1 2 3 4 5 <!DOCTYPE html> 6 <html lang="en"> 7 <head> 8 <title>ImageMagick: MagickWand, C API for ImageMagick</title> 9 <meta charset="utf-8" /> 10 <meta http-equiv="X-UA-Compatible" content="IE=edge" /> 11 <meta name="viewport" content="width=device-width, initial-scale=1" /> 12 <meta http-equiv="content-type" content="text/html; charset=utf-8"/> 13 <meta name="application-name" content="ImageMagick"/> 14 <meta name="description" content="ImageMagick is a software suite to create, edit, compose, or convert bitmap images. It can read and write images in a variety of formats (over 200) including PNG, JPEG, JPEG-2000, GIF, WebP, Postscript, PDF, and SVG. 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Unlike the <a href="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> 61 62 <ul> 63 <li><a href="api/magick-wand.html">Magick Wand Methods</a></li> 64 <li><a href="api/magick-property.html">Set or Get Magick Wand Properties</a></li> 65 <li><a href="api/magick-image.html">Magick Wand Image Methods</a></li> 66 <li><a href="api/pixel-iterator.html">Pixel Iterator Methods</a></li> 67 <li><a href="api/pixel-wand.html">Pixel Wand Methods</a></li> 68 <li><a href="api/drawing-wand.html">Image Vector Drawing</a></li> 69 <li><a href="api/mogrify.html">Command-line Interface</a></li> 70 <li><a href="api/wand-view.html">Wand View Methods</a></li> 71 <li><a href="api/magick-deprecate.html">Deprecated Methods</a></li> 72 <li><a href="exception.html">Error and Warning Codes</a></li> 73 </ul> 74 75 <p>After you write your MagickWand program, compile it like this:</p> 76 77 <pre> 78 cc -o wand wand.c `pkg-config --cflags --libs MagickWand` 79 </pre> 80 81 <p>Set the <code>PKG_CONFIG_PATH</code> environment variable if ImageMagick is not in your default system path:</p> 82 83 <pre> 84 export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig 85 </pre> 86 87 <p>Here is a example program that utilizes the MagickWand API to get you started, <a href="../source/wand.c">wand.c</a>. It reads an image, creates a thumbnail, and writes the result to disk.</p> 88 89 <pre class="pre-scrollable">#include <stdio.h> 90 #include <stdlib.h> 91 #include <wand/MagickWand.h> 92 93 int main(int argc,char **argv) 94 { 95 #define ThrowWandException(wand) \ 96 { \ 97 char \ 98 *description; \ 99 \ 100 ExceptionType \ 101 severity; \ 102 \ 103 description=MagickGetException(wand,&severity); \ 104 (void) fprintf(stderr,"%s %s %lu %s\n",GetMagickModule(),description); \ 105 description=(char *) MagickRelinquishMemory(description); \ 106 exit(-1); \ 107 } 108 109 MagickBooleanType 110 status; 111 112 MagickWand 113 *magick_wand; 114 115 if (argc != 3) 116 { 117 (void) fprintf(stdout,"Usage: %s image thumbnail\n",argv[0]); 118 exit(0); 119 } 120 /* 121 Read an image. 122 */ 123 MagickWandGenesis(); 124 magick_wand=NewMagickWand(); 125 status=MagickReadImage(magick_wand,argv[1]); 126 if (status == MagickFalse) 127 ThrowWandException(magick_wand); 128 /* 129 Turn the images into a thumbnail sequence. 130 */ 131 MagickResetIterator(magick_wand); 132 while (MagickNextImage(magick_wand) != MagickFalse) 133 MagickResizeImage(magick_wand,106,80,LanczosFilter,1.0); 134 /* 135 Write the image then destroy it. 136 */ 137 status=MagickWriteImages(magick_wand,argv[2],MagickTrue); 138 if (status == MagickFalse) 139 ThrowWandException(magick_wand); 140 magick_wand=DestroyMagickWand(magick_wand); 141 MagickWandTerminus(); 142 return(0); 143 } 144 </pre> 145 146 <p>Here is another program that shows one way to get and set image pixels with the MagickWand API, <a href="../source/contrast.c">contrast.c</a>. It reads an image, applies sigmoidal non-linearity contrast control, and writes the result to disk.</p> 147 148 <pre class="pre-scrollable">#include <stdio.h> 149 #include <stdlib.h> 150 #include <math.h> 151 #include <wand/MagickWand.h> 152 153 int main(int argc,char **argv) 154 { 155 #define QuantumScale ((MagickRealType) 1.0/(MagickRealType) QuantumRange) 156 #define SigmoidalContrast(x) \ 157 (QuantumRange*(1.0/(1+exp(10.0*(0.5-QuantumScale*x)))-0.0066928509)*1.0092503) 158 #define ThrowWandException(wand) \ 159 { \ 160 char \ 161 *description; \ 162 \ 163 ExceptionType \ 164 severity; \ 165 \ 166 description=MagickGetException(wand,&severity); \ 167 (void) fprintf(stderr,"%s %s %lu %s\n",GetMagickModule(),description); \ 168 description=(char *) MagickRelinquishMemory(description); \ 169 exit(-1); \ 170 } 171 172 long 173 y; 174 175 MagickBooleanType 176 status; 177 178 MagickPixelPacket 179 pixel; 180 181 MagickWand 182 *contrast_wand, 183 *image_wand; 184 185 PixelIterator 186 *contrast_iterator, 187 *iterator; 188 189 PixelWand 190 **contrast_pixels, 191 **pixels; 192 193 register long 194 x; 195 196 unsigned long 197 width; 198 199 if (argc != 3) 200 { 201 (void) fprintf(stdout,"Usage: %s image sigmoidal-image\n",argv[0]); 202 exit(0); 203 } 204 /* 205 Read an image. 206 */ 207 MagickWandGenesis(); 208 image_wand=NewMagickWand(); 209 status=MagickReadImage(image_wand,argv[1]); 210 if (status == MagickFalse) 211 ThrowWandException(image_wand); 212 contrast_wand=CloneMagickWand(image_wand); 213 /* 214 Sigmoidal non-linearity contrast control. 215 */ 216 iterator=NewPixelIterator(image_wand); 217 contrast_iterator=NewPixelIterator(contrast_wand); 218 if ((iterator == (PixelIterator *) NULL) || 219 (contrast_iterator == (PixelIterator *) NULL)) 220 ThrowWandException(image_wand); 221 for (y=0; y < (long) MagickGetImageHeight(image_wand); y++) 222 { 223 pixels=PixelGetNextIteratorRow(iterator,&width); 224 contrast_pixels=PixelGetNextIteratorRow(contrast_iterator,&width); 225 if ((pixels == (PixelWand **) NULL) || 226 (contrast_pixels == (PixelWand **) NULL)) 227 break; 228 for (x=0; x < (long) width; x++) 229 { 230 PixelGetMagickColor(pixels[x],&pixel); 231 pixel.red=SigmoidalContrast(pixel.red); 232 pixel.green=SigmoidalContrast(pixel.green); 233 pixel.blue=SigmoidalContrast(pixel.blue); 234 pixel.index=SigmoidalContrast(pixel.index); 235 PixelSetMagickColor(contrast_pixels[x],&pixel); 236 } 237 (void) PixelSyncIterator(contrast_iterator); 238 } 239 if (y < (long) MagickGetImageHeight(image_wand)) 240 ThrowWandException(image_wand); 241 contrast_iterator=DestroyPixelIterator(contrast_iterator); 242 iterator=DestroyPixelIterator(iterator); 243 image_wand=DestroyMagickWand(image_wand); 244 /* 245 Write the image then destroy it. 246 */ 247 status=MagickWriteImages(contrast_wand,argv[2],MagickTrue); 248 if (status == MagickFalse) 249 ThrowWandException(image_wand); 250 contrast_wand=DestroyMagickWand(contrast_wand); 251 MagickWandTerminus(); 252 return(0); 253 } 254 </pre> 255 <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="../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> 256 257 <pre class="pre-scrollable">#include <stdio.h> 258 #include <stdlib.h> 259 #include <math.h> 260 #include <wand/MagickWand.h> 261 262 static MagickBooleanType SigmoidalContrast(WandView *pixel_view, 263 const ssize_t y,const int id,void *context) 264 { 265 #define QuantumScale ((MagickRealType) 1.0/(MagickRealType) QuantumRange) 266 #define SigmoidalContrast(x) \ 267 (QuantumRange*(1.0/(1+exp(10.0*(0.5-QuantumScale*x)))-0.0066928509)*1.0092503) 268 269 RectangleInfo 270 extent; 271 272 MagickPixelPacket 273 pixel; 274 275 PixelWand 276 **pixels; 277 278 register long 279 x; 280 281 extent=GetWandViewExtent(contrast_view); 282 pixels=GetWandViewPixels(contrast_view); 283 for (x=0; x < (long) (extent.width-extent.height); x++) 284 { 285 PixelGetMagickColor(pixels[x],&pixel); 286 pixel.red=SigmoidalContrast(pixel.red); 287 pixel.green=SigmoidalContrast(pixel.green); 288 pixel.blue=SigmoidalContrast(pixel.blue); 289 pixel.index=SigmoidalContrast(pixel.index); 290 PixelSetMagickColor(contrast_pixels[x],&pixel); 291 } 292 return(MagickTrue); 293 } 294 295 int main(int argc,char **argv) 296 { 297 #define ThrowViewException(view) \ 298 { \ 299 description=GetWandViewException(view,&severity); \ 300 (void) fprintf(stderr,"%s %s %lu %s\n",GetMagickModule(),description); \ 301 description=(char *) MagickRelinquishMemory(description); \ 302 exit(-1); \ 303 } 304 #define ThrowWandException(wand) \ 305 { \ 306 description=MagickGetException(wand,&severity); \ 307 (void) fprintf(stderr,"%s %s %lu %s\n",GetMagickModule(),description); \ 308 description=(char *) MagickRelinquishMemory(description); \ 309 exit(-1); \ 310 } 311 312 char 313 *description; 314 315 ExceptionType 316 severity; 317 318 MagickBooleanType 319 status; 320 321 MagickPixelPacket 322 pixel; 323 324 MagickWand 325 *contrast_wand; 326 327 WandView 328 *contrast_view; 329 330 if (argc != 3) 331 { 332 (void) fprintf(stdout,"Usage: %s image sigmoidal-image\n",argv[0]); 333 exit(0); 334 } 335 /* 336 Read an image. 337 */ 338 MagickWandGenesis(); 339 contrast_wand=NewMagickWand(); 340 status=MagickReadImage(contrast_wand,argv[1]); 341 if (status == MagickFalse) 342 ThrowWandException(contrast_wand); 343 /* 344 Sigmoidal non-linearity contrast control. 345 */ 346 contrast_view=NewWandView(contrast_wand); 347 if (contrast_view == (WandView *) NULL) 348 ThrowWandException(contrast_wand); 349 status=UpdateWandViewIterator(contrast_view,SigmoidalContrast,(void *) NULL); 350 if (status == MagickFalse) 351 ThrowWandException(contrast_wand); 352 contrast_view=DestroyWandView(contrast_view); 353 /* 354 Write the image then destroy it. 355 */ 356 status=MagickWriteImages(contrast_wand,argv[2],MagickTrue); 357 if (status == MagickFalse) 358 ThrowWandException(contrast_wand); 359 contrast_wand=DestroyMagickWand(contrast_wand); 360 MagickWandTerminus(); 361 return(0); 362 } 363 </pre> 364 <p><a href="http://members.shaw.ca/el.supremo/MagickWand/">MagickWand Examples in C</a> illustrates how to use the ImageMagick MagickWand API. Each example is presented as a C function, complete with headers, so that it can be copied to a file and then included in your own C project.</p> 365 </div> 366 <footer class="magick-footer"> 367 <p><a href="support.html">Donate</a> 368 <a href="sitemap.html">Sitemap</a> 369 <a href="links.html">Related</a> 370 <a href="architecture.html">Architecture</a> 371 </p> 372 <p><a href="magick-wand.html#">Back to top</a> 373 <a href="http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x89AB63D48277377A">Public Key</a> 374 <a href="http://www.imagemagick.org/script/contact.php">Contact Us</a></p> 375 <p><small> 1999-2016 ImageMagick Studio LLC</small></p> 376 </footer> 377 </div><!-- /.container --> 378 379 <script src="https://localhost/ajax/libs/jquery/1.11.3/jquery.min.js"></script> 380 <script src="../js/magick.html"></script> 381 </div> 382 </body> 383 </html> 384
