="top"> 344 <td valign="top"><kbd>Background</kbd></td> 345 <td valign="top"> 346 Set any fully-transparent pixel to the background color. 347 </td></tr> 348 </tbody> 349</table> 350 351<p>Note that while the <a href="#matte" >+matte</a> operation is the same as 352"<kbd><a href="#alpha" >-alpha</a> off</kbd>", the <a href="#matte" 353>-matte</a> operation is the same as "<kbd><a href="#alpha" >-alpha</a> set</kbd>" and 354not "<kbd><a href="#alpha" >-alpha</a> on</kbd>". 355That is, "<kbd><a href="#alpha" >-alpha</a> set</kbd>" will ensure that the 356written image is opaque if the original image had no transparency 357channel enabled, regardless if transparency data is already present. </p> 358 359 360<div style="margin: auto;"> 361 <h4><a name="annotate" id="annotate"></a> 362 -annotate <em class="arg">degrees</em> <em class="arg">text</em><br /> 363 -annotate <em class="arg">Xdegrees</em>x<em class="arg">Ydegrees</em> <em class="arg">text</em><br /> 364 -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> 365</div> 366 367<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> 368 369<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> 370 371 372<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> 373 374<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> 375 376<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> 377<div class="eqn"><img alt="annotate transformation" src="/images/annotate.png"/></div> 378 379<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> 380 381<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> 382 383<div style="margin: auto;"> 384 <h4><a name="antialias" id="antialias"></a>-antialias</h4> 385</div> 386 387<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 388drawing fonts and lines.</td><td style='text-align:right;'></td></tr></table> 389 390<p>By default, objects (e.g. text, lines, polygons, etc.) are antialiased when 391drawn. Use <a href="#antialias">+antialias</a> to disable the addition of 392antialiasing edge pixels. This will then reduce the number of colors added to 393an image to just the colors being directly drawn. That is, no mixed colors 394will be added when drawing such objects. </p> 395 396<div style="margin: auto;"> 397 <h4><a name="append" id="append"></a>-append</h4> 398</div> 399 400<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> 401 402<p>This option creates a single longer image image, by joining all the current 403images in sequence top-to-bottom. Use <a href="#append">+append</a> to 404stack images left-to-right. </p> 405 406<p>If they are not of the same width, narrower images are padded with the 407current <a href="#background">-background</a> color setting, and their 408position relative to each other can be controled by the current <a 409href="#gravity">-gravity</a> setting. </p> 410 411 412<div style="margin: auto;"> 413 <h4><a name="attenuate" id="attenuate"></a>-attenuate <em class="arg">value</em></h4> 414</div> 415 416<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> 417 418 419<div style="margin: auto;"> 420 <h4><a name="authenticate" id="authenticate"></a>-authenticate <em class="arg">password</em></h4> 421</div> 422 423<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> 424 425<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> 426 427<p>For a different encryption method, see <a href="#encipher">-encipher</a> and <a href="#decipher">-decipher</a>. </p> 428 429<div style="margin: auto;"> 430 <h4><a name="auto-gamma" id="auto-gamma"></a>-auto-gamma</h4> 431</div> 432 433<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> 434 435<div style="margin: auto;"> 436 <h4><a name="auto-level" id="auto-level"></a>-auto-level</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 color levels of image.</td><td style='text-align:right;'></td></tr></table> 440 441<div style="margin: auto;"> 442 <h4><a name="auto-orient" id="auto-orient"></a>-auto-orient</h4> 443</div> 444 445<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> 446 447<div style="margin: auto;"> 448 <h4><a name="average" id="average"></a>-average</h4> 449</div> 450 451<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> 452 453<p>An error results if the images are not identically sized.</p> 454 455<p>The sequence of images is terminated by the appearance of any option. If the <a href="#average">-average</a> option appears after all of the input images, all images are averaged.</p> 456 457<div style="margin: auto;"> 458 <h4><a name="backdrop" id="backdrop"></a>-backdrop</h4> 459</div> 460 461<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> 462 463<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> 464 465<div style="margin: auto;"> 466 <h4><a name="background" id="background"></a>-background <em class="arg">color</em></h4> 467</div> 468 469<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> 470 471<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> 472 473<div style="margin: auto;"> 474 <h4><a name="bench" id="bench"></a>-bench <em class="arg">iterations</em></h4> 475</div> 476 477<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> 478 479<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.</p> 480 481<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: -resize 1000% -bench 5 biglogo.png</span><span class='crtout'>Performance: 5i 0.0539724ips 91.750u 2:33</span></p> 482<p>In this example, 5 iterations were completed at 0.0539724 iterations per second, using 91.750 seconds of the user's allotted time, for a total elapsed time of 2 minutes and 33 seconds.</p> 483 484<div style="margin: auto;"> 485 <h4><a name="bias" id="bias"></a>-bias <em class="arg">value</em>{<em class="arg">%</em>}</h4> 486</div> 487 488<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> 489 490<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> 491 492<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> 493 494<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 495negative results without clipping to the color value range 496(0..QuantumRange).</p> 497 498<p>See the discussion on HDRI implementations of ImageMagick on the page 499<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. 500</p> 501 502<div style="margin: auto;"> 503 <h4><a name="black-point-compensation" id="black-point-compensation"></a>-black-point-compensation</h4> 504</div> 505 506<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> 507 508<div style="margin: auto;"> 509 <h4><a name="black-threshold" id="black-threshold"></a>-black-threshold <em class="arg">threshold</em></h4> 510</div> 511 512<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Force to black all pixels at or below the threshold while leaving all pixels above the threshold unchanged.</td><td style='text-align:right;'></td></tr></table> 513 514 515<div style="margin: auto;"> 516 <h4><a name="blend" id="blend"></a>-blend <em class="arg">percent</em></h4> 517</div> 518 519<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> 520 521<p>Blend will average the images together ('plus') according to the 522percentages given and each pixels transparency. If only a single percentage 523value is given it sets the weight of the composite or 'source' image, while 524the background image is weighted by the exact opposite amount. That is a 525<kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of the 526'destination' image. Thus it is equivalent to <kbd>-blend 30x70</kbd>.</p> 527 528 529<div style="margin: auto;"> 530 <h4><a name="blue-primary" id="blue-primary"></a>-blue-primary <em class="arg">x</em>,<em class="arg">y</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 blue chromaticity primary point.</td><td style='text-align:right;'></td></tr></table> 534 535<div style="margin: auto;"> 536 <h4><a name="blue-shift" id="blue-shift"></a>-blue-shift <em class="arg">factor</em></h4> 537</div> 538 539<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> 540 541<div style="margin: auto;"> 542 543<div style="margin: auto;"> 544 <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> 545</div> 546 547<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> 548 549<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p> 550 551<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 552</div> 553 554<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> 555 556<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> 557 558<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 559pixels which are outside the image proper are blurred into the final result. 560</p> 561 562 563<div style="margin: auto;"> 564 <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> 565</div> 566 567<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> 568 569<p>Each pixel in the overlaid region is replaced with an Elliptical Weighted 570Average (EWA) of the source image, scaled according to the grayscale 571mapping. </p> 572 573<p>The ellipse is weighted with sigma set to the given <em class="arg" 574>Width</em> and <em class="arg" >Height</em>. The <em class="arg" >Height</em> 575defaults to the <em class="arg" >Width</em> for a normal circular Guassian 576weighting. The <em class="arg" >Angle</em> will rotate the ellipse from 577horizontal clock-wise. </p> 578 579<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 580pixels which are outside the image proper are blurred into the final result. 581</p> 582 583 584<div style="margin: auto;"> 585 <h4><a name="border" id="border"></a>-border <em class="arg">geometry</em></h4> 586</div> 587 588<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> 589 590<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> 591 592<p>Set the border color by preceding with the <a href="#bordercolor">-bordercolor</a> setting.</p> 593 594<p>See also the <a href="#frame">-frame</a> option, which has more functionality.</p> 595 596<div style="margin: auto;"> 597 <h4><a name="bordercolor" id="bordercolor"></a>-bordercolor <em class="arg">color</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 border color.</td><td style='text-align:right;'></td></tr></table> 601 602<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 603 604<p>The default border color is <kbd>#DFDFDF</kbd>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p> 605 606<div style="margin: auto;"> 607 <h4><a name="borderwidth" id="borderwidth"></a>-borderwidth <em class="arg">geometry</em> </h4> 608</div> 609 610<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> 611 612<div style="margin: auto;"> 613 <h4><a name="cache" id="cache"></a>-cache <em class="arg">threshold</em></h4> 614</div> 615 616<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> 617 618<div style="margin: auto;"> 619 <h4><a name="caption" id="caption"></a>-caption <em class="arg">string</em></h4> 620</div> 621 622<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> 623 624<div style="margin: auto;"> 625 <h4><a name="cdl" id="cdl"></a>-cdl <em class="arg">filename</em></h4> 626</div> 627 628<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> 629 630<p>Here is an example color correction collection:</p> 631 632<pre class="text"> 633<?xml version="1.0" encoding="UTF-8"?> 634<ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2"> 635 <ColorCorrection id="cc06668"> 636 <SOPNode> 637 <Slope> 0.9 1.2 0.5 </Slope> 638 <Offset> 0.4 -0.5 0.6 </Offset> 639 <Power> 1.0 0.8 1.5 </Power> 640 </SOPNode> 641 <SATNode> 642 <Saturation> 0.85 </Saturation> 643 </SATNode> 644 </ColorCorrection> 645</ColorCorrectionCollection> 646</pre> 647 648<div style="margin: auto;"> 649 <h4><a name="channel" id="channel"></a>-channel <em class="arg">type</em></h4> 650</div> 651 652<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> 653 654<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> 655 656<p>To print a complete list of channel types, use <a href="#list">-list channel</a>.</p> 657 658<p>The channels above can be specified as a comma-separated list or can be abbreviated as a 659concatenation of the letters '<kbd>R</kbd>', '<kbd>G</kbd>', '<kbd>B</kbd>', 660'<kbd>A</kbd>', '<kbd>O</kbd>', '<kbd>C</kbd>', '<kbd>M</kbd>', '<kbd>Y</kbd>', 661'<kbd>K</kbd>'. 662 663For example, to negate only the alpha channel of an image, use</p> 664<p class="crtsnip"> 665 -channel Alpha -negate 666</p> 667 668<p>By default, ImageMagick sets <a href="#channel">-channel</a> to the value 669'<kbd>RGB</kbd>', which specifies that operators act on all channels except 670the opacity channel. Using the option <a href="#channel" >+channel</a> will reset the value back to this default. </p> 671 672<p>Operators that are affected by the <a href="#channel" >-channel</a> 673setting include the following. 674<a href="#black-threshold">-black-threshold</a>, 675<a href="#blur">-blur</a>, 676<a href="#clut">-clut</a>, 677<a href="#combine">-combine</a>, 678<a href="#contrast-stretch">-contrast-stretch</a>, 679<a href="#evaluate">-evaluate</a>, 680<a href="#function">-function</a>, 681<a href="#fx">-fx</a>, 682<a href="#clut">-hald-clut</a>, 683<a href="#gaussian-blur">-gaussian-blur</a>, 684<a href="#motion-blur">-motion-blur</a>, 685<a href="#negate">-negate</a>, 686<a href="#normalize">-normalize</a>, 687<a href="#ordered-dither">-ordered-dither</a>, 688<a href="#radial-blur">-radial-blur</a>, 689<a href="#random-threshold">-random-threshold</a>, 690<a href="#separate">-separate</a>, and 691<a href="#white-threshold">-white-threshold</a>. 692</p> 693 694 695<div style="margin: auto;"> 696 <h4><a name="charcoal" id="charcoal"></a>-charcoal <em class="arg">factor</em></h4> 697</div> 698 699<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> 700 701<div style="margin: auto;"> 702 <h4><a name="chop" id="chop"></a>-chop <em class="arg">geometry</em></h4> 703</div> 704 705<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> 706 707<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> 708 709<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> 710 711<div style="margin: auto;"> 712 <h4><a name="clip" id="clip"></a>-clip</h4> 713</div> 714 715<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> 716 717<p>If a clipping path is present, it is applied to subsequent operations.</p> 718 719<p>For example, in the command</p> 720 721<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -clip -negate cockatoo.tif negated.tif</span></p> 722<p>only the pixels within the clipping path are negated.</p> 723 724<p>The <a href="#clip">-clip</a> feature requires the XML library. If the XML library is not present, the option is ignored.</p> 725 726<div style="margin: auto;"> 727 <h4><a name="clip-mask" id="clip-mask"></a>-clip-mask</h4> 728</div> 729 730<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> 731 732<div style="margin: auto;"> 733 <h4><a name="clip-path" id="clip-path"></a>-clip-path <em class="arg">id</em></h4> 734</div> 735 736<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> 737 738<div style="margin: auto;"> 739 <h4><a name="clone" id="clone"></a>-clone <em class="arg">index(s)</em></h4> 740</div> 741 742<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> 743 744<p>Specify the image by its index in the sequence. The first image is index 7450. Negative indexes are relative to the end of the sequence; for example, −1 746represents the last image of the sequence. Specify a range of images with a 747dash (e.g. 0−4). Separate multiple indexes with commas but no spaces (e.g. 0,2,5). Use <a 748href="#clone">+clone</a> make a copy of the last image in the image 749sequence.</p> 750 751<div style="margin: auto;"> 752 <h4><a name="clut" id="clut"></a>-clut</h4> 753</div> 754 755<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 756corresponding channel in the second image as a <b>c</b>olor 757<b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style='text-align:right;'></td></tr></table> 758 759<p>The second (LUT) image is ordinarily a gradient image containing the 760histogram mapping of how each channel should be modified. Typically it is a 761either a single row or column image of replacement color values. If larger 762than a single row or column, values are taken from a diagonal line from 763top-left to bottom-right corners.</p> 764 765<p>The lookup is further controlled by the <a 766href="#interpolate">-interpolate</a> setting, which is especially handy for an 767LUT which is not the full length needed by the ImageMagick installed Quality 768(Q) level. Good settings for this are the '<kbd>bilinear</kbd>' and 769'<kbd>bicubic</kbd>' interpolation settings, which give smooth color 770gradients, and the '<kbd>integer</kbd>' setting for a direct, unsmoothed 771lookup of color values. </p> 772 773<p>This operator is especially suited to replacing a grayscale image with a 774specific color gradient from the CLUT image. </p> 775 776<p>Only the channel values defined by the <a href="#channel">-channel</a> 777setting will have their values replaced. In particular, since the default <a 778href="#channel">-channel</a> setting is <kbd>RGB</kbd>, this means that 779transparency (alpha/matte channel) is not affected, unless the <a 780href="#channel">-channel</a> setting is modified. When the alpha channel is 781set, it is treated by the <a href="#clut" >-clut</a> operator in the same way 782as the other channels, implying that alpha/matte values are replaced using the 783alpha/matte values of the original image. </p> 784 785<p>If either the image being modified, or the lookup image, conatins no 786transparency (i.e. <a href="#alpha" >-alpha</a> is turned 'off') but the <a 787href="#channel">-channel</a> setting includes alpha replacement, then it is 788assumed that image represents a gray-scale graident which will be used for the 789replacement alpha values. That is you can use a gray-scale CLUT image to 790adjust a existing images alpha channel, or you can color a gray-scale image 791using colors form CLUT containing the desired colors, including transparency. 792</p> 793 794<p>See also <a href="#hald-clut" >-hald-clut</a> which replaces colors according 795the lookup of the full color RGB value from a 2D representation of a 3D color 796cube. </p> 797 798 799<div style="margin: auto;"> 800 <h4><a name="coalesce" id="coalesce"></a>-coalesce</h4> 801</div> 802 803<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> 804 805<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> 806 807<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> 808 809 810<div style="margin: auto;"> 811 <h4><a name="colorize" id="colorize"></a>-colorize <em class="arg">value</em></h4> 812</div> 813 814<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> 815 816<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> 817 818<div style="margin: auto;"> 819 <h4><a name="colormap" id="colormap"></a>-colormap <em class="arg">type</em></h4> 820</div> 821 822<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> 823 824<p>The <em class="arg">type</em> can be <kbd>shared</kbd> or <kbd>private</kbd>.</p> 825 826<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> 827 828<div style="margin: auto;"> 829 <h4><a name="colors" id="colors"></a>-colors <em class="arg">value</em></h4> 830</div> 831 832<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> 833 834<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> 835 836<div style="margin: auto;"> 837 <h4><a name="colorspace" id="colorspace"></a>-colorspace <em class="arg">value</em></h4> 838</div> 839 840<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> 841 842<p>Choices are:</p> 843 844<pre class="text"> 845 CMY 846 CMYK 847 Gray 848 HSB 849 HSL 850 HWB 851 Lab 852 Log 853 OHTA 854 Rec601Luma 855 Rec601YCbCr 856 Rec709Luma 857 Rec709YCbCr 858 RGB 859 sRGB 860 Transparent 861 XYZ 862 YCbCr 863 YCC 864 YIQ 865 YPbPr 866 YUV 867</pre> 868 869<p>To print a complete list of colorspaces, use <a href="#list">-list colorspace</a>.</p> 870 871<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> 872 873<table class="doc"> 874 <caption>Conversion Of RGB To Other Color Spaces</caption> 875 <tr><th align="left" valign="middle">CMY</th></tr> 876 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>−R</td></tr> 877 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>−G</td></tr> 878 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>−B</td></tr> 879 <tr><th align="left" valign="middle">CMYK — starts with CMY from above</th></tr> 880 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr> 881 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 882 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 883 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y−K)/(<em class="QR">QuantumRange</em>−K)</td></tr> 884 885 <tr><th align="left" valign="middle">Gray</th></tr> 886 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 887 888 <tr><th align="left" valign="middle">HSB — Hue, Saturation, Brightness; like a cone peak downward</th></tr> 889 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 890 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 891 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr> 892 893 <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> 894 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr> 895 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr> 896 <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> 897 898 <tr><th align="left" valign="middle">HWB — Hue, Whiteness, Blackness</th></tr> 899 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr> 900 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr> 901 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr> 902 903 <tr><th align="left" valign="middle">LAB</th></tr> 904 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr> 905 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr> 906 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr> 907 908 <tr><th align="left" valign="middle">LOG</th></tr> 909 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr> 910 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr> 911 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr> 912 913 <tr><th align="left" valign="middle">OHTA — approximates principal components transformation</th></tr> 914 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr> 915 <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> 916 <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> 917 918 <tr><th align="left" valign="middle">Rec601Luma</th></tr> 919 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr> 920 921 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr> 922 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 923 <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> 924 <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> 925 926 <tr><th align="left" valign="middle">Rec709Luma</th></tr> 927 <tr><td align="left" valign="middle">Gray=0.21260*R+0.71520*G+0.07220*B</td></tr> 928 929 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr> 930 <tr><td align="left" valign="middle">Y=0.212600*R+0.715200*G+0.072200*B; <em>intensity-like</em></td></tr> 931 <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> 932 <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> 933 934 <tr><th align="left" valign="middle">sRGB</th></tr> 935 <tr><td align="left" valign="middle">if Rs ≤ .03928 then Rs=R/12.92 else Rs=((R+.055)/1.055)^2.4</td></tr> 936 <tr><td align="left" valign="middle">if Gs ≤ .03928 then Gs=B/12.92 else Gs=((G+.055)/1.055)^2.4</td></tr> 937 <tr><td align="left" valign="middle">if Bs ≤ .03928 then Bs=B/12.92 else Bs=((B+.055)/1.055)^2.4</td></tr> 938 939 <tr><th align="left" valign="middle">XYZ</th></tr> 940 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr> 941 <tr><td align="left" valign="middle">Y=0.2126560*R+0.7151580*G+0.0721856*B</td></tr> 942 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr> 943 944 <tr><th align="left" valign="middle">YCC</th></tr> 945 <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> 946 <tr><td align="left" valign="middle">C1=(−0.29900*R−0.58700*G+0.88600*B) (with complicated scaling)</td></tr> 947 <tr><td align="left" valign="middle">C2=(0.70100*R−0.58700*G−0.11400*B) (with complicated scaling)</td></tr> 948 949 <tr><th align="left" valign="middle">YCbCr</th></tr> 950 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 951 <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> 952 <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> 953 954 <tr><th align="left" valign="middle">YIQ</th></tr> 955 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 956 <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> 957 <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> 958 959 <tr><th align="left" valign="middle">YPbPr</th></tr> 960 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr> 961 <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> 962 <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> 963 964 <tr><th align="left" valign="middle">YUV</th></tr> 965 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr> 966 <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> 967 <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> 968</table> 969 970<div style="margin: auto;"> 971 <h4><a name="combine" id="combine"></a>-combine</h4> 972</div> 973 974<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> 975 976<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> 977 978<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. 979</p> 980 981<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert original.png -channel RGB -separate sepimage.png</span><span class='crtout'></span><span class="crtprompt"> $magick> </span><span class='crtin'>convert sepimage-0.png sepimage-1.png sepimage-2.png -channel RGB -combine imagecopy.png</span></p> 982<div style="margin: auto;"> 983 <h4><a name="comment" id="comment"></a>-comment <em class="arg">string</em></h4> 984</div> 985 986<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> 987 988<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> 989 990<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> 991 992<p>For example,</p> 993 994<p class="crtsnip"> 995 -comment "%m:%f %wx%h" 996</p> 997 998<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> 999 1000<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> 1001 1002<div style="margin: auto;"> 1003 <h4><a name="compose" id="compose"></a>-compose <em class="arg">operator</em></h4> 1004</div> 1005 1006<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> 1007 1008<p>The description of composition uses abstract terminology in order to allow 1009the description to be more precise, while avoiding constant values which are 1010specific to a particular build configuration. Each image pixel is represented 1011by red, green, and blue levels (which are equal for a gray pixel). The 1012build-dependent value <em class="QR">QuantumRange</em> is the maximum integral 1013value which may be stored, per pixel, in the red, green, or blue channels of 1014the image. Each image pixel may also optionally (if the image matte channel is 1015enabled) have an associated level of opacity, ranging from <em>opaque</em> to 1016<em>transparent</em>, which may be used to determine the influence of the pixel 1017color when compositing the pixel with another image pixel. If the image matte 1018channel is disabled, then all pixels in the image are treated as opaque. The 1019color of an opaque pixel is fully visible while the color of a transparent 1020pixel color is entirely absent (pixel color is ignored).</p> 1021 1022<p>By definition, raster images have a rectangular shape. All image rows are of 1023equal length, as are all image columns. By treating the alpha channel as a 1024visual "mask" the rectangular image may be given a "shape" by treating the 1025alpha channel as a cookie-cutter for the image. This is done by setting the 1026pixels within the shape to be opaque, with pixels outside the shape set as 1027transparent. Pixels on the boundary of the shape may be between opaque and 1028transparent in order to provide antialiasing (visually smooth edges). The 1029description of the composition operators use this concept of image "shape" in 1030order to make the description of the operators easier to understand. While it 1031is convenient to describe the operators in terms of "shapes" they are by no 1032means limited to mask-style operations since they are based on continuous 1033floating-point mathematics rather than simple boolean operations.</p> 1034 1035<p>The following alpha blending (Duff-Porter) compose methods are available:</p> 1036 1037<table class="doc"> 1038 <tbody> 1039 <tr valign="top"> 1040 <th align="left" style="width: 8%">Method</th> 1041 <th align="left">Description</th> 1042 </tr> 1043 1044 <tr valign="top"> 1045 <td valign="top">clear</td> 1046 <td valign="top">Both the color and the alpha of the destination are 1047 cleared. Neither the source nor the destination are used (except for 1048 destinations size and other meta-data which is always preserved.</td> 1049 </tr> 1050 1051 <tr valign="top"> 1052 <td valign="top">src</td> 1053 <td valign="top">The source is copied to the destination. The destination 1054 is not used as input, though it is cleared.</td> 1055 </tr> 1056 1057 <tr valign="top"> 1058 <td valign="top">dst</td> 1059 <td valign="top">The destination is left untouched. The source image is 1060 completely ignored.</td> 1061 </tr> 1062 1063 <tr valign="top"> 1064 <td valign="top">src-over</td> 1065 <td valign="top">The source is composited over the destination. this is 1066 the default alpha blending compose method, when neither the compose 1067 setting is set, nor is set in the image meta-data.</td> 1068 </tr> 1069 1070 <tr valign="top"> 1071 <td valign="top">dst-over</td> 1072 <td valign="top">The destination is composited over the source and the 1073 result replaces the destination.</td> 1074 </tr> 1075 1076 <tr valign="top"> 1077 <td valign="top">src-in</td> 1078 <td valign="top">The part of the source lying inside of the destination 1079 replaces the destination.</td> 1080 </tr> 1081 1082 <tr valign="top"> 1083 <td valign="top">dst-in</td> 1084 <td valign="top">The part of the destination lying inside of the source 1085 replaces the destination. Areas not overlaid are cleared.</td> 1086 </tr> 1087 1088 <tr valign="top"> 1089 <td valign="top">src-out</td> 1090 <td valign="top">The part of the source lying outside of the destination 1091 replaces the destination.</td> 1092 </tr> 1093 1094 <tr valign="top"> 1095 <td valign="top">dst-out</td> 1096 <td valign="top">The part of the destination lying outside of the source 1097 replaces the destination.</td> 1098 </tr> 1099 1100 <tr valign="top"> 1101 <td valign="top">src-atop</td> 1102 <td valign="top">The part of the source lying inside of the destination is 1103 composited onto the destination.</td> 1104 </tr> 1105 1106 <tr valign="top"> 1107 <td valign="top">dst-atop</td> 1108 <td valign="top">The part of the destination lying inside of the source is 1109 composited over the source and replaces the destination. Areas not 1110 overlaid are cleared. </td> 1111 </tr> 1112 1113 <tr valign="top"> 1114 <td valign="top">xor</td> 1115 <td valign="top">The part of the source that lies outside of the 1116 destination is combined with the part of the destination that lies 1117 outside of the source. Source or Destination, but not both. </td> 1118 </tr> 1119 1120 </tbody> 1121</table> 1122 1123<p>Any of the 'Src-*' methods can also be specified without the 'Src-' part. 1124For example the defaul compose method can be specified as just 'Over'.</p> 1125 1126 1127<p>The following mathemathical composition methods are also available. </p> 1128 1129<p>Typically these use the default 'Over' alpha blending when transparencies 1130are also involved, except for 'Plus', 'Minus', 'Add', and 'Subtract', which 1131also composes the alpha channel using the same process as the color channels. 1132This allows them to be used for special image masking techniques. </p> 1133 1134<table class="doc"> 1135 <tbody> 1136 <tr valign="top"> 1137 <th align="left" style="width: 8%">Method</th> 1138 <th align="left">Description</th> 1139 </tr> 1140 1141 <tr valign="top"> 1142 <td valign="top">multiply</td> 1143 <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> 1144 </tr> 1145 1146 <tr valign="top"> 1147 <td valign="top">screen</td> 1148 <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> 1149 </tr> 1150 1151 <tr valign="top"> 1152 <td valign="top">plus</td> 1153 <td valign="top">The source is added to the destination and replaces the 1154 destination. This operator is useful for averaging or a controled 1155 merger of two images, rather than a direct overlay.</td> 1156 </tr> 1157 1158 <tr valign="top"> 1159 <td valign="top">add</td> 1160 <td valign="top">As per 'plus' but transparency data is treated as matte 1161 values. As such any transparent areas in either image remain 1162 transparent. </td> 1163 </tr> 1164 1165 <tr valign="top"> 1166 <td valign="top">minus</td> 1167 <td valign="top">Subtract the colors in the source image from the 1168 destination image. When transparency is involved, opaque areas is 1169 subtracted from any destination opaque areas. </td> 1170 </tr> 1171 1172 <tr valign="top"> 1173 <td valign="top">subtract</td> 1174 <td valign="top">Subtract the colors in the source image from the 1175 destination image. When transparency is involved transparent areas are 1176 subtracted, so only the opaque areas in the source remain opaque in 1177 the destination image. </td> 1178 </tr> 1179 1180 <tr valign="top"> 1181 <td valign="top">difference</td> 1182 <td valign="top">Subtracts the darker of the two constituent colors from 1183 the lighter. Painting with white inverts the destination color. 1184 Painting with black produces no change.</td> 1185 </tr> 1186 1187 <tr valign="top"> 1188 <td valign="top">exclusion</td> 1189 <td valign="top">Produces an effect similar to that of 'difference', but 1190 appears as lower contrast. Painting with white inverts the 1191 destination color. Painting with black produces no change.</td> 1192 </tr> 1193 1194 <tr valign="top"> 1195 <td valign="top">darken</td> 1196 <td valign="top">Selects the darker of the destination and source colors. 1197 The destination is replaced with the source when the source is darker, 1198 otherwise it is left unchanged.</td> 1199 </tr> 1200 1201 <tr valign="top"> 1202 <td valign="top">lighten</td> 1203 <td valign="top">Selects the lighter of the destination and source colors. 1204 The destination is replaced with the source when the source is 1205 lighter, otherwise it is left unchanged. </td> 1206 </tr> 1207 1208 <tr valign="top"> 1209 <td valign="top">linear-dodge</td> 1210 <td valign="top">This is equivelent to 'Plus' in that the color channels 1211 are simply added, however it does not 'Plus' the alpha channel, but 1212 uses the normal 'Over' alpha blending, which transparencies are 1213 involved. Produces a sort of additive multiply-like result. Added 1214 ImageMagick version 6.5.4-3. </td> 1215 </tr> 1216 1217 <tr valign="top"> 1218 <td valign="top">linear-burn</td> 1219 <td valign="top">As 'Linear-Dodge', but also subtract one from the result. 1220 Sort of a additive 'Screen' of the images. Added ImageMagick version 1221 6.5.4-3. </td> 1222 </tr> 1223 1224 <tr valign="top"> 1225 <td valign="top">color-dodge</td> 1226 <td valign="top">Brightens the destination color to reflect the source 1227 color. Painting with black produces no change.</td> 1228 </tr> 1229 1230 <tr valign="top"> 1231 <td valign="top">color-burn</td> 1232 <td valign="top">Darkens the destination color to reflect the source 1233 color. Painting with white produces no change. Fixed in ImageMagick 1234 version 6.5.4-3. </td> 1235 </tr> 1236 1237 <tr valign="top"> 1238 <td valign="top">overlay</td> 1239 <td valign="top">Multiplies or screens the colors, dependent on the 1240 destination color. Source colors overlay the destination whilst 1241 preserving its highlights and shadows. The destination color is not 1242 replaced, but is mixed with the source color to reflect the lightness 1243 or darkness of the destination.</td> 1244 </tr> 1245 1246 <tr valign="top"> 1247 <td valign="top">hard-light</td> 1248 <td valign="top">Multiplies or screens the colors, dependent on the source 1249 color value. If the source color is lighter than 0.5, the destination 1250 is lightened as if it were screened. If the source color is darker 1251 than 0.5, the destination is darkened, as if it were multiplied. The 1252 degree of lightening or darkening is proportional to the difference 1253 between the source color and 0.5. If it is equal to 0.5 the 1254 destination is unchanged. Painting with pure black or white produces 1255 black or white.</td> 1256 </tr> 1257 1258 1259 <tr valign="top"> 1260 <td valign="top">linear-light</td> 1261 <td valign="top">Like 'Hard-Light' but using linear-dodge and linear-burn 1262 instead. Increases contrast slightly with an impact on the 1263 foreground's tonal values.</td> 1264 </tr> 1265 1266 <tr valign="top"> 1267 <td valign="top">soft-light</td> 1268 <td valign="top">Darkens or lightens the colors, dependent on the source 1269 color value. If the source color is lighter than 0.5, the destination 1270 is lightened. If the source color is darker than 0.5, the destination 1271 is darkened, as if it were burned in. The degree of darkening or 1272 lightening is proportional to the difference between the source color 1273 and 0.5. If it is equal to 0.5, the destination is unchanged. Painting 1274 with pure black or white produces a distinctly darker or lighter area, 1275 but does not result in pure black or white. Fixed in ImageMagick 1276 version 6.5.4-3. </td> 1277 </tr> 1278 1279 <tr valign="top"> 1280 <td valign="top">pegtop-light</td> 1281 <td valign="top">Almost equivelent to 'Soft-Light', but using a 1282 continuious mathematical formula rather than two conditionally 1283 selected formulae. Added ImageMagick version 6.5.4-3. </td> 1284 </tr> 1285 1286 <tr valign="top"> 1287 <td valign="top">vivid-light</td> 1288 <td valign="top">A modified 'Linear-Light' designed to preserve very stong 1289 primary and secondary colors in the image. Added ImageMagick version 1290 6.5.4-3. </td> 1291 </tr> 1292 1293 <tr valign="top"> 1294 <td valign="top">pin-light</td> 1295 <td valign="top">Similar to 'Hard-Light', but using sharp linear shadings, 1296 to similate the effects of a strong 'pinhole' light source. Added 1297 ImageMagick version 6.5.4-3. </td> 1298 </tr> 1299 1300 </tbody> 1301</table> 1302 1303 1304<p>Also included are these special purpose compose methods:</p> 1305 1306<table class="doc"> 1307 <tbody> 1308 <tr valign="top"> 1309 <th align="left" style="width: 8%">Method</th> 1310 <th align="left">Description</th> 1311 </tr> 1312 1313 <tr valign="top"> 1314 <td valign="top">copy-*</td> 1315 <td valign="top">Copy the specified channel (Red, Green, Blue, Cyan, 1316 Magenta, Yellow, Black, or Opacity) in the source image to the 1317 same channel in the destination image. If the channel specified 1318 does not exist in the source image, (which can only happen for methods, 1319 '<kbd>copy-opacity</kbd>' or '<kbd>copy-black</kbd>') then it is 1320 assumed that the source image is a special grayscale channel image 1321 of the values to be copied. </td> 1322 </tr> 1323 1324 <tr valign="top"> 1325 <td valign="top">change-mask</td> 1326 <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> 1327 </tr> 1328 </tbody> 1329</table> 1330 1331<p>On top of these composed methods are a few special ones that not only require 1332the two images that are being merged or overlaid, but have some extra numerical 1333arguments, which are tabled below. </p> 1334 1335<p>In the "<code>composite</code>" command these composition methods are 1336selected using special options with the arguments needed. They are usually, 1337but not always, the same name as the composte 'method' they use, and replaces 1338the normal use of the <a href="#compose" >-compose</a> setting in the 1339"<code>composite</code>" command. For example... </p> 1340 1341<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>composite ... -blend 50x50 ...</span></p> 1342<p>As of IM v6.5.3-4 the "<code>convert</code>" command can now also supply 1343these extra arguments to its <a href="#composite" >-composite</a> operator, 1344using the special <a href="#set">-set</a> attribute of '<kbd class="arg">option:compose:args</kbd>'. This means you can now make use of 1345these special argumented <a href="#compose" >-compose</a> methods, those the 1346argument and the method both need to be set separatally. For example... </p> 1347 1348<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert ... -compose blend -set option:compose:args 50x50 -composite ...</span></p> 1349<p>The following is a table of these special 'argumented' compose methods, 1350with a brief summary of what they do. For more details see the equivalent 1351"composite" command option name. </p> 1352 1353<table class="doc"> 1354 <tbody> 1355 <tr valign="top"> 1356 <th align="left" style="width: 8%">Method</th> 1357 <th align="left">Description</th> 1358 </tr> 1359 1360 <tr valign="top"> 1361 <td valign="top">dissolve</td> 1362 <td valign="top">Arguments: 1363 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>] 1364 <br>Equivalent to "<code>composite</code>" <a href="#dissolve">-dissolve</a> 1365 <br>Dissolve the 'source' image by the percentage given before overlaying 1366 'over' the 'destination' image. If <em class="arg">src_percent</em> is 1367 greater than 100, it starts dissolving the main image so it will 1368 become transparent at a value of '<kbd class="arg">200</kbd>'. If 1369 both percentages are given, each image are dissolved to the 1370 percentages given. 1371 </td> 1372 </tr> 1373 1374 <tr valign="top"> 1375 <td valign="top">blend</td> 1376 <td valign="top">Arguments: 1377 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>] 1378 <br>Equivalent to "<code>composite</code>" <a href="#blend">-blend</a> 1379 <br>Average the images together ('plus') according to the percentages 1380 given and each pixels transparency. If only a single percentage value 1381 is given it sets the weight of the composite or 'source' image, while 1382 the background image is weighted by the exact opposite amount. That is 1383 a <kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of 1384 the 'destination' image. Thus it is equivalent to <kbd>-blend 1385 30x70</kbd>. 1386 </td> 1387 </tr> 1388 1389 <tr valign="top"> 1390 <td valign="top">mathematics</td> 1391 <td valign="top">Arguments: <em class="arg">A, B, C, D</em> 1392 <br>Not available in "<code>composite</code>" at this time. 1393 <br>Merge the source and destination images according to the formula 1394 <br> <code>A*Sc*Dc + B*Sc + C*Dc + D</code> 1395 <br>Can be used to generate a custom composition method that would 1396 otherwise need to be implemented using the slow <a href="#fx">-fx</a> 1397 DIY image operator. Added to ImageMagick version 6.5.4-3. 1398 </td> 1399 </tr> 1400 1401 <tr valign="top"> 1402 <td valign="top">modulate</td> 1403 <td valign="top">Arguments: 1404 <em class="arg">brightness</em>[x<em class="arg">saturation</em>] 1405 <br>Equivalent to "<code>composite</code>" <a href="#watermark">-watermark</a> 1406 <br>Take a grayscale image (with alpha mask) and modify the destination 1407 image's brightness according to watermark image's grayscale value and 1408 the <em class="arg">brightness</em> percentage. The destinations 1409 color saturation attribute is just direct modified by the <em 1410 class="arg">saturation</em> percentage, which defaults to 100 percent 1411 (no color change). 1412 1413 </td> 1414 </tr> 1415 1416 <tr valign="top"> 1417 <td valign="top">displace</td> 1418 <td valign="top">Arguments: 1419 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em>][!][%] 1420 <br>Equivalent to "<code>composite</code>" <a href="#displace">-displace</a> 1421 <br>With this option, the 'overlay' image, and optionally the 'mask' 1422 image, is used as a relative displacement map, which is used to 1423 displace the lookup of what part of the destination image is seen at 1424 each point of the overlaid area. Much like the displacement map is a 1425 'lens' that distorts the original 'background' image behind it. 1426 <br><br> 1427 The X-scale is modilated by the 'red' channel of the overlay image 1428 while the Y-scale is modulated by the green channel, (the mask image 1429 if given is rolled into green channel of the overlay image. This 1430 separation allows you to modulate the X and Y lookup displacement 1431 separatally allowing you to di 2 dimentional displacements, rather 1432 than 1 dimentional verctored displacements (using grayscale image). 1433 <br><br> 1434 If the overlay image contains transparency this is used as a mask 1435 of the resulting image to remove 'invalid' pixels. 1436 <br><br> 1437 The '%' flag makes the displacement scale relative to the size of the 1438 overlay image (100% = half width/height of image). Using '!' switches 1439 percentage arguments to refer to the destination image size instead. 1440 <br><br> 1441 Special flags were added Added to ImageMagick version 6.5.3-5. 1442 </td> 1443 </tr> 1444 1445 <tr valign="top"> 1446 <td valign="top">distort</td> 1447 <td valign="top">Arguments: 1448 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em 1449 >[+<em class="arg">X-center</em>+<em class="arg">Y-center</em>]][!][%] 1450 <br>Not available in "<code>composite</code>" at this time. 1451 <br>Exactly as per 'Displace' (above), but using absolute coordinates, 1452 relative to the center of the overlay (or that given). Basically 1453 allows you to generate absolute distortion maps where 'black' will 1454 look up the left/top edge, and 'white' looks up the bottom/right 1455 edge of the destination image, according to the scale given. 1456 <br><br> 1457 The '!' flag not only switches percentage scaling, to use the 1458 destination image, but also the image the center offset of the lookup. 1459 This means the overlay can lookup a completely different region of the 1460 destination image. 1461 <br><br> 1462 Added to ImageMagick version 6.5.3-5. 1463 </td> 1464 </tr> 1465 1466 <tr valign="top"> 1467 <td valign="top">blur</td> 1468 <td valign="top">Arguments: 1469 <em class="arg">Width</em>[x<em class="arg">Height</em 1470 >[+<em class="arg">Angle</em>]] 1471 <br>Equivalent to "<code>composite</code>" 1472 <a href="#blur-composite">-blur</a> 1473 <br>A Variable Blur Mapping Composition method, where each pixel in the 1474 overlaid region is replaced with an Elliptical Weighted Average (EWA), 1475 with an ellipse (typically a circle) of the given sigma size, scaled 1476 according to overlay (source image) grayscale mapping. 1477 <br><br> 1478 As per 'Displace' and 'Distort', the red channel will modulate the 1479 width of the ellipse, while the green channel will modulate the height 1480 of the ellipse. However at this time the ellipse angle is not 1481 modulated though this may be a future posibility (perhaps with a 1482 special flag to enable use of blur channel for this purpose). 1483 <br><br> 1484 Added to ImageMagick version 6.5.4-0. 1485 </td> 1486 </tr> 1487 1488 </tbody> 1489</table> 1490 1491<p>To print a complete list of all the available compose operators, use <a href="#list">-list compose</a>.</p> 1492 1493 1494<div style="margin: auto;"> 1495 <h4><a name="composite" id="composite"></a>-composite</h4> 1496</div> 1497 1498<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> 1499 1500<p>Take the first image 'destination' and overlay the second 'source' image 1501according to the current <a href="#compose">-compose</a> setting. The location 1502of the 'source' or 'overlay' image is controlled according to <a 1503href="#geometry" >-geometry</a>, and <a href="#geometry" >-geometry</a> 1504settings. </p> 1505 1506<p>If a third image is given this is treated as a gray-scale 'mask' image 1507relative to the first 'destination' image. This mask will limit what parts of 1508the destination can be modified by the image composition. However for the 1509'<kbd>displace</kbd>' compose method, the mask is used to provide a separate 1510Y-displacement image instead. </p> 1511 1512<p>If a <a href="#compose">-compose</a> method requires extra numerical 1513arguments or flags these can be provided by setting the <a 1514href="#set">-set</a> '<kbd class="arg">option:compose:args</kbd>' 1515appropriatally for the compose method. </p> 1516 1517<p>Some <a href="#compose">-compose</a> methods can modify the 'destination' 1518image outside the overlay area. You can disable this by setting the special <a 1519href="#set">-set</a> '<kbd class="arg">option:compose:outside-overlay</kbd>' 1520to '<kbd>false</kbd>'. </p> 1521 1522 1523<div style="margin: auto;"> 1524 <h4><a name="compress" id="compress"></a>-compress <em class="arg">type</em></h4> 1525</div> 1526 1527<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> 1528 1529<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> 1530 1531<p>To print a complete list of compression types, use <a href="#list">-list compress</a>.</p> 1532 1533<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> 1534 1535<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> 1536 1537<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> 1538 1539<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> 1540 1541<div style="margin: auto;"> 1542 <h4><a name="contrast" id="contrast"></a>-contrast</h4> 1543</div> 1544 1545<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> 1546 1547<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> 1548 1549<p>For a more pronounced effect you can repeat the option:</p> 1550 1551<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -contrast -contrast rose_c2.png</span></p> 1552<div style="margin: auto;"> 1553 <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> 1554</div> 1555 1556<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> 1557 1558<p>While performing the stretch, black-out at most <em class="arg">black-point</em> pixels and white-out at most <em class="arg">white-point</em> pixels. Or, if percent is used, black-out at most <em class="arg">black-point %</em> pixels and white-out at most <em class="arg">white-point %</em> pixels.</p> 1559 1560<p>Prior to ImageMagick 6.4.7-0, <a href="#contrast-stretch">-contrast-stretch</a> will black-out at most <em class="arg">black-point</em> pixels and white-out at most <em class="arg">total pixels minus white-point</em> pixels. Or, if percent is used, black-out at most <em class="arg">black-point %</em> pixels and white-out at most <em class="arg">100% minus white-point %</em> pixels.</p> 1561 1562<p>Note that <kbd>-contrast-stretch 0</kbd> will modify the image such that the image's 1563min and max values are stretched to 0 and <em class="QR">QuantumRange</em>, respectively, without any loss of data due to burn-out at either end. This is not the same as <a href="#normalize">-normalize</a>, which is equivalent to <kbd>-contrast-stretch 2%x1%</kbd> (or prior to ImageMagick 6.4.7-0, <kbd>-contrast-stretch 2%x99%</kbd>).</p> 1564 1565<p>The channels are stretched in concert. Specify <a href="#channel">-channel</a> to normalize the RGB channels individually.</p> 1566 1567 1568<div style="margin: auto;"> 1569 <h4><a name="convolve" id="convolve"></a>-convolve <em class="arg">kernel</em></h4> 1570</div> 1571 1572<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> 1573 1574<p>The <em class="arg">kernel</em> is a square matrix specified as a comma-separated list of integers (with no spaces), ordered left-to right, starting with the top row. Presently, only odd-dimensioned kernels are supported, and therefore the number of entries in the specified <em class="arg">kernel</em> must be 3<sup>2</sup>=9, 5<sup>2</sup>=25, 7<sup>2</sup>=49, etc. </p> 1575 1576<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 positive and negative results are relative to a user-specified bias value. 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 is clipped at zero. 1577</p> 1578 1579<p>When using an ImageMagick with the HDRI compile-time setting, <a href="/www/command-line-options.html#bias">‑bias</a> is not needed, 1580as ImageMagick is able to store/handle any negative results without 1581clipping to the color value range (0..QuantumRange).</p> 1582 1583<p>See the discussion on HDRI implementations of ImageMagick on the page 1584<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. 1585</p> 1586 1587<div style="margin: auto;"> 1588 <h4><a name="crop" id="crop"></a>-crop <em class="arg">geometry</em></h4> 1589</div> 1590 1591<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> 1592 1593<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> 1594 1595<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> 1596 1597<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> 1598 1599<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> 1600 1601<p>By adding a exclamation character flag to the geometry argument, the 1602cropped images virtual canvas page size and offset is set as if the 1603geometry argument was a viewport or window. This means the canvas page size 1604is set to exactly the same size you specified, the image offset set 1605relative top left corner of the region cropped. </p> 1606 1607<p>If the cropped image 'missed' the actual image on its virtual canvas, a 1608special single pixel transparent 'missed' image is returned, and a 'crop 1609missed' warning given. </p> 1610 1611 1612<div style="margin: auto;"> 1613 <h4><a name="cycle" id="cycle"></a>-cycle <em class="arg">amount</em></h4> 1614</div> 1615 1616<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> 1617 1618<p><em class="arg">Amount</em> defines the number of positions each 1619colormap entry is shifted.</p> 1620 1621 1622<div style="margin: auto;"> 1623 <h4><a name="debug" id="debug"></a>-debug <em class="arg">events</em></h4> 1624</div> 1625 1626<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> 1627 1628<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> 1629 1630 1631<p>For example, to log cache and blob events, use.</p> 1632 1633<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p> 1634<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p> 1635 1636<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p> 1637 1638<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p> 1639 1640<p>Use <a href="#debug">+debug</a> to turn off all logging.</p> 1641 1642<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> 1643 1644 1645<div style="margin: auto;"> 1646 <h4><a name="decipher" id="decipher"></a>-decipher <em class="arg">filename</em></h4> 1647</div> 1648 1649<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> 1650 1651<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 1652 1653<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 1654 1655 1656<div style="margin: auto;"> 1657 <h4><a name="deconstruct" id="deconstruct"></a>-deconstruct</h4> 1658</div> 1659 1660<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> 1661 1662<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> 1663 1664<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> 1665 1666<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p> 1667 1668 1669<div style="margin: auto;"> 1670 <h4><a name="define" id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4> 1671</div> 1672 1673<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> 1674 1675<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> 1676 1677<p>The following definitions may be created:</p> 1678 1679<ul> 1680<dt>jp2:rate=value</dt> 1681 <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 /> 1682<dt>mng:need-cacheoff</dt> 1683 <dd>turn playback caching off for streaming MNG.</dd><br /> 1684<dt>png:bit-depth=value</dt> 1685<dt>png:color-type=value</dt> 1686 <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 /> 1687<dt>ps:imagemask</dt> 1688 <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> 1689</ul> 1690 1691<p>For example, to create a postscript file that will render only the black pixels of a bilevel image, use:</p> 1692 1693<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p> 1694<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> 1695 1696<p class="crtsnip"> 1697-define registry:temporary-path=/data/tmp 1698</p> 1699 1700<div style="margin: auto;"> 1701 <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> 1702</div> 1703 1704<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> 1705 1706<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> 1707 1708<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> 1709 1710 1711<div style="margin: auto;"> 1712 <h4><a name="delete" id="delete"></a>-delete <em class="arg">index</em></h4> 1713</div> 1714 1715<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> 1716 1717<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> 1718 1719 1720<div style="margin: auto;"> 1721 <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> 1722</div> 1723 1724<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> 1725 1726<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> 1727 1728<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> 1729 1730<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> 1731 1732<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> 1733 1734<div style="margin: auto;"> 1735 <h4><a name="depth" id="depth"></a>-depth <em class="arg">value</em></h4> 1736</div> 1737 1738<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> 1739 1740<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> 1741 1742<div style="margin: auto;"> 1743 <h4><a name="descend" id="descend"></a>-descend</h4> 1744</div> 1745 1746<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> 1747 1748<div style="margin: auto;"> 1749 <h4><a name="deskew" id="deskew"></a>-deskew <em class="arg">threshold</em></h4> 1750</div> 1751 1752<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> 1753 1754<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> 1755 1756<div style="margin: auto;"> 1757 <h4><a name="despeckle" id="despeckle"></a>-despeckle</h4> 1758</div> 1759 1760<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> 1761 1762<div style="margin: auto;"> 1763 <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> 1764</div> 1765 1766<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> 1767 1768<p>With this option, the 'overlay' image, and optionally the 'mask' image, 1769will be used as a displacement map, which is used to displace the lookup of 1770what part of the 'background' image is seen at each point of the overlaid 1771area. Much like the displacement map is a 'lens' that redirects light shining 1772through it so as to present a distorted view the original 'background' image 1773behind it. </p> 1774 1775<p>Any perfect grey areas of the displacement map produce a zero 1776displacement of the image. Black areas produce the given maximum negative 1777displacement of the lookup point, while white produce a maximum positive 1778displacement of the lookup. </p> 1779 1780<p>Note that it is the lookup of the 'background' that is displaced, not a 1781displacement of the image itself. As such an area of the displacement map 1782containing 'white' will have the lookup point 'shifted' by a positive amount, 1783and thus generating a copy of the destination image to the right/downward from 1784the correct position. That is the image will look like it may have been 1785'shifted' in a negative left/upward direction. Understanding this is a very 1786important in understanding how displacement maps work. </p> 1787 1788<p>The given arguments define the maximum amount of displacement in pixels 1789that a particular map can produce. If the displacement scale is large enough 1790it is also posible to lookup parts of the 'background' image that lie well 1791outside the bounds of the displacement map itself. That is you could very 1792easilly copy a section of the original image from outside the overlay area 1793into the overlay area. </p> 1794 1795<p>The '%' flag makes the displacement scale relative to the size of the 1796overlay image (100% = half width/height of image). Using '!' switches 1797percentage arguments to refer to the destination image size instead. 1798these flags were added as of IM v6.5.3-5.</p> 1799 1800<p>Normally a single grayscale displacement map is provided, which with the 1801given scaling values will determine a single direction (vector) in which 1802displacements can occur (positivally or negativally). However, if you also 1803specify a third image which is normally used as a <em class="arg">mask</em>, 1804then the <em class="arg">composite image</em> will be used for horizontal X 1805displacement, while the <em class="arg">mask image</em> is used for vertical Y 1806displacement. This allows you to define completely different displacement 1807values for the X and Y directions, and allowing you to lookup any point within 1808the <em class="arg">scale</em> bounds. In other words each pixel can lookup 1809any other nearby pixel, producing complex 2 dimentional displacements, rather 1810than a simple 1 dimentional vector displacements. </p> 1811 1812<p>Alternativally rather than suppling two separate images, as of IM v6.4.4-0, 1813you can use the 'red' channel of the overlay image to specify the horizontal 1814or X displacement, and the 'green' channel for the vertical or Y displacement. 1815</p> 1816 1817<p>As of IM v6.5.3-5 any alpha channel in the overlay image will be used as a 1818mask the transparency of the destination image. However areas outside the 1819overlaid areas will not be effected. </p> 1820 1821 1822<div style="margin: auto;"> 1823 <h4><a name="display" id="display"></a>-display <em class="arg">host:display[.screen]</em></h4> 1824</div> 1825 1826<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> 1827 1828<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p> 1829 1830<div style="margin: auto;"> 1831 <h4><a name="dispose" id="dispose"></a>-dispose <em class="arg">method</em></h4> 1832</div> 1833 1834<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> 1835 1836<p>The layer disposal method defines the way each the displayed image is to be 1837modified after the current 'frame' of an animation has finished being 1838displayed (after its 'delay' period), but before the next frame on an 1839animation is to be overlaid onto the display. </p> 1840 1841<p>Here are the valid methods:</p> 1842 1843<pre class="text"> 1844Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>'). 1845None 1 Do not dispose, just overlay next frame image. 1846Background 2 Clear the frame area with the background color. 1847Previous 3 Clear to the image prior to this frames overlay. 1848</pre> 1849 1850<p>You can also use the numbers given above, which is what the GIF format 1851uses internally to represent the above settings. </p> 1852 1853<p>To print a complete list of dispose methods, use <a href="#list">-list dipose</a>.</p> 1854 1855<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent 1856resetting the layer disposal methods of images being read in. </p> 1857 1858<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image 1859disposal method for images already in memory.</p> 1860 1861<div style="margin: auto;"> 1862 <h4><a name="dissimilarity-threshold" id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4> 1863</div> 1864 1865<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> 1866 1867 1868<div style="margin: auto;"> 1869 <h4><a name="dissolve" id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4> 1870</div> 1871 1872<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> 1873 1874<p>The opacity of the composite image is multiplied by the given percent, then 1875it is composited 'over' the main image. If <em class="arg">src_percent</em> 1876is greater than 100, start dissolving the main image so it will become 1877transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages 1878are given, each image are dissolved to the percentages given. </p> 1879 1880<p>Note that dissolve percentages do not add, two opaque images dissolved 1881'50,50', produce a 75% transparency. For a 50% + 50% blending of the two 1882images, you would need to use dissolve values of '50,100'. </p> 1883 1884<div style="margin: auto;"> 1885 <h4><a name="distort" id="distort"></a>-distort <em class="arg">method arguments</em></h4> 1886</div> 1887 1888<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> 1889 1890<p>The <em class="arg">arguments</em> is a single string containing a list 1891of floating point numbers separated by commas or spaces. The number of 1892and meaning of the floating point values depends on the distortion <em 1893class="arg">method</em> being used. </p> 1894 1895<p>Choose from these distortion types:</p> 1896 1897<table class="doc"> 1898 <tr valign="top"> 1899 <th align="left" style="width: 8%">Method</th> 1900 <th align="left">Description</th> 1901 </tr> 1902 1903 <tr valign="top"> 1904 <td valign="top"><kbd>ScaleRotateTranslate</kbd> 1905 <br/>or <kbd>SRT</kbd></td> 1906 <td valign="top"> 1907 Distort image by first scaling and rotating about a given 'center', 1908 before translating that 'center' to the new location, in that order. It 1909 is an alternative method of specifying a '<kbd>Affine</kbd>' type of 1910 distortion, but without shearing effects. It also provides a good way 1911 of rotating and displacing a smaller image for tiling onto a larger 1912 background (IE 2-dimensional animations). <br/> 1913 1914 The number of arguments determine the specific meaning of each 1915 argument for the scales, rotation, and translation operations. <br/> 1916 1917 <table style="margin-left:auto; margin-right:auto;"> 1918 <tr><td># </td><td>arguments meaning</td></tr> 1919 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr> 1920 <tr><td>2:</td><td><em>Scale Angle</em></td></tr> 1921 <tr><td>3:</td><td><em>ScaleX,ScaleY Angle</em></td></tr> 1922 <tr><td>4:</td><td><em>X,Y Scale Angle</em></td></tr> 1923 <tr><td>5:</td> 1924 <td><em>X,Y ScaleX,ScaleY Angle</em></td></tr> 1925 <tr><td>6:</td> 1926 <td><em>X,Y Scale Angle NewX,NewY</em></td></tr> 1927 <tr><td>7:</td> 1928 <td><em>X,Y ScaleX,ScaleY Angle 1929 NewX,NewY</em></td></tr> 1930 </table> 1931 1932 This is actually an alternative way of specifing a 2 dimensional linear 1933 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr> 1934 1935 <tr valign="top"> 1936 <td valign="top"><kbd>Affine</kbd></td> 1937 <td valign="top"> 1938 Distort the image linearly by moving a list of at least 3 or more sets 1939 of control points (as defined below). Idealy 3 sets or 12 floating 1940 point values are given allowing the image to be linearly scaled, 1941 rotated, sheared, and translated, according to those three points. See 1942 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>' 1943 distortions. <br/> 1944 1945 More than 3 sets given control point pairs (12 numbers) is least 1946 squares fitted to best match a lineary affine distortion. If only 2 1947 control point pairs (8 numbers) are given a two point image translation 1948 rotation and scaling is performed, without any posible shearing, 1949 flipping or changes in aspect ratio to the resulting image. If only one 1950 control point pair is provides the image is only translated, (which may 1951 be a floating point non-integer translation). <br/> 1952 1953 This distortion does not include any form of perspective distortion. 1954 </td> 1955 1956 </tr> 1957 1958 <tr valign="top"> 1959 <td valign="top"><kbd>AffineProjection</kbd></td> 1960 <td valign="top"> 1961 Linearly distort an image using the given Affine Matrix of 6 1962 pre-calculated coefficients forming a set of Affine Equations to map 1963 the source image to the destination image. 1964 1965 <div style="text-align: center"><em> 1966 s<sub>x</sub>, r<sub>x</sub>, 1967 r<sub>y</sub>, s<sub>y</sub>, 1968 t<sub>x</sub>, t<sub>y</sub> 1969 </em></div> 1970 1971 See <a href="#affine" >-affine</a> setting for more detail, and 1972 meanings of these coefficients. <br/> 1973 1974 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide 1975 alternative methods of defining this distortion, with ImageMagick doing the 1976 calculations needed to generate the required coefficients. You can see 1977 the internally generated coefficients, by using a <a href="#verbose" 1978 >-verbose</a> setting. </td> 1979 1980 </tr> 1981 1982<!-- still under development, do not display - Anthony 1983 <tr valign="top"> 1984 <td valign="top"><kbd>Bilinear</kbd></td> 1985 <td valign="top"> 1986 Bilinear (reversed) Distortion, given a minimum of 4 sets of 1987 coordinate pairs, or 16 values (see below). Not that lines may not 1988 appear straight after distortion, though the distance between 1989 coordinates will remain consistant. </td> 1990 </tr> 1991--> 1992 1993 <tr valign="top"> 1994 <td valign="top"><kbd>Perspective</kbd></td> 1995 <td valign="top"> 1996 Perspective distort the images, using a list of 4 or more sets of 1997 control points (as defined below). More that 4 sets (16 numbers) of 1998 control points provide least squares fitting for more accurate 1999 distortions (for the purposes of image registration and panarama 2000 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>' 2001 linear distortion. <br/> 2002 2003 Perspective Distorted images ensures that straight lines remain 2004 straight, but the scale of the distorted image will vary. The horizon 2005 is anti-aliased, and the 'sky' color may be set using the 2006 <a href="#mattecolor" >-mattecolor</a> setting. </td> 2007 </tr> 2008 2009 <tr valign="top"> 2010 <td valign="top"><kbd>PerspectiveProjection</kbd> </td> 2011 <td valign="top"> 2012 Do a '<kbd>Perspective</kbd>' distortion basied on a set of 8 2013 pre-calculated coefficients. You can get these coefficients by looking 2014 at the <a href="#verbose" >-verbose</a> output of a 2015 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself. 2016 If the last two perspective scaling coefficients are zero, the 2017 remaining 6 represents a transposed 'Affine Matrix'. </td> 2018 2019 </tr> 2020 2021 <tr valign="top"> 2022 <td valign="top"><kbd>Arc</kbd></td> 2023 <td valign="top"> 2024 Arc the image (variation of polar mapping) over the angle given around 2025 a circle. <br/> 2026 <table width="90%" style = "margin-left: auto; margin-right: auto;"> 2027 <tr valign="top"><td>Argument</td> 2028 <td>Meaning</td></tr> 2029 <tr valign="top"><td><em>arc_angle</em></td> 2030 <td>The angle over which to arc the image side-to-side</td></tr> 2031 <tr valign="top"><td><em>rotate_angle</em></td> 2032 <td>Angle to rotate resulting image from vertical center</td></tr> 2033 <tr valign="top"><td><em>top_radius</em></td> 2034 <td>Set top edge of source image at this radius</td></tr> 2035 <tr valign="top"><td><em>bottom_radius</em> </td> 2036 <td>Set bottom edge to this radius (radial scaling)</td></tr> 2037 </table> 2038 2039 The resulting image is always resized to best fit the resulting image, 2040 (as if using <a href="#distort" >+distort</a>) while attempting to 2041 preserve scale and aspect ratio of the original image as much as 2042 possible with the arguments given by the user. All four arguments will 2043 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/> 2044 2045 This a variation of a polar distortion designed to try to preserve the 2046 aspect ratio of the image rather than direct Cartesian to Polar 2047 conversion. </td> 2048 </tr> 2049 2050 <tr valign="top"> 2051 <td valign="top"><kbd>Polar</kbd></td> 2052 <td valign="top"> 2053 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of 2054 the image. that is the height of the input image is mapped to the 2055 radius limits, while the width is wrapped around between the 2056 angle limits. <br/> 2057 2058 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/> 2059 2060 All arguments are optional. With <em>Rmin</em> defaulting to zero, the 2061 center to the center of the image, and the angles going from -180 (top) 2062 to +180 (top). If <em>Rmax</em> is given the special value of 2063 '<code>0</code>', the the distance from the center to the nearest edge 2064 is used for the radius of the output image, which will ensure the whole 2065 image is visible (though scaled smaller). However a special value of 2066 '<code>-1</code>' will use the distance from the center to the furthest 2067 corner, This may 'clip' the corners from the input rectangular image, 2068 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with 2069 the same arguments. <br/> 2070 2071 If the plus form of distort (<a href="#distort" >+distort</a>) is used 2072 output image center will default to <code>0,0</code> of the virtual 2073 canvas, and the image size adjusted to ensure the whole input image is 2074 made visible in the output image on the virtual canvas. </td> 2075 2076 </tr> 2077 2078 <tr valign="top"> 2079 <td valign="top"><kbd>DePolar</kbd></td> 2080 <td valign="top"> 2081 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion 2082 but generates the reverse Polar to Cartesian distortion. <br/> 2083 2084 The special <em>Rmax</em> setting of '<code>0</code>' may however clip 2085 the corners of the input image. However using the special 2086 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner 2087 distance) will ensure the whole distorted image is preserved in the 2088 generated result, so that the same argument to '<kbd>Polar</kbd>' will 2089 reverse the distortion re-producing the original. 2090 2091 Note that as this distortion requires the area resampling of a circular 2092 arc, which can not be handled by the builtin EWA resampling function. 2093 As such the normal EWA filters are turned off. It is recomended some 2094 form of 'super-sampling' image processing technique be used to produce 2095 a high quality result. </td> 2096 2097 </tr> 2098 2099 <tr valign="top"> 2100 <td valign="top"><kbd>Barrel</kbd></td> 2101 <td valign="top"> 2102 Given the four coefficients (A,B,C,D) as defined by <a 2103 href="http://www.all-in-one.ee/~dersch/barrel/barrel.html" >Helmut 2104 Dersch</a>, perform a barrell or pincussion distortion appropriate to 2105 correct radial lens distortions. That is in photographs, make straight 2106 lines straight again. <br/> 2107 2108 Arguments: <em>A B C</em> [ <em>D</em> [ 2109 <em>X</em> , <em>Y</em> ] ] <br/> 2110 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> 2111 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> 2112 [ <em>X</em> , <em>Y</em> ] <br/> 2113 So that it forms the function <br/> 2114 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2115 <em>C</em>*r + <em>D</em> )<br/> 2116 2117 Where <em>X</em>,<em>Y</em> is the optional center of the distortion 2118 (defaulting to the center of the image). <br/> 2119 The second form is typically used to distort images, rather than 2120 correct lens distortions. <br/> 2121 </td> 2122 2123 </tr> 2124 2125 <tr valign="top"> 2126 <td valign="top"><kbd>BarrelInverse</kbd></td> 2127 <td valign="top"> 2128 This is very simular to '<kbd>Barrel</kbd>' with the same set of 2129 arguments, and argument handling. However it uses the inverse 2130 of the radial polynomial, 2131 so that it forms the function <br/> 2132 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> + 2133 <em>C</em>*r + <em>D</em> ) 2134 </td> 2135 </tr> 2136 2137 <tr valign="top"> 2138 <td valign="top"><kbd>Shepards</kbd></td> 2139 <td valign="top"> 2140 Distort the given list control points (any number) using an Inverse 2141 Squared Distance Interpolation Method (<a 2142 href="http://www.ems-i.com/smshelp/Data_Module/Interpolation/Inverse_Distance_Weighted.htm" 2143 >Shepards Method</a>). The control points in effect do 'localized' 2144 distortions of the image around the given control point. For best 2145 results extra control points should be added to 'lock' the positions of 2146 the corners and other unchanging parts of the image. <br/> 2147 2148 The distortion has been likened to 'taffy pulling' using nails, pins or 2149 sticks. It basically uses the <a href="#sparse-color" 2150 >-sparse-color</a> method of the same name to generate separate X and Y 2151 displacement maps (see <a href="#displace" >-displace</a>) for source 2152 image color look-up. </td> 2153 2154 </tr> 2155 2156</table> 2157 2158<p>To print a complete list of distortion methods, use <a href="#list">-list distort</a>.</p> 2159 2160<p>Many of the above distortion methods such as '<kbd>Affine</kbd>', 2161'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points 2162defining how these points in the given image should be distorted in the 2163destination image. Each set of four floating point values represent a source 2164image coordinate, followed immediately by the destination image coordinate. 2165This produces a list of values such as...</p> 2166<div style="text-align: center"><em> 2167 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> 2168 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> 2169 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> 2170 ... 2171 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> 2172</em></div> 2173<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the 2174destination image. </p> 2175 2176<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion, 2177needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the 2178perspective distortion of the built-in "rose:" image. Note how spaces were 2179used to group the 4 sets of coordinate pairs, to make it easier to read and 2180understand.</p> 2181 2182<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'> 2183 convert rose: -virtual-pixel black \ <br/> 2184 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \ <br/> 2185 rose_3d_rotated.gif</span></p> 2186<p>If more that the required number of coordinate pairs are given for a 2187distortion, the distortion method is 'least squares' fitted to 2188produce the best result for all the coordinate pairs given. If less than the 2189ideal number of points are given, the distort will generally fall back to a 2190simpler form of distortion that can handles the smaller number of coordinates 2191(usally a linear '<kbd>Affine</kbd>' distortion). </p> 2192 2193<p>By using more coodinates you can make use of image registration tool to 2194find matching coordinate pairs in overlaping images, so as to improve the 'fit' 2195of the distortion. Of course a bad coordinate pair can also make the 'fit' 2196worse. Caution is always advised. </p> 2197 2198<p>Colors are acquired from the source image according to the <a 2199href="#interpolate" >-interpolate</a> color lookup setting, when the image is 2200magnified. However if the viewed image is minified (image becomes smaller), a 2201special area resampling function (added ImageMagick v6.3.5-9), is used to 2202produce a higher quality image. For example you can use a 2203'<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all the 2204way to the horizon. </p> 2205 2206<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \ <br/> 2207 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \ <br/> 2208 checks_tiled.jpg</span></p> 2209<p>Note that a infinitely tiled perspective images involving the horizon can 2210be very slow to generate due to the use of the high quality 'area resampling' 2211function (added ImageMagick v6.3.5-9). You can turn off 'area resampling' 2212using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>' 2213(recommended if you plan to use super-sampling instead). </p> 2214 2215<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last 2216'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a> 2217will use the current <a href="#mattecolor" >-mattecolor</a> setting for these 2218pixels. If you do not what these pixels to be visible, set the color to match 2219the rest of the ground. </p> 2220 2221<p>The output image size will by default be the same as the input image. This 2222means that if the part of the distorted image falls outside the viewed area of 2223the 'distorted space', those parts is clipped and lost. However if you 2224use the plus form of the operator (<a href="#distort" >+distort</a>) the 2225operator will attempt (if posible) to show the whole of the distorted image, 2226while retaining a correct 'virtual canvas' offset, for image layering. This 2227offset may need to be removed using <a href="#repage" >+repage</a>, to remove 2228if it is unwanted. </p> 2229 2230<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a> 2231option:distort:viewport {geometry_string}</kbd>" setting which will specify 2232the size and the offset of the generated 'viewport' image of the distorted 2233image space.</p> 2234 2235<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale 2236{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by 2237that factor without changing the viewed contents of the distorted image. This 2238can be used either for 'super-sampling' the image for a higher quality result, 2239or for panning and zooming around the image (with appropriate viewport 2240changes, or post-distort cropping and resizing). </p> 2241 2242<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a 2243href="#distort" >-distort</a> to attempt to output the internal coefficients, 2244and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study, 2245and debugging purposes. This many not be available for all distorts. </p> 2246 2247<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to 2248produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a> 2249and/or <a href="#shear" >-shear</a> operation, with more control of due to the 2250above settings. It is algorithmically slower, though in ImageMagick it may be faster. 2251</p> 2252 2253 2254<div style="margin: auto;"> 2255 <h4><a name="dither" id="dither"></a>-dither <em class="arg">method</em></h4> 2256</div> 2257 2258<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> 2259 2260<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> 2261 2262<p>Dithering is turned on by default, to turn it off use the plus form of the 2263setting, <a href="#dither">+dither</a>. This will also also render PostScript 2264without text or graphic aliasing. Disabling dithering often (but not always) 2265leads to faster process, a smaller number of colors, but more cartoon like 2266image coloring. Generally resulting in 'color banding' effects in areas with 2267color gradients. </p> 2268 2269<p>The color reduction operators <a href="#colors">-colors</a>, <a 2270href="#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> 2271 2272<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> 2273 2274 2275<div style="margin: auto;"> 2276 <h4><a name="draw" id="draw"></a>-draw <em class="arg">string</em></h4> 2277</div> 2278 2279<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> 2280 2281<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> 2282 2283<p>The shape primitives:</p> 2284 2285<pre class="text"> 2286 point x,y 2287 line x0,y0 x1,y1 2288 rectangle x0,y0 x1,y1 2289 roundRectangle x0,y0 x1,y1 wc,hc 2290 arc x0,y0 x1,y1 a0,a1 2291 ellipse x0,y0 rx,ry a0,a1 2292 circle x0,y0 x1,y1 2293 polyline x0,y0 ... xn,yn 2294 polygon x0,y0 ... xn,yn 2295 bezier x0,y0 ... xn,yn 2296 path path specification 2297 image operator x0,y0 w,h filename 2298</pre> 2299 2300<p>The text primitive:</p> 2301 2302<pre class="text"> 2303 text x0,y0 string 2304</pre> 2305<p>The text gravity primitive:</p> 2306 2307<pre class="text"> 2308 gravity NorthWest, North, NorthEast, West, Center, 2309 East, SouthWest, South, or SouthEast 2310</pre> 2311 2312<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> 2313 2314<p>The transformation primitives:</p> 2315 2316<pre class="text"> 2317 rotate degrees 2318 translate dx,dy 2319 scale sx,sy 2320 skewX degrees 2321 skewY degrees 2322</pre> 2323 2324<p>The pixel operation primitives:</p> 2325 2326<pre class="text"> 2327 color x0,y0 method 2328 matte x0,y0 method 2329</pre> 2330 2331<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> 2332 2333<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> 2334 2335<p>A <kbd>line</kbd> primitive requires a start point and end point.</p> 2336 2337<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p> 2338 2339<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> 2340 2341<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p> 2342 2343<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> 2344 2345<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> 2346 2347<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>. 2348</p> 2349 2350<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p> 2351 2352<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p> 2353 2354<p class="crtsnip"> 2355 -draw 'circle 100,100 150,150' 2356</p> 2357 2358<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 2359draw 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> 2360 2361<p class="crtsnip"> 2362 -draw 'bezier 20,50 45,100 45,0 70,50' 2363</p> 2364<p class="crtsnip"> 2365 -draw 'bezier 70,50 95,100 95,0 120,50' 2366</p> 2367 2368 2369<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> 2370 2371<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> 2372 2373<p class="crtsnip"> 2374 -draw 'image SrcOver 100,100 225,225 image.jpg' 2375</p> 2376 2377<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> 2378 2379<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> 2380 2381<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p> 2382 2383<p class="crtsnip"> 2384 -draw 'text 100,100 "Works like magick!"' 2385</p> 2386 2387<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p> 2388 2389<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> 2390 2391<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p> 2392 2393<p>The <kbd>scale</kbd> primitive scales them.</p> 2394 2395<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> 2396 2397<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 2398matrix.</p> 2399 2400<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> 2401 2402<pre class="text"> 2403 point 2404 replace 2405 floodfill 2406 filltoborder 2407 reset 2408</pre> 2409 2410<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> 2411 2412<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> 2413 2414<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> 2415 2416<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p> 2417 2418<p>Drawing primitives conform to the <a href="/www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p> 2419 2420 2421<div style="margin: auto;"> 2422 <h4><a name="edge" id="edge"></a>-edge <em class="arg">radius</em></h4> 2423</div> 2424 2425<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> 2426 2427<div style="margin: auto;"> 2428 <h4><a name="emboss" id="emboss"></a>-emboss <em class="arg">radius</em></h4> 2429</div> 2430 2431<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> 2432 2433<div style="margin: auto;"> 2434 <h4><a name="encipher" id="encipher"></a>-encipher <em class="arg">filename</em></h4> 2435</div> 2436 2437<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> 2438 2439<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p> 2440 2441<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p> 2442 2443<div style="margin: auto;"> 2444 <h4><a name="encoding" id="encoding"></a>-encoding <em class="arg">type</em></h4> 2445</div> 2446 2447<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> 2448 2449<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> 2450 2451<div style="margin: auto;"> 2452 <h4><a name="endian" id="endian"></a>-endian <em class="arg">type</em></h4> 2453</div> 2454 2455<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> 2456 2457<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p> 2458 2459<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p> 2460 2461 2462<div style="margin: auto;"> 2463 <h4><a name="enhance" id="enhance"></a>-enhance</h4> 2464</div> 2465 2466<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> 2467 2468 2469<div style="margin: auto;"> 2470 <h4><a name="equalize" id="equalize"></a>-equalize</h4> 2471</div> 2472 2473<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> 2474 2475<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> 2476 2477<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p> 2478 2479<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> 2480 2481<div style="margin: auto;"> 2482 <h4><a name="evaluate" id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4> 2483</div> 2484 2485<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> 2486 2487<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> 2488 2489<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> 2490 2491<table class="doc"> 2492 <col width="25%" /> 2493 <col width="75%" /> 2494 <thead> 2495 <tr> 2496 <th><em class="arg">operator</em></th> 2497 <th>Summary (see further below for details)</th> 2498 </tr> 2499 </thead> 2500 <tbody> 2501 2502 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr> 2503 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr> 2504 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr> 2505 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2506 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr> 2507 <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> 2508 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr> 2509 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr> 2510 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr> 2511 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr> 2512 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr> 2513 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr> 2514 <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> 2515 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr> 2516 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr> 2517 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr> 2518 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr> 2519 2520 <tr><td> </td></tr> 2521 2522 <tr><td>Gaussian-noise</td></tr> 2523 <tr><td>Impulse-noise</td></tr> 2524 <tr><td>Laplacian-noise</td></tr> 2525 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr> 2526 <tr><td>PoissonNoise</td></tr> 2527 <tr><td>Uniform-noise</td></tr> 2528 2529 <tr><td> </td></tr> 2530 2531 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr> 2532 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr> 2533 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr> 2534 </tbody> 2535 </table> 2536 2537<p>The specified functions are applied only to each previously set <a 2538href="#channel" >-channel</a> in the image. If necessary, the results of the 2539calculations are truncated (clipped) to fit in the interval [0, <em 2540class="QR">QuantumRange</em>]. The transparency channel of the image is 2541represented as a 'alpha' values (0 = fully transparent), so, for example, a 2542<kbd>Divide</kbd> by 2 of the alpha channel will make the image 2543semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value 2544as a percentage of the <em class="QR">QuantumRange</em>.</p> 2545 2546<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use 2547<a href="#list">-list evaluate</a>.</p> 2548 2549<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and 2550<kbd>Multiply</kbd> methods can also be achieved using either the <a 2551href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with 2552appropriate argument, to linearly modify the overall range of color values. 2553Please note, however, that <a href="#level" >-level</a> treats transparency as 2554'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with 2555'alpha' values.</p> 2556 2557<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> 2558 2559<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> 2560 2561 <div style="text-align:center;"> 2562 log(<em class="arg">value</em> × <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1) 2563 </div> 2564 2565<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on 2566normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a 2567href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent 2568to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used 2569with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used 2570with <kbd>Pow</kbd>.</p> 2571 2572<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and 2573converts the image values into a value according to a (co)sine wave function. 2574The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output 2575is biased 50% and normalized by 50% so as to fit in the respective color value 2576range. The <em class="arg">value</em> scaling of the <em>period</em> of the 2577function (its frequency), and thus determines the number of 'waves' that will 2578be generated over the input color range. For example, if the <em 2579class="arg">value</em> is 1, the effective period is simply the <em 2580class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is 2, 2581then the effective period is the <em>half</em> the <em 2582class="QR">QuantumRange</em>. 2583 2584 <div style="text-align:center;"> 2585 0.5 + 0.5 × cos(2 π <b><em>u</em></b> × <em class="arg">value</em>). 2586 </div> 2587 2588See also the <a href="#function" >-function</a> operator, which is a 2589multi-value version of evaluate. </P> 2590 2591 2592<div style="margin: auto;"> 2593 <h4><a name="extent" id="extent"></a>-extent <em class="arg">geometry</em></h4> 2594</div> 2595 2596<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> 2597 2598<p>If the image is enlarged, unfilled areas are set to the background color. To position the image, use offsets in the <em class="arg">geometry</em> specification or precede with a <a href="#gravity">-gravity</a> setting.</p> 2599 2600<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> 2601 2602<div style="margin: auto;"> 2603 <h4><a name="extract" id="extract"></a>-extract <em class="arg">geometry</em></h4> 2604</div> 2605 2606<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> 2607 2608<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p> 2609 2610<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480+1280+960 image.rgb image.png</span><span class='crtout'></span><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 'image.rgb[640x480+1280+960]' image.rgb image.png</span></p><p>If you omit the offsets, as in</p> 2611 2612<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480 image.rgb image.png</span></p> 2613<p>then the image will be <em>resized</em> to the specified dimensions instead, 2614equivalent to:</p> 2615 2616<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert -size 16000x16000 -depth 8 -resize 640x480 image.rgb image.png</span></p> 2617<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> 2618 2619<div style="margin: auto;"> 2620 <h4><a name="family" id="family"></a>-family <em class="arg">fontFamily</em></h4> 2621</div> 2622 2623<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> 2624 2625<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). 2626</p> 2627 2628<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>. 2629</p> 2630 2631<div style="margin: auto;"> 2632 <h4><a name="fft" id="fft"></a>-fft</h4> 2633</div> 2634 2635<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> 2636 2637<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> 2638 2639<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> 2640 2641<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> 2642 2643<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p> 2644<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> 2645 2646<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -fft fft_image.png</span></p> 2647<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> 2648 2649<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> 2650 2651<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> 2652 2653<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br /> 2654 -evaluate log 1000 fft_image_spectrum.png</span></p> 2655<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> 2656 2657<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>. 2658 2659<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> 2660 2661<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> 2662 2663<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> 2664 2665<p>See the discussion on HDRI implementations of ImageMagick on the page 2666<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. 2667</p> 2668 2669 2670<div style="margin: auto;"> 2671 <h4><a name="fill" id="fill"></a>-fill <em class="arg">color</em></h4> 2672</div> 2673 2674<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> 2675 2676<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> 2677 2678<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p> 2679 2680<p>For example,</p> 2681 2682<p class="crtsnip"> 2683 -fill blue 2684</p> 2685<p class="crtsnip"> 2686 -fill "#ddddff" 2687</p> 2688<p class="crtsnip"> 2689 -fill "rgb(255,255,255)" 2690</p> 2691 2692<p>See <a href="#draw">-draw</a> for further details.</p> 2693 2694<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p> 2695 2696<div style="margin: auto;"> 2697 <h4><a name="filter" id="filter"></a>-filter <em class="arg">type</em></h4> 2698</div> 2699 2700<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> 2701 2702<p>Use this option to affect the resizing operation of an image (see <a 2703href="#resize">-resize</a>). For example you can use a simple resize filter 2704such as:</p> 2705 2706<pre class="text"> 2707 Point Hermite Cubic 2708 Box Gaussian Catrom 2709 Triangle Quadratic Mitchell 2710</pre> 2711 2712<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided, but are 2713by default <kbd>blackman</kbd>-windowed. However these filters define a 2714windowing filter for the Sinc or Bessel filter function, as appropriate for 2715the scaling operator used (usally Sinc for orthogonal <a href="#resize" 2716>-resize</a>). Windowed filters include: </p> 2717 2718<pre class="text"> 2719 Lanczos Hamming Parzen 2720 Blackman Kaiser Welsh 2721 Hanning Bartlett Bohman 2722</pre> 2723 2724<p>Also one special self-windowing filter is also provided 2725<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending 2726on the current 'support' or 'lobes' expert settings (see below).</p> 2727 2728<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> 2729 2730<p>To print a complete list of resize filters, use the <a href="#list">-list filter</a> option.</p> 2731 2732<p>You can modify how the filter behaves as it scales your image through the 2733use of these expert settings:</p> 2734 2735<dl class="doc"> 2736<dt>-set filter:blur <em>factor</em></dt> 2737<dd>Scale the X axis of the filter (and its window). Use > 1.0 for 2738 blurry or < 1.0 for sharp.</dd> 2739 2740<dt>-set filter:support <em>radius</em></dt> 2741<dd>Set the filter support radius.</dd> 2742 2743<dt>-set filter:lobes <em>count</em></dt> 2744<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an 2745 alternative way of specifying the 'support' range of the filter.</dd> 2746 2747<dt>-set filter:b <em>b-spline_factor</em></dt> 2748<dt>-set filter:c <em>keys_alpha_factor</em></dt> 2749<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>, 2750 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as 2751 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values 2752 are defined, the other is set so as to generate a 'Keys' type cubic 2753 filter. 2754 2755<dt>-set filter:filter <em>filter</em></dt> 2756<dd>Use this function directly as the scaling filter. This will allow 2757 you to directly use a 'windowing filter' such as <kbd>blackman</kbd>, 2758 rather than as its normal usage as a windowing function for 'Sinc' or 2759 'Bessel'. If defined, no windowing function is used, unless the following 2760 expert setting is also defined.</dd> 2761 2762<dt>-set filter:window <em>filter</em></dt> 2763<dd>The IIR (infinite impulse response) filters <kbd>bessel</kbd> and 2764 <kbd>sinc</kbd> are windowed (brought down to zero over the defined 2765 support range) with the given filter. This allows you to use a filter that 2766 is not normally used as a windowing function, such as <kbd>box</kbd>, 2767 (which effectivally turns off the windowing function). </dd> 2768 2769</dl> 2770 2771<p>For example, to get a 8 lobe Lanczos-Bessel filter:</p> 2772 2773<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -filter bessel \ <br/> 2774 -set filter:window=bessel -set filter:lobes=8 \ <br/> 2775 -resize 150% image.jpg</span></p> 2776<p>Or a raw un-windowed Sinc filter with 4 lobes:</p> 2777 2778<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/> 2779 -resize 150% image.jpg</span></p> 2780<p>Note that the use of expert options (except for 'blur' with simple resize 2781filters), are provided for image processing experts who have studied and 2782understood how resize filters work. Without this knowledge, and an 2783understanding of the defination of the actual filters involved, using expert 2784settings are more likely to be detremental to your image resizing.</p> 2785 2786 2787<div style="margin: auto;"> 2788 <h4><a name="flatten" id="flatten"></a>-flatten</h4> 2789</div> 2790 2791<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> 2792 2793 2794<div style="margin: auto;"> 2795 <h4><a name="flip" id="flip"></a>-flip</h4> 2796</div> 2797 2798<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> 2799 2800<p>reflect the scanlines in the vertical direction.</p> 2801 2802<div style="margin: auto;"> 2803 <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> 2804</div> 2805 2806<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> 2807 2808<div style="margin: auto;"> 2809 <h4><a name="flop" id="flop"></a>-flop</h4> 2810</div> 2811 2812<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> 2813 2814<p>reflect the scanlines in the horizontal direction.</p> 2815 2816 2817<div style="margin: auto;"> 2818 <h4><a name="font" id="font"></a>-font <em class="arg">name</em></h4> 2819</div> 2820 2821<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> 2822 2823<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> 2824 2825<p>In addition to the fonts specified by the above pre-defined list, you can 2826also specify a font from a specific source. For example <kbd>Arial.ttf</kbd> 2827is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and 2828<kbd>x:fixed</kbd> is X11 font.</p> 2829 2830<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> 2831 2832 2833<div style="margin: auto;"> 2834 <h4><a name="foreground" id="foreground"></a>-foreground <em class="arg">color</em></h4> 2835</div> 2836 2837<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> 2838 2839<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 2840 2841<p>The default foreground color is black.</p> 2842 2843<div style="margin: auto;"> 2844 <h4><a name="format" id="format"></a>-format <em class="arg">type</em></h4> 2845</div> 2846 2847<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> 2848 2849<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> 2850 2851<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> 2852 2853<div style="margin: auto;"> 2854 <h4><a name="format_identify_" id="format_identify_"></a>-format <em class="arg">string</em></h4> 2855</div> 2856 2857<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> 2858 2859<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> 2860 2861<div style="margin: auto;"> 2862 <h4><a name="frame" id="frame"></a>-frame <em class="arg">geometry</em></h4> 2863</div> 2864 2865<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Surround the image with a border or beveled frame.</td><td style='text-align:right;'></td></tr></table> 2866 2867<p>The color of the border is specified with the <a href="#mattecolor">-mattecolor</a> command line option. </p> 2868 2869<p>See <a href="/www/command-line-processing.html#geometry">Image Geometry</a> for complete details about the <em class="arg">geometry</em> argument. 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> 2870 2871 2872<div style="margin: auto;"> 2873 <h4><a name="frame_import_" id="frame_import_"></a>-frame</h4> 2874</div> 2875 2876<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> 2877 2878<div style="margin: auto;"> 2879 <h4><a name="function" id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4> 2880</div> 2881 2882<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> 2883 2884<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> 2885 2886<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> 2887 2888<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> 2889 2890<pre class="text"> 2891 Polynomial 2892 Sinusoid 2893 Arcsin 2894 Arctan 2895</pre> 2896 2897<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p> 2898 2899<dl class="doc"> 2900<dt><kbd>Polynomial</kbd></dt> 2901<dd> 2902<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> 2903 2904<div style="text-align: center"> 2905 -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> 2906</div> 2907 2908<p>will invoke a polynomial function given by</p> 2909 2910<div style="text-align: center"> 2911 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> + 2912 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> + 2913 ··· <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>, 2914</div> 2915 2916<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p> 2917 2918<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> 2919 2920<table class="doc"> 2921 <col width="35%" /> 2922 <col width="35%" /> 2923 <col width="30%" /> 2924 <tr> 2925 <td>-evaluate Set <em class="arg">value</em> </td> 2926 <td>-function Polynomial <em class="arg">value</em></td> 2927 <td>(Constant functions; set <em class="arg">value</em>×100% gray when channels are RGB.)</td> 2928 </tr> 2929 <tr> 2930 <td>-evaluate Add <em class="arg">value</em> </td> 2931 <td>-function Polynomial 1,<em class="arg">value</em></td> 2932 </tr> 2933 <tr> 2934 <td>-evaluate Subtract <em class="arg">value</em> </td> 2935 <td>-function Polynomial 1,−<em class="arg">value</em></td> 2936 </tr> 2937 <tr> 2938 <td>-evaluate Multiply <em class="arg">value</em> </td> 2939 <td>-function Polynomial <em class="arg">value</em>,0</td> 2940 </tr> 2941 <tr> 2942 <td>+level black% x white%</td> 2943 <td>-function Polynomial A,B</td> 2944 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td> 2945 </tr> 2946</table> 2947 2948<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> 2949</dd> 2950 2951<dt><kbd>Sinusoid</kbd></dt> 2952<dd> 2953<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> 2954 2955<div style="text-align: center"> 2956 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]] 2957</div> 2958 2959<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> 2960 2961<div style="text-align: center"> 2962<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> 2963</div> 2964 2965<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> 2966 2967<p class="crtsnip"> 2968 -function Sinusoid 3,-90,.2,.7 2969</p> 2970 2971<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> 2972 2973<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> 2974 2975<table class="doc"> 2976 <tr> 2977 <td>-evaluate Sin <em class="arg">freq</em> </td> 2978 <td>-function Sinusoid <em class="arg">freq</em>,0 </td> 2979 </tr> 2980 <tr> 2981 <td>-evaluate Cos <em class="arg">freq</em> </td> 2982 <td>-function Sinusoid <em class="arg">freq</em>,90 </td> 2983 </tr> 2984</table> 2985</dd> 2986 2987<dt><kbd>ArcSin</kbd></dt> 2988<dd> 2989<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid, 2990and can be used to generate cylindrical distortion and displacement maps. 2991The curve can be adjusted relative to both the input values and output range 2992of values. 2993 2994<div style="text-align: center"> 2995 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 2996</div> 2997 2998<p>with all values given in terms of noramlize color values (0.0 for black, 29991.0 for white). Defaulting to values covering the full range from 0.0 to 1.0 3000for bout input (<em class="arg">width</em>), and output (<em 3001class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p> 3002 3003<div style="text-align: center"> 3004<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> 3005</div> 3006 3007</dd> 3008 3009<dt><kbd>ArcTan</kbd></dt> 3010<dd> 3011<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from 3012limit values at infinities, though a center using the given slope value. 3013All these values can be adjusted via the arguments. 3014 3015<div style="text-align: center"> 3016 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]] 3017</div> 3018 3019<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'. 3020</p> 3021 3022<div style="text-align: center"> 3023<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> 3024</div> 3025 3026</dd> 3027 3028</dl> 3029 3030 3031<div style="margin: auto;"> 3032 <h4><a name="fuzz" id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4> 3033</div> 3034 3035<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> 3036 3037<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> 3038 3039<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> 3040 3041 3042<div style="margin: auto;"> 3043 <h4><a name="fx" id="fx"></a>-fx <em class="arg">expression</em></h4> 3044</div> 3045 3046<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> 3047 3048<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> 3049 3050<p>See <a href="/www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p> 3051 3052 3053<div style="margin: auto;"> 3054 <h4><a name="gamma" id="gamma"></a>-gamma <em class="arg">value</em></h4> 3055</div> 3056 3057<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> 3058 3059<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> 3060 3061<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> 3062 3063<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> 3064 3065<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> 3066 3067<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p> 3068 3069<div style="margin: auto;"> 3070 <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> 3071</div> 3072 3073<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> 3074 3075<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p> 3076 3077<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="/images/gaussian-blur.png"/> 3078</div> 3079 3080<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> 3081 3082<p>This differs from the faster <a href="#blur">-blur</a> operator in that a 3083full 2-dimentional convolution is used to generate the weighted average of the 3084neighbouring pixels. </p> 3085 3086<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 3087pixels which are outside the image proper are blurred into the final result. 3088</p> 3089 3090 3091<div style="margin: auto;"> 3092 <h4><a name="geometry" id="geometry"></a>-geometry <em class="arg">geometry</em></h4> 3093</div> 3094 3095<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> 3096 3097<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> 3098 3099<div style="margin: auto;"> 3100 <h4><a name="gravity" id="gravity"></a>-gravity <em class="arg">type</em></h4> 3101</div> 3102 3103<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> 3104 3105<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>, 3106<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>, 3107<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete 3108list of <a href="#gravity">-gravity</a> settings available in your ImageMagick 3109installation.</p> 3110 3111<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> 3112 3113<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> 3114 3115<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> 3116 3117<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png -gravity Center -region 10x10-40+20 -negate output.png</span></p> 3118<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> 3119 3120<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> 3121 3122 3123<div style="margin: auto;"> 3124 <h4><a name="green-primary" id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4> 3125</div> 3126 3127<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> 3128 3129 3130<div style="margin: auto;"> 3131 <h4><a name="hald-clut" id="hald-clut"></a>-hald-clut</h4> 3132</div> 3133 3134<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> 3135 3136<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2 3137dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You 3138can apply any color transformation to the Hald image and then use this option 3139to apply the transform to the image. </p> 3140 3141<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p> 3142<p>This option provides a convenient method for you to use Gimp or Photoshop 3143to make color corrections to the Hald CLUT image and subsequently apply them 3144to multiple images using an ImageMagick script. </p> 3145 3146<p>Note that the representation is only of the normal RGB color space and that 3147the whole color value triplet is used for the interpolated lookup of the 3148represented Hald color cube image. Because of this the operation is not <a 3149href="#channel" >-channel</a> setting effected, nor can it adjust or modify an 3150images transparency or alpha/matte channel.</p> 3151 3152<p>See also <a href="#clut" >-clut</a> which provides color value replacement 3153of the individual color channels, usally involving a simplier gray-scale 3154image. E.g: gray-scale to color replacement, or modification by a histogram 3155mapping. </p> 3156 3157 3158<div style="margin: auto;"> 3159 <h4><a name="help" id="help"></a>-help</h4> 3160</div> 3161 3162<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> 3163 3164<div style="margin: auto;"> 3165 <h4><a name="highlight-color" id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4> 3166</div> 3167 3168<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> 3169 3170<div style="margin: auto;"> 3171 <h4><a name="iconGeometry" id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4> 3172</div> 3173 3174<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> 3175 3176<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> 3177 3178<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> 3179 3180<div style="margin: auto;"> 3181 <h4><a name="iconic" id="iconic"></a>-iconic</h4> 3182</div> 3183 3184<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> 3185 3186<div style="margin: auto;"> 3187 <h4><a name="identify" id="identify"></a>-identify</h4> 3188</div> 3189 3190<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> 3191 3192<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> 3193 3194<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> 3195 3196<p>If <a href="#verbose">-verbose</a> preceds this option, copious 3197amounts of image properties are displayed including image statistics, profiles, 3198image histogram, and others.</p> 3199 3200<div style="margin: auto;"> 3201 <h4><a name="ift" id="ift"></a>-ift</h4> 3202</div> 3203 3204<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> 3205 3206<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> 3207 3208<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> 3209 3210<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p> 3211<p>or</p> 3212 3213<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> 3214 3215<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. 3216 3217<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>. 3218 3219<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. 3220 3221<div style="margin: auto;"> 3222 <h4><a name="immutable" id="immutable"></a>-immutable</h4> 3223</div> 3224 3225<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> 3226 3227<div style="margin: auto;"> 3228 <h4><a name="implode" id="implode"></a>-implode <em class="arg">factor</em></h4> 3229</div> 3230 3231<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> 3232 3233<div style="margin: auto;"> 3234 <h4><a name="insert" id="insert"></a>-insert <em class="arg">index</em></h4> 3235</div> 3236 3237<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> 3238 3239<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> 3240 3241<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> 3242 3243<div style="margin: auto;"> 3244 <h4><a name="intent" id="intent"></a>-intent <em class="arg">type</em></h4> 3245</div> 3246 3247<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> 3248 3249<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> 3250 3251<p>The default intent is undefined.</p> 3252 3253<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p> 3254 3255<div style="margin: auto;"> 3256 <h4><a name="interlace" id="interlace"></a>-interlace <em class="arg">type</em></h4> 3257</div> 3258 3259<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> 3260 3261<p>Choose from:</p> 3262 3263<pre class="text"> 3264 none 3265 line 3266 plane 3267 partition 3268 JPEG 3269 GIF 3270 PNG 3271</pre> 3272 3273<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> 3274 3275<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p> 3276 3277<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p> 3278 3279<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p> 3280 3281<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R, 3282image.G, and image.B).</p> 3283 3284<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> 3285image.</p> 3286 3287<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p> 3288 3289<div style="margin: auto;"> 3290 <h4><a name="interpolate" id="interpolate"></a>-interpolate <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%'>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> 3294 3295<p>When looking up the color of a pixel using a non-interger floating point 3296value, you typically fall in between the pixel colors defined by the source 3297image. This setting determines how the color is determined from the colors of 3298the pixels surrounding that point. That is how to determine the color of a 3299point that falls between two, or even four different colored pixels. </p> 3300 3301<pre class="text"> 3302 integer: The color of the top-left pixel (floor function) 3303 nearest-neighbor: The nearest pixel to the lookup point (rounded function) 3304 average: The average color of the surrounding four pixels 3305 bilinear A double linear interpolation of pixels (the default) 3306 mesh Divide area into two flat triangular interpolations 3307 bicubic Fitted bicubic-spines of surrounding 16 pixels 3308 spline Direct spline curves (colors are blurred) 3309 filter Use resize <a href="#filter">-filter</a> settings 3310</pre> 3311 3312<p>This most important for distortion operators such as <a href="#distort" 3313>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform" 3314>-transform</a> and <a href="#fx" >-fx</a>. </p> 3315 3316<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p> 3317 3318<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the 3319lookup for positions outside the boundaries of the image. </p> 3320 3321 3322<div style="margin: auto;"> 3323 <h4><a name="interline-spacing" id="interline-spacing"></a>-interline-spacing <em class="arg">value</em></h4> 3324</div> 3325 3326<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> 3327 3328<div style="margin: auto;"> 3329 <h4><a name="interword-spacing" id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4> 3330</div> 3331 3332<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>the space between two words.</td><td style='text-align:right;'></td></tr></table> 3333 3334<div style="margin: auto;"> 3335 <h4><a name="kerning" id="kerning"></a>-kerning <em class="arg">value</em></h4> 3336</div> 3337 3338<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> 3339 3340<div style="margin: auto;"> 3341 <h4><a name="label" id="label"></a>-label <em class="arg">name</em></h4> 3342</div> 3343 3344<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> 3345 3346<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> 3347 3348<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> 3349 3350<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> 3351 3352<p>For example,</p> 3353 3354<p class="crtsnip"> 3355 -label "%m:%f %wx%h" bird.miff 3356</p> 3357 3358<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> 3359 3360<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> 3361 3362<p>The label font can be specified with <a href="#font">-font</a>, and the 3363other font attribute settings.</p> 3364 3365<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> 3366 3367 3368<div style="margin: auto;"> 3369 <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> 3370</div> 3371 3372<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> 3373 3374<p>Adaptively threshold each pixel based on the value of pixels in a 3375surrounding window. If the current pixel is lighter than this average plus 3376the optional <kbd>offset</kbd>, then it is made white, otherwise it is made 3377black. Small variations in pixel values such as found in scanned documents 3378can be ignored if offset is positive. A negative offset will make it more 3379sensitive to those small variations. </p> 3380 3381<p>This is commonly used to threshold images with an uneven background. It is 3382based on the assumption that average color of the small window is the 3383the local background color, from which to separate the forground color. </p> 3384 3385 3386<div style="margin: auto;"> 3387 <h4><a name="layers" id="layers"></a>-layers <em class="arg">method</em></h4> 3388</div> 3389 3390<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> 3391 3392<p>Perform various image operation methods to a ordered sequence of images 3393which may represent either a set of overlaid 'image layers', a GIF disposal 3394animation, or a fully-'coalesced' animation sequence. </p> 3395 3396<table class="doc"> 3397 <tbody> 3398 <tr valign="top"> 3399 <th align="left" style="width: 8%">Method</th> 3400 <th align="left">Description</th> 3401 </tr> 3402 3403 <tr valign="top"> 3404 <td valign="top">compare-any</td> 3405 <td valign="top">Crop the second and later frames to the smallest rectangle 3406 that contains all the differences between the two images. No GIF <a 3407 href="#dispose" >-dispose</a> methods are taken into account. </td> 3408 </tr> 3409 3410 <tr><td></td><td>This exactly the same as the <a href="#deconstruct" 3411 >-deconstruct</a> operator, and does not preserve animations normal 3412 working, especially when animation used layer disposal methods such as 3413 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td> 3414 </tr> 3415 3416 <tr valign="top"> 3417 <td valign="top">compare-clear</td> 3418 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any 3419 opaque pixels which become transparent in the second frame. That is the 3420 smallest image needed to mask or erase pixels for the next frame. </td> 3421 </tr> 3422 3423 <tr valign="top"> 3424 <td valign="top">compare-overlay</td> 3425 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add 3426 extra color to the next image, as a result of overlaying color pixels. 3427 That is the smallest single overlaid image to add or change colors. </td> 3428 </tr> 3429 3430 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha 3431 composition method '<kbd>change-mask</kbd>', to reduce the image to 3432 just the pixels that need to be overlaid. </td> 3433 </tr> 3434 3435 <tr valign="top"> 3436 <td valign="top">coalesce</td> 3437 <td valign="top">Equivalent to a call to the <a href="#coalesce" 3438 >-coalesce</a> operator. Apply the layer disposal methods set in the 3439 current image sequence to form a fully defined animation sequence, as 3440 it should be displayed. Effectively converting a GIF animation into a 3441 'film strip'-like animation. </td> 3442 </tr> 3443 3444 <tr valign="top"> 3445 <td valign="top">composite</td> 3446 <td valign="top">Alpha Composition of two image lists, separated by a 3447 "<kbd>null:</kbd>" image, with the destination image list first, and 3448 the source images last. An image from each list are composited 3449 together until one list is finished. The separator image and source 3450 image lists are removed. </td> 3451 </tr> 3452 3453 3454 <tr><td></td><td>The <a href="#geometry" >-geometry</a> offset is adjusted according to 3455 <a href="#gravity" >-gravity</a> in accordance of the virtual canvas 3456 size of the first image in each list. Unlike a normal <a 3457 href="#composite" >-composite</a> operation, the canvas offset is also 3458 added to the final composite positioning of each image. </td> 3459 </tr> 3460 3461 <tr><td></td><td>If one of the image lists only contains one image, that image is 3462 applied to all the images in the other image list, regardless of which 3463 list it is. In this case it is the image meta-data of the list which 3464 preserved. </td> 3465 </tr> 3466 3467 3468 <tr valign="top"> 3469 <td valign="top">dispose</td> 3470 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of 3471 the animation after the layer disposal method has been applied, before 3472 the next sub-frame image is overlaid. That is the 'dispose' image that 3473 results from the application of the GIF <a href="#dispose" 3474 >-dispose</a> method. This allows you to check what 3475 is going wrong with a particular animation you may be developing. 3476 </td> 3477 </tr> 3478 3479 <tr valign="top"> 3480 <td valign="top">flatten</td> 3481 <td valign="top">Create a canvas the size of the first images virtual 3482 canvas using the current <a href="#background" >-background</a> color, 3483 and <a href="#compose" >-compose</a> each image in turn onto that 3484 canvas. Images falling outside that canvas is clipped. Final 3485 image will have a zero virtual canvas offset. </td> 3486 </tr> 3487 3488 <tr><td></td><td>This usally used as one of the final 'image layering' operations 3489 overlaying all the prepared image layers into a final image. </td> 3490 </tr> 3491 3492 <tr><td></td><td>For a single image this method can also be used to fillout a virtual 3493 canvas with real pixels, or to underlay a opaque color to remove 3494 transparency from an image.</td> 3495 </tr> 3496 3497 3498 <tr valign="top"> 3499 <td valign="top">merge</td> 3500 <td valign="top">As 'flatten' method but merging all the given image 3501 layers into a new layer image just large enough to hold all the image 3502 without clipping or extra space. The new images virtual offset will 3503 prevere the position of the new layer, even if this offset is 3504 negative. the virtual canvas size of the first image is preserved. 3505 </td> 3506 </tr> 3507 3508 <tr><td></td><td>Caution is advised when handling image layers with negative offsets 3509 as few image file formats handle them correctly. </td> 3510 </tr> 3511 3512 <tr valign="top"> 3513 <td valign="top">mosaic</td> 3514 <td valign="top">As 'flatten' method but expanding the initial canvas size 3515 of the first image so as to hold all the image layers. However as a 3516 virtual canvas is 'locked' to the origin, by defination, image layers 3517 with a negative offsets will still be clipped by the top and left 3518 edges.</td> 3519 </tr> 3520 3521 <tr><td></td><td>This method is commonly used to layout individual image using various 3522 offset but without knowning the final canvas size. The resulting image 3523 will, like 'flatten' not have any virtual offset, so can be saved to 3524 any image file format. </td> 3525 </tr> 3526 3527 3528 <tr valign="top"> 3529 <td valign="top">optimize</td> 3530 <td valign="top">Optimize a coalesced animation, into GIF animation using 3531 a number of general techniques. This currently a short cut to 3532 apply both the '<kbd>optimize-frame</kbd>', and 3533 '<kbd>optimize-transparency</kbd>' methods but may be expanded to 3534 include other optimization methods as they are developed. </td> 3535 </tr> 3536 3537 <tr valign="top"> 3538 <td valign="top">optimize-frame</td> 3539 <td valign="top">Optimize a coalesced animation, into GIF animation by 3540 reducing the number of pixels per frame as much as possible by 3541 attempting to pick the best layer disposal method to use, while ensuring 3542 the result will continue to animate properly. </td> 3543 </tr> 3544 3545 <tr><td></td><td> There is no guarantee that the best optimization is found. But 3546 then no reasonably fast GIF optimization algorithm can do this. 3547 However this does seem to do better than most other GIF frame 3548 optimizers seen. </td> 3549 </tr> 3550 3551 <tr valign="top"> 3552 <td valign="top">optimize-plus</td> 3553 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the 3554 overall optimization by adding extra frames to the animation, without 3555 changing the final look or timing of the animation. The frames are 3556 added to attempt to separate the clearing of pixels from the 3557 overlaying of new additional pixels from one animation frame to the 3558 next. If this does not improve the optimization (for the next frame 3559 only), it will fall back to the results of the previous normal 3560 '<kbd>optimize-frame</kbd>' technique. </td> 3561 </tr> 3562 3563 <tr><td></td><td>There is the possibility that the change in the disposal style will 3564 result in a worsening in the optimization of later frames, though this 3565 is unlikely. In other words there no guarantee that it is better than 3566 the normal '<kbd>optimize-frame</kbd>' technique. For some animations 3567 however you can get a vast improvment in the final animation size. </td> 3568 </tr> 3569 3570 <tr valign="top"> 3571 <td valign="top">optimize-transparency</td> 3572 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame 3573 overlay images with transparency, if it does not change the resulting 3574 animation by more than the current <a href="#fuzz" >-fuzz</a> factor. 3575 </td> 3576 </tr> 3577 3578 <tr><td></td><td>This should allow a existing frame optimized GIF animation to compress 3579 into a smaller file size due to larger areas of one (transparent) 3580 color rather than a pattern of multiple colors repeating the current 3581 disposed image of the last frame. </td> 3582 </tr> 3583 3584 <tr valign="top"> 3585 <td valign="top">remove-dups</td> 3586 <td valign="top">Remove (and merge time delays) of duplicate consecutive 3587 images, so as to simplify layer overlays of coalesced animations. 3588 </td> 3589 </tr> 3590 3591 <tr><td></td><td>Usually this a result of using a constant time delay across the 3592 whole animation, or after a larger animation was split into smaller 3593 sub-animations. The duplicate frames could also have been used as 3594 part of some frame optimization methods. </td> 3595 </tr> 3596 3597 <tr valign="top"> 3598 <td valign="top">remove-zero</td> 3599 <td valign="top">Remove any image with a zero time delay, unless ALL the 3600 images have a zero time delay (and is not a proper timed animation, a 3601 warning is then issued). </td> 3602 </tr> 3603 3604 <tr><td></td><td>In a GIF animation, such images are usually frames which provide 3605 partial intermediary updates between the frames that are actually 3606 displayed to users. These frames are usally added for improved frame 3607 optimization in GIF animations. </td> 3608 </tr> 3609 3610 <tr valign="top"> 3611 <td valign="top">trim-bounds</td> 3612 <td valign="top">Find the bounds of all the images in the current 3613 image sequence, then adjust the offsets so all images are contained on 3614 a minimal positive canvas. None of the image data is modified, only 3615 there virtual canvas size and offset. The all the image is given 3616 the same canvas size, and and will have a positive offset, but will 3617 remain in the same position relative to each other. As a result of the 3618 minimal canvas size at least one image will touch every edge of that 3619 canvas. The image data however may be transparent. 3620 </td> 3621 </tr> 3622 3623 </tbody> 3624</table> 3625 3626<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p> 3627 3628<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct" 3629>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic" 3630>-mosaic</a> are only aliases for the above methods. Also see <a 3631href="#page" >-page</a>, <a href="#repage" >-repage</a> operators, the <a 3632href="#compose" >-compose</a> setting, and the GIF <a href="#dispose" 3633>-dispose</a> and <a href="#delay" >-delay</a> settings. </p> 3634 3635 3636<div style="margin: auto;"> 3637 <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> 3638</div> 3639 3640<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> 3641 3642<p>Given one, two or three values delimited with commas: black-point, 3643white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and 3644white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white 3645point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center 3646contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string, 3647both black and white points are percentages of the full color range. Gamma 3648will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is 3649omitted, the default of 1.0 (no gamma correction) is assumed.</p> 3650 3651<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that 3652the given '<kbd>black_point</kbd>' value in the original image is set to 3653zero (or black), while the given '<kbd>white_point</kbd>' value is set to 3654<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments 3655to the image. The '<kbd>gamma</kbd>' of the resulting image will then be 3656adjusted. </p> 3657 3658<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or 3659adding the special '!' flag anywhere in the argument list, will cause the 3660operator to do the reverse of the level adjustment. That is a zero, or 3661<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is 3662adjusted to the given level values, allowing you to de-contrast, or compress 3663the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p> 3664 3665<p>Only the channels defined by the current <a href="#channel">-channel</a> 3666setting are adjusted (defaults to RGB color channels only), allowing you to 3667limit the effect of this operator. </p> 3668 3669<p>Please note that the transparency channel is treated as 'matte' 3670values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 3671 3672 3673<div style="margin: auto;"> 3674 <h4><a name="level-colors" id="level-colors"></a>-level-colors {<em 3675 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4> 3676</div> 3677 3678<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> 3679 3680<p>This function is exactly like <a href="#level">-level</a>, except that the 3681value value for each color channel is determined by the 3682'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as 3683described under the <a href="#fill">-fill</a> option). </p> 3684 3685<p>This effectivally means the colors provided to <kbd>-level-colors</kbd> 3686is mapped to become 'black' and 'white' respectivally, with all the other 3687colors linearly adjusted (or clipped) to match that change. Each channel is 3688adjusted separatally using the channel values of the colors specified. </p> 3689 3690<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>) 3691will map the image color 'black' and 'white' to the given colors 3692respectivally, resulting in a gradient (de-contrasting) tint of the image to 3693those colors. This can also be used to convert a plain gray-scale image into a 3694one using the gradient of colors specified. </p> 3695 3696<p>By supplying a single color with a comma separator either before or after 3697that color, will just replace the respective 'black' or 'white' point 3698respectivally. But if no comma separator is provided, the given color is 3699used for both the black and white color points, making the operator either 3700threshold the images around that color (- form) or set all colors to that 3701color (+ form). </p> 3702 3703 3704<div style="margin: auto;"> 3705 <h4><a name="limit" id="limit"></a>-limit <em class="arg">type value</em></h4> 3706</div> 3707 3708<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> 3709 3710<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> 3711 3712<p>The value for <kbd>file</kbd> is in number of files. The other limits are in bytes. By default the limits are 768 files, 2gb of image area, 1.5gb memory, 8gb memory map, and 16tb of disk. These limits are adjusted relative to the available resources on your computer if this information is available. When any limit is reached, ImageMagick fails in some fashion but attempts to take compensating actions, if possible. For example, the following limits memory:</p> 3713 3714<p class="crtsnip"> 3715 -limit memory 32mb -limit map 64mb 3716</p> 3717 3718<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p> 3719 3720<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 3721------------------------------------------------------------------- 3722 768 3.8187gb 2.864gb 7.6375gb 16eb 2 unlimited</pre> 3723</span></p> 3724<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> 3725 3726<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> 3727 3728<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> 3729 3730<p class="crtsnip"> 3731-limit area 10mb 3732</p> 3733 3734<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> 3735 3736<p class="crtsnip"> 3737-limit area 10mb -limit disk 500mb 3738</p> 3739 3740<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p> 3741 3742<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> 3743 3744<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. 3745</p> 3746 3747<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. 3748</p> 3749 3750<div style="margin: auto;"> 3751 <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> 3752</div> 3753 3754<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> 3755 3756<div style="margin: auto;"> 3757 <h4><a name="linewidth" id="linewidth"></a>-linewidth</h4> 3758</div> 3759 3760<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> 3761 3762<div style="margin: auto;"> 3763 <h4><a name="liquid-rescale" id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4> 3764</div> 3765 3766<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> 3767 3768<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> 3769 3770<div style="margin: auto;"> 3771 <h4><a name="list" id="list"></a>-list <em class="arg">type</em></h4> 3772</div> 3773 3774<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> 3775 3776<pre class="text"> 3777 coder 3778 color 3779 configure 3780 delegate 3781 font 3782 format 3783 list 3784 log 3785 magic 3786 module 3787 resource 3788 threshold 3789</pre> 3790 3791<p>The above lists are only some of the many lists available. These lists vary depending on your version of ImageMagick. For example use "<kbd>-list list</kbd>" to get a complete listing of all the "<kbd>-list</kbd>" arguments available:</p> 3792 3793<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>identify -list list</span></p> 3794<div style="margin: auto;"> 3795 <h4><a name="log" id="log"></a>-log <em class="arg">string</em></h4> 3796</div> 3797 3798<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> 3799 3800<p>This option specifies the format for the log printed when the <a href="#debug">-debug</a> option is active.</p> 3801 3802<p>You can display the following components by embedding special format characters:</p> 3803 3804<pre class="text"> 3805 %d domain 3806 %e event 3807 %f function 3808 %l line 3809 %m module 3810 %p process ID 3811 %r real CPU time 3812 %t wall clock time 3813 %u user CPU time 3814 %% percent sign 3815 \n newline 3816 \r carriage return 3817</pre> 3818 3819<p>For example:</p> 3820 3821<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> 3822<p>The default behavior is to print all of the components.</p> 3823 3824<div style="margin: auto;"> 3825 <h4><a name="loop" id="loop"></a>-loop <em class="arg">iterations</em></h4> 3826</div> 3827 3828<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> 3829 3830<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> 3831 3832<div style="margin: auto;"> 3833 <h4><a name="lowlight-color" id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4> 3834</div> 3835 3836<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> 3837 3838<div style="margin: auto;"> 3839 <h4><a name="magnify" id="magnify"></a>-magnify <em class="arg">factor</em></h4> 3840</div> 3841 3842<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> 3843 3844 3845<div style="margin: auto;"> 3846 <h4><a name="map" id="map"></a>-map <em class="arg">type</em></h4> 3847</div> 3848 3849<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> 3850 3851<p>Choose from these <em class="arg">Standard Colormap</em> types:</p> 3852 3853<pre class="text"> 3854 best 3855 default 3856 gray 3857 red 3858 green 3859 blue 3860</pre> 3861 3862<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> 3863 3864 3865<div style="margin: auto;"> 3866 <h4><a name="map_stream_" id="map_stream_"></a>-map <em class="arg">components</em></h4> 3867</div> 3868 3869<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> 3870 3871<p>Here are the valid components of a map:</p> 3872 3873<pre class="text"> 3874 r red pixel component 3875 g green pixel component 3876 b blue pixel component 3877 a alpha pixel component (0 is transparent) 3878 o opacity pixel component (0 is opaque) 3879 i grayscale intensity pixel component 3880 c cyan pixel component 3881 m magenta pixel component 3882 y yellow pixel component 3883 k black pixel component 3884 p pad component (always 0) 3885</pre> 3886 3887<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> 3888 3889<div style="margin: auto;"> 3890 <h4><a name="mask" id="mask"></a>-mask 3891<em class="arg">filename</em></h4> 3892</div> 3893 3894<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> 3895 3896<p>Use <a href="#mask">+mask</a> to remove the image mask.</p> 3897 3898<div style="margin: auto;"> 3899 <h4><a name="mattecolor" id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4> 3900</div> 3901 3902<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> 3903 3904<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 3905 3906<p>The default matte color is <kbd>#BDBDBD</kbd>, <span style="background-color: #bdbdbd;">this shade of gray</span>.</p> 3907 3908<div style="margin: auto;"> 3909 <h4><a name="median" id="median"></a>-median <em class="arg">radius</em></h4> 3910</div> 3911 3912<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> 3913 3914<div style="margin: auto;"> 3915 <h4><a name="metric" id="metric"></a>-metric <em class="arg">type</em></h4> 3916</div> 3917 3918<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> 3919 3920<p>Choose from:</p> 3921 3922<pre class="text"> 3923 AE absolute number of differnet pixels 3924 MAE mean absolute error (normalized), average channel error distance 3925 MEPP mean error per pixel (normalized mean error, normalized peak error) 3926 MSE mean error squared, average of the channel error squared 3927 PAE peak absolute (normalize peak absolute) 3928 PSNR peak signal to noise ratio 3929 RMSE root mean squared (normalized root mean squared) 3930</pre> 3931 3932<p>The '<kbd>AE</kbd>' or absolute count of pixels that are different, can be 3933controled using a <a href="#fuzz" >-fuzz</a> factor to ignore pixels which 3934only changed by a small amount. The '<kbd>PAE</kbd>' can be used to find the 3935size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels 3936'similar'. </p> 3937 3938<p>The '<kbd>MEPP</kbd>' metric returns three different metrics 3939('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>' 3940normalized) from the single comparision run. </p> 3941 3942<p>To print a complete list of metrics, use the <a href="#list">-list metrics</a> option.</p> 3943 3944 3945<div style="margin: auto;"> 3946 <h4><a name="mode" id="mode"></a>-mode <em class="arg">value</em></h4> 3947</div> 3948 3949<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> 3950 3951<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame, Unframe, or Concatenate</kbd></p> 3952 3953<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>' 3954argument for a list of <a href="#mode" >-mode</a> arguments available 3955in your ImageMagick installation.</p> 3956 3957 3958<div style="margin: auto;"> 3959 <h4><a name="modulate" id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4> 3960</div> 3961 3962<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> 3963 3964<p>The arguments are given as a percentages of variation. A value of 100 means no change, and any 3965missing values are taken to mean 100.</p> 3966 3967<p>The <em class="arg">brightness</em> is a multiplier of the overall brightness of the image, so 0 3968means pure black, 50 is half as bright, 200 is twice as bright. To invert its 3969meaning <a href="#negate">-negate</a> the image before and after. </p> 3970 3971<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> 3972 3973<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 3974shades to purple, and so on. A value of either 0 or 200 results in a complete 3975180 degree rotation of the image. Using a value of 300 is a 360 degree 3976rotation resulting in no change to the original image. </p> 3977 3978<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> 3979 3980<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> 3981 3982<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> 3983<div style="margin: auto;"> 3984 <h4><a name="monitor" id="monitor"></a>-monitor</h4> 3985</div> 3986 3987<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> 3988 3989 3990<div style="margin: auto;"> 3991 <h4><a name="monochrome" id="monochrome"></a>-monochrome</h4> 3992</div> 3993 3994<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> 3995 3996 3997<div style="margin: auto;"> 3998 <h4><a name="morph" id="morph"></a>-morph <em class="arg">frames</em></h4> 3999</div> 4000 4001<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> 4002 4003<p>Both the image pixels and size are linearly interpolated to give the 4004appearance of a meta-morphosis from one image to the next, over all the images 4005in the current image list. The added images are the equivalent of a <a 4006href="#blend">-blend</a> composition. The <em class="arg">frames</em> 4007argument determine how many images to interpolate between each image. </p> 4008 4009 4010<div style="margin: auto;"> 4011 <h4><a name="mosaic" id="mosaic"></a>-mosaic</h4> 4012</div> 4013 4014<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> 4015 4016 4017<div style="margin: auto;"> 4018 <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> 4019</div> 4020 4021<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> 4022 4023<p>Blur with the given radius, standard deviation (sigma), and angle. The 4024angle given is the angle toward which the image is blurred. That is the 4025direction people would consider the object is coming from. </p> 4026 4027<p>Note that the blur is not uniform distribution, giving the motion a 4028definate sense of direction of movement. </p> 4029 4030<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4031pixels which are outside the image proper are blurred into the final result. 4032</p> 4033 4034<div style="margin: auto;"> 4035 <h4><a name="name" id="name"></a>-name</h4> 4036</div> 4037 4038<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> 4039<div style="margin: auto;"> 4040 <h4><a name="negate" id="negate"></a>-negate</h4> 4041</div> 4042 4043<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>replace every pixel with its complementary color.</td><td style='text-align:right;'></td></tr></table> 4044 4045<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> 4046 4047<div style="margin: auto;"> 4048 <h4><a name="noise" id="noise"></a>-noise <em class="arg">radius</em><br/> 4049 +noise <em class="arg">type</em></h4> 4050</div> 4051 4052<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> 4053 4054<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> 4055 4056<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> 4057 4058<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> 4059 4060<pre class="text"> 4061Gaussian 4062Impulse 4063Laplacian 4064Multiplicative 4065Poisson 4066Random 4067Uniform 4068</pre> 4069 4070<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p> 4071 4072 4073<div style="margin: auto;"> 4074 <h4><a name="normalize" id="normalize"></a>-normalize</h4> 4075</div> 4076 4077<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> 4078 4079<p>The intensity values are stretched to cover the entire range of possible values. While doing so, black-out at most <em>2%</em> of the pixels and white-out at most <em>1%</em> of the pixels.</p> 4080 4081<p>Note that as of ImageMagick 6.4.7-0, <a href="#normalize" >-normalize</a> is equivalent to <a href="#contrast-stretch" >-contrast-stretch 2%x1%</a>. (Before this 4082version, it was equivalent to <a href="#contrast-stretch">-contrast-stretch 2%x99%)</a></p> 4083 4084<p>All the channels are normalized in concert by the came amount so as to preserve color integrity. Specify <a href="#channel">-channel</a> to normalize the RGB channels independently.</p> 4085 4086 4087<div style="margin: auto;"> 4088 <h4><a name="ordered-dither" id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4> 4089</div> 4090 4091<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 class="arg">threshold map</em> specified, and a uniform color map with the number of <em class="arg">levels</em> per color channel . </td><td style='text-align:right;'></td></tr></table> 4092 4093<p>You can choose from these standard threshold maps:</p> 4094 4095<pre class="text"> 4096 checks 4097 o2x2 4098 o3x3 4099 o4x4 4100 o8x8 4101 h4x4a 4102 h6x6a 4103 h8x8a 4104 h4x4o 4105 h6x6o 4106 h8x8o 4107 h16x16o 4108</pre> 4109 4110<p>The '<kbd>o</kbd>' are ordered diffused pixel threshold maps, while the 4111'<kbd>h</kbd>' maps are halftone threshold maps which are either 'a' angled, 4112or 'o' orthogonal. The '<kbd>checks</kbd>' produce a 3 level checkerbord 4113dither pattern. Or you can define your own <em class="arg">threshold 4114map</em> in a personal or system "<kbd>thresholds.xml</kbd>" XML file. </p> 4115 4116<p>To print a complete list of threshold, use the <a href="#list">-list threshold</a> option.</p> 4117 4118<p>It is recommended that the <a href="#map">+map</a> operator be used after 4119applying <a href="#ordered-dither">-ordered-dither</a> to reduce the number of 4120colors an animated image sequence, to less that 256 colors. This ensures that 4121a common or global color table is used when saving the result to a color 4122limited file format such as GIF. </p> 4123 4124<p>Note that at this time the exact same map is used for all color channels, no 4125attempt is made to offset or rotate the dither map for different channels is 4126made, at this point in time. (possible future expansion) </p> 4127 4128 4129<div style="margin: auto;"> 4130 <h4><a name="opaque" id="opaque"></a>-opaque <em class="arg">color</em></h4> 4131</div> 4132 4133<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> 4134 4135<p>The <em class="arg">color</em> argument is defined using the format 4136described under the <a href="#fill">-fill</a> option. 4137The <a href="#fuzz">-fuzz</a> setting can be used to match and replace colors similar 4138to the one given.</p> 4139 4140<p>The <a href="#transparent">-transparent</a> operator is exactly the same 4141as <a href="#opaque">-opaque</a> but makes the matching color transparent, 4142rather than the same as the current <a href="#fill">-fill</a> color. </p> 4143 4144<p>Use <em class="arg">+opaque</em> to paint any pixel that does not match the target color.</p> 4145 4146<div style="margin: auto;"> 4147 <h4><a name="orient" id="orient"></a>-orient <em class="arg">image orientation</em></h4> 4148</div> 4149 4150<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> 4151 4152<p>Choose from these orientations:</p> 4153 4154<pre class="text"> 4155 bottom-left 4156 bottom-right 4157 left-bottom 4158 left-top 4159 right-bottom 4160 right-top 4161 top-left 4162 top-right 4163 undefined 4164</pre> 4165 4166<p>To print a complete list of orientations, use the <a href="#list">-list orientation</a> option.</p> 4167 4168 4169<div style="margin: auto;"> 4170 <h4><a name="page" id="page"></a>-page <em class="arg">geometry</em><br/> 4171 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!<></em>}]<br/> 4172 +page 4173 </h4> 4174</div> 4175 4176<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> 4177 4178<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> 4179 4180<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> 4181 4182<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> 4183<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;"> 4184<thead> 4185 <tr valign="top"> 4186 <th align="center"><em class="arg">media</em></th> 4187 <th align="center"><em class="arg">width</em></th> 4188 <th align="center"><em class="arg">height</em></th> 4189 </tr> 4190</thead> 4191<tbody> 4192<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr> 4193<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr> 4194<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr> 4195<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4196<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr> 4197<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr> 4198<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr> 4199<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr> 4200<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr> 4201<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr> 4202<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr> 4203<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr> 4204<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr> 4205<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr> 4206<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4207<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr> 4208<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr> 4209<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr> 4210<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr> 4211<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr> 4212<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr> 4213<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr> 4214<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr> 4215<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr> 4216<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr> 4217<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr> 4218<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr> 4219<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr> 4220<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr> 4221<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr> 4222<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr> 4223<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr> 4224<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr> 4225<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr> 4226<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr> 4227<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4228<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr> 4229<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr> 4230</tbody> 4231</table> 4232 4233 4234 4235 4236<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> 4237 4238<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> 4239 4240<p>The default page dimensions for a TEXT image is 612x792.</p> 4241 4242<p>This option is used in concert with <a href="#density">-density</a>.</p> 4243 4244<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p> 4245 4246<div style="margin: auto;"> 4247 <h4><a name="paint" id="paint"></a>-paint <em class="arg">radius</em></h4> 4248</div> 4249 4250<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> 4251 4252<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> 4253 4254<div style="margin: auto;"> 4255 <h4><a name="path" id="path"></a>-path <em class="arg">path</em></h4></div> 4256 4257<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> 4258 4259<div style="margin: auto;"> 4260 <h4><a name="pause_animate_" id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4> 4261</div> 4262 4263<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> 4264 4265<p>Pause for the specified number of seconds before repeating the animation.</p> 4266 4267<div style="margin: auto;"> 4268 <h4><a name="pause_import_" id="pause_import_"></a>-pause <em class="arg">seconds</em></h4> 4269</div> 4270 4271<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> 4272 4273<p>Pause for the specified number of seconds before taking the next snapshot.</p> 4274 4275<div style="margin: auto;"> 4276 <h4><a name="ping" id="ping"></a>-ping</h4> 4277</div> 4278 4279<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> 4280 4281<div style="margin: auto;"> 4282 <h4><a name="pointsize" id="pointsize"></a>-pointsize <em class="arg">value</em></h4> 4283</div> 4284 4285<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> 4286 4287<div style="margin: auto;"> 4288 <h4><a name="polaroid" id="polaroid"></a>-polaroid <em class="arg">angle</em></h4> 4289</div> 4290 4291<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> 4292 4293<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p> 4294 4295<div style="margin: auto;"> 4296 <h4><a name="posterize" id="posterize"></a>-posterize <em class="arg">levels</em></h4> 4297</div> 4298 4299<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> 4300 4301<div style="margin: auto;"> 4302 <h4><a name="preview" id="preview"></a>-preview <em class="arg">type</em></h4> 4303</div> 4304 4305<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> 4306 4307<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> 4308 4309<pre class="text"> 4310 Rotate 4311 Shear 4312 Roll 4313 Hue 4314 Saturation 4315 Brightness 4316 Gamma 4317 Spiff 4318 Dull 4319 Grayscale 4320 Quantize 4321 Despeckle 4322 ReduceNoise 4323 Add Noise 4324 Sharpen 4325 Blur 4326 Threshold 4327 EdgeDetect 4328 Spread 4329 Shade 4330 Raise 4331 Segment 4332 Solarize 4333 Swirl 4334 Implode 4335 Wave 4336 OilPaint 4337 CharcoalDrawing 4338 JPEG 4339</pre> 4340 4341<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p> 4342 4343<p>The default preview is <kbd>JPEG</kbd>.</p> 4344 4345<div style="margin: auto;"> 4346 <h4><a name="print" id="print"></a>-print <em class="arg">string</em></h4> 4347</div> 4348 4349<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> 4350 4351<div style="margin: auto;"> 4352 <h4><a name="process" id="process"></a>-process <em class="arg">command</em></h4> 4353</div> 4354 4355<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> 4356 4357<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> 4358 4359<div style="margin: auto;"> 4360 <h4><a name="profile" id="profile"></a>-profile <em class="arg">filename</em><br/> 4361 +profile <em class="arg">profile_name</em></h4> 4362</div> 4363 4364<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> 4365 4366<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> 4367 4368<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> 4369 4370<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> 4371 4372<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> 4373 4374<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p> 4375 4376<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p> 4377<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> 4378 4379<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert CMYK.tif -profile "CMYK.icc" -profile "RGB.icc" RGB.tiff</span></p> 4380<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results. 4381CMYK profiles are often very asymmetric since they involve 3−>4 and 4−>3 channel mapping. 4382</p> 4383 4384<div style="margin: auto;"> 4385 <h4><a name="quality" id="quality"></a>-quality <em class="arg">value</em></h4> 4386</div> 4387 4388<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> 4389 4390<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> 4391 4392<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> 4393 4394<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> 4395 4396<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> 4397 4398<p>If filter-type is 4 or less, the specified filter-type is used for all scanlines:</p> 4399 4400<pre class="text"> 4401 0: none 4402 1: sub 4403 2: up 4404 3: average 4405 4: Paeth 4406</pre> 4407 4408<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> 4409 4410<p>If filter-type is 6, adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p> 4411 4412<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> 4413 4414<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> 4415 4416<p>For further information, see the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p> 4417 4418<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> 4419 4420<div style="margin: auto;"> 4421 <h4><a name="quantize" id="quantize"></a>-quantize <em class="arg">colorspace</em></h4> 4422</div> 4423 4424<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> 4425 4426<p>To print a complete list of colorspaces, use the <a href="#list">-list colorspace</a> option.</p> 4427 4428 4429<div style="margin: auto;"> 4430 <h4><a name="quiet" id="quiet"></a>-quiet</h4> 4431</div> 4432 4433<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> 4434 4435<div style="margin: auto;"> 4436 <h4><a name="radial-blur" id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4> 4437</div> 4438 4439<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> 4440 4441<p>Note that this is actually a rotational blur rather than a radial and as 4442such actually mis-named. </p> 4443 4444<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how 4445pixels which are outside the image proper are blurred into the final result. 4446</p> 4447 4448 4449<div style="margin: auto;"> 4450 <h4><a name="raise" id="raise"></a>-raise <em class="arg">thickness</em></h4> 4451</div> 4452 4453<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> 4454 4455<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>. 4456</p> 4457 4458<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p> 4459 4460<div style="margin: auto;"> 4461 <h4><a name="random-threshold" id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4> 4462</div> 4463 4464<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> 4465 4466<div style="margin: auto;"> 4467 <h4><a name="recolor" id="recolor"></a>-recolor <em class="arg">matrix</em></h4> 4468</div> 4469 4470<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> 4471 4472<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. 4473</p> 4474 4475<div style="margin: auto;"> 4476 <h4><a name="red-primary" id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4> 4477</div> 4478 4479<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> 4480 4481<div style="margin: auto;"> 4482 <h4><a name="regard-warnings" id="regard-warnings"></a>-regard-warnings</h4> 4483</div> 4484 4485<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> 4486 4487<div style="margin: auto;"> 4488 <h4><a name="remap" id="remap"></a>-remap <em class="arg">filename</em></h4> 4489</div> 4490 4491<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> 4492 4493<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then 4494the given colors are dithered over the image as necessary, otherwise the closest 4495color (in RGB colorspace) is selected to replace that pixel in the image. </p> 4496 4497<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all 4498images in the current image sequence, all the images will have the same color 4499table. That means that when saved to a file format such as GIF, it will use 4500that color table as a single common or global color table, for all the images, 4501without requiring extra local color tables. </p> 4502 4503<p>Use <a href="#remap">+remap</a> to reduce all images in the current image 4504sequence to use a common color map over all the images. This equivalent to 4505appending all the images together (without extra background colors) and color 4506reducing those images using <a href="#colors">-colors</a> with a 256 color 4507limit, then <a href="#remap">-remap</a> those colors over the original list of 4508images. This ensures all the images follow a single color map. </p> 4509 4510<p>If the number of colors over all the images is less than 256, then <a 4511href="#remap">+remap</a> should not perform any color reduction or dithering, as 4512no color changes are needed. In that case, its only effect is to force the use 4513of a global color table. This recommended after using either <a 4514href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to 4515reduce the number of colors in an animated image sequence. </p> 4516 4517<div style="margin: auto;"> 4518 <h4><a name="region" id="region"></a>-region <em class="arg">geometry</em></h4> 4519</div> 4520 4521<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> 4522 4523<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> 4524 4525<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> 4526 4527<div style="margin: auto;"> 4528 <h4><a name="remote" id="remote"></a>-remote</h4> 4529</div> 4530 4531<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> 4532 4533<p>The only command recognized is the name of an image file to load.</p> 4534 4535<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> 4536 4537<div style="margin: auto;"> 4538 <h4><a name="render" id="render"></a>-render</h4> 4539</div> 4540 4541<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> 4542 4543<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> 4544 4545<div style="margin: auto;"> 4546<h4><a name="repage" id="repage"></a>-repage <em class="arg">geometry</em></h4> 4547</div> 4548 4549<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> 4550 4551<p>This option is like <a href="#page">-page</a> but acts as an image operator 4552rather than a setting. You can separately set the canvas size or the offset 4553of the image on that canvas by only providing those components. </p> 4554 4555<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> 4556 4557<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing 4558offset to move the image relative to its previous position. This useful for 4559animation sequences. </p> 4560 4561<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to 4562recalculate the canvas size so the image (at its current offset) will appear 4563completely on that canvas (unless it has a negative offset).</p> 4564 4565<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual 4566canvas meta-data from the images. </p> 4567 4568<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to 4569directly assign virtual canvas meta-data. </p> 4570 4571 4572<div style="margin: auto;"> 4573 <h4><a name="resample" id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4> 4574</div> 4575 4576<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> 4577 4578<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> 4579 4580<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> 4581 4582<div style="margin: auto;"> 4583 <h4><a name="resize" id="resize"></a>-resize <em class="arg">geometry</em></h4> 4584</div> 4585 4586<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> 4587 4588<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> 4589 4590<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> 4591 4592<div style="margin: auto;"> 4593 <h4><a name="respect-parentheses" id="respect-parentheses"></a>-respect-parentheses</h4> 4594</div> 4595 4596<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> 4597 4598<div style="margin: auto;"> 4599 <h4><a name="reverse" id="reverse"></a>-reverse</h4> 4600</div> 4601 4602<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> 4603 4604 4605<div style="margin: auto;"> 4606 <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> 4607</div> 4608 4609<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> 4610 4611<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> 4612 4613 4614<div style="margin: auto;"> 4615 <h4><a name="rotate" id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg"><</em>}{<em class="arg">></em>}</h4> 4616</div> 4617 4618<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> 4619 4620<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> 4621 4622<p>Empty triangles in the corners, left over from rotating the image, are 4623filled with the <kbd>background</kbd> color. </p> 4624 4625<p>See also the <a href="#distort">-distort</a> operator and specifically the 4626'<kbd>ScaleRotateTranslate</kbd>' distort method. </p> 4627 4628 4629<div style="margin: auto;"> 4630 <h4><a name="sample" id="sample"></a>-sample <em class="arg">geometry</em></h4> 4631</div> 4632 4633<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> 4634 4635<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> 4636 4637<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> 4638 4639 4640<div style="margin: auto;"> 4641 <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> 4642</div> 4643 4644<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> 4645 4646<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> 4647 4648<div style="margin: auto;"> 4649 <h4><a name="scale" id="scale"></a>-scale <em class="arg">geometry</em></h4> 4650</div> 4651 4652<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> 4653 4654<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> 4655 4656<div style="margin: auto;"> 4657 <h4><a name="scene" id="scene"></a>-scene <em class="arg">value</em></h4> 4658</div> 4659 4660<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> 4661 4662<p>This option sets the scene number of an image or the first image in an image sequence.</p> 4663 4664<div style="margin: auto;"> 4665 <h4><a name="screen" id="screen"></a>-screen</h4> 4666</div> 4667 4668<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> 4669 4670<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> 4671 4672<div style="margin: auto;"> 4673 <h4><a name="seed" id="seed"></a>-seed</h4> 4674</div> 4675 4676<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> 4677 4678<div style="margin: auto;"> 4679 <h4><a name="segment" id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4> 4680</div> 4681 4682<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> 4683 4684<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> 4685 4686<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> 4687 4688<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report 4689of the color clusters is returned.</p> 4690 4691 4692<div style="margin: auto;"> 4693 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">geometry</em></h4> 4694</div> 4695 4696<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> 4697 4698<div style="margin: auto;"> 4699 <h4><a name="separate" id="separate"></a>-separate</h4> 4700</div> 4701 4702<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> 4703 4704<div style="margin: auto;"> 4705 <h4><a name="sepia-tone" id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4> 4706</div> 4707 4708<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> 4709 4710<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p> 4711 4712<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> 4713 4714<div style="margin: auto;"> 4715 <h4><a name="set" id="set"></a>-set <em class="arg">attribute value</em></h4> 4716</div> 4717 4718<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> 4719 4720<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> 4721 4722<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert rose: -set comment 'Rose is a rose is a rose is a rose' rose.png</span><span class='crtout'></span><span class="crtprompt"> $magick> </span><span class='crtin'>identify -format %c rose.png</span><span class='crtout'>Rose is a rose is a rose is a rose</span></p> 4723<p>The <a href="#repage">-repage</a> operator will also set the 4724'<kbd>page</kbd>' attribute of images already in memory, but allows you to 4725separately set the virtual canvas's size and offset components, and also allows 4726relative offset changes, and automatic canvas size re-calculating. The above 4727<a href="#set">-set</a> option is purely a direct, unmodified assignment of the 4728virtual canvas (page) meta-data. </p> 4729 4730<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> 4731 4732<div style="margin: auto;"> 4733 <h4><a name="shade" id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4> 4734</div> 4735 4736<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> 4737 4738<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> 4739 4740<div style="margin: auto;"> 4741 <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> 4742</div> 4743 4744<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> 4745 4746<div style="margin: auto;"> 4747 <h4><a name="shared-memory" 4748id="shared-memory"></a>-shared-memory</h4> 4749</div> 4750 4751<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> 4752 4753<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> 4754 4755<div style="margin: auto;"> 4756 <h4><a name="sharpen" id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4> 4757</div> 4758 4759<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> 4760 4761<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p> 4762 4763<div style="margin: auto;"> 4764 <h4><a name="shave" id="shave"></a>-shave <em class="arg">geometry</em></h4> 4765</div> 4766 4767<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> 4768 4769<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> 4770 4771<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> 4772 4773<div style="margin: auto;"> 4774 <h4><a name="shear" id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4> 4775</div> 4776 4777<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> 4778 4779<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> 4780 4781<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> 4782 4783<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> 4784 4785<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> 4786 4787<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> 4788<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> 4789 4790<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p> 4791<div style="margin: auto;"> 4792 <h4><a name="sigmoidal" id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4> 4793</div> 4794 4795<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> 4796 4797<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> 4798 4799<div style="margin: auto;"> 4800 <h4><a name="silent" id="silent"></a>-silent</h4> 4801</div> 4802 4803<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> 4804 4805<div style="margin: auto;"> 4806 <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> 4807</div> 4808 4809<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> 4810 4811<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> 4812 4813<p>For Photo CD images, choose from these sizes:</p> 4814 4815<pre class="text"> 4816 192x128 4817 384x256 4818 768x512 4819 1536x1024 4820 3072x2048 4821</pre> 4822 4823<div style="margin: auto;"> 4824 <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> 4825</div> 4826 4827<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> 4828 4829<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> 4830 4831<div style="margin: auto;"> 4832 <h4><a name="snaps" id="snaps"></a>-snaps <em class="arg">value</em></h4> 4833</div> 4834 4835<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> 4836 4837<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p> 4838 4839<div style="margin: auto;"> 4840 <h4><a name="solarize" id="solarize"></a>-solarize <em class="arg">threshold</em></h4> 4841</div> 4842 4843<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> 4844 4845<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p> 4846 4847<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p> 4848 4849<div style="margin: auto;"> 4850 <h4><a name="sparse-color" id="sparse-color"></a>-sparse-color <em 4851 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4> 4852</div> 4853 4854<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> 4855 4856 4857<table class="doc"> 4858 <tbody> 4859 <tr valign="top"> 4860 <th align="left" style="width: 8%">Method</th> 4861 <th align="left">Description</th> 4862 </tr> 4863 4864 <tr valign="top"> 4865 <td valign="top">voronoi</td> 4866 <td valign="top">Simply map each pixel to the to nearest color point 4867 given. The result are polygonal 'cells' of solid color. </td> 4868 </tr> 4869 4870 <tr valign="top"> 4871 <td valign="top">shepards</td> 4872 <td valign="top">Colors points basied on the ratio of inverse distance 4873 squared. Generating spots of color in a sea of the average of 4874 colors. </td> 4875 </tr> 4876 4877 <tr valign="top"> 4878 <td valign="top">barycentric</td> 4879 <td valign="top">three point triangle of color given 3 points. 4880 Giving only 2 points will form a linear gradient between those points. 4881 Gradient is however not restricted to just the triangle or line. </td> 4882 </tr> 4883 4884 <tr valign="top"> 4885 <td valign="top">bilinear</td> 4886 <td valign="top">Like barycentric but for 4 points. Less than 4 points 4887 fall back to barycentric. </td> 4888 </tr> 4889 4890 </tbody> 4891</table> 4892 4893<p>The points are placed according to the images location on the virtual 4894canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a> 4895offset), and do not actually have to exist on the given image, but may be 4896some point beyond the edge of the image. All points are floating point values. 4897</p> 4898 4899<p>Only the color channels defined by the <a href="#channel" >-channel</a> are 4900modified, whcih means the matte/alpha transparency channel is not effected by 4901default. If enabled, the image also needs a the matte/alpha channel to be 4902enabled for this operator to effect an images transparency. This is typical 4903transparency handling for images. </p> 4904 4905<p>All the above methods when given a single point of color will replace all 4906the colors in the image with the color given, regardless of the point. This is 4907logical, and provides an alternative technique to recolor a image to some 4908default value. </p> 4909 4910 4911<div style="margin: auto;"> 4912 <h4><a name="splice" id="splice"></a>-splice <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%'>Splice the current background color into the image.</td><td style='text-align:right;'></td></tr></table> 4916 4917<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> 4918 4919<div style="margin: auto;"> 4920 <h4><a name="spread" id="spread"></a>-spread <em class="arg">amount</em></h4> 4921</div> 4922 4923<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> 4924 4925<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> 4926 4927<div style="margin: auto;"> 4928 <h4><a name="stegano" id="stegano"></a>-stegano <em class="arg">offset</em></h4> 4929</div> 4930 4931<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> 4932 4933<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> 4934 4935<div style="margin: auto;"> 4936 <h4><a name="stereo" id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4> 4937</div> 4938 4939<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> 4940 4941<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> 4942 4943<div style="margin: auto;"> 4944 <h4><a name="storage-type" id="storage-type"></a>-storage-type <em class="arg">type</em></h4> 4945</div> 4946 4947<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> 4948 4949<pre class="text"> 4950 char store pixels as unsigned characters 4951 double store pixels as doubles 4952 float store pixels as floats 4953 integer store pixels as integers 4954 long store pixels as longs 4955 quantum store pixels in the native depth of your ImageMagick distribution 4956 short store pixels as unsigned shorts 4957</pre> 4958 4959<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels 4960values range from 0 to the maximum value the storage type can support.</p> 4961 4962<div style="margin: auto;"> 4963 <h4><a name="stretch" id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4> 4964</div> 4965 4966<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> 4967 4968<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> 4969 4970<pre class="text"> 4971 Any 4972 Condensed 4973 Expanded 4974 ExtraCondensed 4975 ExtraExpanded 4976 Normal 4977 SemiCondensed 4978 SemiExpanded 4979 UltraCondensed 4980 UltraExpanded 4981</pre> 4982 4983<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p> 4984 4985<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> 4986 4987<div style="margin: auto;"> 4988 <h4><a name="strip" id="strip"></a>-strip</h4> 4989</div> 4990 4991<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> 4992 4993<div style="margin: auto;"> 4994 <h4><a name="stroke" id="stroke"></a>-stroke <em class="arg">color</em></h4> 4995</div> 4996 4997<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> 4998 4999<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p> 5000 5001<p>See <a href="#draw">-draw</a> for further details.</p> 5002 5003<div style="margin: auto;"> 5004 <h4><a name="strokewidth" id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4> 5005</div> 5006 5007<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> 5008 5009<p>See <a href="#draw">-draw</a> for further details.</p> 5010 5011<div style="margin: auto;"> 5012 <h4><a name="style" id="style"></a>-style <em class="arg">fontStyle</em></h4> 5013</div> 5014 5015<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> 5016 5017<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> 5018 5019<pre class="text"> 5020 Any 5021 Italic 5022 Normal 5023 Oblique 5024</pre> 5025 5026<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> 5027 5028<div style="margin: auto;"> 5029 <h4><a name="swap" id="swap"></a>-swap <em class="arg">index,index</em></h4> 5030</div> 5031 5032<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> 5033 5034<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> 5035 5036<div style="margin: auto;"> 5037 <h4><a name="swirl" id="swirl"></a>-swirl <em class="arg">degrees</em></h4> 5038</div> 5039 5040<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> 5041 5042<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p> 5043 5044<div style="margin: auto;"> 5045 <h4><a name="taint" id="taint"></a>-taint</h4> 5046</div> 5047 5048<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> 5049 5050<div style="margin: auto;"> 5051 <h4><a name="text-font" id="text-font"></a>-text-font <em class="arg">name</em></h4> 5052</div> 5053 5054<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> 5055 5056<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> 5057 5058<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> 5059 5060<div style="margin: auto;"> 5061 <h4><a name="texture" id="texture"></a>-texture <em class="arg">filename</em></h4> 5062</div> 5063 5064<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> 5065 5066<div style="margin: auto;"> 5067 <h4><a name="threshold" id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4> 5068</div> 5069 5070<!-- {<em class="arg">green,blue,opacity</em>} 5071<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> 5072--> 5073 5074<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> 5075 5076<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> 5077 5078<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. 5079</p> 5080 5081<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> 5082 5083<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p> 5084<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> 5085 5086 5087<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> 5088<p>Note that the values of the transparency channel is treated as 'matte' 5089values (0 is opaque) and not as 'alpha' values (0 is transparent).</p> 5090 5091<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>. 5092</p> 5093 5094<div style="margin: auto;"> 5095 <h4><a name="thumbnail" id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4> 5096</div> 5097 5098<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> 5099 5100<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> 5101 5102<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> 5103 5104<div style="margin: auto;"> 5105 <h4><a name="tile" id="tile"></a>-tile <em class="arg">filename</em></h4> 5106</div> 5107 5108<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> 5109 5110<div style="margin: auto;"> 5111 <h4>-tile <em class="arg">geometry</em></h4> 5112</div> 5113 5114<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> 5115 5116<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> 5117 5118<div style="margin: auto;"> 5119 <h4>-tile</h4> 5120</div> 5121 5122<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> 5123 5124<div style="margin: auto;"> 5125 <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> 5126</div> 5127 5128<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> 5129 5130<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> 5131 5132<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> 5133 5134<div style="margin: auto;"> 5135 <h4><a name="tint" id="tint"></a>-tint <em class="arg">value</em></h4> 5136</div> 5137 5138<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> 5139 5140<p>Tint the image with the fill color.</p> 5141 5142<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> 5143 5144<div style="margin: auto;"> 5145 <h4><a name="title" id="title"></a>-title <em class="arg">string</em></h4> 5146</div> 5147 5148<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> 5149 5150<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> 5151 5152<p>For example,</p> 5153 5154<p class="crtsnip"> 5155 -title "%m:%f %wx%h" 5156</p> 5157 5158<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> 5159 5160 5161<div style="margin: auto;"> 5162 <h4><a name="transform" id="transform"></a>-transform</h4> 5163</div> 5164 5165<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> 5166 5167<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p> 5168 5169<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> 5170<div style="margin: auto;"> 5171 <h4><a name="transparent" id="transparent"></a>-transparent <em class="arg">color</em></h4> 5172</div> 5173 5174<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> 5175 5176<p>The <em class="arg">color</em> argument is defined using the format 5177described under the <a href="#fill">-fill</a> option. The <a href="#fuzz" 5178>-fuzz</a> setting can be used to match and replace colors similar to the one 5179given. </p> 5180 5181<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a 5182href="#transparent" >-transparent</a> but replaces the matching color same as 5183the current <a href="#fill">-fill</a> color setting. </p> 5184 5185<p>This does not define the 'transparency color' used for color-mapped image 5186formats, such as GIF. For that use <a href="#transparent-color" 5187>-transparent-color</a> </p> 5188 5189<p>Use <a href="#opaque">+opaque</a> to invered the pixels matched, that is 5190paint any pixel that does not match the target color, with the fill color.</p> 5191 5192 5193<div style="margin: auto;"> 5194 <h4><a name="transparent-color" id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4> 5195</div> 5196 5197<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> 5198 5199<p>Sometimes this is used for saving to image formats such as 5200GIF and PNG8 which uses this color to represent boolean transparency. This 5201does not make a color transparent, it only defines what color the transparent 5202color is in the color palette of the saved image. Use <a 5203href="#transparent">-transparent</a> to make an opaque color transparent.</p> 5204 5205<p>This option allows you to have both an opaque visible color, as well as a 5206transparent color of the same color value without conflict. That is, you can 5207use the same color for both the transparent and opaque color areas within an 5208image. This, in turn, frees to you to select a transparent color that is 5209appropriate when an image is displayed by an application that does not handle a 5210transparent color index, while allowing ImageMagick to correctly handle images of this 5211type. </p> 5212 5213<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p> 5214 5215<div style="margin: auto;"> 5216 <h4><a name="transpose" id="transpose"></a>-transpose</h4> 5217</div> 5218 5219<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> 5220 5221<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>. 5222</p> 5223 5224<div style="margin: auto;"> 5225 <h4><a name="transverse" id="transverse"></a>-transverse</h4> 5226</div> 5227 5228<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> 5229 5230 5231<div style="margin: auto;"> 5232 <h4><a name="treedepth" id="treedepth"></a>-treedepth <em class="arg">value</em></h4> 5233</div> 5234 5235<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> 5236 5237<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> 5238 5239<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> 5240 5241<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> 5242 5243<div style="margin: auto;"> 5244 <h4><a name="trim" id="trim"></a>-trim</h4> 5245</div> 5246 5247<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> 5248 5249<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> 5250 5251<p>The page or virtual canvas information of the image is preserved allowing 5252you to extract the result of the <a href="#trim">-trim</a> operation from the 5253image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page 5254information if it is unwanted.</p> 5255 5256<p>If the trimmed image 'disappears' an warning is produced, and a special 5257single pixel transparent 'missed' image is returned, in the same way as when a 5258<a href="#crop">-crop</a> operation 'misses' the image proper. </p> 5259 5260 5261<div style="margin: auto;"> 5262 <h4><a name="type" id="type"></a>-type <em class="arg">type</em></h4> 5263</div> 5264 5265<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> 5266 <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> 5267 5268<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> 5269 5270<p class='crt'><span class="crtprompt"> $magick> </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p> 5271<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> 5272 5273<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p> 5274 5275<div style="margin: auto;"> 5276 <h4><a name="undercolor" id="undercolor"></a>-undercolor <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%'>set the color of the annotation bounding box.</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 5286<div style="margin: auto;"> 5287 <h4><a name="update" id="update"></a>-update <em class="arg">seconds</em></h4> 5288</div> 5289 5290<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> 5291 5292<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> 5293 5294 5295<div style="margin: auto;"> 5296 <h4><a name="unique-colors" id="unique-colors"></a>-unique-colors</h4> 5297</div> 5298 5299<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> 5300 5301 5302<div style="margin: auto;"> 5303 <h4><a name="units" id="units"></a>-units <em class="arg">type</em></h4> 5304</div> 5305 5306<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> 5307 5308<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> 5309 5310 5311<div style="margin: auto;"> 5312 <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> 5313</div> 5314 5315<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> 5316 5317<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> 5318 5319<p>The parameters are:</p> 5320 5321<pre class="text"> 5322 radius: The radius of the Gaussian, in pixels, not counting the center 5323 pixel (default 0). 5324 sigma: The standard deviation of the Gaussian, in pixels (default 1.0). 5325 amount: The fraction of the difference between the original and the blur 5326 image that is added back into the original (default 1.0). 5327 threshold: The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the 5328 difference amount (default 0.05). 5329</pre> 5330 5331 5332<div style="margin: auto;"> 5333 <h4><a name="verbose" id="verbose"></a>-verbose</h4> 5334</div> 5335 5336<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> 5337 5338 5339<div style="margin: auto;"> 5340 <h4><a name="version" id="version"></a>-version</h4> 5341</div> 5342 5343<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> 5344 5345 5346<div style="margin: auto;"> 5347 <h4><a name="view" id="view"></a>-view <em class="arg">string</em></h4> 5348</div> 5349 5350<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> 5351 5352 5353<div style="margin: auto;"> 5354 <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> 5355</div> 5356 5357<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> 5358 5359 5360<div style="margin: auto;"> 5361 <h4><a name="virtual-pixel" id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4> 5362</div> 5363 5364<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> 5365 5366<p>This option defines what color source should be used if and when a color 5367lookup completely 'misses' the source image. The color(s) that appear to 5368surround the source image. Generally this color is derived from the source 5369image, but could also be set to a specify background color. </p> 5370 5371<p>Choose from these methods:</p> 5372 5373<pre class="text"> 5374 background: the area surrounding the image is the background color 5375 black: the area surrounding the image is black 5376 checker-tile: alternate squares with image and background color 5377 dither: non-random 32x32 dithered pattern 5378 edge: extend the edge pixel toward infinity 5379 gray: the area surrounding the image is gray 5380 horizontal-tile: horizontally tile the image, background color above/below 5381 horizontal-tile-edge: horizontally tile the image and replicate the side edge pixels 5382 mirror: mirror tile the image 5383 random: choose a random pixel from the image 5384 tile: tile the image (default) 5385 transparent: the area surrounding the image is transparent blackness 5386 vertical-tile: vertically tile the image, sides are background color 5387 vertical-tile-edge: vertically tile the image and replicate the side edge pixels 5388 white: the area surrounding the image is white 5389</pre> 5390 5391<p>The default value is "edge".</p> 5392 5393<p>This most important for distortion operators such as <a href="#distort" 5394>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>. 5395However it also effects operations that may access pixels just outside the 5396image proper, such as <a href="#convolve">-convolve</a>, <a 5397href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p> 5398 5399<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p> 5400 5401 5402<div style="margin: auto;"> 5403 <h4><a name="visual" id="visual"></a>-visual <em class="arg">type</em></h4> 5404</div> 5405 5406<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> 5407 5408<p>Choose from these visual classes:</p> 5409 5410<pre class="text"> 5411 StaticGray 5412 GrayScale 5413 StaticColor 5414 PseudoColor 5415 TrueColor 5416 DirectColor 5417 default 5418 visual id 5419</pre> 5420 5421<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> 5422 5423 5424<div style="margin: auto;"> 5425 <h4><a name="watermark" id="watermark"></a>-watermark <em 5426 class="arg">brightness</em>x<em class="arg">saturation</em></h4> 5427</div> 5428 5429<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 5430saturation.</td><td style='text-align:right;'>[<a href="/www/composite.html">composite</a>]</td></tr></table> 5431 5432<p>Take a grayscale image (with alpha mask) and modify the destination image's 5433brightness according to watermark image's grayscale value and the <em 5434class="arg">brightness</em> percentage. The destinations color saturation 5435attribute is just direct modified by the <em class="arg">saturation</em> 5436percentage, which defaults to 100 percent (no color change). </p> 5437 5438 5439<div style="margin: auto;"> 5440 <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> 5441</div> 5442 5443<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> 5444 5445<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p> 5446 5447<div style="margin: auto;"> 5448 <h4><a name="weight" id="weight"></a>-weight <em class="arg">fontWeight</em></h4> 5449</div> 5450 5451<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> 5452 5453<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> 5454 5455<table class="doc"> 5456 <col width="25%" /> 5457 <col width="75%" /> 5458 <thead> 5459 <tr> 5460 <th><em class="arg">fontWeight</em></th> 5461 <th>Description</th> 5462 </tr> 5463 </thead> 5464 <tbody> 5465 <tr><td>All </td> <td>No effect. </td></tr> 5466 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr> 5467 <tr><td>Bolder </td> <td>Add 100 to font weight if currently ≤ 800.</td></tr> 5468 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently ≤ 100.</td></tr> 5469 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr> 5470 </tbody> 5471 </table> 5472 5473<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p> 5474 5475<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> 5476 5477<div style="margin: auto;"> 5478 <h4><a name="white-point" id="white-point"></a>-white-point <em class="arg">x,y</em></h4> 5479</div> 5480 5481<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> 5482 5483<div style="margin: auto;"> 5484 <h4><a name="white-threshold" id="white-threshold"></a>-white-threshold <em class="arg">threshold</em></h4> 5485</div> 5486 5487<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Force to white all pixels at or above the threshold.</td><td style='text-align:right;'></td></tr></table> 5488 5489<div style="margin: auto;"> 5490 <h4><a name="window" id="window"></a>-window <em class="arg">id</em></h4> 5491</div> 5492 5493<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> 5494 5495<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> 5496 5497<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> 5498 5499<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> 5500 5501<div style="margin: auto;"> 5502 <h4><a name="window-group" id="window-group"></a>-window-group</h4> 5503</div> 5504 5505<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> 5506 5507<div style="margin: auto;"> 5508 <h4><a name="write" id="write"></a>-write <em class="arg">filename</em></h4> 5509</div> 5510 5511<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> 5512 <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> 5513 5514<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p> 5515 5516 5517</div> 5518 5519<div id="linkbar"> 5520 <!-- <span id="linkbar-west"> </span> --> 5521 <span id="linkbar-center"> 5522 <a href="http://www.imagemagick.org/discourse-server/">Discourse Server</a> • 5523 <a href="/www/mailing-list.html">Mailing Lists</a> • 5524 <a href="http://studio.webbyland.com/ImageMagick/MagickStudio/scripts/MagickStudio.cgi">Studio</a> 5525 </span> 5526 <span id="linkbar-east"> </span> 5527 </div> 5528 <div class="footer"> 5529 <span id="footer-west">© 1999-2009 ImageMagick Studio LLC</span> 5530 <span id="footer-east"> <a href="http://www.imagemagick.org/script/contact.php">Contact the Wizards</a></span> 5531 </div> 5532 <div style="clear: both; margin: 0; width: 100%; "></div> 5533</body> 5534</html> 5535
