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18 <meta name="Description" content="ImageMagick® is a software suite to create, edit, and compose bitmap images. It can read, convert and write images in a variety of formats (about 100) including GIF, JPEG, JPEG-2000, PNG, PDF, PhotoCD, TIFF, and DPX. Use ImageMagick to translate, flip, mirror, rotate, scale, shear and transform images, adjust image colors, apply various special effects, or draw text, lines, polygons, ellipses and Bézier curves. ImageMagick is free software delivered as a ready-to-run binary distribution or as source code that you can freely use, copy, modify, and distribute. Its license is compatible with the GPL. It runs on all major operating systems. The functionality of ImageMagick is typically utilized from the command line or you can use the features from programs written in your favorite programming language. Choose from these interfaces: MagickCore (C), MagickWand (C), ChMagick (Ch), Magick++ (C++), JMagick (Java), L-Magick (Lisp), PascalMagick (Pascal), PerlMagick (Perl), MagickWand for PHP (PHP), PythonMagick (Python), RMagick (Ruby), or TclMagick (Tcl/TK). With a language interface, use ImageMagick to modify or create images automagically and dynamically."/>
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152<p class="navigation-index"></p>
153
154<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>
155
156<ul>
157 <li><a href="../www/api/magick-wand.html">Magick Wand Methods</a></li>
158 <li><a href="../www/api/magick-property.html">Set or Get Magick Wand Properties</a></li>
159 <li><a href="../www/api/magick-image.html">Magick Wand Image Methods</a></li>
160 <li><a href="../www/api/pixel-iterator.html">Pixel Iterator Methods</a></li>
161 <li><a href="../www/api/pixel-view.html">Pixel View Methods</a></li>
162 <li><a href="../www/api/pixel-wand.html">Pixel Wand Methods</a></li>
163 <li><a href="../www/api/drawing-wand.html">Image Vector Drawing</a></li>
164 <li><a href="../www/api/magick-deprecate.html">Deprecated Methods</a></li>
165 <li><a href="../www/exception.html">Error and Warning Codes</a></li>
166</li>
167</ul>
168
169<p>After you write your MagickWand program, compile it like this:</p>
170
171<p class='crt'><span class="crtprompt"> $magick&gt; </span><span class='crtin'>cc `MagickWand-config --cflags --cppflags` -o wand wand.c `MagickWand-config --ldflags --libs`</span></p>
172<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>
173
174<div class="viewport">
175<pre class="code">
176#include &lt;stdio.h>
177#include &lt;stdlib.h>
178#include &lt;wand/MagickWand.h>
179
180int main(int argc,char **argv)
181{
182#define ThrowWandException(wand) \
183{ \
184 char \
185 *description; \
186 \
187 ExceptionType \
188 severity; \
189 \
190 description=MagickGetException(wand,&amp;severity); \
191 (void) fprintf(stderr,"%s %s %lu %s\n",GetMagickModule(),description); \
192 description=(char *) MagickRelinquishMemory(description); \
193 exit(-1); \
194}
195
196 MagickBooleanType
197 status;
198
199 MagickWand
200 *magick_wand;
201
202 if (argc != 3)
203 {
204 (void) fprintf(stdout,"Usage: %s image thumbnail\n",argv[0]);
205 exit(0);
206 }
207 /*
208 Read an image.
209 */
210 MagickWandGenesis();
211 magick_wand=NewMagickWand();
212 status=MagickReadImage(magick_wand,argv[1]);
213 if (status == MagickFalse)
214 ThrowWandException(magick_wand);
215 /*
216 Turn the images into a thumbnail sequence.
217 */
218 MagickResetIterator(magick_wand);
219 while (MagickNextImage(magick_wand) != MagickFalse)
220 MagickResizeImage(magick_wand,106,80,LanczosFilter,1.0);
221 /*
222 Write the image then destroy it.
223 */
224 status=MagickWriteImages(magick_wand,argv[2],MagickTrue);
225 if (status == MagickFalse)
226 ThrowWandException(magick_wand);
227 magick_wand=DestroyMagickWand(magick_wand);
228 MagickWandTerminus();
229 return(0);
230}
231</pre>
232</div>
233
234<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>
235
236<div class="viewport">
237<pre class="code">
238#include &lt;stdio.h>
239#include &lt;stdlib.h>
240#include &lt;math.h>
241#include &lt;wand/MagickWand.h>
242
243int main(int argc,char **argv)
244{
245#define QuantumScale ((MagickRealType) 1.0/(MagickRealType) QuantumRange)
246#define SigmoidalContrast(x) \
247 (QuantumRange*(1.0/(1+exp(10.0*(0.5-QuantumScale*x)))-0.0066928509)*1.0092503)
248#define ThrowWandException(wand) \
249{ \
250 char \
251 *description; \
252 \
253 ExceptionType \
254 severity; \
255 \
256 description=MagickGetException(wand,&amp;severity); \
257 (void) fprintf(stderr,"%s %s %lu %s\n",GetMagickModule(),description); \
258 description=(char *) MagickRelinquishMemory(description); \
259 exit(-1); \
260}
261
262 long
263 y;
264
265 MagickBooleanType
266 status;
267
268 MagickPixelPacket
269 pixel;
270
271 MagickWand
272 *contrast_wand,
273 *image_wand;
274
275 PixelIterator
276 *contrast_iterator,
277 *iterator;
278
279 PixelWand
280 **contrast_pixels,
281 **pixels;
282
283 register long
284 x;
285
286 unsigned long
287 width;
288
289 if (argc != 3)
290 {
291 (void) fprintf(stdout,"Usage: %s image sigmoidal-image\n",argv[0]);
292 exit(0);
293 }
294 /*
295 Read an image.
296 */
297 MagickWandGenesis();
298 image_wand=NewMagickWand();
299 status=MagickReadImage(image_wand,argv[1]);
300 if (status == MagickFalse)
301 ThrowWandException(image_wand);
302 contrast_wand=CloneMagickWand(image_wand);
303 /*
304 Sigmoidal non-linearity contrast control.
305 */
306 iterator=NewPixelIterator(image_wand);
307 contrast_iterator=NewPixelIterator(contrast_wand);
308 if ((iterator == (PixelIterator *) NULL) ||
309 (contrast_iterator == (PixelIterator *) NULL))
310 ThrowWandException(image_wand);
311 for (y=0; y &lt; (long) MagickGetImageHeight(image_wand); y++)
312 {
313 pixels=PixelGetNextIteratorRow(iterator,&amp;width);
314 contrast_pixels=PixelGetNextIteratorRow(contrast_iterator,&amp;width);
315 if ((pixels == (PixelWand **) NULL) ||
316 (contrast_pixels == (PixelWand **) NULL))
317 break;
318 for (x=0; x &lt; (long) width; x++)
319 {
320 PixelGetMagickColor(pixels[x],&amp;pixel);
321 pixel.red=SigmoidalContrast(pixel.red);
322 pixel.green=SigmoidalContrast(pixel.green);
323 pixel.blue=SigmoidalContrast(pixel.blue);
324 pixel.index=SigmoidalContrast(pixel.index);
325 PixelSetMagickColor(contrast_pixels[x],&amp;pixel);
326 }
327 (void) PixelSyncIterator(contrast_iterator);
328 }
329 if (y &lt; (long) MagickGetImageHeight(image_wand))
330 ThrowWandException(image_wand);
331 contrast_iterator=DestroyPixelIterator(contrast_iterator);
332 iterator=DestroyPixelIterator(iterator);
333 image_wand=DestroyMagickWand(image_wand);
334 /*
335 Write the image then destroy it.
336 */
337 status=MagickWriteImages(contrast_wand,argv[2],MagickTrue);
338 if (status == MagickFalse)
339 ThrowWandException(image_wand);
340 contrast_wand=DestroyMagickWand(contrast_wand);
341 MagickWandTerminus();
342 return(0);
343}
344</pre>
345</div>
346<p>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 pixel views. The <a href="../www/source/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>
347
348<div class="viewport">
349<pre class="code">
350#include &lt;stdio.h>
351#include &lt;stdlib.h>
352#include &lt;math.h>
353#include &lt;wand/MagickWand.h>
354
355static MagickBooleanType SigmoidalContrast(PixelView *pixel_view,
356 void *context)
357{
358#define QuantumScale ((MagickRealType) 1.0/(MagickRealType) QuantumRange)
359#define SigmoidalContrast(x) \
360 (QuantumRange*(1.0/(1+exp(10.0*(0.5-QuantumScale*x)))-0.0066928509)*1.0092503)
361
362 MagickPixelPacket
363 pixel;
364
365 PixelWand
366 **pixels;
367
368 register long
369 x;
370
371 pixels=GetPixelViewPixels(contrast_view);
372 for (x=0; x &lt; (long) GetPixelViewWidth(contrast_view); x++)
373 {
374 PixelGetMagickColor(pixels[x],&amp;pixel);
375 pixel.red=SigmoidalContrast(pixel.red);
376 pixel.green=SigmoidalContrast(pixel.green);
377 pixel.blue=SigmoidalContrast(pixel.blue);
378 pixel.index=SigmoidalContrast(pixel.index);
379 PixelSetMagickColor(contrast_pixels[x],&amp;pixel);
380 }
381 return(MagickTrue);
382}
383
384int main(int argc,char **argv)
385{
386#define ThrowWandException(wand) \
387{ \
388 char \
389 *description; \
390 \
391 ExceptionType \
392 severity; \
393 \
394 description=MagickGetException(wand,&amp;severity); \
395 (void) fprintf(stderr,"%s %s %lu %s\n",GetMagickModule(),description); \
396 description=(char *) MagickRelinquishMemory(description); \
397 exit(-1); \
398}
399
400 MagickBooleanType
401 status;
402
403 MagickPixelPacket
404 pixel;
405
406 MagickWand
407 *contrast_wand;
408
409 PixelView
410 *contrast_view;
411
412 if (argc != 3)
413 {
414 (void) fprintf(stdout,"Usage: %s image sigmoidal-image\n",argv[0]);
415 exit(0);
416 }
417 /*
418 Read an image.
419 */
420 MagickWandGenesis();
421 contrast_wand=NewMagickWand();
422 status=MagickReadImage(contrast_wand,argv[1]);
423 if (status == MagickFalse)
424 ThrowWandException(contrast_wand);
425 /*
426 Sigmoidal non-linearity contrast control.
427 */
428 contrast_view=NewPixelView(contrast_wand);
429 if (contrast_view == (PixelView *) NULL)
430 ThrowWandException(contrast_wand);
431 status=UpdatePixelViewIterator(contrast_view,SigmoidalContrast,(void *) NULL);
432 if (status == MagickFalse)
433 ThrowWandException(contrast_wand);
434 contrast_view=DestroyPixelView(contrast_view);
435 /*
436 Write the image then destroy it.
437 */
438 status=MagickWriteImages(contrast_wand,argv[2],MagickTrue);
439 if (status == MagickFalse)
440 ThrowWandException(contrast_wand);
441 contrast_wand=DestroyMagickWand(contrast_wand);
442 MagickWandTerminus();
443 return(0);
444}
445</pre>
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