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gerrit-public.fairphone.software / platform / external / ImageMagick / baacd1791168d71a29884bfbe0ac39d95edf0978 / . / www / magick-wand.html
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cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
3 "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
cristy2bd2a982011-02-15 00:52:58 +0000[diff] [blame]4<html version="-//W3C//DTD XHTML 1.1//EN"
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cristyffb69ed2010-12-25 00:06:48 +0000[diff] [blame]12 <title>ImageMagick: MagickWand, C API for ImageMagick</title>
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34 @import url("../www/magick.css");
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198<div class="main">
199
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]200<h1>MagickWand C API</h1>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]201
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]202<div class="doc-section">
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]203<p>The <a href="../www/api/MagickWand/index.html">MagickWand API</a> is the recommended interface between the C programming language and the ImageMagick image processing libraries. Unlike the <a href="../www/magick-core.html">MagickCore</a> C API, MagickWand uses only a few opaque types. Accessors are available to set or get important wand properties. A description of the MagickWand public methods are found here:</p>
204
205<ul>
206 <li><a href="../www/api/magick-wand.html">Magick Wand Methods</a></li>
207 <li><a href="../www/api/magick-property.html">Set or Get Magick Wand Properties</a></li>
208 <li><a href="../www/api/magick-image.html">Magick Wand Image Methods</a></li>
209 <li><a href="../www/api/pixel-iterator.html">Pixel Iterator Methods</a></li>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]210 <li><a href="../www/api/pixel-wand.html">Pixel Wand Methods</a></li>
211 <li><a href="../www/api/drawing-wand.html">Image Vector Drawing</a></li>
cristy5063d812010-10-19 16:28:10 +0000[diff] [blame]212 <li><a href="../www/api/mogrify.html">Command-line Interface</a></li>
cristyd6dfc0d2010-06-27 19:30:49 +0000[diff] [blame]213 <li><a href="../www/api/wand-view.html">Wand View Methods</a></li>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]214 <li><a href="../www/api/magick-deprecate.html">Deprecated Methods</a></li>
215 <li><a href="../www/exception.html">Error and Warning Codes</a></li>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]216</ul>
217
218<p>After you write your MagickWand program, compile it like this:</p>
219
cristyd4d64ed2010-08-22 22:19:33 +0000[diff] [blame]220<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>cc `MagickWand-config --cflags --cppflags` -O2 -o wand wand.c \ <br/> `MagickWand-config --ldflags --libs`</span></p>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]221<p>Here is a example program that utilizes the MagickWand API to get you started, <a href="../www/source/wand.c">wand.c</a>. It reads an image, creates a thumbnail, and writes the result to disk.</p>
222
223<div class="viewport">
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]224#include &lt;stdio.h>
225#include &lt;stdlib.h>
226#include &lt;wand/MagickWand.h>
227
228int main(int argc,char **argv)
229{
230#define ThrowWandException(wand) \
231{ \
232 char \
233 *description; \
234 \
235 ExceptionType \
236 severity; \
237 \
238 description=MagickGetException(wand,&amp;severity); \
cristyc3186d52010-06-04 13:55:23 +0000[diff] [blame]239 (void) fprintf(stderr,"%s %s %u %s\n",GetMagickModule(),description); \
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]240 description=(char *) MagickRelinquishMemory(description); \
241 exit(-1); \
242}
243
244 MagickBooleanType
245 status;
246
247 MagickWand
248 *magick_wand;
249
250 if (argc != 3)
251 {
252 (void) fprintf(stdout,"Usage: %s image thumbnail\n",argv[0]);
253 exit(0);
254 }
255 /*
256 Read an image.
257 */
258 MagickWandGenesis();
259 magick_wand=NewMagickWand();
260 status=MagickReadImage(magick_wand,argv[1]);
261 if (status == MagickFalse)
262 ThrowWandException(magick_wand);
263 /*
264 Turn the images into a thumbnail sequence.
265 */
266 MagickResetIterator(magick_wand);
267 while (MagickNextImage(magick_wand) != MagickFalse)
268 MagickResizeImage(magick_wand,106,80,LanczosFilter,1.0);
269 /*
270 Write the image then destroy it.
271 */
272 status=MagickWriteImages(magick_wand,argv[2],MagickTrue);
273 if (status == MagickFalse)
274 ThrowWandException(magick_wand);
275 magick_wand=DestroyMagickWand(magick_wand);
276 MagickWandTerminus();
277 return(0);
278}
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]279</div>
280
281<p>Here is another program that shows one way to get and set image pixels with the MagickWand API, <a href="../www/source/contrast.c">contrast.c</a>. It reads an image, applies sigmoidal non-linearity contrast control, and writes the result to disk.</p>
282
283<div class="viewport">
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]284#include &lt;stdio.h>
285#include &lt;stdlib.h>
286#include &lt;math.h>
287#include &lt;wand/MagickWand.h>
288
289int main(int argc,char **argv)
290{
291#define QuantumScale ((MagickRealType) 1.0/(MagickRealType) QuantumRange)
292#define SigmoidalContrast(x) \
293 (QuantumRange*(1.0/(1+exp(10.0*(0.5-QuantumScale*x)))-0.0066928509)*1.0092503)
294#define ThrowWandException(wand) \
295{ \
296 char \
297 *description; \
298 \
299 ExceptionType \
300 severity; \
301 \
302 description=MagickGetException(wand,&amp;severity); \
303 (void) fprintf(stderr,"%s %s %lu %s\n",GetMagickModule(),description); \
304 description=(char *) MagickRelinquishMemory(description); \
305 exit(-1); \
306}
307
308 long
309 y;
310
311 MagickBooleanType
312 status;
313
314 MagickPixelPacket
315 pixel;
316
317 MagickWand
318 *contrast_wand,
319 *image_wand;
320
321 PixelIterator
322 *contrast_iterator,
323 *iterator;
324
325 PixelWand
326 **contrast_pixels,
327 **pixels;
328
329 register long
330 x;
331
332 unsigned long
333 width;
334
335 if (argc != 3)
336 {
337 (void) fprintf(stdout,"Usage: %s image sigmoidal-image\n",argv[0]);
338 exit(0);
339 }
340 /*
341 Read an image.
342 */
343 MagickWandGenesis();
344 image_wand=NewMagickWand();
345 status=MagickReadImage(image_wand,argv[1]);
346 if (status == MagickFalse)
347 ThrowWandException(image_wand);
348 contrast_wand=CloneMagickWand(image_wand);
349 /*
350 Sigmoidal non-linearity contrast control.
351 */
352 iterator=NewPixelIterator(image_wand);
353 contrast_iterator=NewPixelIterator(contrast_wand);
354 if ((iterator == (PixelIterator *) NULL) ||
355 (contrast_iterator == (PixelIterator *) NULL))
356 ThrowWandException(image_wand);
357 for (y=0; y &lt; (long) MagickGetImageHeight(image_wand); y++)
358 {
359 pixels=PixelGetNextIteratorRow(iterator,&amp;width);
360 contrast_pixels=PixelGetNextIteratorRow(contrast_iterator,&amp;width);
361 if ((pixels == (PixelWand **) NULL) ||
362 (contrast_pixels == (PixelWand **) NULL))
363 break;
364 for (x=0; x &lt; (long) width; x++)
365 {
366 PixelGetMagickColor(pixels[x],&amp;pixel);
367 pixel.red=SigmoidalContrast(pixel.red);
368 pixel.green=SigmoidalContrast(pixel.green);
369 pixel.blue=SigmoidalContrast(pixel.blue);
370 pixel.index=SigmoidalContrast(pixel.index);
371 PixelSetMagickColor(contrast_pixels[x],&amp;pixel);
372 }
373 (void) PixelSyncIterator(contrast_iterator);
374 }
375 if (y &lt; (long) MagickGetImageHeight(image_wand))
376 ThrowWandException(image_wand);
377 contrast_iterator=DestroyPixelIterator(contrast_iterator);
378 iterator=DestroyPixelIterator(iterator);
379 image_wand=DestroyMagickWand(image_wand);
380 /*
381 Write the image then destroy it.
382 */
383 status=MagickWriteImages(contrast_wand,argv[2],MagickTrue);
384 if (status == MagickFalse)
385 ThrowWandException(image_wand);
386 contrast_wand=DestroyMagickWand(contrast_wand);
387 MagickWandTerminus();
388 return(0);
389}
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]390</div>
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]391<p><a id="wand-view"></a>Now lets perform the same contrast enhancement while taking advantage of our dual or quad-core processing system by running the algorithm in parallel utilizing wand views. The <a href="../www/source/wand/sigmoidal-contrast.c">sigmoidal-contrast.c</a> module reads an image, applies sigmoidal non-linearity contrast control, and writes the result to disk just like the previous contrast enhancement program, but now it does its work in parallel (assumes ImageMagick is built with OpenMP support).</p>
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]392
393<div class="viewport">
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]394#include &lt;stdio.h>
395#include &lt;stdlib.h>
396#include &lt;math.h>
397#include &lt;wand/MagickWand.h>
398
cristy10c87152010-06-26 16:12:21 +0000[diff] [blame]399static MagickBooleanType SigmoidalContrast(WandView *pixel_view,
cristyc3ebda22010-06-27 17:11:57 +0000[diff] [blame]400 const ssize_t y,const int id,void *context)
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]401{
402#define QuantumScale ((MagickRealType) 1.0/(MagickRealType) QuantumRange)
403#define SigmoidalContrast(x) \
404 (QuantumRange*(1.0/(1+exp(10.0*(0.5-QuantumScale*x)))-0.0066928509)*1.0092503)
405
cristyc3ebda22010-06-27 17:11:57 +0000[diff] [blame]406 RectangleInfo
407 extent;
408
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]409 MagickPixelPacket
410 pixel;
411
412 PixelWand
413 **pixels;
414
415 register long
416 x;
417
cristyc3ebda22010-06-27 17:11:57 +0000[diff] [blame]418 extent=GetWandViewExtent(contrast_view);
cristy10c87152010-06-26 16:12:21 +0000[diff] [blame]419 pixels=GetWandViewPixels(contrast_view);
cristyc3ebda22010-06-27 17:11:57 +0000[diff] [blame]420 for (x=0; x &lt; (long) (extent.width-extent.height); x++)
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]421 {
422 PixelGetMagickColor(pixels[x],&amp;pixel);
423 pixel.red=SigmoidalContrast(pixel.red);
424 pixel.green=SigmoidalContrast(pixel.green);
425 pixel.blue=SigmoidalContrast(pixel.blue);
426 pixel.index=SigmoidalContrast(pixel.index);
427 PixelSetMagickColor(contrast_pixels[x],&amp;pixel);
428 }
429 return(MagickTrue);
430}
431
432int main(int argc,char **argv)
433{
cristyc3ebda22010-06-27 17:11:57 +0000[diff] [blame]434#define ThrowViewException(view) \
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]435{ \
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]436 description=GetWandViewException(view,&amp;severity); \
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]437 (void) fprintf(stderr,"%s %s %lu %s\n",GetMagickModule(),description); \
438 description=(char *) MagickRelinquishMemory(description); \
439 exit(-1); \
440}
cristyc3ebda22010-06-27 17:11:57 +0000[diff] [blame]441#define ThrowWandException(wand) \
442{ \
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]443 description=MagickGetException(wand,&amp;severity); \
cristyc3ebda22010-06-27 17:11:57 +0000[diff] [blame]444 (void) fprintf(stderr,"%s %s %lu %s\n",GetMagickModule(),description); \
445 description=(char *) MagickRelinquishMemory(description); \
446 exit(-1); \
447}
448
449 char
450 *description;
451
452 ExceptionType
453 severity;
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]454
455 MagickBooleanType
456 status;
457
458 MagickPixelPacket
459 pixel;
460
461 MagickWand
462 *contrast_wand;
463
cristy10c87152010-06-26 16:12:21 +0000[diff] [blame]464 WandView
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]465 *contrast_view;
466
467 if (argc != 3)
468 {
469 (void) fprintf(stdout,"Usage: %s image sigmoidal-image\n",argv[0]);
470 exit(0);
471 }
472 /*
473 Read an image.
474 */
475 MagickWandGenesis();
476 contrast_wand=NewMagickWand();
477 status=MagickReadImage(contrast_wand,argv[1]);
478 if (status == MagickFalse)
479 ThrowWandException(contrast_wand);
480 /*
481 Sigmoidal non-linearity contrast control.
482 */
cristy10c87152010-06-26 16:12:21 +0000[diff] [blame]483 contrast_view=NewWandView(contrast_wand);
484 if (contrast_view == (WandView *) NULL)
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]485 ThrowWandException(contrast_wand);
cristy10c87152010-06-26 16:12:21 +0000[diff] [blame]486 status=UpdateWandViewIterator(contrast_view,SigmoidalContrast,(void *) NULL);
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]487 if (status == MagickFalse)
488 ThrowWandException(contrast_wand);
cristy10c87152010-06-26 16:12:21 +0000[diff] [blame]489 contrast_view=DestroyWandView(contrast_view);
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]490 /*
491 Write the image then destroy it.
492 */
493 status=MagickWriteImages(contrast_wand,argv[2],MagickTrue);
494 if (status == MagickFalse)
495 ThrowWandException(contrast_wand);
496 contrast_wand=DestroyMagickWand(contrast_wand);
497 MagickWandTerminus();
498 return(0);
499}
cristy3ed852e2009-09-05 21:47:34 +0000[diff] [blame]500</div>
cristydcca3fa2010-12-29 21:50:07 +0000[diff] [blame]501</div>
cristy3eaa0ef2010-03-06 20:35:26 +0000[diff] [blame]502
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