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</span> <a href="../www/command-line-options.html#window-group">&#x2011;window&#x2011;group</a> <span class='bull'>&nbsp;&bull; </span> <a href="../www/command-line-options.html#write">&#x2011;write</a> ] </p>
cristy3ed852e2009-09-05 21:47:34 +0000157
158<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
159<a href="../www/convert.html">convert</a>, <a href="../www/mogrify.html">mogrify</a>, and .... </p>
160
161<div style="margin: auto;">
162 <h4><a name="adaptive-blur" id="adaptive-blur"></a>-adaptive-blur <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4>
163</div>
164
165<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>
166
167<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>
168
169<div style="margin: auto;">
170 <h4><a name="adaptive-resize" id="adaptive-resize"></a>-adaptive-resize <em class="arg">geometry</em></h4>
171</div>
172
173<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>
174
175<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>
176
177<div style="margin: auto;">
178 <h4><a name="adaptive-sharpen" id="adaptive-sharpen"></a>-adaptive-sharpen <em class="arg">radius</em>[x<em class="arg">sigma</em>]</h4>
179</div>
180
181<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>
182
183<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>
184
185<div style="margin: auto;">
186 <h4><a name="adjoin" id="adjoin"></a>-adjoin</h4>
187</div>
188
189<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>
190
191<p>This option is enabled by default. An attempt is made to save all
192images of an image sequence into the given output file.
193However, some formats, such as JPEG and PNG, do not support more than one
194image per file, and in that case ImageMagick is forced to write each image as a separate file. As
195such, if more than one image needs to be written, the filename given is
196modified by adding a <a href="#scene">-scene</a> number before the
197suffix, in order to make distinct names for each image. </p>
198
199<p>Use <a href="#adjoin">+adjoin</a> to force each image to be written
200to separate files, whether or not the file format allows multiple images
201per file (for example, GIF, MIFF, and TIFF). </p>
202
203<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>
204
205<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: rose: -morph 15 my%02dmorph.jpg</span></p>
206<p>will create a sequence of 17 images named my00morph.jpg, my01morph.jpg, my02morph.jpg, ..., my16morph.jpg.
207</p>
208
209<p>In summary, ImageMagick tries to write all images to one file, but will use
210multiple files if either (1) the output image's file format does not allow multi-image files,
211(2) the <a href="#adjoin">+adjoin</a> option is given, or (3) a C-style integer format string is
212present in the output filename. </p>
213
214
215<div style="margin: auto;">
216 <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/>
217 -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>
218</div>
219
220<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>
221
222<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>
223
224<p>The matrix entries are entered as comma-separated numeric values <i>with no spaces</i>. </p>
225
226<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>
227
228<div class="eqn">
229<img alt="affine transformation" src="../images/affine.png"/>
230</div>
231
232<p>
233The 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>
234
235<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>
236
237<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>
238
239<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>
240
241<p class="crtsnip">
242 -affine <em class="arg">s<sub>x</sub></em>,0,0,<em class="arg">s<sub>y</sub></em>
243</p>
244
245<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>
246
247<p class="crtsnip">
248 -affine 1,0,0,1,<em class="arg">t<sub>x</sub></em>,<em class="arg">t<sub>y</sub></em>
249</p>
250
251<p>Rotate clockwise about the origin (the upper left-hand corner) by an angle <em>a</em> by letting
252<em>c</em> = cos(<em>a</em>), <em>s</em> = sin(<em>a</em>), and using the following.</p>
253
254<p class="crtsnip">
255 -affine <em>c</em>,<em>s</em>,-<em>s</em>,<em>c</em>
256</p>
257
258<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>
259
260<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>
261
262<div style="margin: auto;">
263 <h4><a name="alpha" id="alpha"></a>-alpha <em class="arg">type</em></h4>
264</div>
265
266<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>
267
268<p>Used to set a flag on an image indicating whether or not to use existing alpha
269channel 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>
270
271
272<table class="doc">
273 <tbody>
274 <tr valign="top">
275 <th align="left" style="width: 8%">type</th>
276 <th align="left">Description</th>
277 </tr>
278
279 <tr valign="top">
280 <td valign="top"><kbd>Off</kbd>&nbsp; or
281 <kbd>Deactivate</kbd></td>
282 <td valign="top">
283 Disables the image's transparency channel. Does not delete or change the
284 existing data, just turns off the use of that data. This is the same as
285 the older <a href="#matte" >+matte</a> operator. </td></tr>
286
287 <tr valign="top">
288 <td valign="top"><kbd>On</kbd>&nbsp; or
289 <kbd>Activate</kbd></td>
290 <td valign="top">
291 Enables the image's use of transparency. If transparency data does not
292 already exist, allocates the data and sets it to opaque. If the image has
293 transparency data, the channel is enabled and the transparency data is not changed or modified in any way. This is NOT
294 the same as the older <a href="#matte" >-matte</a> operator. </td></tr>
295
296 <tr valign="top">
297 <td valign="top"><kbd>Set</kbd></td>
298 <td valign="top">
299 Turns '<kbd>On</kbd>' the alpha/matte channel and if it was previously
300 turned off resets the channel to opaque. If the image already had the
301 alpha channel turned on, it will have no effect. This is the same as the older <a href="#matte">-matte</a> operator. </td></tr>
302
303 <tr valign="top">
304 <td valign="top"><kbd>Opaque</kbd></td>
305 <td valign="top">
306 Turns '<kbd>On</kbd>' the alpha/matte channel and forces it to be fully
307 opaque. </td></tr>
308
309 <tr valign="top">
310 <td valign="top"><kbd>Transparent</kbd></td>
311 <td valign="top">
312 Turns '<kbd>On</kbd>' the alpha/matte channel and forces it to be fully
313 transparent. This effectively creates a fully transparent image the same
314 size as the original and with all its original RGB data still intact. </td></tr>
315
316 <tr valign="top">
317 <td valign="top"><kbd>Extract</kbd></td>
318 <td valign="top">
319 Copies the alpha channel values into all the color channels and turns
320 '<kbd>Off</kbd>' the the image's transparency, so as to generate a
321 gray-scale mask of the image's shape. This is the inverse of
322 '<kbd>Copy</kbd>'. </td></tr>
323
324 <tr valign="top">
325 <td valign="top"><kbd>Copy</kbd></td>
326 <td valign="top">
327 Turns '<kbd>On</kbd>' the alpha/matte channel, then copies the
328 gray-scale intensity of the image, as an alpha mask, into the alpha
329 channel, converting a gray-scale mask into a transparent shaped image
330 ready to be colored appropriately. The color channels are not modified.
331 </td></tr>
332
333 <tr valign="top">
334 <td valign="top"><kbd>Shape</kbd></td>
335 <td valign="top">
336 As per '<kbd>Copy</kbd>' but also colors the resulting shape mask with
337 the current background color.
338 </td></tr>
339
340 <tr valign="top">
341 <td valign="top"><kbd>Background</kbd></td>
342 <td valign="top">
343 Set any fully-transparent pixel to the background color.
344 </td></tr>
345 </tbody>
346</table>
347
348<p>Note that while the <a href="#matte" >+matte</a> operation is the same as
349"<kbd><a href="#alpha" >-alpha</a> off</kbd>", the <a href="#matte"
350>-matte</a> operation is the same as "<kbd><a href="#alpha" >-alpha</a> set</kbd>" and
351not "<kbd><a href="#alpha" >-alpha</a> on</kbd>".
352That is, "<kbd><a href="#alpha" >-alpha</a> set</kbd>" will ensure that the
353written image is opaque if the original image had no transparency
354channel enabled, regardless if transparency data is already present. </p>
355
356
357<div style="margin: auto;">
358 <h4><a name="annotate" id="annotate"></a>
359 -annotate <em class="arg">degrees</em> <em class="arg">text</em><br />
360 -annotate <em class="arg">Xdegrees</em>x<em class="arg">Ydegrees</em> <em class="arg">text</em><br />
361 -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>
362</div>
363
364<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>
365
366<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>
367
368
369<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>
370
371<p>Using <a href="#annotate">-annotate</a>&nbsp;<em class="arg">degrees</em> or <a href="#annotate">-annotate</a>&nbsp;<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>&ndash;direction is conventionally considered to be <em>downward</em> for images.)</p>
372
373<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>
374<div class="eqn"><img alt="annotate transformation" src="../images/annotate.png"/></div>
375
376<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>
377
378<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>
379
380<div style="margin: auto;">
381 <h4><a name="antialias" id="antialias"></a>-antialias</h4>
382</div>
383
384<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
385drawing fonts and lines.</td><td style='text-align:right;'></td></tr></table>
386
387<p>By default, objects (e.g. text, lines, polygons, etc.) are antialiased when
388drawn. Use <a href="#antialias">+antialias</a> to disable the addition of
389antialiasing edge pixels. This will then reduce the number of colors added to
390an image to just the colors being directly drawn. That is, no mixed colors
391will be added when drawing such objects. </p>
392
393<div style="margin: auto;">
394 <h4><a name="append" id="append"></a>-append</h4>
395</div>
396
397<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>
398
399<p>This option creates a single longer image image, by joining all the current
400images in sequence top-to-bottom. Use <a href="#append">+append</a> to
401stack images left-to-right. </p>
402
403<p>If they are not of the same width, narrower images are padded with the
404current <a href="#background">-background</a> color setting, and their
405position relative to each other can be controled by the current <a
406href="#gravity">-gravity</a> setting. </p>
407
408
409<div style="margin: auto;">
410 <h4><a name="attenuate" id="attenuate"></a>-attenuate <em class="arg">value</em></h4>
411</div>
412
413<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>
414
415
416<div style="margin: auto;">
417 <h4><a name="authenticate" id="authenticate"></a>-authenticate <em class="arg">password</em></h4>
418</div>
419
420<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>
421
422<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>
423
424<p>For a different encryption method, see <a href="#encipher">-encipher</a> and <a href="#decipher">-decipher</a>. </p>
425
426<div style="margin: auto;">
427 <h4><a name="auto-gamma" id="auto-gamma"></a>-auto-gamma</h4>
428</div>
429
430<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>
431
432<div style="margin: auto;">
433 <h4><a name="auto-level" id="auto-level"></a>-auto-level</h4>
434</div>
435
436<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>
437
438<div style="margin: auto;">
439 <h4><a name="auto-orient" id="auto-orient"></a>-auto-orient</h4>
440</div>
441
442<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>
443
444<div style="margin: auto;">
445 <h4><a name="average" id="average"></a>-average</h4>
446</div>
447
448<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>
449
450<p>An error results if the images are not identically sized.</p>
451
452<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>
453
454<div style="margin: auto;">
455 <h4><a name="backdrop" id="backdrop"></a>-backdrop</h4>
456</div>
457
458<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>
459
460<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>
461
462<div style="margin: auto;">
463 <h4><a name="background" id="background"></a>-background <em class="arg">color</em></h4>
464</div>
465
466<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>
467
468<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>
469
470<div style="margin: auto;">
471 <h4><a name="bench" id="bench"></a>-bench <em class="arg">iterations</em></h4>
472</div>
473
474<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>
475
476<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>
477
478<p class='crt'><span class="crtprompt"> $magick&gt; </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>
479<p>In this example, 5&nbsp;iterations were completed at 0.0539724&nbsp;iterations per second, using 91.750&nbsp;seconds of the user's allotted time, for a total elapsed time of 2&nbsp;minutes&nbsp;and&nbsp;33&nbsp;seconds.</p>
480
481<div style="margin: auto;">
482 <h4><a name="bias" id="bias"></a>-bias <em class="arg">value</em>{<em class="arg">%</em>}</h4>
483</div>
484
485<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>
486
487<p>This option shifts the output of <a href="../www/command-line-options.html#convolve">&#x2011;convolve</a> so that positive and negative results are relative to the specified bias value. </p>
488
489<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>
490
491<p>When using an ImageMagick with the HDRI compile-time setting, <a href="../www/command-line-options.html#bias">&#x2011;bias</a> is not needed, as ImageMagick is able to store/handle any
492negative results without clipping to the color value range
493(0..QuantumRange).</p>
494
495<p>See the discussion on HDRI implementations of ImageMagick on the page
496<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.
497</p>
498
499<div style="margin: auto;">
500 <h4><a name="black-point-compensation" id="black-point-compensation"></a>-black-point-compensation</h4>
501</div>
502
503<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>
504
505<div style="margin: auto;">
506 <h4><a name="black-threshold" id="black-threshold"></a>-black-threshold <em class="arg">threshold</em></h4>
507</div>
508
509<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>
510
511
512<div style="margin: auto;">
513 <h4><a name="blend" id="blend"></a>-blend <em class="arg">percent</em></h4>
514</div>
515
516<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>
517
518<p>Blend will average the images together ('plus') according to the
519percentages given and each pixels transparency. If only a single percentage
520value is given it sets the weight of the composite or 'source' image, while
521the background image is weighted by the exact opposite amount. That is a
522<kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of the
523'destination' image. Thus it is equivalent to <kbd>-blend 30x70</kbd>.</p>
524
525
526<div style="margin: auto;">
527 <h4><a name="blue-primary" id="blue-primary"></a>-blue-primary <em class="arg">x</em>,<em class="arg">y</em></h4>
528</div>
529
530<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>
531
532<div style="margin: auto;">
533 <h4><a name="blue-shift" id="blue-shift"></a>-blue-shift <em class="arg">factor</em></h4>
534</div>
535
536<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>
537
538<div style="margin: auto;">
539
540<div style="margin: auto;">
541 <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>
542</div>
543
544<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>
545
546<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p>
547
548<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/>
549</div>
550
551<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 &sigma; is the standard deviation of the Gaussian distribution. As a guideline, set <i>r</i> to approximately 3&sigma;. If a radius of 0 is specified, ImageMagick selects a suitable radius for you.</p>
552
553<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>
554
555<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
556pixels which are outside the image proper are blurred into the final result.
557</p>
558
559
560<div style="margin: auto;">
561 <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>
562</div>
563
564<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>
565
566<p>Each pixel in the overlaid region is replaced with an Elliptical Weighted
567Average (EWA) of the source image, scaled according to the grayscale
568mapping. </p>
569
570<p>The ellipse is weighted with sigma set to the given <em class="arg"
571>Width</em> and <em class="arg" >Height</em>. The <em class="arg" >Height</em>
572defaults to the <em class="arg" >Width</em> for a normal circular Guassian
573weighting. The <em class="arg" >Angle</em> will rotate the ellipse from
574horizontal clock-wise. </p>
575
576<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
577pixels which are outside the image proper are blurred into the final result.
578</p>
579
580
581<div style="margin: auto;">
582 <h4><a name="border" id="border"></a>-border <em class="arg">geometry</em></h4>
583</div>
584
585<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>
586
587<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>
588
589<p>Set the border color by preceding with the <a href="#bordercolor">-bordercolor</a> setting.</p>
590
591<p>See also the <a href="#frame">-frame</a> option, which has more functionality.</p>
592
593<div style="margin: auto;">
594 <h4><a name="bordercolor" id="bordercolor"></a>-bordercolor <em class="arg">color</em></h4>
595</div>
596
597<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>
598
599<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
600
601<p>The default border color is <kbd>#DFDFDF</kbd>, <span style="background-color: #dfdfdf;">this shade of gray</span>.</p>
602
603<div style="margin: auto;">
604 <h4><a name="borderwidth" id="borderwidth"></a>-borderwidth <em class="arg">geometry</em> </h4>
605</div>
606
607<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>
608
609<div style="margin: auto;">
610 <h4><a name="cache" id="cache"></a>-cache <em class="arg">threshold</em></h4>
611</div>
612
613<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>
614
615<div style="margin: auto;">
616 <h4><a name="caption" id="caption"></a>-caption <em class="arg">string</em></h4>
617</div>
618
619<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>
620
621<div style="margin: auto;">
622 <h4><a name="cdl" id="cdl"></a>-cdl <em class="arg">filename</em></h4>
623</div>
624
625<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>
626
627<p>Here is an example color correction collection:</p>
628
629<pre class="text">
630&lt;?xml version="1.0" encoding="UTF-8"?>
631&lt;ColorCorrectionCollection xmlns="urn:ASC:CDL:v1.2">
632 &lt;ColorCorrection id="cc06668">
633 &lt;SOPNode>
634 &lt;Slope> 0.9 1.2 0.5 &lt;/Slope>
635 &lt;Offset> 0.4 -0.5 0.6 &lt;/Offset>
636 &lt;Power> 1.0 0.8 1.5 &lt;/Power>
637 &lt;/SOPNode>
638 &lt;SATNode>
639 &lt;Saturation> 0.85 &lt;/Saturation>
640 &lt;/SATNode>
641 &lt;/ColorCorrection>
642&lt;/ColorCorrectionCollection>
643</pre>
644
645<div style="margin: auto;">
646 <h4><a name="channel" id="channel"></a>-channel <em class="arg">type</em></h4>
647</div>
648
649<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>
650
651<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>
652
653<p>To print a complete list of channel types, use <a href="#list">-list channel</a>.</p>
654
655<p>The channels above can be specified as a comma-separated list or can be abbreviated as a
656concatenation of the letters '<kbd>R</kbd>', '<kbd>G</kbd>', '<kbd>B</kbd>',
657'<kbd>A</kbd>', '<kbd>O</kbd>', '<kbd>C</kbd>', '<kbd>M</kbd>', '<kbd>Y</kbd>',
658'<kbd>K</kbd>'.
659
660For example, to negate only the alpha channel of an image, use</p>
661<p class="crtsnip">
662 -channel Alpha -negate
663</p>
664
665<p>By default, ImageMagick sets <a href="#channel">-channel</a> to the value
666'<kbd>RGB</kbd>', which specifies that operators act on all channels except
667the opacity channel. Using the option <a href="#channel" >+channel</a> will reset the value back to this default. </p>
668
669<p>Operators that are affected by the <a href="#channel" >-channel</a>
670setting include the following.
671<a href="#black-threshold">-black-threshold</a>,
672<a href="#blur">-blur</a>,
673<a href="#clut">-clut</a>,
674<a href="#combine">-combine</a>,
675<a href="#contrast-stretch">-contrast-stretch</a>,
676<a href="#evaluate">-evaluate</a>,
677<a href="#function">-function</a>,
678<a href="#fx">-fx</a>,
679<a href="#clut">-hald-clut</a>,
680<a href="#gaussian-blur">-gaussian-blur</a>,
681<a href="#motion-blur">-motion-blur</a>,
682<a href="#negate">-negate</a>,
683<a href="#normalize">-normalize</a>,
684<a href="#ordered-dither">-ordered-dither</a>,
685<a href="#radial-blur">-radial-blur</a>,
686<a href="#random-threshold">-random-threshold</a>,
687<a href="#separate">-separate</a>, and
688<a href="#white-threshold">-white-threshold</a>.
689</p>
690
691
692<div style="margin: auto;">
693 <h4><a name="charcoal" id="charcoal"></a>-charcoal <em class="arg">factor</em></h4>
694</div>
695
696<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>
697
698<div style="margin: auto;">
699 <h4><a name="chop" id="chop"></a>-chop <em class="arg">geometry</em></h4>
700</div>
701
702<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>
703
704<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>
705
706<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>
707
708<div style="margin: auto;">
709 <h4><a name="clip" id="clip"></a>-clip</h4>
710</div>
711
712<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>
713
714<p>If a clipping path is present, it is applied to subsequent operations.</p>
715
716<p>For example, in the command</p>
717
718<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -clip -negate cockatoo.tif negated.tif</span></p>
719<p>only the pixels within the clipping path are negated.</p>
720
721<p>The <a href="#clip">-clip</a> feature requires the XML library. If the XML library is not present, the option is ignored.</p>
722
723<div style="margin: auto;">
724 <h4><a name="clip-mask" id="clip-mask"></a>-clip-mask</h4>
725</div>
726
727<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>
728
729<div style="margin: auto;">
730 <h4><a name="clip-path" id="clip-path"></a>-clip-path <em class="arg">id</em></h4>
731</div>
732
733<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>
734
735<div style="margin: auto;">
736 <h4><a name="clone" id="clone"></a>-clone <em class="arg">index(s)</em></h4>
737</div>
738
739<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>
740
741<p>Specify the image by its index in the sequence. The first image is index
7420. Negative indexes are relative to the end of the sequence; for example, &minus;1
743represents the last image of the sequence. Specify a range of images with a
744dash (e.g. 0&minus;4). Separate multiple indexes with commas but no spaces (e.g. 0,2,5). Use <a
745href="#clone">+clone</a> make a copy of the last image in the image
746sequence.</p>
747
748<div style="margin: auto;">
749 <h4><a name="clut" id="clut"></a>-clut</h4>
750</div>
751
752<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
753corresponding channel in the second image as a <b>c</b>olor
754<b>l</b>ook<b>u</b>p <b>t</b>able.</td><td style='text-align:right;'></td></tr></table>
755
756<p>The second (LUT) image is ordinarily a gradient image containing the
757histogram mapping of how each channel should be modified. Typically it is a
758either a single row or column image of replacement color values. If larger
759than a single row or column, values are taken from a diagonal line from
760top-left to bottom-right corners.</p>
761
762<p>The lookup is further controlled by the <a
763href="#interpolate">-interpolate</a> setting, which is especially handy for an
764LUT which is not the full length needed by the ImageMagick installed Quality
765(Q) level. Good settings for this are the '<kbd>bilinear</kbd>' and
766'<kbd>bicubic</kbd>' interpolation settings, which give smooth color
767gradients, and the '<kbd>integer</kbd>' setting for a direct, unsmoothed
768lookup of color values. </p>
769
770<p>This operator is especially suited to replacing a grayscale image with a
771specific color gradient from the CLUT image. </p>
772
773<p>Only the channel values defined by the <a href="#channel">-channel</a>
774setting will have their values replaced. In particular, since the default <a
775href="#channel">-channel</a> setting is <kbd>RGB</kbd>, this means that
776transparency (alpha/matte channel) is not affected, unless the <a
777href="#channel">-channel</a> setting is modified. When the alpha channel is
778set, it is treated by the <a href="#clut" >-clut</a> operator in the same way
779as the other channels, implying that alpha/matte values are replaced using the
780alpha/matte values of the original image. </p>
781
782<p>If either the image being modified, or the lookup image, conatins no
783transparency (i.e. <a href="#alpha" >-alpha</a> is turned 'off') but the <a
784href="#channel">-channel</a> setting includes alpha replacement, then it is
785assumed that image represents a gray-scale graident which will be used for the
786replacement alpha values. That is you can use a gray-scale CLUT image to
787adjust a existing images alpha channel, or you can color a gray-scale image
788using colors form CLUT containing the desired colors, including transparency.
789</p>
790
791<p>See also <a href="#hald-clut" >-hald-clut</a> which replaces colors according
792the lookup of the full color RGB value from a 2D representation of a 3D color
793cube. </p>
794
795
796<div style="margin: auto;">
797 <h4><a name="coalesce" id="coalesce"></a>-coalesce</h4>
798</div>
799
800<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>
801
802<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>
803
804<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>
805
806
807<div style="margin: auto;">
808 <h4><a name="colorize" id="colorize"></a>-colorize <em class="arg">value</em></h4>
809</div>
810
811<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>
812
813<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>
814
815<div style="margin: auto;">
816 <h4><a name="colormap" id="colormap"></a>-colormap <em class="arg">type</em></h4>
817</div>
818
819<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>
820
821<p>The <em class="arg">type</em> can be <kbd>shared</kbd> or <kbd>private</kbd>.</p>
822
823<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>
824
825<div style="margin: auto;">
826 <h4><a name="colors" id="colors"></a>-colors <em class="arg">value</em></h4>
827</div>
828
829<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>
830
831<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>
832
833<div style="margin: auto;">
834 <h4><a name="colorspace" id="colorspace"></a>-colorspace <em class="arg">value</em></h4>
835</div>
836
837<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>
838
839<p>Choices are:</p>
840
841<pre class="text">
842 CMY
843 CMYK
844 Gray
845 HSB
846 HSL
847 HWB
848 Lab
849 Log
850 OHTA
851 Rec601Luma
852 Rec601YCbCr
853 Rec709Luma
854 Rec709YCbCr
855 RGB
856 sRGB
857 Transparent
858 XYZ
859 YCbCr
860 YCC
861 YIQ
862 YPbPr
863 YUV
864</pre>
865
866<p>To print a complete list of colorspaces, use <a href="#list">-list colorspace</a>.</p>
867
868<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>
869
870<table class="doc">
871 <caption>Conversion Of RGB To Other Color Spaces</caption>
872 <tr><th align="left" valign="middle">CMY</th></tr>
873 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>&minus;R</td></tr>
874 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>&minus;G</td></tr>
875 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>&minus;B</td></tr>
876 <tr><th align="left" valign="middle">CMYK &mdash; starts with CMY from above</th></tr>
877 <tr><td align="left" valign="middle">K=min(C,Y,M)</td></tr>
878 <tr><td align="left" valign="middle">C=<em class="QR">QuantumRange</em>*(C&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
879 <tr><td align="left" valign="middle">M=<em class="QR">QuantumRange</em>*(M&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
880 <tr><td align="left" valign="middle">Y=<em class="QR">QuantumRange</em>*(Y&minus;K)/(<em class="QR">QuantumRange</em>&minus;K)</td></tr>
881
882 <tr><th align="left" valign="middle">Gray</th></tr>
883 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr>
884
885 <tr><th align="left" valign="middle">HSB &mdash; Hue, Saturation, Brightness; like a cone peak downward</th></tr>
886 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
887 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr>
888 <tr><td align="left" valign="middle">B=distance along axis from bottom upward; B=max(R,G,B); <em>intensity-like</em></td></tr>
889
890 <tr><th align="left" valign="middle">HSL &mdash; Hue, Saturation, Lightness; like a double cone end-to-end with peaks at very top and bottom</th></tr>
891 <tr><td align="left" valign="middle">H=angle around perimeter (0 to 360 deg); H=0 is red; increasing angles toward green</td></tr>
892 <tr><td align="left" valign="middle">S=distance from axis outward</td></tr>
893 <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>
894
895 <tr><th align="left" valign="middle">HWB &mdash; Hue, Whiteness, Blackness</th></tr>
896 <tr><td align="left" valign="middle">Hue (complicated equation)</td></tr>
897 <tr><td align="left" valign="middle">Whiteness (complicated equation)</td></tr>
898 <tr><td align="left" valign="middle">Blackness (complicated equation)</td></tr>
899
900 <tr><th align="left" valign="middle">LAB</th></tr>
901 <tr><td align="left" valign="middle">L (complicated equation relating X,Y,Z)</td></tr>
902 <tr><td align="left" valign="middle">A (complicated equation relating X,Y,Z)</td></tr>
903 <tr><td align="left" valign="middle">B (complicated equation relating X,Y,Z)</td></tr>
904
905 <tr><th align="left" valign="middle">LOG</th></tr>
906 <tr><td align="left" valign="middle">I1 (complicated equation involving logarithm of R)</td></tr>
907 <tr><td align="left" valign="middle">I2 (complicated equation involving logarithm of G)</td></tr>
908 <tr><td align="left" valign="middle">I3 (complicated equation involving logarithm of B)</td></tr>
909
910 <tr><th align="left" valign="middle">OHTA &mdash; approximates principal components transformation</th></tr>
911 <tr><td align="left" valign="middle">I1=0.33333*R+0.33334*G+0.33333*B; <em>intensity-like</em></td></tr>
912 <tr><td align="left" valign="middle">I2=(0.50000*R+0.00000*G&minus;0.50000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
913 <tr><td align="left" valign="middle">I3=(&minus;0.25000*R+0.50000*G&minus;0.25000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
914
915 <tr><th align="left" valign="middle">Rec601Luma</th></tr>
916 <tr><td align="left" valign="middle">Gray = 0.29900*R+0.58700*G+0.11400*B</td></tr>
917
918 <tr><th align="left" valign="middle">Rec601YCbCr</th></tr>
919 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
920 <tr><td align="left" valign="middle">Cb=(&minus;0.168736*R-0.331264*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
921 <tr><td align="left" valign="middle">Cr=(0.500000*R&minus;0.418688*G&minus;0.081312*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
922
923 <tr><th align="left" valign="middle">Rec709Luma</th></tr>
924 <tr><td align="left" valign="middle">Gray=0.21260*R+0.71520*G+0.07220*B</td></tr>
925
926 <tr><th align="left" valign="middle">Rec709YCbCr</th></tr>
927 <tr><td align="left" valign="middle">Y=0.212600*R+0.715200*G+0.072200*B; <em>intensity-like</em></td></tr>
928 <tr><td align="left" valign="middle">Cb=(&minus;0.114572*R&minus;0.385428*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
929 <tr><td align="left" valign="middle">Cr=(0.500000*R&minus;0.454153*G&minus;0.045847*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
930
931 <tr><th align="left" valign="middle">sRGB</th></tr>
932 <tr><td align="left" valign="middle">if Rs &le; .03928 then Rs=R/12.92 else Rs=((R+.055)/1.055)^2.4</td></tr>
933 <tr><td align="left" valign="middle">if Gs &le; .03928 then Gs=B/12.92 else Gs=((G+.055)/1.055)^2.4</td></tr>
934 <tr><td align="left" valign="middle">if Bs &le; .03928 then Bs=B/12.92 else Bs=((B+.055)/1.055)^2.4</td></tr>
935
936 <tr><th align="left" valign="middle">XYZ</th></tr>
937 <tr><td align="left" valign="middle">X=0.4124240*R+0.3575790*G+0.1804640*B</td></tr>
938 <tr><td align="left" valign="middle">Y=0.2126560*R+0.7151580*G+0.0721856*B</td></tr>
939 <tr><td align="left" valign="middle">Z=0.0193324*R+0.1191930*G+0.9504440*B</td></tr>
940
941 <tr><th align="left" valign="middle">YCC</th></tr>
942 <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>
943 <tr><td align="left" valign="middle">C1=(&minus;0.29900*R&minus;0.58700*G+0.88600*B) (with complicated scaling)</td></tr>
944 <tr><td align="left" valign="middle">C2=(0.70100*R&minus;0.58700*G&minus;0.11400*B) (with complicated scaling)</td></tr>
945
946 <tr><th align="left" valign="middle">YCbCr</th></tr>
947 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
948 <tr><td align="left" valign="middle">Cb=(&minus;0.168736*R&minus;0.331264*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
949 <tr><td align="left" valign="middle">Cr=(0.500000*R&minus;0.418688*G&minus;0.081312*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
950
951 <tr><th align="left" valign="middle">YIQ</th></tr>
952 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr>
953 <tr><td align="left" valign="middle">I=(0.59600*R&minus;0.27400*G&minus;0.32200*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
954 <tr><td align="left" valign="middle">Q=(0.21100*R&minus;0.52300*G+0.31200*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
955
956 <tr><th align="left" valign="middle">YPbPr</th></tr>
957 <tr><td align="left" valign="middle">Y=0.299000*R+0.587000*G+0.114000*B; <em>intensity-like</em></td></tr>
958 <tr><td align="left" valign="middle">Pb=(&minus;0.168736*R&minus;0.331264*G+0.500000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
959 <tr><td align="left" valign="middle">Pr=(0.500000*R&minus;0.418688*G&minus;0.081312*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
960
961 <tr><th align="left" valign="middle">YUV</th></tr>
962 <tr><td align="left" valign="middle">Y=0.29900*R+0.58700*G+0.11400*B; <em>intensity-like</em></td></tr>
963 <tr><td align="left" valign="middle">U=(&minus;0.14740*R&minus;0.28950*G+0.43690*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
964 <tr><td align="left" valign="middle">V=(0.61500*R&minus;0.51500*G&minus;0.10000*B)*(<em class="QR">QuantumRange</em>+1)/2</td></tr>
965</table>
966
967<div style="margin: auto;">
968 <h4><a name="combine" id="combine"></a>-combine</h4>
969</div>
970
971<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>
972
973<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>
974
975<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.
976</p>
977
978<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert original.png -channel RGB -separate sepimage.png</span><span class='crtout'></span><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert sepimage-0.png sepimage-1.png sepimage-2.png -channel RGB -combine imagecopy.png</span></p>
979<div style="margin: auto;">
980 <h4><a name="comment" id="comment"></a>-comment <em class="arg">string</em></h4>
981</div>
982
983<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>
984
985<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>
986
987<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>
988
989<p>For example,</p>
990
991<p class="crtsnip">
992 -comment "%m:%f %wx%h"
993</p>
994
995<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>
996
997<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>
998
999<div style="margin: auto;">
1000 <h4><a name="compose" id="compose"></a>-compose <em class="arg">operator</em></h4>
1001</div>
1002
1003<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>
1004
1005<p>The description of composition uses abstract terminology in order to allow
1006the description to be more precise, while avoiding constant values which are
1007specific to a particular build configuration. Each image pixel is represented
1008by red, green, and blue levels (which are equal for a gray pixel). The
1009build-dependent value <em class="QR">QuantumRange</em> is the maximum integral
1010value which may be stored, per pixel, in the red, green, or blue channels of
1011the image. Each image pixel may also optionally (if the image matte channel is
1012enabled) have an associated level of opacity, ranging from <em>opaque</em> to
1013<em>transparent</em>, which may be used to determine the influence of the pixel
1014color when compositing the pixel with another image pixel. If the image matte
1015channel is disabled, then all pixels in the image are treated as opaque. The
1016color of an opaque pixel is fully visible while the color of a transparent
1017pixel color is entirely absent (pixel color is ignored).</p>
1018
1019<p>By definition, raster images have a rectangular shape. All image rows are of
1020equal length, as are all image columns. By treating the alpha channel as a
1021visual "mask" the rectangular image may be given a "shape" by treating the
1022alpha channel as a cookie-cutter for the image. This is done by setting the
1023pixels within the shape to be opaque, with pixels outside the shape set as
1024transparent. Pixels on the boundary of the shape may be between opaque and
1025transparent in order to provide antialiasing (visually smooth edges). The
1026description of the composition operators use this concept of image "shape" in
1027order to make the description of the operators easier to understand. While it
1028is convenient to describe the operators in terms of "shapes" they are by no
1029means limited to mask-style operations since they are based on continuous
1030floating-point mathematics rather than simple boolean operations.</p>
1031
1032<p>The following alpha blending (Duff-Porter) compose methods are available:</p>
1033
1034<table class="doc">
1035 <tbody>
1036 <tr valign="top">
1037 <th align="left" style="width: 8%">Method</th>
1038 <th align="left">Description</th>
1039 </tr>
1040
1041 <tr valign="top">
1042 <td valign="top">clear</td>
1043 <td valign="top">Both the color and the alpha of the destination are
1044 cleared. Neither the source nor the destination are used (except for
1045 destinations size and other meta-data which is always preserved.</td>
1046 </tr>
1047
1048 <tr valign="top">
1049 <td valign="top">src</td>
1050 <td valign="top">The source is copied to the destination. The destination
1051 is not used as input, though it is cleared.</td>
1052 </tr>
1053
1054 <tr valign="top">
1055 <td valign="top">dst</td>
1056 <td valign="top">The destination is left untouched. The source image is
1057 completely ignored.</td>
1058 </tr>
1059
1060 <tr valign="top">
1061 <td valign="top">src-over</td>
1062 <td valign="top">The source is composited over the destination. this is
1063 the default alpha blending compose method, when neither the compose
1064 setting is set, nor is set in the image meta-data.</td>
1065 </tr>
1066
1067 <tr valign="top">
1068 <td valign="top">dst-over</td>
1069 <td valign="top">The destination is composited over the source and the
1070 result replaces the destination.</td>
1071 </tr>
1072
1073 <tr valign="top">
1074 <td valign="top">src-in</td>
1075 <td valign="top">The part of the source lying inside of the destination
1076 replaces the destination.</td>
1077 </tr>
1078
1079 <tr valign="top">
1080 <td valign="top">dst-in</td>
1081 <td valign="top">The part of the destination lying inside of the source
1082 replaces the destination. Areas not overlaid are cleared.</td>
1083 </tr>
1084
1085 <tr valign="top">
1086 <td valign="top">src-out</td>
1087 <td valign="top">The part of the source lying outside of the destination
1088 replaces the destination.</td>
1089 </tr>
1090
1091 <tr valign="top">
1092 <td valign="top">dst-out</td>
1093 <td valign="top">The part of the destination lying outside of the source
1094 replaces the destination.</td>
1095 </tr>
1096
1097 <tr valign="top">
1098 <td valign="top">src-atop</td>
1099 <td valign="top">The part of the source lying inside of the destination is
1100 composited onto the destination.</td>
1101 </tr>
1102
1103 <tr valign="top">
1104 <td valign="top">dst-atop</td>
1105 <td valign="top">The part of the destination lying inside of the source is
1106 composited over the source and replaces the destination. Areas not
1107 overlaid are cleared. </td>
1108 </tr>
1109
1110 <tr valign="top">
1111 <td valign="top">xor</td>
1112 <td valign="top">The part of the source that lies outside of the
1113 destination is combined with the part of the destination that lies
1114 outside of the source. Source or Destination, but not both. </td>
1115 </tr>
1116
1117 </tbody>
1118</table>
1119
1120<p>Any of the 'Src-*' methods can also be specified without the 'Src-' part.
1121For example the defaul compose method can be specified as just 'Over'.</p>
1122
1123
1124<p>The following mathemathical composition methods are also available. </p>
1125
1126<p>Typically these use the default 'Over' alpha blending when transparencies
1127are also involved, except for 'Plus', 'Minus', 'Add', and 'Subtract', which
1128also composes the alpha channel using the same process as the color channels.
1129This allows them to be used for special image masking techniques. </p>
1130
1131<table class="doc">
1132 <tbody>
1133 <tr valign="top">
1134 <th align="left" style="width: 8%">Method</th>
1135 <th align="left">Description</th>
1136 </tr>
1137
1138 <tr valign="top">
1139 <td valign="top">multiply</td>
1140 <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>
1141 </tr>
1142
1143 <tr valign="top">
1144 <td valign="top">screen</td>
1145 <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>
1146 </tr>
1147
1148 <tr valign="top">
1149 <td valign="top">plus</td>
1150 <td valign="top">The source is added to the destination and replaces the
1151 destination. This operator is useful for averaging or a controled
1152 merger of two images, rather than a direct overlay.</td>
1153 </tr>
1154
1155 <tr valign="top">
1156 <td valign="top">add</td>
1157 <td valign="top">As per 'plus' but transparency data is treated as matte
1158 values. As such any transparent areas in either image remain
1159 transparent. </td>
1160 </tr>
1161
1162 <tr valign="top">
1163 <td valign="top">minus</td>
1164 <td valign="top">Subtract the colors in the source image from the
1165 destination image. When transparency is involved, opaque areas is
1166 subtracted from any destination opaque areas. </td>
1167 </tr>
1168
1169 <tr valign="top">
1170 <td valign="top">subtract</td>
1171 <td valign="top">Subtract the colors in the source image from the
1172 destination image. When transparency is involved transparent areas are
1173 subtracted, so only the opaque areas in the source remain opaque in
1174 the destination image. </td>
1175 </tr>
1176
1177 <tr valign="top">
1178 <td valign="top">difference</td>
1179 <td valign="top">Subtracts the darker of the two constituent colors from
1180 the lighter. Painting with white inverts the destination color.
1181 Painting with black produces no change.</td>
1182 </tr>
1183
1184 <tr valign="top">
1185 <td valign="top">exclusion</td>
1186 <td valign="top">Produces an effect similar to that of 'difference', but
1187 appears as lower contrast. Painting with white inverts the
1188 destination color. Painting with black produces no change.</td>
1189 </tr>
1190
1191 <tr valign="top">
1192 <td valign="top">darken</td>
1193 <td valign="top">Selects the darker of the destination and source colors.
1194 The destination is replaced with the source when the source is darker,
1195 otherwise it is left unchanged.</td>
1196 </tr>
1197
1198 <tr valign="top">
1199 <td valign="top">lighten</td>
1200 <td valign="top">Selects the lighter of the destination and source colors.
1201 The destination is replaced with the source when the source is
1202 lighter, otherwise it is left unchanged. </td>
1203 </tr>
1204
1205 <tr valign="top">
1206 <td valign="top">linear-dodge</td>
1207 <td valign="top">This is equivelent to 'Plus' in that the color channels
1208 are simply added, however it does not 'Plus' the alpha channel, but
1209 uses the normal 'Over' alpha blending, which transparencies are
1210 involved. Produces a sort of additive multiply-like result. Added
1211 ImageMagick version 6.5.4-3. </td>
1212 </tr>
1213
1214 <tr valign="top">
1215 <td valign="top">linear-burn</td>
1216 <td valign="top">As 'Linear-Dodge', but also subtract one from the result.
1217 Sort of a additive 'Screen' of the images. Added ImageMagick version
1218 6.5.4-3. </td>
1219 </tr>
1220
1221 <tr valign="top">
1222 <td valign="top">color-dodge</td>
1223 <td valign="top">Brightens the destination color to reflect the source
1224 color. Painting with black produces no change.</td>
1225 </tr>
1226
1227 <tr valign="top">
1228 <td valign="top">color-burn</td>
1229 <td valign="top">Darkens the destination color to reflect the source
1230 color. Painting with white produces no change. Fixed in ImageMagick
1231 version 6.5.4-3. </td>
1232 </tr>
1233
1234 <tr valign="top">
1235 <td valign="top">overlay</td>
1236 <td valign="top">Multiplies or screens the colors, dependent on the
1237 destination color. Source colors overlay the destination whilst
1238 preserving its highlights and shadows. The destination color is not
1239 replaced, but is mixed with the source color to reflect the lightness
1240 or darkness of the destination.</td>
1241 </tr>
1242
1243 <tr valign="top">
1244 <td valign="top">hard-light</td>
1245 <td valign="top">Multiplies or screens the colors, dependent on the source
1246 color value. If the source color is lighter than 0.5, the destination
1247 is lightened as if it were screened. If the source color is darker
1248 than 0.5, the destination is darkened, as if it were multiplied. The
1249 degree of lightening or darkening is proportional to the difference
1250 between the source color and 0.5. If it is equal to 0.5 the
1251 destination is unchanged. Painting with pure black or white produces
1252 black or white.</td>
1253 </tr>
1254
1255
1256 <tr valign="top">
1257 <td valign="top">linear-light</td>
1258 <td valign="top">Like 'Hard-Light' but using linear-dodge and linear-burn
1259 instead. Increases contrast slightly with an impact on the
1260 foreground's tonal values.</td>
1261 </tr>
1262
1263 <tr valign="top">
1264 <td valign="top">soft-light</td>
1265 <td valign="top">Darkens or lightens the colors, dependent on the source
1266 color value. If the source color is lighter than 0.5, the destination
1267 is lightened. If the source color is darker than 0.5, the destination
1268 is darkened, as if it were burned in. The degree of darkening or
1269 lightening is proportional to the difference between the source color
1270 and 0.5. If it is equal to 0.5, the destination is unchanged. Painting
1271 with pure black or white produces a distinctly darker or lighter area,
1272 but does not result in pure black or white. Fixed in ImageMagick
1273 version 6.5.4-3. </td>
1274 </tr>
1275
1276 <tr valign="top">
1277 <td valign="top">pegtop-light</td>
1278 <td valign="top">Almost equivelent to 'Soft-Light', but using a
1279 continuious mathematical formula rather than two conditionally
1280 selected formulae. Added ImageMagick version 6.5.4-3. </td>
1281 </tr>
1282
1283 <tr valign="top">
1284 <td valign="top">vivid-light</td>
1285 <td valign="top">A modified 'Linear-Light' designed to preserve very stong
1286 primary and secondary colors in the image. Added ImageMagick version
1287 6.5.4-3. </td>
1288 </tr>
1289
1290 <tr valign="top">
1291 <td valign="top">pin-light</td>
1292 <td valign="top">Similar to 'Hard-Light', but using sharp linear shadings,
1293 to similate the effects of a strong 'pinhole' light source. Added
1294 ImageMagick version 6.5.4-3. </td>
1295 </tr>
1296
1297 </tbody>
1298</table>
1299
1300
1301<p>Also included are these special purpose compose methods:</p>
1302
1303<table class="doc">
1304 <tbody>
1305 <tr valign="top">
1306 <th align="left" style="width: 8%">Method</th>
1307 <th align="left">Description</th>
1308 </tr>
1309
1310 <tr valign="top">
1311 <td valign="top">copy-*</td>
1312 <td valign="top">Copy the specified channel (Red, Green, Blue, Cyan,
1313 Magenta, Yellow, Black, or Opacity) in the source image to the
1314 same channel in the destination image. If the channel specified
1315 does not exist in the source image, (which can only happen for methods,
1316 '<kbd>copy-opacity</kbd>' or '<kbd>copy-black</kbd>') then it is
1317 assumed that the source image is a special grayscale channel image
1318 of the values to be copied. </td>
1319 </tr>
1320
1321 <tr valign="top">
1322 <td valign="top">change-mask</td>
1323 <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>
1324 </tr>
1325 </tbody>
1326</table>
1327
1328<p>On top of these composed methods are a few special ones that not only require
1329the two images that are being merged or overlaid, but have some extra numerical
1330arguments, which are tabled below. </p>
1331
1332<p>In the "<code>composite</code>" command these composition methods are
1333selected using special options with the arguments needed. They are usually,
1334but not always, the same name as the composte 'method' they use, and replaces
1335the normal use of the <a href="#compose" >-compose</a> setting in the
1336"<code>composite</code>" command. For example... </p>
1337
1338<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>composite ... -blend 50x50 ...</span></p>
1339<p>As of IM v6.5.3-4 the "<code>convert</code>" command can now also supply
1340these extra arguments to its <a href="#composite" >-composite</a> operator,
1341using the special <a href="#set">-set</a> attribute of '<kbd class="arg">option:compose:args</kbd>'. This means you can now make use of
1342these special argumented <a href="#compose" >-compose</a> methods, those the
1343argument and the method both need to be set separatally. For example... </p>
1344
1345<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert ... -compose blend -set option:compose:args 50x50 -composite ...</span></p>
1346<p>The following is a table of these special 'argumented' compose methods,
1347with a brief summary of what they do. For more details see the equivalent
1348"composite" command option name. </p>
1349
1350<table class="doc">
1351 <tbody>
1352 <tr valign="top">
1353 <th align="left" style="width: 8%">Method</th>
1354 <th align="left">Description</th>
1355 </tr>
1356
1357 <tr valign="top">
1358 <td valign="top">dissolve</td>
1359 <td valign="top">Arguments:
1360 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
1361 <br>Equivalent to "<code>composite</code>" <a href="#dissolve">-dissolve</a>
1362 <br>Dissolve the 'source' image by the percentage given before overlaying
1363 'over' the 'destination' image. If <em class="arg">src_percent</em> is
1364 greater than 100, it starts dissolving the main image so it will
1365 become transparent at a value of '<kbd class="arg">200</kbd>'. If
1366 both percentages are given, each image are dissolved to the
1367 percentages given.
1368 </td>
1369 </tr>
1370
1371 <tr valign="top">
1372 <td valign="top">blend</td>
1373 <td valign="top">Arguments:
1374 <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]
1375 <br>Equivalent to "<code>composite</code>" <a href="#blend">-blend</a>
1376 <br>Average the images together ('plus') according to the percentages
1377 given and each pixels transparency. If only a single percentage value
1378 is given it sets the weight of the composite or 'source' image, while
1379 the background image is weighted by the exact opposite amount. That is
1380 a <kbd>-blend 30</kbd> merges 30% of the 'source' image with 70% of
1381 the 'destination' image. Thus it is equivalent to <kbd>-blend
1382 30x70</kbd>.
1383 </td>
1384 </tr>
1385
1386 <tr valign="top">
1387 <td valign="top">mathematics</td>
1388 <td valign="top">Arguments: <em class="arg">A, B, C, D</em>
1389 <br>Not available in "<code>composite</code>" at this time.
1390 <br>Merge the source and destination images according to the formula
1391 <br>&nbsp; &nbsp; &nbsp;<code>A*Sc*Dc + B*Sc + C*Dc + D</code>
1392 <br>Can be used to generate a custom composition method that would
1393 otherwise need to be implemented using the slow <a href="#fx">-fx</a>
1394 DIY image operator. Added to ImageMagick version 6.5.4-3.
1395 </td>
1396 </tr>
1397
1398 <tr valign="top">
1399 <td valign="top">modulate</td>
1400 <td valign="top">Arguments:
1401 <em class="arg">brightness</em>[x<em class="arg">saturation</em>]
1402 <br>Equivalent to "<code>composite</code>" <a href="#watermark">-watermark</a>
1403 <br>Take a grayscale image (with alpha mask) and modify the destination
1404 image's brightness according to watermark image's grayscale value and
1405 the <em class="arg">brightness</em> percentage. The destinations
1406 color saturation attribute is just direct modified by the <em
1407 class="arg">saturation</em> percentage, which defaults to 100 percent
1408 (no color change).
1409
1410 </td>
1411 </tr>
1412
1413 <tr valign="top">
1414 <td valign="top">displace</td>
1415 <td valign="top">Arguments:
1416 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em>][!][%]
1417 <br>Equivalent to "<code>composite</code>" <a href="#displace">-displace</a>
1418 <br>With this option, the 'overlay' image, and optionally the 'mask'
1419 image, is used as a relative displacement map, which is used to
1420 displace the lookup of what part of the destination image is seen at
1421 each point of the overlaid area. Much like the displacement map is a
1422 'lens' that distorts the original 'background' image behind it.
1423 <br><br>
1424 The X-scale is modilated by the 'red' channel of the overlay image
1425 while the Y-scale is modulated by the green channel, (the mask image
1426 if given is rolled into green channel of the overlay image. This
1427 separation allows you to modulate the X and Y lookup displacement
1428 separatally allowing you to di 2 dimentional displacements, rather
1429 than 1 dimentional verctored displacements (using grayscale image).
1430 <br><br>
1431 If the overlay image contains transparency this is used as a mask
1432 of the resulting image to remove 'invalid' pixels.
1433 <br><br>
1434 The '%' flag makes the displacement scale relative to the size of the
1435 overlay image (100% = half width/height of image). Using '!' switches
1436 percentage arguments to refer to the destination image size instead.
1437 <br><br>
1438 Special flags were added Added to ImageMagick version 6.5.3-5.
1439 </td>
1440 </tr>
1441
1442 <tr valign="top">
1443 <td valign="top">distort</td>
1444 <td valign="top">Arguments:
1445 <em class="arg">X-scale</em>[x<em class="arg">Y-scale</em
1446 >[+<em class="arg">X-center</em>+<em class="arg">Y-center</em>]][!][%]
1447 <br>Not available in "<code>composite</code>" at this time.
1448 <br>Exactly as per 'Displace' (above), but using absolute coordinates,
1449 relative to the center of the overlay (or that given). Basically
1450 allows you to generate absolute distortion maps where 'black' will
1451 look up the left/top edge, and 'white' looks up the bottom/right
1452 edge of the destination image, according to the scale given.
1453 <br><br>
1454 The '!' flag not only switches percentage scaling, to use the
1455 destination image, but also the image the center offset of the lookup.
1456 This means the overlay can lookup a completely different region of the
1457 destination image.
1458 <br><br>
1459 Added to ImageMagick version 6.5.3-5.
1460 </td>
1461 </tr>
1462
1463 <tr valign="top">
1464 <td valign="top">blur</td>
1465 <td valign="top">Arguments:
1466 <em class="arg">Width</em>[x<em class="arg">Height</em
1467 >[+<em class="arg">Angle</em>]]
1468 <br>Equivalent to "<code>composite</code>"
1469 <a href="#blur-composite">-blur</a>
1470 <br>A Variable Blur Mapping Composition method, where each pixel in the
1471 overlaid region is replaced with an Elliptical Weighted Average (EWA),
1472 with an ellipse (typically a circle) of the given sigma size, scaled
1473 according to overlay (source image) grayscale mapping.
1474 <br><br>
1475 As per 'Displace' and 'Distort', the red channel will modulate the
1476 width of the ellipse, while the green channel will modulate the height
1477 of the ellipse. However at this time the ellipse angle is not
1478 modulated though this may be a future posibility (perhaps with a
1479 special flag to enable use of blur channel for this purpose).
1480 <br><br>
1481 Added to ImageMagick version 6.5.4-0.
1482 </td>
1483 </tr>
1484
1485 </tbody>
1486</table>
1487
1488<p>To print a complete list of all the available compose operators, use <a href="#list">-list compose</a>.</p>
1489
1490
1491<div style="margin: auto;">
1492 <h4><a name="composite" id="composite"></a>-composite</h4>
1493</div>
1494
1495<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>
1496
1497<p>Take the first image 'destination' and overlay the second 'source' image
1498according to the current <a href="#compose">-compose</a> setting. The location
1499of the 'source' or 'overlay' image is controlled according to <a
1500href="#geometry" >-geometry</a>, and <a href="#geometry" >-geometry</a>
1501settings. </p>
1502
1503<p>If a third image is given this is treated as a gray-scale 'mask' image
1504relative to the first 'destination' image. This mask will limit what parts of
1505the destination can be modified by the image composition. However for the
1506'<kbd>displace</kbd>' compose method, the mask is used to provide a separate
1507Y-displacement image instead. </p>
1508
1509<p>If a <a href="#compose">-compose</a> method requires extra numerical
1510arguments or flags these can be provided by setting the <a
1511href="#set">-set</a> '<kbd class="arg">option:compose:args</kbd>'
1512appropriatally for the compose method. </p>
1513
1514<p>Some <a href="#compose">-compose</a> methods can modify the 'destination'
1515image outside the overlay area. You can disable this by setting the special <a
1516href="#set">-set</a> '<kbd class="arg">option:compose:outside-overlay</kbd>'
1517to '<kbd>false</kbd>'. </p>
1518
1519
1520<div style="margin: auto;">
1521 <h4><a name="compress" id="compress"></a>-compress <em class="arg">type</em></h4>
1522</div>
1523
1524<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>
1525
1526<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>
1527
1528<p>To print a complete list of compression types, use <a href="#list">-list compress</a>.</p>
1529
1530<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>
1531
1532<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>
1533
1534<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>
1535
1536<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>
1537
1538<div style="margin: auto;">
1539 <h4><a name="contrast" id="contrast"></a>-contrast</h4>
1540</div>
1541
1542<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>
1543
1544<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>
1545
1546<p>For a more pronounced effect you can repeat the option:</p>
1547
1548<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert rose: -contrast -contrast rose_c2.png</span></p>
1549<div style="margin: auto;">
1550 <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>
1551</div>
1552
1553<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>
1554
1555<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>
1556
1557<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>
1558
1559<p>Note that <kbd>-contrast-stretch 0</kbd> will modify the image such that the image's
1560min 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>
1561
1562<p>The channels are stretched in concert. Specify <a href="#channel">-channel</a> to normalize the RGB channels individually.</p>
1563
1564
1565<div style="margin: auto;">
1566 <h4><a name="convolve" id="convolve"></a>-convolve <em class="arg">kernel</em></h4>
1567</div>
1568
1569<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>
1570
1571<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>
1572
1573<p>Note that the <a href="../www/command-line-options.html#convolve">&#x2011;convolve</a> operator supports the <a href="../www/command-line-options.html#bias">&#x2011;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.
1574</p>
1575
1576<p>When using an ImageMagick with the HDRI compile-time setting, <a href="../www/command-line-options.html#bias">&#x2011;bias</a> is not needed,
1577as ImageMagick is able to store/handle any negative results without
1578clipping to the color value range (0..QuantumRange).</p>
1579
1580<p>See the discussion on HDRI implementations of ImageMagick on the page
1581<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.
1582</p>
1583
1584<div style="margin: auto;">
1585 <h4><a name="crop" id="crop"></a>-crop <em class="arg">geometry</em></h4>
1586</div>
1587
1588<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>
1589
1590<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>
1591
1592<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>
1593
1594<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>
1595
1596<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>
1597
1598<p>By adding a exclamation character flag to the geometry argument, the
1599cropped images virtual canvas page size and offset is set as if the
1600geometry argument was a viewport or window. This means the canvas page size
1601is set to exactly the same size you specified, the image offset set
1602relative top left corner of the region cropped. </p>
1603
1604<p>If the cropped image 'missed' the actual image on its virtual canvas, a
1605special single pixel transparent 'missed' image is returned, and a 'crop
1606missed' warning given. </p>
1607
1608
1609<div style="margin: auto;">
1610 <h4><a name="cycle" id="cycle"></a>-cycle <em class="arg">amount</em></h4>
1611</div>
1612
1613<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>
1614
1615<p><em class="arg">Amount</em> defines the number of positions each
1616colormap entry is shifted.</p>
1617
1618
1619<div style="margin: auto;">
1620 <h4><a name="debug" id="debug"></a>-debug <em class="arg">events</em></h4>
1621</div>
1622
1623<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>
1624
1625<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>
1626
1627
1628<p>For example, to log cache and blob events, use.</p>
1629
1630<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -debug "Cache,Blob" rose: rose.png</span></p>
1631<p>The <kbd>User</kbd> domain is normally empty, but developers can log user events in their private copy of ImageMagick.</p>
1632
1633<p>To print the complete list of debug methods, use <a href="#list">-list debug</a>.</p>
1634
1635<p>Use the <a href="#log">-log</a> option to specify the format for debugging output.</p>
1636
1637<p>Use <a href="#debug">+debug</a> to turn off all logging.</p>
1638
1639<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>
1640
1641
1642<div style="margin: auto;">
1643 <h4><a name="decipher" id="decipher"></a>-decipher <em class="arg">filename</em></h4>
1644</div>
1645
1646<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>
1647
1648<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
1649
1650<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p>
1651
1652
1653<div style="margin: auto;">
1654 <h4><a name="deconstruct" id="deconstruct"></a>-deconstruct</h4>
1655</div>
1656
1657<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>
1658
1659<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>
1660
1661<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>
1662
1663<p>This option is actually equivalent to the <a href="#layers">-layers</a> method '<kbd>compare-any</kbd>'. </p>
1664
1665
1666<div style="margin: auto;">
1667 <h4><a name="define" id="define"></a>-define <em class="arg">key</em>{<em class="arg">=value</em>}<em class="arg">...</em></h4>
1668</div>
1669
1670<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>
1671
1672<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>
1673
1674<p>The following definitions may be created:</p>
1675
1676<ul>
1677<dt>jp2:rate=value</dt>
1678 <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 />
1679<dt>mng:need-cacheoff</dt>
1680 <dd>turn playback caching off for streaming MNG.</dd><br />
1681<dt>png:bit-depth=value</dt>
1682<dt>png:color-type=value</dt>
1683 <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 />
1684<dt>ps:imagemask</dt>
1685 <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>
1686</ul>
1687
1688<p>For example, to create a postscript file that will render only the black pixels of a bilevel image, use:</p>
1689
1690<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert bilevel.tif -define ps:imagemask eps3:stencil.ps</span></p>
1691<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>
1692
1693<p class="crtsnip">
1694-define registry:temporary-path=/data/tmp
1695</p>
1696
1697<div style="margin: auto;">
1698 <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">&lt;</em>} {<em class="arg">&gt;</em>}</h4>
1699</div>
1700
1701<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>
1702
1703<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>
1704
1705<p>Use <kbd>&gt;</kbd> to change the image delay <em>only</em> if its current value exceeds the given delay. <kbd>&lt;</kbd> changes the image delay <em>only</em> if current value is less than the given delay. For example, if you specify <kbd>30&gt;</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>&lt;</kbd> or <kbd>&gt;</kbd> from being interpreted by your shell as a file redirection.</p>
1706
1707
1708<div style="margin: auto;">
1709 <h4><a name="delete" id="delete"></a>-delete <em class="arg">index</em></h4>
1710</div>
1711
1712<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>
1713
1714<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>
1715
1716
1717<div style="margin: auto;">
1718 <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>
1719</div>
1720
1721<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>
1722
1723<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>
1724
1725<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>
1726
1727<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>
1728
1729<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>
1730
1731<div style="margin: auto;">
1732 <h4><a name="depth" id="depth"></a>-depth <em class="arg">value</em></h4>
1733</div>
1734
1735<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>
1736
1737<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>
1738
1739<div style="margin: auto;">
1740 <h4><a name="descend" id="descend"></a>-descend</h4>
1741</div>
1742
1743<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>
1744
1745<div style="margin: auto;">
1746 <h4><a name="deskew" id="deskew"></a>-deskew <em class="arg">threshold</em></h4>
1747</div>
1748
1749<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>
1750
1751<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>
1752
1753<div style="margin: auto;">
1754 <h4><a name="despeckle" id="despeckle"></a>-despeckle</h4>
1755</div>
1756
1757<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>
1758
1759<div style="margin: auto;">
1760 <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>
1761</div>
1762
1763<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>
1764
1765<p>With this option, the 'overlay' image, and optionally the 'mask' image,
1766will be used as a displacement map, which is used to displace the lookup of
1767what part of the 'background' image is seen at each point of the overlaid
1768area. Much like the displacement map is a 'lens' that redirects light shining
1769through it so as to present a distorted view the original 'background' image
1770behind it. </p>
1771
1772<p>Any perfect grey areas of the displacement map produce a zero
1773displacement of the image. Black areas produce the given maximum negative
1774displacement of the lookup point, while white produce a maximum positive
1775displacement of the lookup. </p>
1776
1777<p>Note that it is the lookup of the 'background' that is displaced, not a
1778displacement of the image itself. As such an area of the displacement map
1779containing 'white' will have the lookup point 'shifted' by a positive amount,
1780and thus generating a copy of the destination image to the right/downward from
1781the correct position. That is the image will look like it may have been
1782'shifted' in a negative left/upward direction. Understanding this is a very
1783important in understanding how displacement maps work. </p>
1784
1785<p>The given arguments define the maximum amount of displacement in pixels
1786that a particular map can produce. If the displacement scale is large enough
1787it is also posible to lookup parts of the 'background' image that lie well
1788outside the bounds of the displacement map itself. That is you could very
1789easilly copy a section of the original image from outside the overlay area
1790into the overlay area. </p>
1791
1792<p>The '%' flag makes the displacement scale relative to the size of the
1793overlay image (100% = half width/height of image). Using '!' switches
1794percentage arguments to refer to the destination image size instead.
1795these flags were added as of IM v6.5.3-5.</p>
1796
1797<p>Normally a single grayscale displacement map is provided, which with the
1798given scaling values will determine a single direction (vector) in which
1799displacements can occur (positivally or negativally). However, if you also
1800specify a third image which is normally used as a <em class="arg">mask</em>,
1801then the <em class="arg">composite image</em> will be used for horizontal X
1802displacement, while the <em class="arg">mask image</em> is used for vertical Y
1803displacement. This allows you to define completely different displacement
1804values for the X and Y directions, and allowing you to lookup any point within
1805the <em class="arg">scale</em> bounds. In other words each pixel can lookup
1806any other nearby pixel, producing complex 2 dimentional displacements, rather
1807than a simple 1 dimentional vector displacements. </p>
1808
1809<p>Alternativally rather than suppling two separate images, as of IM v6.4.4-0,
1810you can use the 'red' channel of the overlay image to specify the horizontal
1811or X displacement, and the 'green' channel for the vertical or Y displacement.
1812</p>
1813
1814<p>As of IM v6.5.3-5 any alpha channel in the overlay image will be used as a
1815mask the transparency of the destination image. However areas outside the
1816overlaid areas will not be effected. </p>
1817
1818
1819<div style="margin: auto;">
1820 <h4><a name="display" id="display"></a>-display <em class="arg">host:display[.screen]</em></h4>
1821</div>
1822
1823<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>
1824
1825<p>This option is used with convert for obtaining image or font from this X server. See <em class="arg">X(1)</em>.</p>
1826
1827<div style="margin: auto;">
1828 <h4><a name="dispose" id="dispose"></a>-dispose <em class="arg">method</em></h4>
1829</div>
1830
1831<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>
1832
1833<p>The layer disposal method defines the way each the displayed image is to be
1834modified after the current 'frame' of an animation has finished being
1835displayed (after its 'delay' period), but before the next frame on an
1836animation is to be overlaid onto the display. </p>
1837
1838<p>Here are the valid methods:</p>
1839
1840<pre class="text">
1841Undefined 0 No disposal specified (equivalent to '<kbd>none</kbd>').
1842None 1 Do not dispose, just overlay next frame image.
1843Background 2 Clear the frame area with the background color.
1844Previous 3 Clear to the image prior to this frames overlay.
1845</pre>
1846
1847<p>You can also use the numbers given above, which is what the GIF format
1848uses internally to represent the above settings. </p>
1849
1850<p>To print a complete list of dispose methods, use <a href="#list">-list dipose</a>.</p>
1851
1852<p>Use <a href="#dispose" >+dispose</a>, turn off the setting and prevent
1853resetting the layer disposal methods of images being read in. </p>
1854
1855<p>Use <a href="#set">-set</a> '<kbd>dispose</kbd>' method to set the image
1856disposal method for images already in memory.</p>
1857
1858<div style="margin: auto;">
1859 <h4><a name="dissimilarity-threshold" id="dissimilarity-threshold"></a>-dissimilarity-threshold <em class="arg">value</em></h4>
1860</div>
1861
1862<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>
1863
1864
1865<div style="margin: auto;">
1866 <h4><a name="dissolve" id="dissolve"></a>-dissolve <em class="arg">src_percent</em>[x<em class="arg">dst_percent</em>]</h4>
1867</div>
1868
1869<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>
1870
1871<p>The opacity of the composite image is multiplied by the given percent, then
1872it is composited 'over' the main image. If <em class="arg">src_percent</em>
1873is greater than 100, start dissolving the main image so it will become
1874transparent at a value of '<kbd class="arg">200</kbd>'. If both percentages
1875are given, each image are dissolved to the percentages given. </p>
1876
1877<p>Note that dissolve percentages do not add, two opaque images dissolved
1878'50,50', produce a 75% transparency. For a 50% + 50% blending of the two
1879images, you would need to use dissolve values of '50,100'. </p>
1880
1881<div style="margin: auto;">
1882 <h4><a name="distort" id="distort"></a>-distort <em class="arg">method arguments</em></h4>
1883</div>
1884
1885<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>
1886
1887<p>The <em class="arg">arguments</em> is a single string containing a list
1888of floating point numbers separated by commas or spaces. The number of
1889and meaning of the floating point values depends on the distortion <em
1890class="arg">method</em> being used. </p>
1891
1892<p>Choose from these distortion types:</p>
1893
1894<table class="doc">
1895 <tr valign="top">
1896 <th align="left" style="width: 8%">Method</th>
1897 <th align="left">Description</th>
1898 </tr>
1899
1900 <tr valign="top">
1901 <td valign="top"><kbd>ScaleRotateTranslate</kbd>&nbsp;&nbsp;
1902 <br/>or &nbsp; <kbd>SRT</kbd></td>
1903 <td valign="top">
1904 Distort image by first scaling and rotating about a given 'center',
1905 before translating that 'center' to the new location, in that order. It
1906 is an alternative method of specifying a '<kbd>Affine</kbd>' type of
1907 distortion, but without shearing effects. It also provides a good way
1908 of rotating and displacing a smaller image for tiling onto a larger
1909 background (IE 2-dimensional animations). <br/>
1910
1911 The number of arguments determine the specific meaning of each
1912 argument for the scales, rotation, and translation operations. <br/>
1913
1914 <table style="margin-left:auto; margin-right:auto;">
1915 <tr><td># &nbsp;</td><td>arguments meaning</td></tr>
1916 <tr><td>1:</td><td><em>Angle_of_Rotation</em></td></tr>
1917 <tr><td>2:</td><td><em>Scale &nbsp; Angle</em></td></tr>
1918 <tr><td>3:</td><td><em>ScaleX,ScaleY &nbsp; Angle</em></td></tr>
1919 <tr><td>4:</td><td><em>X,Y &nbsp; Scale &nbsp; Angle</em></td></tr>
1920 <tr><td>5:</td>
1921 <td><em>X,Y &nbsp; ScaleX,ScaleY &nbsp; Angle</em></td></tr>
1922 <tr><td>6:</td>
1923 <td><em>X,Y &nbsp; Scale &nbsp; Angle &nbsp; NewX,NewY</em></td></tr>
1924 <tr><td>7:</td>
1925 <td><em>X,Y &nbsp; ScaleX,ScaleY &nbsp; Angle
1926 &nbsp; NewX,NewY</em></td></tr>
1927 </table>
1928
1929 This is actually an alternative way of specifing a 2 dimensional linear
1930 '<kbd>Affine</kbd>' or '<kbd>AffineProjection</kbd>' distortion. </td> </tr>
1931
1932 <tr valign="top">
1933 <td valign="top"><kbd>Affine</kbd></td>
1934 <td valign="top">
1935 Distort the image linearly by moving a list of at least 3 or more sets
1936 of control points (as defined below). Idealy 3 sets or 12 floating
1937 point values are given allowing the image to be linearly scaled,
1938 rotated, sheared, and translated, according to those three points. See
1939 also the related '<kbd>AffineProjection</kbd>' and '<kbd>SRT</kbd>'
1940 distortions. <br/>
1941
1942 More than 3 sets given control point pairs (12 numbers) is least
1943 squares fitted to best match a lineary affine distortion. If only 2
1944 control point pairs (8 numbers) are given a two point image translation
1945 rotation and scaling is performed, without any posible shearing,
1946 flipping or changes in aspect ratio to the resulting image. If only one
1947 control point pair is provides the image is only translated, (which may
1948 be a floating point non-integer translation). <br/>
1949
1950 This distortion does not include any form of perspective distortion.
1951 </td>
1952
1953 </tr>
1954
1955 <tr valign="top">
1956 <td valign="top"><kbd>AffineProjection</kbd></td>
1957 <td valign="top">
1958 Linearly distort an image using the given Affine Matrix of 6
1959 pre-calculated coefficients forming a set of Affine Equations to map
1960 the source image to the destination image.
1961
1962 <div style="text-align: center"><em>
1963 s<sub>x</sub>, r<sub>x</sub>,
1964 r<sub>y</sub>, s<sub>y</sub>,
1965 t<sub>x</sub>, t<sub>y</sub>
1966 </em></div>
1967
1968 See <a href="#affine" >-affine</a> setting for more detail, and
1969 meanings of these coefficients. <br/>
1970
1971 The distortions '<kbd>Affine</kbd>' and '<kbd>SRT</kbd>' provide
1972 alternative methods of defining this distortion, with ImageMagick doing the
1973 calculations needed to generate the required coefficients. You can see
1974 the internally generated coefficients, by using a <a href="#verbose"
1975 >-verbose</a> setting. </td>
1976
1977 </tr>
1978
1979<!-- still under development, do not display - Anthony
1980 <tr valign="top">
1981 <td valign="top"><kbd>Bilinear</kbd></td>
1982 <td valign="top">
1983 Bilinear (reversed) Distortion, given a minimum of 4 sets of
1984 coordinate pairs, or 16 values (see below). Not that lines may not
1985 appear straight after distortion, though the distance between
1986 coordinates will remain consistant. </td>
1987 </tr>
1988-->
1989
1990 <tr valign="top">
1991 <td valign="top"><kbd>Perspective</kbd></td>
1992 <td valign="top">
1993 Perspective distort the images, using a list of 4 or more sets of
1994 control points (as defined below). More that 4 sets (16 numbers) of
1995 control points provide least squares fitting for more accurate
1996 distortions (for the purposes of image registration and panarama
1997 effects). Less than 4 sets will fall back to a '<kbd>Affine</kbd>'
1998 linear distortion. <br/>
1999
2000 Perspective Distorted images ensures that straight lines remain
2001 straight, but the scale of the distorted image will vary. The horizon
2002 is anti-aliased, and the 'sky' color may be set using the
2003 <a href="#mattecolor" >-mattecolor</a> setting. </td>
2004 </tr>
2005
2006 <tr valign="top">
2007 <td valign="top"><kbd>PerspectiveProjection</kbd>&nbsp;&nbsp;</td>
2008 <td valign="top">
2009 Do a '<kbd>Perspective</kbd>' distortion basied on a set of 8
2010 pre-calculated coefficients. You can get these coefficients by looking
2011 at the <a href="#verbose" >-verbose</a> output of a
2012 '<kbd>Prespective</kbd>' distortion, or by calculating them yourself.
2013 If the last two perspective scaling coefficients are zero, the
2014 remaining 6 represents a transposed 'Affine Matrix'. </td>
2015
2016 </tr>
2017
2018 <tr valign="top">
2019 <td valign="top"><kbd>Arc</kbd></td>
2020 <td valign="top">
2021 Arc the image (variation of polar mapping) over the angle given around
2022 a circle. <br/>
2023 <table width="90%" style = "margin-left: auto; margin-right: auto;">
2024 <tr valign="top"><td>Argument</td>
2025 <td>Meaning</td></tr>
2026 <tr valign="top"><td><em>arc_angle</em></td>
2027 <td>The angle over which to arc the image side-to-side</td></tr>
2028 <tr valign="top"><td><em>rotate_angle</em></td>
2029 <td>Angle to rotate resulting image from vertical center</td></tr>
2030 <tr valign="top"><td><em>top_radius</em></td>
2031 <td>Set top edge of source image at this radius</td></tr>
2032 <tr valign="top"><td><em>bottom_radius</em>&nbsp;</td>
2033 <td>Set bottom edge to this radius (radial scaling)</td></tr>
2034 </table>
2035
2036 The resulting image is always resized to best fit the resulting image,
2037 (as if using <a href="#distort" >+distort</a>) while attempting to
2038 preserve scale and aspect ratio of the original image as much as
2039 possible with the arguments given by the user. All four arguments will
2040 be needed to change the overall aspect ratio of an 'Arc'ed image. <br/>
2041
2042 This a variation of a polar distortion designed to try to preserve the
2043 aspect ratio of the image rather than direct Cartesian to Polar
2044 conversion. </td>
2045 </tr>
2046
2047 <tr valign="top">
2048 <td valign="top"><kbd>Polar</kbd></td>
2049 <td valign="top">
2050 Like '<kbd>Arc</kbd>' but do a complete Cartesian to Polar mapping of
2051 the image. that is the height of the input image is mapped to the
2052 radius limits, while the width is wrapped around between the
2053 angle limits. <br/>
2054
2055 Arguments: <em>Rmax,Rmin CenterX,CenterY, start,end_angle</em> <br/>
2056
2057 All arguments are optional. With <em>Rmin</em> defaulting to zero, the
2058 center to the center of the image, and the angles going from -180 (top)
2059 to +180 (top). If <em>Rmax</em> is given the special value of
2060 '<code>0</code>', the the distance from the center to the nearest edge
2061 is used for the radius of the output image, which will ensure the whole
2062 image is visible (though scaled smaller). However a special value of
2063 '<code>-1</code>' will use the distance from the center to the furthest
2064 corner, This may 'clip' the corners from the input rectangular image,
2065 but will generate the exact reverse of a '<kbd>DePolar</kbd>' with
2066 the same arguments. <br/>
2067
2068 If the plus form of distort (<a href="#distort" >+distort</a>) is used
2069 output image center will default to <code>0,0</code> of the virtual
2070 canvas, and the image size adjusted to ensure the whole input image is
2071 made visible in the output image on the virtual canvas. </td>
2072
2073 </tr>
2074
2075 <tr valign="top">
2076 <td valign="top"><kbd>DePolar</kbd></td>
2077 <td valign="top">
2078 Uses the same arguments and meanings as a '<kbd>Polar</kbd>' distortion
2079 but generates the reverse Polar to Cartesian distortion. <br/>
2080
2081 The special <em>Rmax</em> setting of '<code>0</code>' may however clip
2082 the corners of the input image. However using the special
2083 <em>Rmax</em> setting of '<code>-1</code>' (maximum center to corner
2084 distance) will ensure the whole distorted image is preserved in the
2085 generated result, so that the same argument to '<kbd>Polar</kbd>' will
2086 reverse the distortion re-producing the original.
2087
2088 Note that as this distortion requires the area resampling of a circular
2089 arc, which can not be handled by the builtin EWA resampling function.
2090 As such the normal EWA filters are turned off. It is recomended some
2091 form of 'super-sampling' image processing technique be used to produce
2092 a high quality result. </td>
2093
2094 </tr>
2095
2096 <tr valign="top">
2097 <td valign="top"><kbd>Barrel</kbd></td>
2098 <td valign="top">
2099 Given the four coefficients (A,B,C,D) as defined by <a
2100 href="http://www.all-in-one.ee/~dersch/barrel/barrel.html" >Helmut
2101 Dersch</a>, perform a barrell or pincussion distortion appropriate to
2102 correct radial lens distortions. That is in photographs, make straight
2103 lines straight again. <br/>
2104
2105 Arguments: <em>A &nbsp; B &nbsp; C</em> &nbsp; [ <em>D</em> &nbsp; [
2106 <em>X</em> , <em>Y</em> ] ] <br/>
2107 or <em>A<sub>x</sub> B<sub>x</sub> C<sub>x</sub> D<sub>x</sub> &nbsp;
2108 A<sub>y</sub> B<sub>y</sub> C<sub>y</sub> D<sub>y</sub></em> &nbsp;
2109 [ <em>X</em> , <em>Y</em> ] <br/>
2110 So that it forms the function <br/>
2111 Rsrc = r * ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
2112 <em>C</em>*r + <em>D</em> )<br/>
2113
2114 Where <em>X</em>,<em>Y</em> is the optional center of the distortion
2115 (defaulting to the center of the image). <br/>
2116 The second form is typically used to distort images, rather than
2117 correct lens distortions. <br/>
2118 </td>
2119
2120 </tr>
2121
2122 <tr valign="top">
2123 <td valign="top"><kbd>BarrelInverse</kbd></td>
2124 <td valign="top">
2125 This is very simular to '<kbd>Barrel</kbd>' with the same set of
2126 arguments, and argument handling. However it uses the inverse
2127 of the radial polynomial,
2128 so that it forms the function <br/>
2129 Rsrc = r / ( <em>A</em>*r<sup>3</sup> + <em>B</em>*r<sup>2</sup> +
2130 <em>C</em>*r + <em>D</em> )
2131 </td>
2132 </tr>
2133
2134 <tr valign="top">
2135 <td valign="top"><kbd>Shepards</kbd></td>
2136 <td valign="top">
2137 Distort the given list control points (any number) using an Inverse
2138 Squared Distance Interpolation Method (<a
2139 href="http://www.ems-i.com/smshelp/Data_Module/Interpolation/Inverse_Distance_Weighted.htm"
2140 >Shepards Method</a>). The control points in effect do 'localized'
2141 distortions of the image around the given control point. For best
2142 results extra control points should be added to 'lock' the positions of
2143 the corners and other unchanging parts of the image. <br/>
2144
2145 The distortion has been likened to 'taffy pulling' using nails, pins or
2146 sticks. It basically uses the <a href="#sparse-color"
2147 >-sparse-color</a> method of the same name to generate separate X and Y
2148 displacement maps (see <a href="#displace" >-displace</a>) for source
2149 image color look-up. </td>
2150
2151 </tr>
2152
2153</table>
2154
2155<p>To print a complete list of distortion methods, use <a href="#list">-list distort</a>.</p>
2156
2157<p>Many of the above distortion methods such as '<kbd>Affine</kbd>',
2158'<kbd>Perspective</kbd>', and '<kbd>Shepards</kbd>' use a list control points
2159defining how these points in the given image should be distorted in the
2160destination image. Each set of four floating point values represent a source
2161image coordinate, followed immediately by the destination image coordinate.
2162This produces a list of values such as...</p>
2163<div style="text-align: center"><em>
2164 U<sub>1</sub>,V<sub>1</sub> X<sub>1</sub>,Y<sub>1</sub> &nbsp;
2165 U<sub>2</sub>,V<sub>2</sub> X<sub>2</sub>,Y<sub>2</sub> &nbsp;
2166 U<sub>3</sub>,V<sub>3</sub> X<sub>3</sub>,Y<sub>3</sub> &nbsp;
2167 ... &nbsp;
2168 U<sub>n</sub>,V<sub>n</sub> X<sub>n</sub>,Y<sub>n</sub> &nbsp;
2169</em></div>
2170<p>where <em>U,V</em> on the source image is mapped to <em>X,Y</em> on the
2171destination image. </p>
2172
2173<p>For example, to warp an image using '<kbd>perspective</kbd>' distortion,
2174needs a list of at least 4 sets of coordinates, or 16 numbers. Here is the
2175perspective distortion of the built-in "rose:" image. Note how spaces were
2176used to group the 4 sets of coordinate pairs, to make it easier to read and
2177understand.</p>
2178
2179<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>
2180 convert rose: -virtual-pixel black \ <br/>
2181 -distort Perspective '0,0,0,0 0,45,0,45 69,0,60,10 69,45,60,35' \ <br/>
2182 rose_3d_rotated.gif</span></p>
2183<p>If more that the required number of coordinate pairs are given for a
2184distortion, the distortion method is 'least squares' fitted to
2185produce the best result for all the coordinate pairs given. If less than the
2186ideal number of points are given, the distort will generally fall back to a
2187simpler form of distortion that can handles the smaller number of coordinates
2188(usally a linear '<kbd>Affine</kbd>' distortion). </p>
2189
2190<p>By using more coodinates you can make use of image registration tool to
2191find matching coordinate pairs in overlaping images, so as to improve the 'fit'
2192of the distortion. Of course a bad coordinate pair can also make the 'fit'
2193worse. Caution is always advised. </p>
2194
2195<p>Colors are acquired from the source image according to the <a
2196href="#interpolate" >-interpolate</a> color lookup setting, when the image is
2197magnified. However if the viewed image is minified (image becomes smaller), a
2198special area resampling function (added ImageMagick v6.3.5-9), is used to
2199produce a higher quality image. For example you can use a
2200'<kbd>perspective</kbd>' distortion to view a infinitely tiled 'plane' all the
2201way to the horizon. </p>
2202
2203<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 90x90 pattern:checkerboard -normalize -virtual-pixel tile \ <br/>
2204 -distort perspective '0,0,5,45 89,0,45,46 0,89,0,89 89,89,89,89' \ <br/>
2205 checks_tiled.jpg</span></p>
2206<p>Note that a infinitely tiled perspective images involving the horizon can
2207be very slow to generate due to the use of the high quality 'area resampling'
2208function (added ImageMagick v6.3.5-9). You can turn off 'area resampling'
2209using a <a href="#filter" >-filter</a> setting of '<kbd>point</kbd>'
2210(recommended if you plan to use super-sampling instead). </p>
2211
2212<p>If an image generates <i>invalid pixels</i>, such as the 'sky' in the last
2213'<kbd>perspective</kbd>' distortion example, <a href="#distort" >-distort</a>
2214will use the current <a href="#mattecolor" >-mattecolor</a> setting for these
2215pixels. If you do not what these pixels to be visible, set the color to match
2216the rest of the ground. </p>
2217
2218<p>The output image size will by default be the same as the input image. This
2219means that if the part of the distorted image falls outside the viewed area of
2220the 'distorted space', those parts is clipped and lost. However if you
2221use the plus form of the operator (<a href="#distort" >+distort</a>) the
2222operator will attempt (if posible) to show the whole of the distorted image,
2223while retaining a correct 'virtual canvas' offset, for image layering. This
2224offset may need to be removed using <a href="#repage" >+repage</a>, to remove
2225if it is unwanted. </p>
2226
2227<p>You can alternatively specify a special "<kbd><a href="#set" >-set</a>
2228option:distort:viewport {geometry_string}</kbd>" setting which will specify
2229the size and the offset of the generated 'viewport' image of the distorted
2230image space.</p>
2231
2232<p>Adding a "<kbd><a href="#set" >-set</a> option:distort:scale
2233{scale_factor}</kbd>" will scale the output image (viewport or otherwise) by
2234that factor without changing the viewed contents of the distorted image. This
2235can be used either for 'super-sampling' the image for a higher quality result,
2236or for panning and zooming around the image (with appropriate viewport
2237changes, or post-distort cropping and resizing). </p>
2238
2239<p>Setting <a href="#verbose" >-verbose</a> setting, will cause <a
2240href="#distort" >-distort</a> to attempt to output the internal coefficients,
2241and the <a href="#fx" >-fx</a> equivalent to the distortion, for expert study,
2242and debugging purposes. This many not be available for all distorts. </p>
2243
2244<p>Affine rotations and shears (such as '<kbd>SRT</kbd>' distortion), tend to
2245produce a cleaner result that the equivalent <a href="#rotate" >-rotate</a>
2246and/or <a href="#shear" >-shear</a> operation, with more control of due to the
2247above settings. It is algorithmically slower, though in ImageMagick it may be faster.
2248</p>
2249
2250
2251<div style="margin: auto;">
2252 <h4><a name="dither" id="dither"></a>-dither <em class="arg">method</em></h4>
2253</div>
2254
2255<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>
2256
2257<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>
2258
2259<p>Dithering is turned on by default, to turn it off use the plus form of the
2260setting, <a href="#dither">+dither</a>. This will also also render PostScript
2261without text or graphic aliasing. Disabling dithering often (but not always)
2262leads to faster process, a smaller number of colors, but more cartoon like
2263image coloring. Generally resulting in 'color banding' effects in areas with
2264color gradients. </p>
2265
2266<p>The color reduction operators <a href="#colors">-colors</a>, <a
2267href="#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>
2268
2269<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>
2270
2271
2272<div style="margin: auto;">
2273 <h4><a name="draw" id="draw"></a>-draw <em class="arg">string</em></h4>
2274</div>
2275
2276<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>
2277
2278<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>
2279
2280<p>The shape primitives:</p>
2281
2282<pre class="text">
2283 point x,y
2284 line x0,y0 x1,y1
2285 rectangle x0,y0 x1,y1
2286 roundRectangle x0,y0 x1,y1 wc,hc
2287 arc x0,y0 x1,y1 a0,a1
2288 ellipse x0,y0 rx,ry a0,a1
2289 circle x0,y0 x1,y1
2290 polyline x0,y0 ... xn,yn
2291 polygon x0,y0 ... xn,yn
2292 bezier x0,y0 ... xn,yn
2293 path path specification
2294 image operator x0,y0 w,h filename
2295</pre>
2296
2297<p>The text primitive:</p>
2298
2299<pre class="text">
2300 text x0,y0 string
2301</pre>
2302<p>The text gravity primitive:</p>
2303
2304<pre class="text">
2305 gravity NorthWest, North, NorthEast, West, Center,
2306 East, SouthWest, South, or SouthEast
2307</pre>
2308
2309<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>
2310
2311<p>The transformation primitives:</p>
2312
2313<pre class="text">
2314 rotate degrees
2315 translate dx,dy
2316 scale sx,sy
2317 skewX degrees
2318 skewY degrees
2319</pre>
2320
2321<p>The pixel operation primitives:</p>
2322
2323<pre class="text">
2324 color x0,y0 method
2325 matte x0,y0 method
2326</pre>
2327
2328<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>
2329
2330<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>
2331
2332<p>A <kbd>line</kbd> primitive requires a start point and end point.</p>
2333
2334<p>A <kbd>rectangle</kbd> primitive is specified by the pair of points at the upper left and lower right corners.</p>
2335
2336<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>
2337
2338<p>The <kbd>circle</kbd> primitive makes a disk (filled) or circle (unfilled). Give the center and any point on the perimeter (boundary).</p>
2339
2340<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>
2341
2342<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>
2343
2344<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>.
2345</p>
2346
2347<p>A <em>coordinate</em> is a pair of integers separated by a space or optional comma. </p>
2348
2349<p>As an example, to define a circle centered at 100,100 that extends to 150,150 use:</p>
2350
2351<p class="crtsnip">
2352 -draw 'circle 100,100 150,150'
2353</p>
2354
2355<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
2356draw 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>
2357
2358<p class="crtsnip">
2359 -draw 'bezier 20,50 45,100 45,0 70,50'
2360</p>
2361<p class="crtsnip">
2362 -draw 'bezier 70,50 95,100 95,0 120,50'
2363</p>
2364
2365
2366<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>
2367
2368<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>
2369
2370<p class="crtsnip">
2371 -draw 'image SrcOver 100,100 225,225 image.jpg'
2372</p>
2373
2374<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>
2375
2376<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>
2377
2378<p>For example, the following annotates the image with <kbd>Works like magick!</kbd> for an image titled <kbd>bird.miff</kbd>. </p>
2379
2380<p class="crtsnip">
2381 -draw 'text 100,100 "Works like magick!"'
2382</p>
2383
2384<p>See the <a href="#annotate">-annotate</a> option for another convenient way to annotate an image with text.</p>
2385
2386<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>
2387
2388<p>The <kbd>translate</kbd> primitive translates subsequent shape and text primitives.</p>
2389
2390<p>The <kbd>scale</kbd> primitive scales them.</p>
2391
2392<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>
2393
2394<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
2395matrix.</p>
2396
2397<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>
2398
2399<pre class="text">
2400 point
2401 replace
2402 floodfill
2403 filltoborder
2404 reset
2405</pre>
2406
2407<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>
2408
2409<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>
2410
2411<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>
2412
2413<p>Strings that begin with a number must be quoted (e.g. use '1.png' rather than 1.png).</p>
2414
2415<p>Drawing primitives conform to the <a href="../www/magick-vector-graphics.html">Magick Vector Graphics</a> format.</p>
2416
2417
2418<div style="margin: auto;">
2419 <h4><a name="edge" id="edge"></a>-edge <em class="arg">radius</em></h4>
2420</div>
2421
2422<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>
2423
2424<div style="margin: auto;">
2425 <h4><a name="emboss" id="emboss"></a>-emboss <em class="arg">radius</em></h4>
2426</div>
2427
2428<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>
2429
2430<div style="margin: auto;">
2431 <h4><a name="encipher" id="encipher"></a>-encipher <em class="arg">filename</em></h4>
2432</div>
2433
2434<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>
2435
2436<p>Get the passphrase from the file specified by <em class="arg">filename</em>.</p>
2437
2438<p>For more information, see the webpage, <a href="http://www.imagemagick.org/www/cipher.html">ImageMagick: Encipher or Decipher an Image</a>.</p>
2439
2440<div style="margin: auto;">
2441 <h4><a name="encoding" id="encoding"></a>-encoding <em class="arg">type</em></h4>
2442</div>
2443
2444<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>
2445
2446<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>
2447
2448<div style="margin: auto;">
2449 <h4><a name="endian" id="endian"></a>-endian <em class="arg">type</em></h4>
2450</div>
2451
2452<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>
2453
2454<p>To print a complete list of endian types, use the <a href="#list">-list endian</a> option.</p>
2455
2456<p>Use <a href="#endian">+endian</a> to revert to unspecified endianness.</p>
2457
2458
2459<div style="margin: auto;">
2460 <h4><a name="enhance" id="enhance"></a>-enhance</h4>
2461</div>
2462
2463<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>
2464
2465
2466<div style="margin: auto;">
2467 <h4><a name="equalize" id="equalize"></a>-equalize</h4>
2468</div>
2469
2470<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>
2471
2472<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>
2473
2474<p>For example using HSL, we have: ... <kbd>-colorspace HSL -channel lightness -equalize -colorspace RGB</kbd> ...</p>
2475
2476<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>
2477
2478<div style="margin: auto;">
2479 <h4><a name="evaluate" id="evaluate"></a>-evaluate <em class="arg">operator value</em></h4>
2480</div>
2481
2482<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>
2483
2484<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>
2485
2486<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>
2487
2488<table class="doc">
2489 <col width="25%" />
2490 <col width="75%" />
2491 <thead>
2492 <tr>
2493 <th><em class="arg">operator</em></th>
2494 <th>Summary (see further below for details)</th>
2495 </tr>
2496 </thead>
2497 <tbody>
2498
2499 <tr><td>Add </td> <td>Add <em class="arg">value</em> to pixels. </td></tr>
2500 <tr><td>AddModulus </td> <td>Add <em class="arg">value</em> to pixels modulo <em class="QR">QuantumRange</em>.</td></tr>
2501 <tr><td>And </td> <td>Binary AND of pixels with <em class="arg">value</em>.</td></tr>
2502 <tr><td>Cos, Cosine </td> <td>Apply cosine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
2503 <tr><td>Divide </td> <td>Divide pixels by <em class="arg">value</em>.</td></tr>
2504 <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>
2505 <tr><td>Log </td> <td>Apply scaled logarithm to normalized pixels.</td></tr>
2506 <tr><td>Max </td> <td>Clip pixels at lower bound <em class="arg">value</em>.</td></tr>
2507 <tr><td>Min </td> <td>Clip pixels at upper bound <em class="arg">value</em>.</td></tr>
2508 <tr><td>Multiply </td> <td>Multiply pixels by <em class="arg">value</em>.</td></tr>
2509 <tr><td>Or </td> <td>Binary OR of pixels with <em class="arg">value</em>.</td></tr>
2510 <tr><td>Pow </td> <td>Raise normalized pixels to the power <em class="arg">value</em>.</td></tr>
2511 <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>
2512 <tr><td>Set </td> <td>Set pixel equal to <em class="arg">value</em>.</td></tr>
2513 <tr><td>Sin, Sine </td> <td>Apply sine to pixels with frequency <em class="arg">value</em> with 50% bias added.</td></tr>
2514 <tr><td>Subtract </td> <td>Subtract <em class="arg">value</em> from pixels.</td></tr>
2515 <tr><td>Xor </td> <td>Binary XOR of pixels with <em class="arg">value.</em></td></tr>
2516
2517 <tr><td>&nbsp;</td></tr>
2518
2519 <tr><td>Gaussian-noise</td></tr>
2520 <tr><td>Impulse-noise</td></tr>
2521 <tr><td>Laplacian-noise</td></tr>
2522 <tr><td>Multiplicative-noise</td> <td>(These are equivalent to the corresponding <a href="#noise" >-noise</a> operators.)</td></tr>
2523 <tr><td>PoissonNoise</td></tr>
2524 <tr><td>Uniform-noise</td></tr>
2525
2526 <tr><td>&nbsp;</td></tr>
2527
2528 <tr><td>Threshold </td> <td>Threshold pixels larger than <em class="arg">value</em>.</td></tr>
2529 <tr><td>ThresholdBlack </td> <td>Threshold pixels to zero values equal to or below <em class="arg">value</em>.</td></tr>
2530 <tr><td>ThresholdWhite </td> <td>Threshold pixels to maximum values above <em class="arg">value</em>. </td></tr>
2531 </tbody>
2532 </table>
2533
2534<p>The specified functions are applied only to each previously set <a
2535href="#channel" >-channel</a> in the image. If necessary, the results of the
2536calculations are truncated (clipped) to fit in the interval [0,&nbsp;<em
2537class="QR">QuantumRange</em>]. The transparency channel of the image is
2538represented as a 'alpha' values (0 = fully transparent), so, for example, a
2539<kbd>Divide</kbd> by&nbsp;2 of the alpha channel will make the image
2540semi-transparent. Append the percent symbol '<kbd>%</kbd>' to specify a value
2541as a percentage of the <em class="QR">QuantumRange</em>.</p>
2542
2543<p>To print a complete list of <a href="#evaluate">-evaluate</a> operators, use
2544<a href="#list">-list evaluate</a>.</p>
2545
2546<p>The results of the <kbd>Add</kbd>, <kbd>Subtract</kbd> and
2547<kbd>Multiply</kbd> methods can also be achieved using either the <a
2548href="#level" >-level</a> or the <a href="#level" >+level</a> operator, with
2549appropriate argument, to linearly modify the overall range of color values.
2550Please note, however, that <a href="#level" >-level</a> treats transparency as
2551'matte' values (0 = opaque), while <a href="#level" >-evaluate</a> works with
2552'alpha' values.</p>
2553
2554<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,&nbsp;<em class="QR">QuantumRange</em>]. </p>
2555
2556<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>
2557
2558 <div style="text-align:center;">
2559 log(<em class="arg">value</em> &times; <b><em>u</em></b> + 1) / log(<em class="arg">value</em> + 1)
2560 </div>
2561
2562<p><kbd>Pow</kbd> has been added as of ImageMagick 6.4.1-9, and works on
2563normalized pixel values. Note that <kbd>Pow</kbd> is related to the <a
2564href="#gamma" >-gamma</a> operator. For example, <b>-gamma 2</b> is equivalent
2565to <b>-evaluate pow 0.5</b>, i.e., a 'square root' function. The value used
2566with <a href="#gamma" >-gamma</a> is simply the reciprocal of the value used
2567with <kbd>Pow</kbd>.</p>
2568
2569<p><kbd>Cosine</kbd> and <kbd>Sine</kbd> was added as of IM v6.4.8-8 and
2570converts the image values into a value according to a (co)sine wave function.
2571The synonyms <kbd>Cos</kbd> and <kbd>Sin</kbd> may also be used. The output
2572is biased 50% and normalized by 50% so as to fit in the respective color value
2573range. The <em class="arg">value</em> scaling of the <em>period</em> of the
2574function (its frequency), and thus determines the number of 'waves' that will
2575be generated over the input color range. For example, if the <em
2576class="arg">value</em> is&nbsp;1, the effective period is simply the <em
2577class="QR">QuantumRange</em>; but if the <em class="arg">value</em> is&nbsp;2,
2578then the effective period is the <em>half</em> the <em
2579class="QR">QuantumRange</em>.
2580
2581 <div style="text-align:center;">
2582 0.5 + 0.5 &times; cos(2 &pi; <b><em>u</em></b> &times; <em class="arg">value</em>).
2583 </div>
2584
2585See also the <a href="#function" >-function</a> operator, which is a
2586multi-value version of evaluate. </P>
2587
2588
2589<div style="margin: auto;">
2590 <h4><a name="extent" id="extent"></a>-extent <em class="arg">geometry</em></h4>
2591</div>
2592
2593<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>
2594
2595<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>
2596
2597<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>
2598
2599<div style="margin: auto;">
2600 <h4><a name="extract" id="extract"></a>-extract <em class="arg">geometry</em></h4>
2601</div>
2602
2603<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>
2604
2605<p>This option is most useful for extracting a subregion of a very large raw image. Note that these two commands are equivalent:</p>
2606
2607<p class='crt'><span class="crtprompt"> $magick&gt; </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&gt; </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>
2608
2609<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 16000x16000 -depth 8 -extract 640x480 image.rgb image.png</span></p>
2610<p>then the image will be <em>resized</em> to the specified dimensions instead,
2611equivalent to:</p>
2612
2613<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -size 16000x16000 -depth 8 -resize 640x480 image.rgb image.png</span></p>
2614<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>
2615
2616<div style="margin: auto;">
2617 <h4><a name="family" id="family"></a>-family <em class="arg">fontFamily</em></h4>
2618</div>
2619
2620<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>
2621
2622<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).
2623</p>
2624
2625<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>.
2626</p>
2627
2628<div style="margin: auto;">
2629 <h4><a name="fft" id="fft"></a>-fft</h4>
2630</div>
2631
2632<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>
2633
2634<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>
2635
2636<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>
2637
2638<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>
2639
2640<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -fft fft_image.miff</span></p>
2641<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>
2642
2643<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -fft fft_image.png</span></p>
2644<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>
2645
2646<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>
2647
2648<p>Both output components will have dynamic ranges that fit within [0,&nbsp;<em class="QR">QuantumRange</em>], so that HDRI need not be enabled. Phase values nominally range from 0 to 2*&pi;, 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>
2649
2650<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image.miff[0] -contrast-stretch 0 \ <br />
2651 -evaluate log 1000 fft_image_spectrum.png</span></p>
2652<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>
2653
2654<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#fft">-fft</a>.
2655
2656<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>
2657
2658<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>
2659
2660<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>
2661
2662<p>See the discussion on HDRI implementations of ImageMagick on the page
2663<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.
2664</p>
2665
2666
2667<div style="margin: auto;">
2668 <h4><a name="fill" id="fill"></a>-fill <em class="arg">color</em></h4>
2669</div>
2670
2671<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>
2672
2673<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>
2674
2675<p>Enclose the color specification in quotation marks to prevent the "#" or the parentheses from being interpreted by your shell.</p>
2676
2677<p>For example,</p>
2678
2679<p class="crtsnip">
2680 -fill blue
2681</p>
2682<p class="crtsnip">
2683 -fill "#ddddff"
2684</p>
2685<p class="crtsnip">
2686 -fill "rgb(255,255,255)"
2687</p>
2688
2689<p>See <a href="#draw">-draw</a> for further details.</p>
2690
2691<p>To print a complete list of color names, use the <a href="#list">-list color</a> option.</p>
2692
2693<div style="margin: auto;">
2694 <h4><a name="filter" id="filter"></a>-filter <em class="arg">type</em></h4>
2695</div>
2696
2697<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>
2698
2699<p>Use this option to affect the resizing operation of an image (see <a
2700href="#resize">-resize</a>). For example you can use a simple resize filter
2701such as:</p>
2702
2703<pre class="text">
2704 Point Hermite Cubic
2705 Box Gaussian Catrom
2706 Triangle Quadratic Mitchell
2707</pre>
2708
2709<p>The <kbd>Bessel</kbd> and <kbd>Sinc</kbd> filter is also provided, but are
2710by default <kbd>blackman</kbd>-windowed. However these filters define a
2711windowing filter for the Sinc or Bessel filter function, as appropriate for
2712the scaling operator used (usally Sinc for orthogonal <a href="#resize"
2713>-resize</a>). Windowed filters include: </p>
2714
2715<pre class="text">
2716 Lanczos Hamming Parzen
2717 Blackman Kaiser Welsh
2718 Hanning Bartlett Bohman
2719</pre>
2720
2721<p>Also one special self-windowing filter is also provided
2722<kbd>Lagrange</kbd>, which will automagically re-adjust its function depending
2723on the current 'support' or 'lobes' expert settings (see below).</p>
2724
2725<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>
2726
2727<p>To print a complete list of resize filters, use the <a href="#list">-list filter</a> option.</p>
2728
2729<p>You can modify how the filter behaves as it scales your image through the
2730use of these expert settings:</p>
2731
2732<dl class="doc">
2733<dt>-set filter:blur <em>factor</em></dt>
2734<dd>Scale the X axis of the filter (and its window). Use &gt; 1.0 for
2735 blurry or &lt; 1.0 for sharp.</dd>
2736
2737<dt>-set filter:support <em>radius</em></dt>
2738<dd>Set the filter support radius.</dd>
2739
2740<dt>-set filter:lobes <em>count</em></dt>
2741<dd>Set the number of lobes to use for the Sinc/Bessel filter. This an
2742 alternative way of specifying the 'support' range of the filter.</dd>
2743
2744<dt>-set filter:b <em>b-spline_factor</em></dt>
2745<dt>-set filter:c <em>keys_alpha_factor</em></dt>
2746<dd>Redefine the values used for cubic filters such as <kbd>Cubic</kbd>,
2747 <kbd>Catrom</kbd>, <kbd>Mitchel</kbd>, and <kbd>Hermite</kbd>, as well as
2748 the <kbd>Parzen</kbd> Sinc windowing function. If only one of the values
2749 are defined, the other is set so as to generate a 'Keys' type cubic
2750 filter.
2751
2752<dt>-set filter:filter <em>filter</em></dt>
2753<dd>Use this function directly as the scaling filter. This will allow
2754 you to directly use a 'windowing filter' such as <kbd>blackman</kbd>,
2755 rather than as its normal usage as a windowing function for 'Sinc' or
2756 'Bessel'. If defined, no windowing function is used, unless the following
2757 expert setting is also defined.</dd>
2758
2759<dt>-set filter:window <em>filter</em></dt>
2760<dd>The IIR (infinite impulse response) filters <kbd>bessel</kbd> and
2761 <kbd>sinc</kbd> are windowed (brought down to zero over the defined
2762 support range) with the given filter. This allows you to use a filter that
2763 is not normally used as a windowing function, such as <kbd>box</kbd>,
2764 (which effectivally turns off the windowing function). </dd>
2765
2766</dl>
2767
2768<p>For example, to get a 8 lobe Lanczos-Bessel filter:</p>
2769
2770<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -filter bessel \ <br/>
2771 -set filter:window=bessel -set filter:lobes=8 \ <br/>
2772 -resize 150% image.jpg</span></p>
2773<p>Or a raw un-windowed Sinc filter with 4 lobes:</p>
2774
2775<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -set filter:filter=sinc -set filter:lobes=4 \ <br/>
2776 -resize 150% image.jpg</span></p>
2777<p>Note that the use of expert options (except for 'blur' with simple resize
2778filters), are provided for image processing experts who have studied and
2779understood how resize filters work. Without this knowledge, and an
2780understanding of the defination of the actual filters involved, using expert
2781settings are more likely to be detremental to your image resizing.</p>
2782
2783
2784<div style="margin: auto;">
2785 <h4><a name="flatten" id="flatten"></a>-flatten</h4>
2786</div>
2787
2788<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>
2789
2790
2791<div style="margin: auto;">
2792 <h4><a name="flip" id="flip"></a>-flip</h4>
2793</div>
2794
2795<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>
2796
2797<p>reflect the scanlines in the vertical direction.</p>
2798
2799<div style="margin: auto;">
2800 <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>
2801</div>
2802
2803<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>
2804
2805<div style="margin: auto;">
2806 <h4><a name="flop" id="flop"></a>-flop</h4>
2807</div>
2808
2809<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>
2810
2811<p>reflect the scanlines in the horizontal direction.</p>
2812
2813
2814<div style="margin: auto;">
2815 <h4><a name="font" id="font"></a>-font <em class="arg">name</em></h4>
2816</div>
2817
2818<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>
2819
2820<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>
2821
2822<p>In addition to the fonts specified by the above pre-defined list, you can
2823also specify a font from a specific source. For example <kbd>Arial.ttf</kbd>
2824is a TrueType font file, <kbd>ps:helvetica</kbd> is PostScript font, and
2825<kbd>x:fixed</kbd> is X11 font.</p>
2826
2827<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>
2828
2829
2830<div style="margin: auto;">
2831 <h4><a name="foreground" id="foreground"></a>-foreground <em class="arg">color</em></h4>
2832</div>
2833
2834<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>
2835
2836<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
2837
2838<p>The default foreground color is black.</p>
2839
2840<div style="margin: auto;">
2841 <h4><a name="format" id="format"></a>-format <em class="arg">type</em></h4>
2842</div>
2843
2844<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>
2845
2846<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>
2847
2848<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>
2849
2850<div style="margin: auto;">
2851 <h4><a name="format_identify_" id="format_identify_"></a>-format <em class="arg">string</em></h4>
2852</div>
2853
2854<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>
2855
2856<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>
2857
2858<div style="margin: auto;">
2859 <h4><a name="frame" id="frame"></a>-frame <em class="arg">geometry</em></h4>
2860</div>
2861
2862<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>
2863
2864<p>The color of the border is specified with the <a href="#mattecolor">-mattecolor</a> command line option. </p>
2865
2866<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>&nbsp;pixels and an inner bevel of thickness <em>y</em>&nbsp;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>
2867
2868
2869<div style="margin: auto;">
2870 <h4><a name="frame_import_" id="frame_import_"></a>-frame</h4>
2871</div>
2872
2873<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>
2874
2875<div style="margin: auto;">
2876 <h4><a name="function" id="function"></a>-function <em class="arg">function</em> <em class="arg">parameters</em></h4>
2877</div>
2878
2879<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>
2880
2881<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>
2882
2883<p>This is can be considered a multi-argument version of the <a href="#evaluate">-evaluate</a> operator. (Added in ImageMagick&nbsp;6.4.8&minus;8.)</p>
2884
2885<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>
2886
2887<pre class="text">
2888 Polynomial
2889 Sinusoid
2890 Arcsin
2891 Arctan
2892</pre>
2893
2894<p>To print a complete list of <a href="#function">-function</a> operators, use <a href="#list">-list function</a>. Descriptions follow.</p>
2895
2896<dl class="doc">
2897<dt><kbd>Polynomial</kbd></dt>
2898<dd>
2899<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>
2900
2901<div style="text-align: center">
2902 -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>
2903</div>
2904
2905<p>will invoke a polynomial function given by</p>
2906
2907<div style="text-align: center">
2908 <em>a</em><sub><em>n</em></sub> <b><em>u</em></b><sup><em>n</em></sup> +
2909 <em>a</em><sub><em>n</em>-1</sub> <b><em>u</em></b><sup><em>n</em>-1</sup> +
2910 &middot;&middot;&middot; <em>a</em><sub>1</sub> <b><em>u</em></b> + <em>a</em><sub>0</sub>,
2911</div>
2912
2913<p>where <b><em>u</em></b> is pixel's original normalized channel value.</p>
2914
2915<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>
2916
2917<table class="doc">
2918 <col width="35%" />
2919 <col width="35%" />
2920 <col width="30%" />
2921 <tr>
2922 <td>-evaluate Set <em class="arg">value</em> </td>
2923 <td>-function Polynomial <em class="arg">value</em></td>
2924 <td>(Constant functions; set <em class="arg">value</em>&times;100% gray when channels are RGB.)</td>
2925 </tr>
2926 <tr>
2927 <td>-evaluate Add <em class="arg">value</em> </td>
2928 <td>-function Polynomial 1,<em class="arg">value</em></td>
2929 </tr>
2930 <tr>
2931 <td>-evaluate Subtract <em class="arg">value</em> </td>
2932 <td>-function Polynomial 1,&minus;<em class="arg">value</em></td>
2933 </tr>
2934 <tr>
2935 <td>-evaluate Multiply <em class="arg">value</em> </td>
2936 <td>-function Polynomial <em class="arg">value</em>,0</td>
2937 </tr>
2938 <tr>
2939 <td>+level black% x white%</td>
2940 <td>-function Polynomial A,B</td>
2941 <td>(Reduce contrast. Here, A=(white-black)/100 and B=black/100.)</td>
2942 </tr>
2943</table>
2944
2945<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>
2946</dd>
2947
2948<dt><kbd>Sinusoid</kbd></dt>
2949<dd>
2950<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>
2951
2952<div style="text-align: center">
2953 -function <kbd>Sinusoid</kbd> <em class="arg">freq</em>,[<em class="arg">phase</em>,[<em class="arg">amp</em>,[<em class="arg">bias</em>]]]
2954</div>
2955
2956<p>where <em>phase</em> is in degrees. (The domain [0,1] of the function corresponds to 0 through <em class="arg">freq</em>&times;360&nbsp;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>
2957
2958<div style="text-align: center">
2959<em class="arg">amp</em> * sin(2*&pi;* (<em class="arg">freq</em> * <b><em>u</em></b> + <em class="arg">phase</em> / 360)) + <em class="arg">bias</em>
2960</div>
2961
2962<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&minus;.2=.5 and .7+.2=.9. </p>
2963
2964<p class="crtsnip">
2965 -function Sinusoid 3,-90,.2,.7
2966</p>
2967
2968<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>
2969
2970<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>
2971
2972<table class="doc">
2973 <tr>
2974 <td>-evaluate Sin <em class="arg">freq</em> </td>
2975 <td>-function Sinusoid <em class="arg">freq</em>,0 </td>
2976 </tr>
2977 <tr>
2978 <td>-evaluate Cos <em class="arg">freq</em> </td>
2979 <td>-function Sinusoid <em class="arg">freq</em>,90 </td>
2980 </tr>
2981</table>
2982</dd>
2983
2984<dt><kbd>ArcSin</kbd></dt>
2985<dd>
2986<p>The <kbd>ArcSin</kbd> function generates the inverse curve of a Sinusoid,
2987and can be used to generate cylindrical distortion and displacement maps.
2988The curve can be adjusted relative to both the input values and output range
2989of values.
2990
2991<div style="text-align: center">
2992 -function <kbd>ArcSin</kbd> <em class="arg">width</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
2993</div>
2994
2995<p>with all values given in terms of noramlize color values (0.0 for black,
29961.0 for white). Defaulting to values covering the full range from 0.0 to 1.0
2997for bout input (<em class="arg">width</em>), and output (<em
2998class="arg">width</em>) values. '<code>1.0,0.5,1.0,0.5</code>' </p>
2999
3000<div style="text-align: center">
3001<em class="arg">range</em>/&pi; * asin( 2/<em class="arg">width</em> * ( <b><em>u</em></b> - <em class="arg">center</em> ) ) + <em class="arg">bias</em>
3002</div>
3003
3004</dd>
3005
3006<dt><kbd>ArcTan</kbd></dt>
3007<dd>
3008<p>The <kbd>ArcTan</kbd> function generates a curve that smooth crosses from
3009limit values at infinities, though a center using the given slope value.
3010All these values can be adjusted via the arguments.
3011
3012<div style="text-align: center">
3013 -function <kbd>ArcTan</kbd> <em class="arg">slope</em>,[<em class="arg">center</em>,[<em class="arg">range</em>,[<em class="arg">bias</em>]]]
3014</div>
3015
3016<p>Defaulting to '<code>1.0,0.5,1.0,0.5</code>'.
3017</p>
3018
3019<div style="text-align: center">
3020<em class="arg">range</em>/&pi; * atan( <em class="arg">slope</em>*&pi; * ( <b><em>u</em></b> - <em class="arg">center</em> ) ) + <em class="arg">bias</em>
3021</div>
3022
3023</dd>
3024
3025</dl>
3026
3027
3028<div style="margin: auto;">
3029 <h4><a name="fuzz" id="fuzz"></a>-fuzz <em class="arg">distance</em>{<em class="arg">%</em>}</h4>
3030</div>
3031
3032<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>
3033
3034<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>
3035
3036<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>
3037
3038
3039<div style="margin: auto;">
3040 <h4><a name="fx" id="fx"></a>-fx <em class="arg">expression</em></h4>
3041</div>
3042
3043<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>
3044
3045<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>
3046
3047<p>See <a href="../www/fx.html">FX, The Special Effects Image Operator</a> for a detailed discussion of this option.</p>
3048
3049
3050<div style="margin: auto;">
3051 <h4><a name="gamma" id="gamma"></a>-gamma <em class="arg">value</em></h4>
3052</div>
3053
3054<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>
3055
3056<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>
3057
3058<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>
3059
3060<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>
3061
3062<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>
3063
3064<p>Note that gamma adjustments are also available via the <a href="#level">-level</a> operator.</p>
3065
3066<div style="margin: auto;">
3067 <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>
3068</div>
3069
3070<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>
3071
3072<p>Convolve the image with a Gaussian or normal distribution. The formula is:</p>
3073
3074<div class="eqn"><img alt="gaussian distribution" width="243px" height="42px" src="../images/gaussian-blur.png"/>
3075</div>
3076
3077<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 &sigma; is the standard deviation of the Gaussian distribution. As a guideline, set <i>r</i> to approximately 3&sigma;. Specify a radius of 0 and ImageMagick selects a suitable radius for you.</p>
3078
3079<p>This differs from the faster <a href="#blur">-blur</a> operator in that a
3080full 2-dimentional convolution is used to generate the weighted average of the
3081neighbouring pixels. </p>
3082
3083<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
3084pixels which are outside the image proper are blurred into the final result.
3085</p>
3086
3087
3088<div style="margin: auto;">
3089 <h4><a name="geometry" id="geometry"></a>-geometry <em class="arg">geometry</em></h4>
3090</div>
3091
3092<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>
3093
3094<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>
3095
3096<div style="margin: auto;">
3097 <h4><a name="gravity" id="gravity"></a>-gravity <em class="arg">type</em></h4>
3098</div>
3099
3100<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>
3101
3102<p>Choices include: <kbd>NorthWest</kbd>, <kbd>North</kbd>, <kbd>NorthEast</kbd>,
3103<kbd>West</kbd>, <kbd>Center</kbd>, <kbd>East</kbd>, <kbd>SouthWest</kbd>,
3104<kbd>South</kbd>, <kbd>SouthEast</kbd>. Use <a href="#list">-list gravity</a> to get a complete
3105list of <a href="#gravity">-gravity</a> settings available in your ImageMagick
3106installation.</p>
3107
3108<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>
3109
3110<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>
3111
3112<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 (&minus;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 (&minus;40,20) is applied to that point, giving (100&minus;40,50+20)=(60,70), so the specified 10x10&nbsp;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&nbsp;(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>
3113
3114<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -gravity Center -region 10x10-40+20 -negate output.png</span></p>
3115<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>
3116
3117<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>
3118
3119
3120<div style="margin: auto;">
3121 <h4><a name="green-primary" id="green-primary"></a>-green-primary <em class="arg">x,y</em></h4>
3122</div>
3123
3124<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>
3125
3126
3127<div style="margin: auto;">
3128 <h4><a name="hald-clut" id="hald-clut"></a>-hald-clut</h4>
3129</div>
3130
3131<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>
3132
3133<p>A Hald color lookup table is a 3-dimensional color cube mapped to 2
3134dimensions. Create it with the <kbd>HALD:</kbd> prefix (e.g. HALD:8). You
3135can apply any color transformation to the Hald image and then use this option
3136to apply the transform to the image. </p>
3137
3138<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png hald.png -hald-clut transform.png</span></p>
3139<p>This option provides a convenient method for you to use Gimp or Photoshop
3140to make color corrections to the Hald CLUT image and subsequently apply them
3141to multiple images using an ImageMagick script. </p>
3142
3143<p>Note that the representation is only of the normal RGB color space and that
3144the whole color value triplet is used for the interpolated lookup of the
3145represented Hald color cube image. Because of this the operation is not <a
3146href="#channel" >-channel</a> setting effected, nor can it adjust or modify an
3147images transparency or alpha/matte channel.</p>
3148
3149<p>See also <a href="#clut" >-clut</a> which provides color value replacement
3150of the individual color channels, usally involving a simplier gray-scale
3151image. E.g: gray-scale to color replacement, or modification by a histogram
3152mapping. </p>
3153
3154
3155<div style="margin: auto;">
3156 <h4><a name="help" id="help"></a>-help</h4>
3157</div>
3158
3159<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>
3160
3161<div style="margin: auto;">
3162 <h4><a name="highlight-color" id="highlight-color"></a>-highlight-color <em class="arg">color</em></h4>
3163</div>
3164
3165<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>
3166
3167<div style="margin: auto;">
3168 <h4><a name="iconGeometry" id="iconGeometry"></a>-iconGeometry <em class="arg">geometry</em></h4>
3169</div>
3170
3171<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>
3172
3173<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>
3174
3175<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>
3176
3177<div style="margin: auto;">
3178 <h4><a name="iconic" id="iconic"></a>-iconic</h4>
3179</div>
3180
3181<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>
3182
3183<div style="margin: auto;">
3184 <h4><a name="identify" id="identify"></a>-identify</h4>
3185</div>
3186
3187<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>
3188
3189<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>
3190
3191<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>
3192
3193<p>If <a href="#verbose">-verbose</a> preceds this option, copious
3194amounts of image properties are displayed including image statistics, profiles,
3195image histogram, and others.</p>
3196
3197<div style="margin: auto;">
3198 <h4><a name="ift" id="ift"></a>-ift</h4>
3199</div>
3200
3201<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>
3202
3203<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>
3204
3205<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>
3206
3207<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image.miff -ift fft_image_ift.png</span></p>
3208<p>or</p>
3209
3210<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert fft_image-0.png fft_image-1.png -ift fft_image_ift.png</span></p>
3211
3212<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.
3213
3214<p>The <a href="http://www.fftw.org/" target="_blank">FFTW</a> delegate library is required to use <a href="#ift">-ift</a>.
3215
3216<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.
3217
3218<div style="margin: auto;">
3219 <h4><a name="immutable" id="immutable"></a>-immutable</h4>
3220</div>
3221
3222<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>
3223
3224<div style="margin: auto;">
3225 <h4><a name="implode" id="implode"></a>-implode <em class="arg">factor</em></h4>
3226</div>
3227
3228<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>
3229
3230<div style="margin: auto;">
3231 <h4><a name="insert" id="insert"></a>-insert <em class="arg">index</em></h4>
3232</div>
3233
3234<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>
3235
3236<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>
3237
3238<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>
3239
3240<div style="margin: auto;">
3241 <h4><a name="intent" id="intent"></a>-intent <em class="arg">type</em></h4>
3242</div>
3243
3244<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>
3245
3246<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>
3247
3248<p>The default intent is undefined.</p>
3249
3250<p>To print a complete list of rendering intents, use <a href="#list">-list intent</a>.</p>
3251
3252<div style="margin: auto;">
3253 <h4><a name="interlace" id="interlace"></a>-interlace <em class="arg">type</em></h4>
3254</div>
3255
3256<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>
3257
3258<p>Choose from:</p>
3259
3260<pre class="text">
3261 none
3262 line
3263 plane
3264 partition
3265 JPEG
3266 GIF
3267 PNG
3268</pre>
3269
3270<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>
3271
3272<p><kbd>None</kbd> means do not interlace (RGBRGBRGBRGBRGBRGB...),</p>
3273
3274<p><kbd>Line</kbd> uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and.</p>
3275
3276<p><kbd>Plane</kbd> uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).</p>
3277
3278<p><kbd>Partition</kbd> is like plane except the different planes are saved to individual files (e.g. image.R,
3279image.G, and image.B).</p>
3280
3281<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>
3282image.</p>
3283
3284<p>To print a complete list of interlacing schemes, use <a href="#list">-list interlace</a>.</p>
3285
3286<div style="margin: auto;">
3287 <h4><a name="interpolate" id="interpolate"></a>-interpolate <em class="arg">type</em></h4>
3288</div>
3289
3290<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>
3291
3292<p>When looking up the color of a pixel using a non-interger floating point
3293value, you typically fall in between the pixel colors defined by the source
3294image. This setting determines how the color is determined from the colors of
3295the pixels surrounding that point. That is how to determine the color of a
3296point that falls between two, or even four different colored pixels. </p>
3297
3298<pre class="text">
3299 integer: The color of the top-left pixel (floor function)
3300 nearest-neighbor: The nearest pixel to the lookup point (rounded function)
3301 average: The average color of the surrounding four pixels
3302 bilinear A double linear interpolation of pixels (the default)
3303 mesh Divide area into two flat triangular interpolations
3304 bicubic Fitted bicubic-spines of surrounding 16 pixels
3305 spline Direct spline curves (colors are blurred)
3306 filter Use resize <a href="#filter">-filter</a> settings
3307</pre>
3308
3309<p>This most important for distortion operators such as <a href="#distort"
3310>-distort</a>, <a href="#implode" >-implode</a>, <a href="#transform"
3311>-transform</a> and <a href="#fx" >-fx</a>. </p>
3312
3313<p>To print a complete list of interpolation methods, use <a href="#list">-list interpolate</a>.</p>
3314
3315<p>See also <a href="#virtual-pixel" >-virtual-pixel</a>, for control of the
3316lookup for positions outside the boundaries of the image. </p>
3317
3318
3319<div style="margin: auto;">
cristyf3bb4782009-09-08 13:10:04 +00003320 <h4><a name="interline-spacing" id="interline-spacing"></a>-interline-spacing <em class="arg">value</em></h4>
3321</div>
3322
3323<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>
3324
3325<div style="margin: auto;">
cristy3ed852e2009-09-05 21:47:34 +00003326 <h4><a name="interword-spacing" id="interword-spacing"></a>-interword-spacing <em class="arg">value</em></h4>
3327</div>
3328
3329<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>
3330
3331<div style="margin: auto;">
3332 <h4><a name="kerning" id="kerning"></a>-kerning <em class="arg">value</em></h4>
3333</div>
3334
3335<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>
3336
3337<div style="margin: auto;">
3338 <h4><a name="label" id="label"></a>-label <em class="arg">name</em></h4>
3339</div>
3340
3341<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>
3342
3343<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>
3344
3345<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>
3346
3347<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>
3348
3349<p>For example,</p>
3350
3351<p class="crtsnip">
3352 -label "%m:%f %wx%h" bird.miff
3353</p>
3354
3355<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>
3356
3357<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>
3358
3359<p>The label font can be specified with <a href="#font">-font</a>, and the
3360other font attribute settings.</p>
3361
3362<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>
3363
3364
3365<div style="margin: auto;">
3366 <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>
3367</div>
3368
3369<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>
3370
3371<p>Adaptively threshold each pixel based on the value of pixels in a
3372surrounding window. If the current pixel is lighter than this average plus
3373the optional <kbd>offset</kbd>, then it is made white, otherwise it is made
3374black. Small variations in pixel values such as found in scanned documents
3375can be ignored if offset is positive. A negative offset will make it more
3376sensitive to those small variations. </p>
3377
3378<p>This is commonly used to threshold images with an uneven background. It is
3379based on the assumption that average color of the small window is the
3380the local background color, from which to separate the forground color. </p>
3381
3382
3383<div style="margin: auto;">
3384 <h4><a name="layers" id="layers"></a>-layers <em class="arg">method</em></h4>
3385</div>
3386
3387<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>
3388
3389<p>Perform various image operation methods to a ordered sequence of images
3390which may represent either a set of overlaid 'image layers', a GIF disposal
3391animation, or a fully-'coalesced' animation sequence. </p>
3392
3393<table class="doc">
3394 <tbody>
3395 <tr valign="top">
3396 <th align="left" style="width: 8%">Method</th>
3397 <th align="left">Description</th>
3398 </tr>
3399
3400 <tr valign="top">
3401 <td valign="top">compare-any</td>
3402 <td valign="top">Crop the second and later frames to the smallest rectangle
3403 that contains all the differences between the two images. No GIF <a
3404 href="#dispose" >-dispose</a> methods are taken into account. </td>
3405 </tr>
3406
3407 <tr><td></td><td>This exactly the same as the <a href="#deconstruct"
3408 >-deconstruct</a> operator, and does not preserve animations normal
3409 working, especially when animation used layer disposal methods such as
3410 '<kbd>Previous</kbd>' or '<kbd>Background</kbd>'. </td>
3411 </tr>
3412
3413 <tr valign="top">
3414 <td valign="top">compare-clear</td>
3415 <td valign="top">As '<kbd>compare-any</kbd>' but crop to the bounds of any
3416 opaque pixels which become transparent in the second frame. That is the
3417 smallest image needed to mask or erase pixels for the next frame. </td>
3418 </tr>
3419
3420 <tr valign="top">
3421 <td valign="top">compare-overlay</td>
3422 <td valign="top">As '<kbd>compare-any</kbd>' but crop to pixels that add
3423 extra color to the next image, as a result of overlaying color pixels.
3424 That is the smallest single overlaid image to add or change colors. </td>
3425 </tr>
3426
3427 <tr><td></td><td>This can be used with the <a href="#compose" >-compose</a> alpha
3428 composition method '<kbd>change-mask</kbd>', to reduce the image to
3429 just the pixels that need to be overlaid. </td>
3430 </tr>
3431
3432 <tr valign="top">
3433 <td valign="top">coalesce</td>
3434 <td valign="top">Equivalent to a call to the <a href="#coalesce"
3435 >-coalesce</a> operator. Apply the layer disposal methods set in the
3436 current image sequence to form a fully defined animation sequence, as
3437 it should be displayed. Effectively converting a GIF animation into a
3438 'film strip'-like animation. </td>
3439 </tr>
3440
3441 <tr valign="top">
3442 <td valign="top">composite</td>
3443 <td valign="top">Alpha Composition of two image lists, separated by a
3444 "<kbd>null:</kbd>" image, with the destination image list first, and
3445 the source images last. An image from each list are composited
3446 together until one list is finished. The separator image and source
3447 image lists are removed. </td>
3448 </tr>
3449
3450
3451 <tr><td></td><td>The <a href="#geometry" >-geometry</a> offset is adjusted according to
3452 <a href="#gravity" >-gravity</a> in accordance of the virtual canvas
3453 size of the first image in each list. Unlike a normal <a
3454 href="#composite" >-composite</a> operation, the canvas offset is also
3455 added to the final composite positioning of each image. </td>
3456 </tr>
3457
3458 <tr><td></td><td>If one of the image lists only contains one image, that image is
3459 applied to all the images in the other image list, regardless of which
3460 list it is. In this case it is the image meta-data of the list which
3461 preserved. </td>
3462 </tr>
3463
3464
3465 <tr valign="top">
3466 <td valign="top">dispose</td>
3467 <td valign="top">This like '<kbd>coalesce</kbd>' but shows the look of
3468 the animation after the layer disposal method has been applied, before
3469 the next sub-frame image is overlaid. That is the 'dispose' image that
3470 results from the application of the GIF <a href="#dispose"
3471 >-dispose</a> method. This allows you to check what
3472 is going wrong with a particular animation you may be developing.
3473 </td>
3474 </tr>
3475
3476 <tr valign="top">
3477 <td valign="top">flatten</td>
3478 <td valign="top">Create a canvas the size of the first images virtual
3479 canvas using the current <a href="#background" >-background</a> color,
3480 and <a href="#compose" >-compose</a> each image in turn onto that
3481 canvas. Images falling outside that canvas is clipped. Final
3482 image will have a zero virtual canvas offset. </td>
3483 </tr>
3484
3485 <tr><td></td><td>This usally used as one of the final 'image layering' operations
3486 overlaying all the prepared image layers into a final image. </td>
3487 </tr>
3488
3489 <tr><td></td><td>For a single image this method can also be used to fillout a virtual
3490 canvas with real pixels, or to underlay a opaque color to remove
3491 transparency from an image.</td>
3492 </tr>
3493
3494
3495 <tr valign="top">
3496 <td valign="top">merge</td>
3497 <td valign="top">As 'flatten' method but merging all the given image
3498 layers into a new layer image just large enough to hold all the image
3499 without clipping or extra space. The new images virtual offset will
3500 prevere the position of the new layer, even if this offset is
3501 negative. the virtual canvas size of the first image is preserved.
3502 </td>
3503 </tr>
3504
3505 <tr><td></td><td>Caution is advised when handling image layers with negative offsets
3506 as few image file formats handle them correctly. </td>
3507 </tr>
3508
3509 <tr valign="top">
3510 <td valign="top">mosaic</td>
3511 <td valign="top">As 'flatten' method but expanding the initial canvas size
3512 of the first image so as to hold all the image layers. However as a
3513 virtual canvas is 'locked' to the origin, by defination, image layers
3514 with a negative offsets will still be clipped by the top and left
3515 edges.</td>
3516 </tr>
3517
3518 <tr><td></td><td>This method is commonly used to layout individual image using various
3519 offset but without knowning the final canvas size. The resulting image
3520 will, like 'flatten' not have any virtual offset, so can be saved to
3521 any image file format. </td>
3522 </tr>
3523
3524
3525 <tr valign="top">
3526 <td valign="top">optimize</td>
3527 <td valign="top">Optimize a coalesced animation, into GIF animation using
3528 a number of general techniques. This currently a short cut to
3529 apply both the '<kbd>optimize-frame</kbd>', and
3530 '<kbd>optimize-transparency</kbd>' methods but may be expanded to
3531 include other optimization methods as they are developed. </td>
3532 </tr>
3533
3534 <tr valign="top">
3535 <td valign="top">optimize-frame</td>
3536 <td valign="top">Optimize a coalesced animation, into GIF animation by
3537 reducing the number of pixels per frame as much as possible by
3538 attempting to pick the best layer disposal method to use, while ensuring
3539 the result will continue to animate properly. </td>
3540 </tr>
3541
3542 <tr><td></td><td> There is no guarantee that the best optimization is found. But
3543 then no reasonably fast GIF optimization algorithm can do this.
3544 However this does seem to do better than most other GIF frame
3545 optimizers seen. </td>
3546 </tr>
3547
3548 <tr valign="top">
3549 <td valign="top">optimize-plus</td>
3550 <td valign="top">As '<kbd>optimize-frame</kbd>' but attempt to improve the
3551 overall optimization by adding extra frames to the animation, without
3552 changing the final look or timing of the animation. The frames are
3553 added to attempt to separate the clearing of pixels from the
3554 overlaying of new additional pixels from one animation frame to the
3555 next. If this does not improve the optimization (for the next frame
3556 only), it will fall back to the results of the previous normal
3557 '<kbd>optimize-frame</kbd>' technique. </td>
3558 </tr>
3559
3560 <tr><td></td><td>There is the possibility that the change in the disposal style will
3561 result in a worsening in the optimization of later frames, though this
3562 is unlikely. In other words there no guarantee that it is better than
3563 the normal '<kbd>optimize-frame</kbd>' technique. For some animations
3564 however you can get a vast improvment in the final animation size. </td>
3565 </tr>
3566
3567 <tr valign="top">
3568 <td valign="top">optimize-transparency</td>
3569 <td valign="top">Given a GIF animation, replace any pixel in the sub-frame
3570 overlay images with transparency, if it does not change the resulting
3571 animation by more than the current <a href="#fuzz" >-fuzz</a> factor.
3572 </td>
3573 </tr>
3574
3575 <tr><td></td><td>This should allow a existing frame optimized GIF animation to compress
3576 into a smaller file size due to larger areas of one (transparent)
3577 color rather than a pattern of multiple colors repeating the current
3578 disposed image of the last frame. </td>
3579 </tr>
3580
3581 <tr valign="top">
3582 <td valign="top">remove-dups</td>
3583 <td valign="top">Remove (and merge time delays) of duplicate consecutive
3584 images, so as to simplify layer overlays of coalesced animations.
3585 </td>
3586 </tr>
3587
3588 <tr><td></td><td>Usually this a result of using a constant time delay across the
3589 whole animation, or after a larger animation was split into smaller
3590 sub-animations. The duplicate frames could also have been used as
3591 part of some frame optimization methods. </td>
3592 </tr>
3593
3594 <tr valign="top">
3595 <td valign="top">remove-zero</td>
3596 <td valign="top">Remove any image with a zero time delay, unless ALL the
3597 images have a zero time delay (and is not a proper timed animation, a
3598 warning is then issued). </td>
3599 </tr>
3600
3601 <tr><td></td><td>In a GIF animation, such images are usually frames which provide
3602 partial intermediary updates between the frames that are actually
3603 displayed to users. These frames are usally added for improved frame
3604 optimization in GIF animations. </td>
3605 </tr>
3606
3607 <tr valign="top">
3608 <td valign="top">trim-bounds</td>
3609 <td valign="top">Find the bounds of all the images in the current
3610 image sequence, then adjust the offsets so all images are contained on
3611 a minimal positive canvas. None of the image data is modified, only
3612 there virtual canvas size and offset. The all the image is given
3613 the same canvas size, and and will have a positive offset, but will
3614 remain in the same position relative to each other. As a result of the
3615 minimal canvas size at least one image will touch every edge of that
3616 canvas. The image data however may be transparent.
3617 </td>
3618 </tr>
3619
3620 </tbody>
3621</table>
3622
3623<p>To print a complete list of layer types, use <a href="#list">-list layers</a>.</p>
3624
3625<p>The operators <a href="#coalesce" >-coalesce</a>, <a href="#deconstruct"
3626>-deconstruct</a>, <a href="#flatten" >-flatten</a>, and <a href="#mosaic"
3627>-mosaic</a> are only aliases for the above methods. Also see <a
3628href="#page" >-page</a>, <a href="#repage" >-repage</a> operators, the <a
3629href="#compose" >-compose</a> setting, and the GIF <a href="#dispose"
3630>-dispose</a> and <a href="#delay" >-delay</a> settings. </p>
3631
3632
3633<div style="margin: auto;">
3634 <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>
3635</div>
3636
3637<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>
3638
3639<p>Given one, two or three values delimited with commas: black-point,
3640white-point, gamma (for example: 10,250,1.0 or 2%,98%,0.5). The black and
3641white points range from 0 to <em class="QR">QuantumRange</em>, or from 0 to 100%; if the white
3642point is omitted it is set to (<em class="QR">QuantumRange</em> - black_point), so as to center
3643contrast changes. If a <kbd>%</kbd> sign is present anywhere in the string,
3644both black and white points are percentages of the full color range. Gamma
3645will do a <a href="#gamma">-gamma</a> adjustment of the values. If it is
3646omitted, the default of 1.0 (no gamma correction) is assumed.</p>
3647
3648<p>In normal usage (<kbd>-level</kbd>) the image values are stretched so that
3649the given '<kbd>black_point</kbd>' value in the original image is set to
3650zero (or black), while the given '<kbd>white_point</kbd>' value is set to
3651<em class="QR">QuantumRange</em> (or white). This provides you with direct contrast adjustments
3652to the image. The '<kbd>gamma</kbd>' of the resulting image will then be
3653adjusted. </p>
3654
3655<p>From ImageMagick v6.4.1-9 using the plus form of the operator (<kbd>+level</kbd>) or
3656adding the special '!' flag anywhere in the argument list, will cause the
3657operator to do the reverse of the level adjustment. That is a zero, or
3658<em class="QR">QuantumRange</em> value (black, and white, resp.) in the original image, is
3659adjusted to the given level values, allowing you to de-contrast, or compress
3660the channel values within the image. The '<kbd>gamma</kbd>' is adjusted before the level adjustment to de-contrast the image is made. </p>
3661
3662<p>Only the channels defined by the current <a href="#channel">-channel</a>
3663setting are adjusted (defaults to RGB color channels only), allowing you to
3664limit the effect of this operator. </p>
3665
3666<p>Please note that the transparency channel is treated as 'matte'
3667values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
3668
3669
3670<div style="margin: auto;">
3671 <h4><a name="level-colors" id="level-colors"></a>-level-colors {<em
3672 class="arg">black_color</em>}{,}{<em class="arg">white_color</em>}</h4>
3673</div>
3674
3675<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>
3676
3677<p>This function is exactly like <a href="#level">-level</a>, except that the
3678value value for each color channel is determined by the
3679'<kbd>black_color</kbd>' and '<kbd>white_color</kbd>' colors given (as
3680described under the <a href="#fill">-fill</a> option). </p>
3681
3682<p>This effectivally means the colors provided to <kbd>-level-colors</kbd>
3683is mapped to become 'black' and 'white' respectivally, with all the other
3684colors linearly adjusted (or clipped) to match that change. Each channel is
3685adjusted separatally using the channel values of the colors specified. </p>
3686
3687<p>On the other hand the plus form of the operator (<kbd>+level-colors</kbd>)
3688will map the image color 'black' and 'white' to the given colors
3689respectivally, resulting in a gradient (de-contrasting) tint of the image to
3690those colors. This can also be used to convert a plain gray-scale image into a
3691one using the gradient of colors specified. </p>
3692
3693<p>By supplying a single color with a comma separator either before or after
3694that color, will just replace the respective 'black' or 'white' point
3695respectivally. But if no comma separator is provided, the given color is
3696used for both the black and white color points, making the operator either
3697threshold the images around that color (- form) or set all colors to that
3698color (+ form). </p>
3699
3700
3701<div style="margin: auto;">
3702 <h4><a name="limit" id="limit"></a>-limit <em class="arg">type value</em></h4>
3703</div>
3704
3705<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>
3706
3707<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>
3708
3709<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>
3710
3711<p class="crtsnip">
3712 -limit memory 32mb -limit map 64mb
3713</p>
3714
3715<p>Use <a href="#list">-list resource</a> to list the current limits. For example, our system shows these limits:</p>
3716
3717<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>identify -list resource</span><span class='crtout'><pre>File Area Memory Map Disk Thread Time
3718-------------------------------------------------------------------
3719 768 3.8187gb 2.864gb 7.6375gb 16eb 2 unlimited</pre>
3720</span></p>
3721<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">&#x2011;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>
3722
3723<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>
3724
3725<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>
3726
3727<p class="crtsnip">
3728-limit area 10mb
3729</p>
3730
3731<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>
3732
3733<p class="crtsnip">
3734-limit area 10mb -limit disk 500mb
3735</p>
3736
3737<p>Here ImageMagick stops processing if an image requires more than 500MB of disk storage.</p>
3738
3739<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>
3740
3741<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.
3742</p>
3743
3744<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.
3745</p>
3746
3747<div style="margin: auto;">
3748 <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>
3749</div>
3750
3751<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>
3752
3753<div style="margin: auto;">
3754 <h4><a name="linewidth" id="linewidth"></a>-linewidth</h4>
3755</div>
3756
3757<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>
3758
3759<div style="margin: auto;">
3760 <h4><a name="liquid-rescale" id="liquid-rescale"></a>-liquid-rescale <em class="arg">geometry</em></h4>
3761</div>
3762
3763<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>
3764
3765<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>
3766
3767<div style="margin: auto;">
3768 <h4><a name="list" id="list"></a>-list <em class="arg">type</em></h4>
3769</div>
3770
3771<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>
3772
3773<pre class="text">
3774 coder
3775 color
3776 configure
3777 delegate
3778 font
3779 format
3780 list
3781 log
3782 magic
3783 module
3784 resource
3785 threshold
3786</pre>
3787
3788<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>
3789
3790<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>identify -list list</span></p>
3791<div style="margin: auto;">
3792 <h4><a name="log" id="log"></a>-log <em class="arg">string</em></h4>
3793</div>
3794
3795<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>
3796
3797<p>This option specifies the format for the log printed when the <a href="#debug">-debug</a> option is active.</p>
3798
3799<p>You can display the following components by embedding special format characters:</p>
3800
3801<pre class="text">
3802 %d domain
3803 %e event
3804 %f function
3805 %l line
3806 %m module
3807 %p process ID
3808 %r real CPU time
3809 %t wall clock time
3810 %u user CPU time
3811 %% percent sign
3812 \n newline
3813 \r carriage return
3814</pre>
3815
3816<p>For example:</p>
3817
3818<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -debug coders -log "%u %m:%l %e" in.gif out.png</span></p>
3819<p>The default behavior is to print all of the components.</p>
3820
3821<div style="margin: auto;">
3822 <h4><a name="loop" id="loop"></a>-loop <em class="arg">iterations</em></h4>
3823</div>
3824
3825<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>
3826
3827<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>
3828
3829<div style="margin: auto;">
3830 <h4><a name="lowlight-color" id="lowlight-color"></a>-lowlight-color <em class="arg">color</em></h4>
3831</div>
3832
3833<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>
3834
3835<div style="margin: auto;">
3836 <h4><a name="magnify" id="magnify"></a>-magnify <em class="arg">factor</em></h4>
3837</div>
3838
3839<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>
3840
3841
3842<div style="margin: auto;">
3843 <h4><a name="map" id="map"></a>-map <em class="arg">type</em></h4>
3844</div>
3845
3846<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>
3847
3848<p>Choose from these <em class="arg">Standard Colormap</em> types:</p>
3849
3850<pre class="text">
3851 best
3852 default
3853 gray
3854 red
3855 green
3856 blue
3857</pre>
3858
3859<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>
3860
3861
3862<div style="margin: auto;">
3863 <h4><a name="map_stream_" id="map_stream_"></a>-map <em class="arg">components</em></h4>
3864</div>
3865
3866<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>
3867
3868<p>Here are the valid components of a map:</p>
3869
3870<pre class="text">
3871 r red pixel component
3872 g green pixel component
3873 b blue pixel component
3874 a alpha pixel component (0 is transparent)
3875 o opacity pixel component (0 is opaque)
3876 i grayscale intensity pixel component
3877 c cyan pixel component
3878 m magenta pixel component
3879 y yellow pixel component
3880 k black pixel component
3881 p pad component (always 0)
3882</pre>
3883
3884<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>
3885
3886<div style="margin: auto;">
3887 <h4><a name="mask" id="mask"></a>-mask
3888<em class="arg">filename</em></h4>
3889</div>
3890
3891<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>
3892
3893<p>Use <a href="#mask">+mask</a> to remove the image mask.</p>
3894
3895<div style="margin: auto;">
3896 <h4><a name="mattecolor" id="mattecolor"></a>-mattecolor <em class="arg">color</em></h4>
3897</div>
3898
3899<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>
3900
3901<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
3902
3903<p>The default matte color is <kbd>#BDBDBD</kbd>, <span style="background-color: #bdbdbd;">this shade of gray</span>.</p>
3904
3905<div style="margin: auto;">
3906 <h4><a name="median" id="median"></a>-median <em class="arg">radius</em></h4>
3907</div>
3908
3909<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>
3910
3911<div style="margin: auto;">
3912 <h4><a name="metric" id="metric"></a>-metric <em class="arg">type</em></h4>
3913</div>
3914
3915<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>
3916
3917<p>Choose from:</p>
3918
3919<pre class="text">
3920 AE absolute number of differnet pixels
3921 MAE mean absolute error (normalized), average channel error distance
3922 MEPP mean error per pixel (normalized mean error, normalized peak error)
3923 MSE mean error squared, average of the channel error squared
3924 PAE peak absolute (normalize peak absolute)
3925 PSNR peak signal to noise ratio
3926 RMSE root mean squared (normalized root mean squared)
3927</pre>
3928
3929<p>The '<kbd>AE</kbd>' or absolute count of pixels that are different, can be
3930controled using a <a href="#fuzz" >-fuzz</a> factor to ignore pixels which
3931only changed by a small amount. The '<kbd>PAE</kbd>' can be used to find the
3932size of the <a href="#fuzz" >-fuzz</a> factor needed to make all pixels
3933'similar'. </p>
3934
3935<p>The '<kbd>MEPP</kbd>' metric returns three different metrics
3936('<kbd>MAE</kbd>', '<kbd>MAE</kbd>' normalized, and '<kbd>PAE</kbd>'
3937normalized) from the single comparision run. </p>
3938
3939<p>To print a complete list of metrics, use the <a href="#list">-list metrics</a> option.</p>
3940
3941
3942<div style="margin: auto;">
3943 <h4><a name="mode" id="mode"></a>-mode <em class="arg">value</em></h4>
3944</div>
3945
3946<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>
3947
3948<p>Choose the <em class="arg">value</em> from these styles: <kbd>Frame, Unframe, or Concatenate</kbd></p>
3949
3950<p>Use the <a href="#list" >-list</a> option with a '<kbd>Mode</kbd>'
3951argument for a list of <a href="#mode" >-mode</a> arguments available
3952in your ImageMagick installation.</p>
3953
3954
3955<div style="margin: auto;">
3956 <h4><a name="modulate" id="modulate"></a>-modulate <em class="arg">brightness</em>[,<em class="arg">saturation</em>,<em class="arg">hue</em>]</h4>
3957</div>
3958
3959<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>
3960
3961<p>The arguments are given as a percentages of variation. A value of 100 means no change, and any
3962missing values are taken to mean 100.</p>
3963
3964<p>The <em class="arg">brightness</em> is a multiplier of the overall brightness of the image, so 0
3965means pure black, 50 is half as bright, 200 is twice as bright. To invert its
3966meaning <a href="#negate">-negate</a> the image before and after. </p>
3967
3968<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>
3969
3970<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
3971shades to purple, and so on. A value of either 0 or 200 results in a complete
3972180 degree rotation of the image. Using a value of 300 is a 360 degree
3973rotation resulting in no change to the original image. </p>
3974
3975<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>
3976
3977<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>
3978
3979<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert image.png -set option:modulate:colorspace hsb -modulate 120,90 modulate.png</span></p>
3980<div style="margin: auto;">
3981 <h4><a name="monitor" id="monitor"></a>-monitor</h4>
3982</div>
3983
3984<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>
3985
3986
3987<div style="margin: auto;">
3988 <h4><a name="monochrome" id="monochrome"></a>-monochrome</h4>
3989</div>
3990
3991<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>
3992
3993
3994<div style="margin: auto;">
3995 <h4><a name="morph" id="morph"></a>-morph <em class="arg">frames</em></h4>
3996</div>
3997
3998<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>
3999
4000<p>Both the image pixels and size are linearly interpolated to give the
4001appearance of a meta-morphosis from one image to the next, over all the images
4002in the current image list. The added images are the equivalent of a <a
4003href="#blend">-blend</a> composition. The <em class="arg">frames</em>
4004argument determine how many images to interpolate between each image. </p>
4005
4006
4007<div style="margin: auto;">
4008 <h4><a name="mosaic" id="mosaic"></a>-mosaic</h4>
4009</div>
4010
4011<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>
4012
4013
4014<div style="margin: auto;">
4015 <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>
4016</div>
4017
4018<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>
4019
4020<p>Blur with the given radius, standard deviation (sigma), and angle. The
4021angle given is the angle toward which the image is blurred. That is the
4022direction people would consider the object is coming from. </p>
4023
4024<p>Note that the blur is not uniform distribution, giving the motion a
4025definate sense of direction of movement. </p>
4026
4027<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
4028pixels which are outside the image proper are blurred into the final result.
4029</p>
4030
4031<div style="margin: auto;">
4032 <h4><a name="name" id="name"></a>-name</h4>
4033</div>
4034
4035<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>
4036<div style="margin: auto;">
4037 <h4><a name="negate" id="negate"></a>-negate</h4>
4038</div>
4039
4040<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>
4041
4042<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>
4043
4044<div style="margin: auto;">
4045 <h4><a name="noise" id="noise"></a>-noise <em class="arg">radius</em><br/>
4046 +noise <em class="arg">type</em></h4>
4047</div>
4048
4049<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>
4050
4051<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>
4052
4053<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>
4054
4055<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>
4056
4057<pre class="text">
4058Gaussian
4059Impulse
4060Laplacian
4061Multiplicative
4062Poisson
4063Random
4064Uniform
4065</pre>
4066
4067<p>To print a complete list of noises, use the <a href="#list">-list noise</a> option.</p>
4068
4069
4070<div style="margin: auto;">
4071 <h4><a name="normalize" id="normalize"></a>-normalize</h4>
4072</div>
4073
4074<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>
4075
4076<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>
4077
4078<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
4079version, it was equivalent to <a href="#contrast-stretch">-contrast-stretch 2%x99%)</a></p>
4080
4081<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>
4082
4083
4084<div style="margin: auto;">
4085 <h4><a name="ordered-dither" id="ordered-dither"></a>-ordered-dither <em class="arg">threshold_map</em>{,<em class="arg">level</em>...}</h4>
4086</div>
4087
4088<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>
4089
4090<p>You can choose from these standard threshold maps:</p>
4091
4092<pre class="text">
4093 checks
4094 o2x2
4095 o3x3
4096 o4x4
4097 o8x8
4098 h4x4a
4099 h6x6a
4100 h8x8a
4101 h4x4o
4102 h6x6o
4103 h8x8o
4104 h16x16o
4105</pre>
4106
4107<p>The '<kbd>o</kbd>' are ordered diffused pixel threshold maps, while the
4108'<kbd>h</kbd>' maps are halftone threshold maps which are either 'a' angled,
4109or 'o' orthogonal. The '<kbd>checks</kbd>' produce a 3 level checkerbord
4110dither pattern. Or you can define your own <em class="arg">threshold
4111map</em> in a personal or system "<kbd>thresholds.xml</kbd>" XML file. </p>
4112
4113<p>To print a complete list of threshold, use the <a href="#list">-list threshold</a> option.</p>
4114
4115<p>It is recommended that the <a href="#map">+map</a> operator be used after
4116applying <a href="#ordered-dither">-ordered-dither</a> to reduce the number of
4117colors an animated image sequence, to less that 256 colors. This ensures that
4118a common or global color table is used when saving the result to a color
4119limited file format such as GIF. </p>
4120
4121<p>Note that at this time the exact same map is used for all color channels, no
4122attempt is made to offset or rotate the dither map for different channels is
4123made, at this point in time. (possible future expansion) </p>
4124
4125
4126<div style="margin: auto;">
4127 <h4><a name="opaque" id="opaque"></a>-opaque <em class="arg">color</em></h4>
4128</div>
4129
4130<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>
4131
4132<p>The <em class="arg">color</em> argument is defined using the format
4133described under the <a href="#fill">-fill</a> option.
4134The <a href="#fuzz">-fuzz</a> setting can be used to match and replace colors similar
4135to the one given.</p>
4136
4137<p>The <a href="#transparent">-transparent</a> operator is exactly the same
4138as <a href="#opaque">-opaque</a> but makes the matching color transparent,
4139rather than the same as the current <a href="#fill">-fill</a> color. </p>
4140
4141<p>Use <em class="arg">+opaque</em> to paint any pixel that does not match the target color.</p>
4142
4143<div style="margin: auto;">
4144 <h4><a name="orient" id="orient"></a>-orient <em class="arg">image orientation</em></h4>
4145</div>
4146
4147<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>
4148
4149<p>Choose from these orientations:</p>
4150
4151<pre class="text">
4152 bottom-left
4153 bottom-right
4154 left-bottom
4155 left-top
4156 right-bottom
4157 right-top
4158 top-left
4159 top-right
4160 undefined
4161</pre>
4162
4163<p>To print a complete list of orientations, use the <a href="#list">-list orientation</a> option.</p>
4164
4165
4166<div style="margin: auto;">
4167 <h4><a name="page" id="page"></a>-page <em class="arg">geometry</em><br/>
4168 -page <em class="arg">media</em>[<em class="arg">offset</em>][{<em class="arg">^!&lt;&gt;</em>}]<br/>
4169 +page
4170 </h4>
4171</div>
4172
4173<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>
4174
4175<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>
4176
4177<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>&nbsp;<kbd>Letter+43+43</kbd>).</p>
4178
4179<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>
4180<table id="geometryTable" cellpadding="2" cellspacing="0" border="1" width="50%" style="margin-left: auto; margin-right: auto;">
4181<thead>
4182 <tr valign="top">
4183 <th align="center"><em class="arg">media</em></th>
4184 <th align="center"><em class="arg">width</em></th>
4185 <th align="center"><em class="arg">height</em></th>
4186 </tr>
4187</thead>
4188<tbody>
4189<tr><td align="left"> 11x17 </td> <td align="right"> 792</td> <td align="right"> 1224</td> </tr>
4190<tr><td align="left"> Ledger </td> <td align="right"> 1224</td> <td align="right"> 792</td> </tr>
4191<tr><td align="left"> Legal </td> <td align="right"> 612</td> <td align="right"> 1008</td> </tr>
4192<tr><td align="left"> Letter </td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
4193<tr><td align="left"> LetterSmall</td> <td align="right"> 612</td> <td align="right"> 792</td> </tr>
4194<tr><td align="left"> ArchE </td> <td align="right"> 2592</td> <td align="right"> 3456</td> </tr>
4195<tr><td align="left"> ArchD </td> <td align="right"> 1728</td> <td align="right"> 2592</td> </tr>
4196<tr><td align="left"> ArchC </td> <td align="right"> 1296</td> <td align="right"> 1728</td> </tr>
4197<tr><td align="left"> ArchB </td> <td align="right"> 864</td> <td align="right"> 1296</td> </tr>
4198<tr><td align="left"> ArchA </td> <td align="right"> 648</td> <td align="right"> 864</td> </tr>
4199<tr><td align="left"> A0 </td> <td align="right"> 2380</td> <td align="right"> 3368</td> </tr>
4200<tr><td align="left"> A1 </td> <td align="right"> 1684</td> <td align="right"> 2380</td> </tr>
4201<tr><td align="left"> A2 </td> <td align="right"> 1190</td> <td align="right"> 1684</td> </tr>
4202<tr><td align="left"> A3 </td> <td align="right"> 842</td> <td align="right"> 1190</td> </tr>
4203<tr><td align="left"> A4 </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
4204<tr><td align="left"> A4Small </td> <td align="right"> 595</td> <td align="right"> 842</td> </tr>
4205<tr><td align="left"> A5 </td> <td align="right"> 421</td> <td align="right"> 595</td> </tr>
4206<tr><td align="left"> A6 </td> <td align="right"> 297</td> <td align="right"> 421</td> </tr>
4207<tr><td align="left"> A7 </td> <td align="right"> 210</td> <td align="right"> 297</td> </tr>
4208<tr><td align="left"> A8 </td> <td align="right"> 148</td> <td align="right"> 210</td> </tr>
4209<tr><td align="left"> A9 </td> <td align="right"> 105</td> <td align="right"> 148</td> </tr>
4210<tr><td align="left"> A10 </td> <td align="right"> 74</td> <td align="right"> 105</td> </tr>
4211<tr><td align="left"> B0 </td> <td align="right"> 2836</td> <td align="right"> 4008</td> </tr>
4212<tr><td align="left"> B1 </td> <td align="right"> 2004</td> <td align="right"> 2836</td> </tr>
4213<tr><td align="left"> B2 </td> <td align="right"> 1418</td> <td align="right"> 2004</td> </tr>
4214<tr><td align="left"> B3 </td> <td align="right"> 1002</td> <td align="right"> 1418</td> </tr>
4215<tr><td align="left"> B4 </td> <td align="right"> 709</td> <td align="right"> 1002</td> </tr>
4216<tr><td align="left"> B5 </td> <td align="right"> 501</td> <td align="right"> 709</td> </tr>
4217<tr><td align="left"> C0 </td> <td align="right"> 2600</td> <td align="right"> 3677</td> </tr>
4218<tr><td align="left"> C1 </td> <td align="right"> 1837</td> <td align="right"> 2600</td> </tr>
4219<tr><td align="left"> C2 </td> <td align="right"> 1298</td> <td align="right"> 1837</td> </tr>
4220<tr><td align="left"> C3 </td> <td align="right"> 918</td> <td align="right"> 1298</td> </tr>
4221<tr><td align="left"> C4 </td> <td align="right"> 649</td> <td align="right"> 918</td> </tr>
4222<tr><td align="left"> C5 </td> <td align="right"> 459</td> <td align="right"> 649</td> </tr>
4223<tr><td align="left"> C6 </td> <td align="right"> 323</td> <td align="right"> 459</td> </tr>
4224<tr><td align="left"> Flsa </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
4225<tr><td align="left"> Flse </td> <td align="right"> 612</td> <td align="right"> 936</td> </tr>
4226<tr><td align="left"> HalfLetter </td> <td align="right"> 396</td> <td align="right"> 612</td> </tr>
4227</tbody>
4228</table>
4229
4230
4231
4232
4233<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>
4234
4235<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>
4236
4237<p>The default page dimensions for a TEXT image is 612x792.</p>
4238
4239<p>This option is used in concert with <a href="#density">-density</a>.</p>
4240
4241<p>Use <a href="#page">+page</a> to remove the page settings for an image.</p>
4242
4243<div style="margin: auto;">
4244 <h4><a name="paint" id="paint"></a>-paint <em class="arg">radius</em></h4>
4245</div>
4246
4247<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>
4248
4249<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>
4250
4251<div style="margin: auto;">
4252 <h4><a name="path" id="path"></a>-path <em class="arg">path</em></h4></div>
4253
4254<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>
4255
4256<div style="margin: auto;">
4257 <h4><a name="pause_animate_" id="pause_animate_"></a>-pause <em class="arg">seconds</em></h4>
4258</div>
4259
4260<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>
4261
4262<p>Pause for the specified number of seconds before repeating the animation.</p>
4263
4264<div style="margin: auto;">
4265 <h4><a name="pause_import_" id="pause_import_"></a>-pause <em class="arg">seconds</em></h4>
4266</div>
4267
4268<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>
4269
4270<p>Pause for the specified number of seconds before taking the next snapshot.</p>
4271
4272<div style="margin: auto;">
4273 <h4><a name="ping" id="ping"></a>-ping</h4>
4274</div>
4275
4276<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>
4277
4278<div style="margin: auto;">
4279 <h4><a name="pointsize" id="pointsize"></a>-pointsize <em class="arg">value</em></h4>
4280</div>
4281
4282<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>
4283
4284<div style="margin: auto;">
4285 <h4><a name="polaroid" id="polaroid"></a>-polaroid <em class="arg">angle</em></h4>
4286</div>
4287
4288<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>
4289
4290<p>Use <kbd>+polaroid</kbd> to rotate the image at a random angle between -15 and +15 degrees.</p>
4291
4292<div style="margin: auto;">
4293 <h4><a name="posterize" id="posterize"></a>-posterize <em class="arg">levels</em></h4>
4294</div>
4295
4296<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>
4297
4298<div style="margin: auto;">
4299 <h4><a name="preview" id="preview"></a>-preview <em class="arg">type</em></h4>
4300</div>
4301
4302<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>
4303
4304<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>
4305
4306<pre class="text">
4307 Rotate
4308 Shear
4309 Roll
4310 Hue
4311 Saturation
4312 Brightness
4313 Gamma
4314 Spiff
4315 Dull
4316 Grayscale
4317 Quantize
4318 Despeckle
4319 ReduceNoise
4320 Add Noise
4321 Sharpen
4322 Blur
4323 Threshold
4324 EdgeDetect
4325 Spread
4326 Shade
4327 Raise
4328 Segment
4329 Solarize
4330 Swirl
4331 Implode
4332 Wave
4333 OilPaint
4334 CharcoalDrawing
4335 JPEG
4336</pre>
4337
4338<p>To print a complete list of previews, use the <a href="#list">-list preview</a> option.</p>
4339
4340<p>The default preview is <kbd>JPEG</kbd>.</p>
4341
4342<div style="margin: auto;">
4343 <h4><a name="print" id="print"></a>-print <em class="arg">string</em></h4>
4344</div>
4345
4346<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>
4347
4348<div style="margin: auto;">
4349 <h4><a name="process" id="process"></a>-process <em class="arg">command</em></h4>
4350</div>
4351
4352<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>
4353
4354<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>
4355
4356<div style="margin: auto;">
4357 <h4><a name="profile" id="profile"></a>-profile <em class="arg">filename</em><br/>
4358 +profile <em class="arg">profile_name</em></h4>
4359</div>
4360
4361<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>
4362
4363<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>
4364
4365<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>
4366
4367<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>
4368
4369<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>
4370
4371<p>For example, to extract the Exif data (which is stored in JPEG files in the <em class="arg">APP1</em> profile), use.</p>
4372
4373<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert cockatoo.jpg profile.exif</span></p>
4374<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>
4375
4376<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert CMYK.tif -profile "CMYK.icc" -profile "RGB.icc" RGB.tiff</span></p>
4377<p>Furthermore, since ICC profiles are not necessarily symmetric, extra conversion steps can yield unwanted results.
4378CMYK profiles are often very asymmetric since they involve 3&minus;&gt;4 and 4&minus;&gt;3 channel mapping.
4379</p>
4380
4381<div style="margin: auto;">
4382 <h4><a name="quality" id="quality"></a>-quality <em class="arg">value</em></h4>
4383</div>
4384
4385<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>
4386
4387<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>
4388
4389<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>
4390
4391<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>
4392
4393<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>
4394
4395<p>If filter-type is 4 or less, the specified filter-type is used for all scanlines:</p>
4396
4397<pre class="text">
4398 0: none
4399 1: sub
4400 2: up
4401 3: average
4402 4: Paeth
4403</pre>
4404
4405<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>
4406
4407<p>If filter-type is 6, adaptive filtering with <em class="arg">minimum-sum-of-absolute-values</em> is used.</p>
4408
4409<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>
4410
4411<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>
4412
4413<p>For further information, see the <a href="http://www.w3.org/pub/WWW/TR">PNG</a> specification.</p>
4414
4415<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>
4416
4417<div style="margin: auto;">
4418 <h4><a name="quantize" id="quantize"></a>-quantize <em class="arg">colorspace</em></h4>
4419</div>
4420
4421<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>
4422
4423<p>To print a complete list of colorspaces, use the <a href="#list">-list colorspace</a> option.</p>
4424
4425
4426<div style="margin: auto;">
4427 <h4><a name="quiet" id="quiet"></a>-quiet</h4>
4428</div>
4429
4430<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>
4431
4432<div style="margin: auto;">
4433 <h4><a name="radial-blur" id="radial-blur"></a>-radial-blur <em class="arg">angle</em></h4>
4434</div>
4435
4436<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>
4437
4438<p>Note that this is actually a rotational blur rather than a radial and as
4439such actually mis-named. </p>
4440
4441<p>The <a href="#virtual-pixel">-virtual-pixel</a> setting will determine how
4442pixels which are outside the image proper are blurred into the final result.
4443</p>
4444
4445
4446<div style="margin: auto;">
4447 <h4><a name="raise" id="raise"></a>-raise <em class="arg">thickness</em></h4>
4448</div>
4449
4450<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>
4451
4452<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>.
4453</p>
4454
4455<p>Unlike the similar <a href="#frame">-frame</a> option, <a href="#raise">-raise</a> does not alter the dimensions of the image.</p>
4456
4457<div style="margin: auto;">
4458 <h4><a name="random-threshold" id="random-threshold"></a>-random-threshold <em class="arg">low</em>x<em class="arg">high</em></h4>
4459</div>
4460
4461<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>
4462
4463<div style="margin: auto;">
4464 <h4><a name="recolor" id="recolor"></a>-recolor <em class="arg">matrix</em></h4>
4465</div>
4466
4467<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>
4468
4469<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.
4470</p>
4471
4472<div style="margin: auto;">
4473 <h4><a name="red-primary" id="red-primary"></a>-red-primary <em class="arg">x,y</em></h4>
4474</div>
4475
4476<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>
4477
4478<div style="margin: auto;">
4479 <h4><a name="regard-warnings" id="regard-warnings"></a>-regard-warnings</h4>
4480</div>
4481
4482<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>
4483
4484<div style="margin: auto;">
4485 <h4><a name="remap" id="remap"></a>-remap <em class="arg">filename</em></h4>
4486</div>
4487
4488<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>
4489
4490<p>If the <a href="#dither">-dither</a> setting is enabled (the default) then
4491the given colors are dithered over the image as necessary, otherwise the closest
4492color (in RGB colorspace) is selected to replace that pixel in the image. </p>
4493
4494<p>As a side effect of applying a <a href="#remap">-remap</a> of colors across all
4495images in the current image sequence, all the images will have the same color
4496table. That means that when saved to a file format such as GIF, it will use
4497that color table as a single common or global color table, for all the images,
4498without requiring extra local color tables. </p>
4499
4500<p>Use <a href="#remap">+remap</a> to reduce all images in the current image
4501sequence to use a common color map over all the images. This equivalent to
4502appending all the images together (without extra background colors) and color
4503reducing those images using <a href="#colors">-colors</a> with a 256 color
4504limit, then <a href="#remap">-remap</a> those colors over the original list of
4505images. This ensures all the images follow a single color map. </p>
4506
4507<p>If the number of colors over all the images is less than 256, then <a
4508href="#remap">+remap</a> should not perform any color reduction or dithering, as
4509no color changes are needed. In that case, its only effect is to force the use
4510of a global color table. This recommended after using either <a
4511href="#colors">-colors</a> or <a href="#ordered-dither">-ordered-dither</a> to
4512reduce the number of colors in an animated image sequence. </p>
4513
4514<div style="margin: auto;">
4515 <h4><a name="region" id="region"></a>-region <em class="arg">geometry</em></h4>
4516</div>
4517
4518<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>
4519
4520<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>
4521
4522<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>
4523
4524<div style="margin: auto;">
4525 <h4><a name="remote" id="remote"></a>-remote</h4>
4526</div>
4527
4528<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>
4529
4530<p>The only command recognized is the name of an image file to load.</p>
4531
4532<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>
4533
4534<div style="margin: auto;">
4535 <h4><a name="render" id="render"></a>-render</h4>
4536</div>
4537
4538<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>
4539
4540<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>
4541
4542<div style="margin: auto;">
4543<h4><a name="repage" id="repage"></a>-repage <em class="arg">geometry</em></h4>
4544</div>
4545
4546<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>
4547
4548<p>This option is like <a href="#page">-page</a> but acts as an image operator
4549rather than a setting. You can separately set the canvas size or the offset
4550of the image on that canvas by only providing those components. </p>
4551
4552<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>
4553
4554<p>If a <kbd>!</kbd> flag is given the offset given is added to the existing
4555offset to move the image relative to its previous position. This useful for
4556animation sequences. </p>
4557
4558<p>A given a canvas size of zero such as '<kbd>0x0</kbd>' forces it to
4559recalculate the canvas size so the image (at its current offset) will appear
4560completely on that canvas (unless it has a negative offset).</p>
4561
4562<p>Use <a href="#repage">+repage</a> to completely remove/reset the virtual
4563canvas meta-data from the images. </p>
4564
4565<p>The <a href="#set">-set</a> '<kbd>page</kbd>' option can be used to
4566directly assign virtual canvas meta-data. </p>
4567
4568
4569<div style="margin: auto;">
4570 <h4><a name="resample" id="resample"></a>-resample <em class="arg">horizontal</em>x<em class="arg">vertical</em></h4>
4571</div>
4572
4573<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>
4574
4575<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>
4576
4577<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>
4578
4579<div style="margin: auto;">
4580 <h4><a name="resize" id="resize"></a>-resize <em class="arg">geometry</em></h4>
4581</div>
4582
4583<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>
4584
4585<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>
4586
4587<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>
4588
4589<div style="margin: auto;">
4590 <h4><a name="respect-parentheses" id="respect-parentheses"></a>-respect-parentheses</h4>
4591</div>
4592
4593<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>
4594
4595<div style="margin: auto;">
4596 <h4><a name="reverse" id="reverse"></a>-reverse</h4>
4597</div>
4598
4599<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>
4600
4601
4602<div style="margin: auto;">
4603 <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>
4604</div>
4605
4606<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>
4607
4608<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>
4609
4610
4611<div style="margin: auto;">
4612 <h4><a name="rotate" id="rotate"></a>-rotate <em class="arg">degrees</em>{<em class="arg">&lt;</em>}{<em class="arg">&gt;</em>}</h4>
4613</div>
4614
4615<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>
4616
4617<p>Use <kbd>&gt;</kbd> to rotate the image only if its width exceeds the height. <kbd>&lt;</kbd> rotates the image <em>only</em> if its width is less than the height. For example, if you specify <kbd>-rotate "-90&gt;"</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>&gt;</kbd> or <kbd>&lt;</kbd>, enclose it in quotation marks to prevent it from being misinterpreted as a file redirection.</p>
4618
4619<p>Empty triangles in the corners, left over from rotating the image, are
4620filled with the <kbd>background</kbd> color. </p>
4621
4622<p>See also the <a href="#distort">-distort</a> operator and specifically the
4623'<kbd>ScaleRotateTranslate</kbd>' distort method. </p>
4624
4625
4626<div style="margin: auto;">
4627 <h4><a name="sample" id="sample"></a>-sample <em class="arg">geometry</em></h4>
4628</div>
4629
4630<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>
4631
4632<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>
4633
4634<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>
4635
4636
4637<div style="margin: auto;">
4638 <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>
4639</div>
4640
4641<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>
4642
4643<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>
4644
4645<div style="margin: auto;">
4646 <h4><a name="scale" id="scale"></a>-scale <em class="arg">geometry</em></h4>
4647</div>
4648
4649<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>
4650
4651<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>
4652
4653<div style="margin: auto;">
4654 <h4><a name="scene" id="scene"></a>-scene <em class="arg">value</em></h4>
4655</div>
4656
4657<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>
4658
4659<p>This option sets the scene number of an image or the first image in an image sequence.</p>
4660
4661<div style="margin: auto;">
4662 <h4><a name="screen" id="screen"></a>-screen</h4>
4663</div>
4664
4665<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>
4666
4667<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>
4668
4669<div style="margin: auto;">
4670 <h4><a name="seed" id="seed"></a>-seed</h4>
4671</div>
4672
4673<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>
4674
4675<div style="margin: auto;">
4676 <h4><a name="segment" id="segment"></a>-segment <em class="arg">cluster-threshold</em>x<em class="arg">smoothing-threshold</em></h4>
4677</div>
4678
4679<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>
4680
4681<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>
4682
4683<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>
4684
4685<p>If the <a href="#verbose">-verbose</a> setting is defined, a detailed report
4686of the color clusters is returned.</p>
4687
4688
4689<div style="margin: auto;">
4690 <h4><a name="selective-blur" id="selective-blur"></a>-selective-blur <em class="arg">geometry</em></h4>
4691</div>
4692
4693<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>
4694
4695<div style="margin: auto;">
4696 <h4><a name="separate" id="separate"></a>-separate</h4>
4697</div>
4698
4699<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>
4700
4701<div style="margin: auto;">
4702 <h4><a name="sepia-tone" id="sepia-tone"></a>-sepia-tone <em class="arg">threshold</em></h4>
4703</div>
4704
4705<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>
4706
4707<p>Specify <em class="arg">threshold</em> as the percent threshold of the intensity (0 - 99.9%).</p>
4708
4709<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>
4710
4711<div style="margin: auto;">
4712 <h4><a name="set" id="set"></a>-set <em class="arg">attribute value</em></h4>
4713</div>
4714
4715<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>
4716
4717<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>
4718
4719<p class='crt'><span class="crtprompt"> $magick&gt; </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&gt; </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>
4720<p>The <a href="#repage">-repage</a> operator will also set the
4721'<kbd>page</kbd>' attribute of images already in memory, but allows you to
4722separately set the virtual canvas's size and offset components, and also allows
4723relative offset changes, and automatic canvas size re-calculating. The above
4724<a href="#set">-set</a> option is purely a direct, unmodified assignment of the
4725virtual canvas (page) meta-data. </p>
4726
4727<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>
4728
4729<div style="margin: auto;">
4730 <h4><a name="shade" id="shade"></a>-shade <em class="arg">azimuth</em>x<em class="arg">elevation</em></h4>
4731</div>
4732
4733<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>
4734
4735<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>
4736
4737<div style="margin: auto;">
4738 <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>
4739</div>
4740
4741<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>
4742
4743<div style="margin: auto;">
4744 <h4><a name="shared-memory"
4745id="shared-memory"></a>-shared-memory</h4>
4746</div>
4747
4748<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>
4749
4750<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>
4751
4752<div style="margin: auto;">
4753 <h4><a name="sharpen" id="sharpen"></a>-sharpen <em class="arg">radius</em>{x<em class="arg">sigma</em>}</h4>
4754</div>
4755
4756<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>
4757
4758<p>Use a Gaussian operator of the given radius and standard deviation (sigma).</p>
4759
4760<div style="margin: auto;">
4761 <h4><a name="shave" id="shave"></a>-shave <em class="arg">geometry</em></h4>
4762</div>
4763
4764<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>
4765
4766<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>
4767
4768<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>
4769
4770<div style="margin: auto;">
4771 <h4><a name="shear" id="shear"></a>-shear <em class="arg">Xdegrees</em>[x<em class="arg">Ydegrees</em>]</h4>
4772</div>
4773
4774<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>
4775
4776<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>
4777
4778<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&deg;&lt;<em class="arg">Xdegrees</em>&lt;90&deg; and to the left when 90&deg;&lt;<em class="arg">Xdegrees</em>&lt;180&deg;. 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&deg;&lt;<em class="arg">Ydegrees</em>&lt;90&deg; and up when 90&deg;&lt;<em class="arg">Ydegrees</em>&lt;180&deg;.</p>
4779
4780<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>
4781
4782<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>
4783
4784<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: -shear 20x0 -shear 0x60 logo-sheared.png</span><span class='crtout'></span><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: -shear 0x60 -shear 20x0 logo-sheared.png</span></p>
4785<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>
4786
4787<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert logo: -shear 20x60 logo-sheared.png</span></p>
4788<div style="margin: auto;">
4789 <h4><a name="sigmoidal" id="sigmoidal-contrast"></a>-sigmoidal-contrast <em class="arg">contrast</em>x<em class="arg">mid-point</em></h4>
4790</div>
4791
4792<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>
4793
4794<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>
4795
4796<div style="margin: auto;">
4797 <h4><a name="silent" id="silent"></a>-silent</h4>
4798</div>
4799
4800<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>
4801
4802<div style="margin: auto;">
4803 <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>
4804</div>
4805
4806<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>
4807
4808<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>
4809
4810<p>For Photo CD images, choose from these sizes:</p>
4811
4812<pre class="text">
4813 192x128
4814 384x256
4815 768x512
4816 1536x1024
4817 3072x2048
4818</pre>
4819
cristy3ed852e2009-09-05 21:47:34 +00004820<div style="margin: auto;">
4821 <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>
4822</div>
4823
4824<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>
4825
4826<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>
4827
4828<div style="margin: auto;">
4829 <h4><a name="snaps" id="snaps"></a>-snaps <em class="arg">value</em></h4>
4830</div>
4831
4832<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>
4833
4834<p>Use this option to grab more than one image from the X server screen, to create an animation sequence.</p>
4835
4836<div style="margin: auto;">
4837 <h4><a name="solarize" id="solarize"></a>-solarize <em class="arg">threshold</em></h4>
4838</div>
4839
4840<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>
4841
4842<p>Specify <em class="arg">factor</em> as the percent threshold of the intensity (0 - 99.9%).</p>
4843
4844<p>This option produces a <em class="arg">solarization</em> effect seen when exposing a photographic film to light during the development process.</p>
4845
4846<div style="margin: auto;">
4847 <h4><a name="sparse-color" id="sparse-color"></a>-sparse-color <em
4848 class="arg">method</em> '<em class="arg">x</em>,<em class="arg">y</em> <em class="arg">color</em> ...'</h4>
4849</div>
4850
4851<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>
4852
4853
4854<table class="doc">
4855 <tbody>
4856 <tr valign="top">
4857 <th align="left" style="width: 8%">Method</th>
4858 <th align="left">Description</th>
4859 </tr>
4860
4861 <tr valign="top">
4862 <td valign="top">voronoi</td>
4863 <td valign="top">Simply map each pixel to the to nearest color point
4864 given. The result are polygonal 'cells' of solid color. </td>
4865 </tr>
4866
4867 <tr valign="top">
4868 <td valign="top">shepards</td>
4869 <td valign="top">Colors points basied on the ratio of inverse distance
4870 squared. Generating spots of color in a sea of the average of
4871 colors. </td>
4872 </tr>
4873
4874 <tr valign="top">
4875 <td valign="top">barycentric</td>
4876 <td valign="top">three point triangle of color given 3 points.
4877 Giving only 2 points will form a linear gradient between those points.
4878 Gradient is however not restricted to just the triangle or line. </td>
4879 </tr>
4880
4881 <tr valign="top">
4882 <td valign="top">bilinear</td>
4883 <td valign="top">Like barycentric but for 4 points. Less than 4 points
4884 fall back to barycentric. </td>
4885 </tr>
4886
4887 </tbody>
4888</table>
4889
4890<p>The points are placed according to the images location on the virtual
4891canvas (<a href="#page" >-page</a> or <a href="#repage" >-repage</a>
4892offset), and do not actually have to exist on the given image, but may be
4893some point beyond the edge of the image. All points are floating point values.
4894</p>
4895
4896<p>Only the color channels defined by the <a href="#channel" >-channel</a> are
4897modified, whcih means the matte/alpha transparency channel is not effected by
4898default. If enabled, the image also needs a the matte/alpha channel to be
4899enabled for this operator to effect an images transparency. This is typical
4900transparency handling for images. </p>
4901
4902<p>All the above methods when given a single point of color will replace all
4903the colors in the image with the color given, regardless of the point. This is
4904logical, and provides an alternative technique to recolor a image to some
4905default value. </p>
4906
4907
4908<div style="margin: auto;">
4909 <h4><a name="splice" id="splice"></a>-splice <em class="arg">geometry</em></h4>
4910</div>
4911
4912<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>
4913
4914<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>
4915
4916<div style="margin: auto;">
4917 <h4><a name="spread" id="spread"></a>-spread <em class="arg">amount</em></h4>
4918</div>
4919
4920<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>
4921
4922<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>
4923
4924<div style="margin: auto;">
4925 <h4><a name="stegano" id="stegano"></a>-stegano <em class="arg">offset</em></h4>
4926</div>
4927
4928<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>
4929
4930<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>
4931
4932<div style="margin: auto;">
4933 <h4><a name="stereo" id="stereo"></a>-stereo <em class="arg">+x</em>{<em class="arg">+y</em>}</h4>
4934</div>
4935
4936<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>
4937
4938<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>
4939
4940<div style="margin: auto;">
4941 <h4><a name="storage-type" id="storage-type"></a>-storage-type <em class="arg">type</em></h4>
4942</div>
4943
4944<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>
4945
4946<pre class="text">
4947 char store pixels as unsigned characters
4948 double store pixels as doubles
4949 float store pixels as floats
4950 integer store pixels as integers
4951 long store pixels as longs
4952 quantum store pixels in the native depth of your ImageMagick distribution
4953 short store pixels as unsigned shorts
4954</pre>
4955
4956<p>Float and double types are normalized from 0.0 to 1.0 otherwise the pixels
4957values range from 0 to the maximum value the storage type can support.</p>
4958
4959<div style="margin: auto;">
4960 <h4><a name="stretch" id="stretch"></a>-stretch <em class="arg">fontStretch</em></h4>
4961</div>
4962
4963<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>
4964
4965<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>
4966
4967<pre class="text">
4968 Any
4969 Condensed
4970 Expanded
4971 ExtraCondensed
4972 ExtraExpanded
4973 Normal
4974 SemiCondensed
4975 SemiExpanded
4976 UltraCondensed
4977 UltraExpanded
4978</pre>
4979
4980<p>To print a complete list of stretch types, use <a href="#list">-list stretch</a>.</p>
4981
4982<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>
4983
4984<div style="margin: auto;">
4985 <h4><a name="strip" id="strip"></a>-strip</h4>
4986</div>
4987
4988<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>
4989
4990<div style="margin: auto;">
4991 <h4><a name="stroke" id="stroke"></a>-stroke <em class="arg">color</em></h4>
4992</div>
4993
4994<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>
4995
4996<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
4997
4998<p>See <a href="#draw">-draw</a> for further details.</p>
4999
5000<div style="margin: auto;">
5001 <h4><a name="strokewidth" id="strokewidth"></a>-strokewidth <em class="arg">value</em></h4>
5002</div>
5003
5004<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>set the stroke width.</td><td style='text-align:right;'></td></tr></table>
5005
5006<p>See <a href="#draw">-draw</a> for further details.</p>
5007
5008<div style="margin: auto;">
5009 <h4><a name="style" id="style"></a>-style <em class="arg">fontStyle</em></h4>
5010</div>
5011
5012<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>
5013
5014<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>
5015
5016<pre class="text">
5017 Any
5018 Italic
5019 Normal
5020 Oblique
5021</pre>
5022
5023<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>
5024
5025<div style="margin: auto;">
5026 <h4><a name="swap" id="swap"></a>-swap <em class="arg">index,index</em></h4>
5027</div>
5028
5029<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>
5030
5031<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>
5032
5033<div style="margin: auto;">
5034 <h4><a name="swirl" id="swirl"></a>-swirl <em class="arg">degrees</em></h4>
5035</div>
5036
5037<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>
5038
5039<p><em class="arg">Degrees</em> defines the tightness of the swirl.</p>
5040
5041<div style="margin: auto;">
5042 <h4><a name="taint" id="taint"></a>-taint</h4>
5043</div>
5044
5045<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>
5046
5047<div style="margin: auto;">
5048 <h4><a name="text-font" id="text-font"></a>-text-font <em class="arg">name</em></h4>
5049</div>
5050
5051<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>
5052
5053<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>
5054
5055<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>
5056
5057<div style="margin: auto;">
5058 <h4><a name="texture" id="texture"></a>-texture <em class="arg">filename</em></h4>
5059</div>
5060
5061<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>
5062
5063<div style="margin: auto;">
5064 <h4><a name="threshold" id="threshold"></a>-threshold <em class="arg">value</em>{<em class="arg">%</em>}</h4>
5065</div>
5066
5067<!-- {<em class="arg">green,blue,opacity</em>}
5068<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>
5069-->
5070
5071<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>
5072
5073<p>Any pixel values (more specifically, those channels set using <a href="../www/command-line-options.html#channel">&#x2011;channel</a>) that exceed the specified threshold are reassigned the maximum channel value, while all other values are assigned the minimum.</p>
5074
5075<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.
5076</p>
5077
5078<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>
5079
5080<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert in.png -channel red -threshold 50% out.png</span></p>
5081<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>
5082
5083
5084<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert in.png -threshold 100% black.png</span><span class='crtout'></span><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert in.png -threshold -1 white.png</span></p>
5085<p>Note that the values of the transparency channel is treated as 'matte'
5086values (0 is opaque) and not as 'alpha' values (0 is transparent).</p>
5087
5088<p> See also <a href="../www/command-line-options.html#black-threshold">&#x2011;black&#x2011;threshold</a> and <a href="../www/command-line-options.html#white-threshold">&#x2011;white&#x2011;threshold</a>.
5089</p>
5090
5091<div style="margin: auto;">
5092 <h4><a name="thumbnail" id="thumbnail"></a>-thumbnail <em class="arg">geometry</em></h4>
5093</div>
5094
5095<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>
5096
5097<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>
5098
5099<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>
5100
5101<div style="margin: auto;">
5102 <h4><a name="tile" id="tile"></a>-tile <em class="arg">filename</em></h4>
5103</div>
5104
5105<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>
5106
5107<div style="margin: auto;">
5108 <h4>-tile <em class="arg">geometry</em></h4>
5109</div>
5110
5111<table style='background-color:#FFFFE0; margin-left:40px; margin-right:40px; width:88%'><tr><td style='width:75%'>Specify the layout of images .</td><td style='text-align:right;'>[<a href="../www/montage.html">montage</a>]</td></tr></table>
5112
5113<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>
5114
5115<div style="margin: auto;">
5116 <h4>-tile</h4>
5117</div>
5118
5119<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>
5120
5121<div style="margin: auto;">
5122 <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>
5123</div>
5124
5125<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>
5126
5127<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>
5128
5129<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>
5130
5131<div style="margin: auto;">
5132 <h4><a name="tint" id="tint"></a>-tint <em class="arg">value</em></h4>
5133</div>
5134
5135<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>
5136
5137<p>Tint the image with the fill color.</p>
5138
5139<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>
5140
5141<div style="margin: auto;">
5142 <h4><a name="title" id="title"></a>-title <em class="arg">string</em></h4>
5143</div>
5144
5145<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>
5146
5147<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>
5148
5149<p>For example,</p>
5150
5151<p class="crtsnip">
5152 -title "%m:%f %wx%h"
5153</p>
5154
5155<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>
5156
5157
5158<div style="margin: auto;">
5159 <h4><a name="transform" id="transform"></a>-transform</h4>
5160</div>
5161
5162<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>
5163
5164<p>This option applies the transformation matrix from a previous <a href="#affine">-affine</a> option.</p>
5165
5166<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert -affine 2,2,-2,2,0,0 -transform bird.ppm bird.jpg</span></p>
5167<div style="margin: auto;">
5168 <h4><a name="transparent" id="transparent"></a>-transparent <em class="arg">color</em></h4>
5169</div>
5170
5171<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>
5172
5173<p>The <em class="arg">color</em> argument is defined using the format
5174described under the <a href="#fill">-fill</a> option. The <a href="#fuzz"
5175>-fuzz</a> setting can be used to match and replace colors similar to the one
5176given. </p>
5177
5178<p>The <a href="#opaque">-opaque</a> operator is exactly the same as <a
5179href="#transparent" >-transparent</a> but replaces the matching color same as
5180the current <a href="#fill">-fill</a> color setting. </p>
5181
5182<p>This does not define the 'transparency color' used for color-mapped image
5183formats, such as GIF. For that use <a href="#transparent-color"
5184>-transparent-color</a> </p>
5185
5186<p>Use <a href="#opaque">+opaque</a> to invered the pixels matched, that is
5187paint any pixel that does not match the target color, with the fill color.</p>
5188
5189
5190<div style="margin: auto;">
5191 <h4><a name="transparent-color" id="transparent-color"></a>-transparent-color <em class="arg">color</em></h4>
5192</div>
5193
5194<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>
5195
5196<p>Sometimes this is used for saving to image formats such as
5197GIF and PNG8 which uses this color to represent boolean transparency. This
5198does not make a color transparent, it only defines what color the transparent
5199color is in the color palette of the saved image. Use <a
5200href="#transparent">-transparent</a> to make an opaque color transparent.</p>
5201
5202<p>This option allows you to have both an opaque visible color, as well as a
5203transparent color of the same color value without conflict. That is, you can
5204use the same color for both the transparent and opaque color areas within an
5205image. This, in turn, frees to you to select a transparent color that is
5206appropriate when an image is displayed by an application that does not handle a
5207transparent color index, while allowing ImageMagick to correctly handle images of this
5208type. </p>
5209
5210<p>The default transparent color is <kbd>#00000000</kbd>, which is fully transparent black.</p>
5211
5212<div style="margin: auto;">
5213 <h4><a name="transpose" id="transpose"></a>-transpose</h4>
5214</div>
5215
5216<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>
5217
5218<p> This option mathematically transposes the pixel array. It is equivalent to the sequence <kbd>-flip -rotate 90</kbd>.
5219</p>
5220
5221<div style="margin: auto;">
5222 <h4><a name="transverse" id="transverse"></a>-transverse</h4>
5223</div>
5224
5225<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>
5226
5227
5228<div style="margin: auto;">
5229 <h4><a name="treedepth" id="treedepth"></a>-treedepth <em class="arg">value</em></h4>
5230</div>
5231
5232<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>
5233
5234<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>
5235
5236<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>
5237
5238<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>
5239
5240<div style="margin: auto;">
5241 <h4><a name="trim" id="trim"></a>-trim</h4>
5242</div>
5243
5244<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>
5245
5246<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>
5247
5248<p>The page or virtual canvas information of the image is preserved allowing
5249you to extract the result of the <a href="#trim">-trim</a> operation from the
5250image. Use a <a href="#repage">+repage</a> to remove the virtual canvas page
5251information if it is unwanted.</p>
5252
5253<p>If the trimmed image 'disappears' an warning is produced, and a special
5254single pixel transparent 'missed' image is returned, in the same way as when a
5255<a href="#crop">-crop</a> operation 'misses' the image proper. </p>
5256
5257
5258<div style="margin: auto;">
5259 <h4><a name="type" id="type"></a>-type <em class="arg">type</em></h4>
5260</div>
5261
5262<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>
5263 <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>
5264
5265<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>
5266
5267<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>convert bird.png -type TrueColor bird.jpg</span></p>
5268<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>
5269
5270<p>Use <a href="#type">-type optimize</a> to ensure the image is written in the smallest possible file size.</p>
5271
5272<div style="margin: auto;">
5273 <h4><a name="undercolor" id="undercolor"></a>-undercolor <em class="arg">color</em></h4>
5274</div>
5275
5276<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>
5277
5278<p>The color is specified using the format described under the <a href="#fill">-fill</a> option.</p>
5279
5280<p>See <a href="#draw">-draw</a> for further details.</p>
5281
5282
5283<div style="margin: auto;">
5284 <h4><a name="update" id="update"></a>-update <em class="arg">seconds</em></h4>
5285</div>
5286
5287<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>
5288
5289<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>
5290
5291
5292<div style="margin: auto;">
5293 <h4><a name="unique-colors" id="unique-colors"></a>-unique-colors</h4>
5294</div>
5295
5296<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>
5297
5298
5299<div style="margin: auto;">
5300 <h4><a name="units" id="units"></a>-units <em class="arg">type</em></h4>
5301</div>
5302
5303<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>
5304
5305<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>
5306
5307
5308<div style="margin: auto;">
5309 <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>
5310</div>
5311
5312<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>
5313
5314<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>
5315
5316<p>The parameters are:</p>
5317
5318<pre class="text">
5319 radius: The radius of the Gaussian, in pixels, not counting the center
5320 pixel (default 0).
5321 sigma: The standard deviation of the Gaussian, in pixels (default 1.0).
5322 amount: The fraction of the difference between the original and the blur
5323 image that is added back into the original (default 1.0).
5324 threshold: The threshold, as a fraction of <em class="QR">QuantumRange</em>, needed to apply the
5325 difference amount (default 0.05).
5326</pre>
5327
5328
5329<div style="margin: auto;">
5330 <h4><a name="verbose" id="verbose"></a>-verbose</h4>
5331</div>
5332
5333<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>
5334
5335
5336<div style="margin: auto;">
5337 <h4><a name="version" id="version"></a>-version</h4>
5338</div>
5339
5340<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>
5341
5342
5343<div style="margin: auto;">
5344 <h4><a name="view" id="view"></a>-view <em class="arg">string</em></h4>
5345</div>
5346
5347<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>
5348
5349
5350<div style="margin: auto;">
5351 <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>
5352</div>
5353
5354<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>
5355
5356
5357<div style="margin: auto;">
5358 <h4><a name="virtual-pixel" id="virtual-pixel"></a>-virtual-pixel <em class="arg">method</em></h4>
5359</div>
5360
5361<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>
5362
5363<p>This option defines what color source should be used if and when a color
5364lookup completely 'misses' the source image. The color(s) that appear to
5365surround the source image. Generally this color is derived from the source
5366image, but could also be set to a specify background color. </p>
5367
5368<p>Choose from these methods:</p>
5369
5370<pre class="text">
5371 background: the area surrounding the image is the background color
5372 black: the area surrounding the image is black
5373 checker-tile: alternate squares with image and background color
5374 dither: non-random 32x32 dithered pattern
5375 edge: extend the edge pixel toward infinity
5376 gray: the area surrounding the image is gray
5377 horizontal-tile: horizontally tile the image, background color above/below
5378 horizontal-tile-edge: horizontally tile the image and replicate the side edge pixels
5379 mirror: mirror tile the image
5380 random: choose a random pixel from the image
5381 tile: tile the image (default)
5382 transparent: the area surrounding the image is transparent blackness
5383 vertical-tile: vertically tile the image, sides are background color
5384 vertical-tile-edge: vertically tile the image and replicate the side edge pixels
5385 white: the area surrounding the image is white
5386</pre>
5387
5388<p>The default value is "edge".</p>
5389
5390<p>This most important for distortion operators such as <a href="#distort"
5391>-distort</a>, <a href="#implode" >-implode</a>, and <a href="#fx" >-fx</a>.
5392However it also effects operations that may access pixels just outside the
5393image proper, such as <a href="#convolve">-convolve</a>, <a
5394href="#blur">-blur</a>, and <a href="#sharpen">-sharpen</a>. </p>
5395
5396<p>To print a complete list of virtual pixel types, use the <a href="#list">-list virtual-pixel</a> option.</p>
5397
5398
5399<div style="margin: auto;">
5400 <h4><a name="visual" id="visual"></a>-visual <em class="arg">type</em></h4>
5401</div>
5402
5403<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>
5404
5405<p>Choose from these visual classes:</p>
5406
5407<pre class="text">
5408 StaticGray
5409 GrayScale
5410 StaticColor
5411 PseudoColor
5412 TrueColor
5413 DirectColor
5414 default
5415 visual id
5416</pre>
5417
5418<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>
5419
5420
5421<div style="margin: auto;">
5422 <h4><a name="watermark" id="watermark"></a>-watermark <em
5423 class="arg">brightness</em>x<em class="arg">saturation</em></h4>
5424</div>
5425
5426<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
5427saturation.</td><td style='text-align:right;'>[<a href="../www/composite.html">composite</a>]</td></tr></table>
5428
5429<p>Take a grayscale image (with alpha mask) and modify the destination image's
5430brightness according to watermark image's grayscale value and the <em
5431class="arg">brightness</em> percentage. The destinations color saturation
5432attribute is just direct modified by the <em class="arg">saturation</em>
5433percentage, which defaults to 100 percent (no color change). </p>
5434
5435
5436<div style="margin: auto;">
5437 <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>
5438</div>
5439
5440<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>
5441
5442<p>Specify <em class="arg">amplitude</em> and <em class="arg">wavelength</em> of the wave.</p>
5443
5444<div style="margin: auto;">
5445 <h4><a name="weight" id="weight"></a>-weight <em class="arg">fontWeight</em></h4>
5446</div>
5447
5448<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>
5449
5450<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>
5451
5452<table class="doc">
5453 <col width="25%" />
5454 <col width="75%" />
5455 <thead>
5456 <tr>
5457 <th><em class="arg">fontWeight</em></th>
5458 <th>Description</th>
5459 </tr>
5460 </thead>
5461 <tbody>
5462 <tr><td>All </td> <td>No effect. </td></tr>
5463 <tr><td>Bold </td> <td>Same as <em class="arg">fontWeight</em> = 700.</td></tr>
5464 <tr><td>Bolder </td> <td>Add 100 to font weight if currently &le; 800.</td></tr>
5465 <tr><td>Lighter </td> <td>Subtract 100 to font weight if currently &le; 100.</td></tr>
5466 <tr><td>Normal </td> <td>Same as <em class="arg">fontWeight</em> = 400.</td></tr>
5467 </tbody>
5468 </table>
5469
5470<p>To print a complete list of weight types, use <a href="#list">-list weight</a>.</p>
5471
5472<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>
5473
5474<div style="margin: auto;">
5475 <h4><a name="white-point" id="white-point"></a>-white-point <em class="arg">x,y</em></h4>
5476</div>
5477
5478<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>
5479
5480<div style="margin: auto;">
5481 <h4><a name="white-threshold" id="white-threshold"></a>-white-threshold <em class="arg">threshold</em></h4>
5482</div>
5483
5484<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>
5485
5486<div style="margin: auto;">
5487 <h4><a name="window" id="window"></a>-window <em class="arg">id</em></h4>
5488</div>
5489
5490<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>
5491
5492<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>
5493
5494<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>
5495
5496<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>
5497
5498<div style="margin: auto;">
5499 <h4><a name="window-group" id="window-group"></a>-window-group</h4>
5500</div>
5501
5502<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>
5503
5504<div style="margin: auto;">
5505 <h4><a name="write" id="write"></a>-write <em class="arg">filename</em></h4>
5506</div>
5507
5508<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>
5509 <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>
5510
5511<p>Use <a href="#compress">-compress</a> to specify the type of image compression.</p>
5512
cristyf3bb4782009-09-08 13:10:04 +00005513
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