granicus.if.org Git - imagemagick/blob - magick/gem.c

   1 /*
   2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   3 %                                                                             %
   4 %                                                                             %
   5 %                                                                             %
   6 %                              GGGG  EEEEE  M   M                             %
   7 %                             G      E      MM MM                             %
   8 %                             G GG   EEE    M M M                             %
   9 %                             G   G  E      M   M                             %
  10 %                              GGGG  EEEEE  M   M                             %
  11 %                                                                             %
  12 %                                                                             %
  13 %                    Graphic Gems - Graphic Support Methods                   %
  14 %                                                                             %
  15 %                               Software Design                               %
  16 %                                 John Cristy                                 %
  17 %                                 August 1996                                 %
  18 %                                                                             %
  19 %                                                                             %
  20 %  Copyright 1999-2009 ImageMagick Studio LLC, a non-profit organization      %
  21 %  dedicated to making software imaging solutions freely available.           %
  22 %                                                                             %
  23 %  You may not use this file except in compliance with the License.  You may  %
  24 %  obtain a copy of the License at                                            %
  25 %                                                                             %
  26 %    http://www.imagemagick.org/script/license.php                            %
  27 %                                                                             %
  28 %  Unless required by applicable law or agreed to in writing, software        %
  29 %  distributed under the License is distributed on an "AS IS" BASIS,          %
  30 %  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   %
  31 %  See the License for the specific language governing permissions and        %
  32 %  limitations under the License.                                             %
  33 %                                                                             %
  34 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  35 %
  36 %
  37 %
  38 */
  39 \f
  40 /*
  41   Include declarations.
  42 */
  43 #include "magick/studio.h"
  44 #include "magick/color-private.h"
  45 #include "magick/draw.h"
  46 #include "magick/gem.h"
  47 #include "magick/image.h"
  48 #include "magick/image-private.h"
  49 #include "magick/log.h"
  50 #include "magick/memory_.h"
  51 #include "magick/pixel-private.h"
  52 #include "magick/quantum.h"
  53 #include "magick/random_.h"
  54 #include "magick/resize.h"
  55 #include "magick/transform.h"
  56 #include "magick/signature-private.h"
  57 \f
  58 /*
  59 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  60 %                                                                             %
  61 %                                                                             %
  62 %                                                                             %
  63 %   C o n v e r t H S B T o R G B                                             %
  64 %                                                                             %
  65 %                                                                             %
  66 %                                                                             %
  67 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  68 %
  69 %  ConvertHSBToRGB() transforms a (hue, saturation, brightness) to a (red,
  70 %  green, blue) triple.
  71 %
  72 %  The format of the ConvertHSBToRGBImage method is:
  73 %
  74 %      void ConvertHSBToRGB(const double hue,const double saturation,
  75 %        const double brightness,Quantum *red,Quantum *green,Quantum *blue)
  76 %
  77 %  A description of each parameter follows:
  78 %
  79 %    o hue, saturation, brightness: A double value representing a
  80 %      component of the HSB color space.
  81 %
  82 %    o red, green, blue: A pointer to a pixel component of type Quantum.
  83 %
  84 */
  85 MagickExport void ConvertHSBToRGB(const double hue,const double saturation,
  86   const double brightness,Quantum *red,Quantum *green,Quantum *blue)
  87 {
  88   MagickRealType
  89     f,
  90     h,
  91     p,
  92     q,
  93     t;
  94
  95   /*
  96     Convert HSB to RGB colorspace.
  97   */
  98   assert(red != (Quantum *) NULL);
  99   assert(green != (Quantum *) NULL);
 100   assert(blue != (Quantum *) NULL);
 101   if (saturation == 0.0)
 102     {
 103       *red=RoundToQuantum((MagickRealType) QuantumRange*brightness);
 104       *green=(*red);
 105       *blue=(*red);
 106       return;
 107     }
 108   h=6.0*(hue-floor(hue));
 109   f=h-floor((double) h);
 110   p=brightness*(1.0-saturation);
 111   q=brightness*(1.0-saturation*f);
 112   t=brightness*(1.0-(saturation*(1.0-f)));
 113   switch ((int) h)
 114   {
 115     case 0:
 116     default:
 117     {
 118       *red=RoundToQuantum((MagickRealType) QuantumRange*brightness);
 119       *green=RoundToQuantum((MagickRealType) QuantumRange*t);
 120       *blue=RoundToQuantum((MagickRealType) QuantumRange*p);
 121       break;
 122     }
 123     case 1:
 124     {
 125       *red=RoundToQuantum((MagickRealType) QuantumRange*q);
 126       *green=RoundToQuantum((MagickRealType) QuantumRange*brightness);
 127       *blue=RoundToQuantum((MagickRealType) QuantumRange*p);
 128       break;
 129     }
 130     case 2:
 131     {
 132       *red=RoundToQuantum((MagickRealType) QuantumRange*p);
 133       *green=RoundToQuantum((MagickRealType) QuantumRange*brightness);
 134       *blue=RoundToQuantum((MagickRealType) QuantumRange*t);
 135       break;
 136     }
 137     case 3:
 138     {
 139       *red=RoundToQuantum((MagickRealType) QuantumRange*p);
 140       *green=RoundToQuantum((MagickRealType) QuantumRange*q);
 141       *blue=RoundToQuantum((MagickRealType) QuantumRange*brightness);
 142       break;
 143     }
 144     case 4:
 145     {
 146       *red=RoundToQuantum((MagickRealType) QuantumRange*t);
 147       *green=RoundToQuantum((MagickRealType) QuantumRange*p);
 148       *blue=RoundToQuantum((MagickRealType) QuantumRange*brightness);
 149       break;
 150     }
 151     case 5:
 152     {
 153       *red=RoundToQuantum((MagickRealType) QuantumRange*brightness);
 154       *green=RoundToQuantum((MagickRealType) QuantumRange*p);
 155       *blue=RoundToQuantum((MagickRealType) QuantumRange*q);
 156       break;
 157     }
 158   }
 159 }
 160 \f
 161 /*
 162 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 163 %                                                                             %
 164 %                                                                             %
 165 %                                                                             %
 166 %   C o n v e r t H S L T o R G B                                             %
 167 %                                                                             %
 168 %                                                                             %
 169 %                                                                             %
 170 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 171 %
 172 %  ConvertHSLToRGB() transforms a (hue, saturation, lightness) to a (red,
 173 %  green, blue) triple.
 174 %
 175 %  The format of the ConvertHSLToRGBImage method is:
 176 %
 177 %      void ConvertHSLToRGB(const double hue,const double saturation,
 178 %        const double lightness,Quantum *red,Quantum *green,Quantum *blue)
 179 %
 180 %  A description of each parameter follows:
 181 %
 182 %    o hue, saturation, lightness: A double value representing a
 183 %      component of the HSL color space.
 184 %
 185 %    o red, green, blue: A pointer to a pixel component of type Quantum.
 186 %
 187 */
 188
 189 static inline MagickRealType ConvertHueToRGB(MagickRealType m1,
 190   MagickRealType m2,MagickRealType hue)
 191 {
 192   if (hue < 0.0)
 193     hue+=1.0;
 194   if (hue > 1.0)
 195     hue-=1.0;
 196   if ((6.0*hue) < 1.0)
 197     return(m1+6.0*(m2-m1)*hue);
 198   if ((2.0*hue) < 1.0)
 199     return(m2);
 200   if ((3.0*hue) < 2.0)
 201     return(m1+6.0*(m2-m1)*(2.0/3.0-hue));
 202   return(m1);
 203 }
 204
 205 MagickExport void ConvertHSLToRGB(const double hue,const double saturation,
 206   const double lightness,Quantum *red,Quantum *green,Quantum *blue)
 207 {
 208   MagickRealType
 209     b,
 210     g,
 211     r,
 212     m1,
 213     m2;
 214
 215   /*
 216     Convert HSL to RGB colorspace.
 217   */
 218   assert(red != (Quantum *) NULL);
 219   assert(green != (Quantum *) NULL);
 220   assert(blue != (Quantum *) NULL);
 221   if (saturation == 0)
 222     {
 223       *red=RoundToQuantum((MagickRealType) QuantumRange*lightness);
 224       *green=(*red);
 225       *blue=(*red);
 226       return;
 227     }
 228   if (lightness <= 0.5)
 229     m2=lightness*(saturation+1.0);
 230   else
 231     m2=(lightness+saturation)-(lightness*saturation);
 232   m1=2.0*lightness-m2;
 233   r=ConvertHueToRGB(m1,m2,hue+1.0/3.0);
 234   g=ConvertHueToRGB(m1,m2,hue);
 235   b=ConvertHueToRGB(m1,m2,hue-1.0/3.0);
 236   *red=RoundToQuantum((MagickRealType) QuantumRange*r);
 237   *green=RoundToQuantum((MagickRealType) QuantumRange*g);
 238   *blue=RoundToQuantum((MagickRealType) QuantumRange*b);
 239 }
 240 \f
 241 /*
 242 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 243 %                                                                             %
 244 %                                                                             %
 245 %                                                                             %
 246 %   C o n v e r t H W B T o R G B                                             %
 247 %                                                                             %
 248 %                                                                             %
 249 %                                                                             %
 250 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 251 %
 252 %  ConvertHWBToRGB() transforms a (hue, whiteness, blackness) to a (red, green,
 253 %  blue) triple.
 254 %
 255 %  The format of the ConvertHWBToRGBImage method is:
 256 %
 257 %      void ConvertHWBToRGB(const double hue,const double whiteness,
 258 %        const double blackness,Quantum *red,Quantum *green,Quantum *blue)
 259 %
 260 %  A description of each parameter follows:
 261 %
 262 %    o hue, whiteness, blackness: A double value representing a
 263 %      component of the HWB color space.
 264 %
 265 %    o red, green, blue: A pointer to a pixel component of type Quantum.
 266 %
 267 */
 268 MagickExport void ConvertHWBToRGB(const double hue,const double whiteness,
 269   const double blackness,Quantum *red,Quantum *green,Quantum *blue)
 270 {
 271   MagickRealType
 272     b,
 273     f,
 274     g,
 275     n,
 276     r,
 277     v;
 278
 279   register long
 280     i;
 281
 282   /*
 283     Convert HWB to RGB colorspace.
 284   */
 285   assert(red != (Quantum *) NULL);
 286   assert(green != (Quantum *) NULL);
 287   assert(blue != (Quantum *) NULL);
 288   v=1.0-blackness;
 289   if (hue == 0.0)
 290     {
 291       *red=RoundToQuantum((MagickRealType) QuantumRange*v);
 292       *green=RoundToQuantum((MagickRealType) QuantumRange*v);
 293       *blue=RoundToQuantum((MagickRealType) QuantumRange*v);
 294       return;
 295     }
 296   i=(long) floor(6.0*hue);
 297   f=6.0*hue-i;
 298   if ((i & 0x01) != 0)
 299     f=1.0-f;
 300   n=whiteness+f*(v-whiteness);  /* linear interpolation */
 301   switch (i)
 302   {
 303     default:
 304     case 6:
 305     case 0: r=v; g=n; b=whiteness; break;
 306     case 1: r=n; g=v; b=whiteness; break;
 307     case 2: r=whiteness; g=v; b=n; break;
 308     case 3: r=whiteness; g=n; b=v; break;
 309     case 4: r=n; g=whiteness; b=v; break;
 310     case 5: r=v; g=whiteness; b=n; break;
 311   }
 312   *red=RoundToQuantum((MagickRealType) QuantumRange*r);
 313   *green=RoundToQuantum((MagickRealType) QuantumRange*g);
 314   *blue=RoundToQuantum((MagickRealType) QuantumRange*b);
 315 }
 316 \f
 317 /*
 318 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 319 %                                                                             %
 320 %                                                                             %
 321 %                                                                             %
 322 %   C o n v e r t R G B T o H S B                                             %
 323 %                                                                             %
 324 %                                                                             %
 325 %                                                                             %
 326 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 327 %
 328 %  ConvertRGBToHSB() transforms a (red, green, blue) to a (hue, saturation,
 329 %  brightness) triple.
 330 %
 331 %  The format of the ConvertRGBToHSB method is:
 332 %
 333 %      void ConvertRGBToHSB(const Quantum red,const Quantum green,
 334 %        const Quantum blue,double *hue,double *saturation,double *brightness)
 335 %
 336 %  A description of each parameter follows:
 337 %
 338 %    o red, green, blue: A Quantum value representing the red, green, and
 339 %      blue component of a pixel..
 340 %
 341 %    o hue, saturation, brightness: A pointer to a double value representing a
 342 %      component of the HSB color space.
 343 %
 344 */
 345 MagickExport void ConvertRGBToHSB(const Quantum red,const Quantum green,
 346   const Quantum blue,double *hue,double *saturation,double *brightness)
 347 {
 348   MagickRealType
 349     delta,
 350     max,
 351     min;
 352
 353   /*
 354     Convert RGB to HSB colorspace.
 355   */
 356   assert(hue != (double *) NULL);
 357   assert(saturation != (double *) NULL);
 358   assert(brightness != (double *) NULL);
 359   *hue=0.0;
 360   *saturation=0.0;
 361   *brightness=0.0;
 362   min=(MagickRealType) (red < green ? red : green);
 363   if ((MagickRealType) blue < min)
 364     min=(MagickRealType) blue;
 365   max=(MagickRealType) (red > green ? red : green);
 366   if ((MagickRealType) blue > max)
 367     max=(MagickRealType) blue;
 368   if (max == 0.0)
 369     return;
 370   delta=max-min;
 371   *saturation=(double) (delta/max);
 372   *brightness=(double) (QuantumScale*max);
 373   if (delta == 0.0)
 374     return;
 375   if (red == max)
 376     *hue=((((max-blue)/6.0)+(delta/2.0))-(((max-green)/6.0)+(delta/2.0)))/delta;
 377   else
 378     if (green == max)
 379       *hue=(1.0/3.0)+((((max-red)/6.0)+(delta/2.0))-(((max-blue)/6.0)+
 380         (delta/2.0)))/delta;
 381     else
 382       if (blue == max)
 383         *hue=(2.0/3.0)+((((max-green)/6.0)+(delta/2.0))-(((max-red)/6.0)+
 384           (delta/2.0)))/delta;
 385   if (*hue < 0.0)
 386     *hue+=1.0;
 387   if (*hue > 1.0)
 388     *hue-=1.0;
 389 }
 390 \f
 391 /*
 392 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 393 %                                                                             %
 394 %                                                                             %
 395 %                                                                             %
 396 %   C o n v e r t R G B T o H S L                                             %
 397 %                                                                             %
 398 %                                                                             %
 399 %                                                                             %
 400 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 401 %
 402 %  ConvertRGBToHSL() transforms a (red, green, blue) to a (hue, saturation,
 403 %  lightness) triple.
 404 %
 405 %  The format of the ConvertRGBToHSL method is:
 406 %
 407 %      void ConvertRGBToHSL(const Quantum red,const Quantum green,
 408 %        const Quantum blue,double *hue,double *saturation,double *lightness)
 409 %
 410 %  A description of each parameter follows:
 411 %
 412 %    o red, green, blue: A Quantum value representing the red, green, and
 413 %      blue component of a pixel..
 414 %
 415 %    o hue, saturation, lightness: A pointer to a double value representing a
 416 %      component of the HSL color space.
 417 %
 418 */
 419
 420 static inline double MagickMax(const double x,const double y)
 421 {
 422   if (x > y)
 423     return(x);
 424   return(y);
 425 }
 426
 427 static inline double MagickMin(const double x,const double y)
 428 {
 429   if (x < y)
 430     return(x);
 431   return(y);
 432 }
 433
 434 MagickExport void ConvertRGBToHSL(const Quantum red,const Quantum green,
 435   const Quantum blue,double *hue,double *saturation,double *lightness)
 436 {
 437   MagickRealType
 438     b,
 439     delta,
 440     g,
 441     max,
 442     min,
 443     r;
 444
 445   /*
 446     Convert RGB to HSL colorspace.
 447   */
 448   assert(hue != (double *) NULL);
 449   assert(saturation != (double *) NULL);
 450   assert(lightness != (double *) NULL);
 451   r=QuantumScale*red;
 452   g=QuantumScale*green;
 453   b=QuantumScale*blue;
 454   max=MagickMax(r,MagickMax(g,b));
 455   min=MagickMin(r,MagickMin(g,b));
 456   *lightness=(double) ((min+max)/2.0);
 457   delta=max-min;
 458   if (delta == 0.0)
 459     {
 460       *hue=0.0;
 461       *saturation=0.0;
 462       return;
 463     }
 464   if (*lightness < 0.5)
 465     *saturation=(double) (delta/(min+max));
 466   else
 467     *saturation=(double) (delta/(2.0-max-min));
 468   if (r == max)
 469     *hue=((((max-b)/6.0)+(delta/2.0))-(((max-g)/6.0)+(delta/2.0)))/delta;
 470   else
 471     if (g == max)
 472       *hue=(1.0/3.0)+((((max-r)/6.0)+(delta/2.0))-(((max-b)/6.0)+(delta/2.0)))/
 473         delta;
 474     else
 475       if (b == max)
 476         *hue=(2.0/3.0)+((((max-g)/6.0)+(delta/2.0))-(((max-r)/6.0)+
 477           (delta/2.0)))/delta;
 478   if (*hue < 0.0)
 479     *hue+=1.0;
 480   if (*hue > 1.0)
 481     *hue-=1.0;
 482 }
 483 \f
 484 /*
 485 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 486 %                                                                             %
 487 %                                                                             %
 488 %                                                                             %
 489 %   C o n v e r t R G B T o H W B                                             %
 490 %                                                                             %
 491 %                                                                             %
 492 %                                                                             %
 493 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 494 %
 495 %  ConvertRGBToHWB() transforms a (red, green, blue) to a (hue, whiteness,
 496 %  blackness) triple.
 497 %
 498 %  The format of the ConvertRGBToHWB method is:
 499 %
 500 %      void ConvertRGBToHWB(const Quantum red,const Quantum green,
 501 %        const Quantum blue,double *hue,double *whiteness,double *blackness)
 502 %
 503 %  A description of each parameter follows:
 504 %
 505 %    o red, green, blue: A Quantum value representing the red, green, and
 506 %      blue component of a pixel.
 507 %
 508 %    o hue, whiteness, blackness: A pointer to a double value representing a
 509 %      component of the HWB color space.
 510 %
 511 */
 512 MagickExport void ConvertRGBToHWB(const Quantum red,const Quantum green,
 513   const Quantum blue,double *hue,double *whiteness,double *blackness)
 514 {
 515   MagickRealType
 516     f,
 517     v,
 518     w;
 519
 520   register long
 521     i;
 522
 523   /*
 524     Convert RGB to HWB colorspace.
 525   */
 526   assert(hue != (double *) NULL);
 527   assert(whiteness != (double *) NULL);
 528   assert(blackness != (double *) NULL);
 529   w=(MagickRealType) MagickMin((double) red,MagickMin((double) green,(double)
 530     blue));
 531   v=(MagickRealType) MagickMax((double) red,MagickMax((double) green,(double)
 532     blue));
 533   *blackness=1.0-QuantumScale*v;
 534   *whiteness=QuantumScale*w;
 535   if (v == w)
 536     {
 537       *hue=0.0;
 538       return;
 539     }
 540   f=((MagickRealType) red == w) ? green-(MagickRealType) blue :
 541     (((MagickRealType) green == w) ? blue-(MagickRealType) red : red-
 542     (MagickRealType) green);
 543   i=((MagickRealType) red == w) ? 3 : (((MagickRealType) green == w) ? 5 : 1);
 544   *hue=((double) i-f/(v-1.0*w))/6.0;
 545 }
 546 \f
 547 /*
 548 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 549 %                                                                             %
 550 %                                                                             %
 551 %                                                                             %
 552 %   E x p a n d A f f i n e                                                   %
 553 %                                                                             %
 554 %                                                                             %
 555 %                                                                             %
 556 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 557 %
 558 %  ExpandAffine() computes the affine's expansion factor, i.e. the square root
 559 %  of the factor by which the affine transform affects area. In an affine
 560 %  transform composed of scaling, rotation, shearing, and translation, returns
 561 %  the amount of scaling.
 562 %
 563 %  The format of the ExpandAffine method is:
 564 %
 565 %      double ExpandAffine(const AffineMatrix *affine)
 566 %
 567 %  A description of each parameter follows:
 568 %
 569 %    o expansion: Method ExpandAffine returns the affine's expansion factor.
 570 %
 571 %    o affine: A pointer the affine transform of type AffineMatrix.
 572 %
 573 */
 574 MagickExport double ExpandAffine(const AffineMatrix *affine)
 575 {
 576   assert(affine != (const AffineMatrix *) NULL);
 577   return(sqrt(fabs(affine->sx*affine->sy-affine->rx*affine->ry)));
 578 }
 579 \f
 580 /*
 581 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 582 %                                                                             %
 583 %                                                                             %
 584 %                                                                             %
 585 %   G e n e r a t e D i f f e r e n t i a l N o i s e                         %
 586 %                                                                             %
 587 %                                                                             %
 588 %                                                                             %
 589 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 590 %
 591 %  GenerateDifferentialNoise() generates differentual noise.
 592 %
 593 %  The format of the GenerateDifferentialNoise method is:
 594 %
 595 %      double GenerateDifferentialNoise(RandomInfo *random_info,
 596 %        const Quantum pixel,const NoiseType noise_type,
 597 %        const MagickRealType attenuate)
 598 %
 599 %  A description of each parameter follows:
 600 %
 601 %    o random_info: the random info.
 602 %
 603 %    o pixel: noise is relative to this pixel value.
 604 %
 605 %    o noise_type: the type of noise.
 606 %
 607 %    o attenuate:  attenuate the noise.
 608 %
 609 */
 610 MagickExport double GenerateDifferentialNoise(RandomInfo *random_info,
 611   const Quantum pixel,const NoiseType noise_type,const MagickRealType attenuate)
 612 {
 613 #define NoiseEpsilon  (attenuate*1.0e-5)
 614 #define SigmaUniform  (attenuate*4.0)
 615 #define SigmaGaussian  (attenuate*4.0)
 616 #define SigmaImpulse  (attenuate*0.10)
 617 #define SigmaLaplacian (attenuate*10.0)
 618 #define SigmaMultiplicativeGaussian  (attenuate*1.0)
 619 #define SigmaPoisson  (attenuate*0.05)
 620 #define TauGaussian  (attenuate*20.0)
 621
 622   double
 623     alpha,
 624     beta,
 625     noise,
 626     sigma;
 627
 628   alpha=GetPseudoRandomValue(random_info);
 629   switch (noise_type)
 630   {
 631     case UniformNoise:
 632     default:
 633     {
 634       noise=(double) pixel+ScaleCharToQuantum((unsigned char)
 635         (SigmaUniform*(alpha)));
 636       break;
 637     }
 638     case GaussianNoise:
 639     {
 640       double
 641         tau;
 642
 643       if (alpha == 0.0)
 644         alpha=1.0;
 645       beta=GetPseudoRandomValue(random_info);
 646       sigma=sqrt(-2.0*log(alpha))*cos(2.0*MagickPI*beta);
 647       tau=sqrt(-2.0*log(alpha))*sin(2.0*MagickPI*beta);
 648       noise=(double) pixel+sqrt((double) pixel)*SigmaGaussian*sigma+
 649         TauGaussian*tau;
 650       break;
 651     }
 652     case MultiplicativeGaussianNoise:
 653     {
 654       if (alpha <= NoiseEpsilon)
 655         sigma=(double) QuantumRange;
 656       else
 657         sigma=sqrt(-2.0*log(alpha));
 658       beta=GetPseudoRandomValue(random_info);
 659       noise=(double) pixel+pixel*SigmaMultiplicativeGaussian*sigma/2.0*
 660         cos((2.0*MagickPI*beta));
 661       break;
 662     }
 663     case ImpulseNoise:
 664     {
 665       if (alpha < (SigmaImpulse/2.0))
 666         noise=0.0;
 667        else
 668          if (alpha >= (1.0-(SigmaImpulse/2.0)))
 669            noise=(double) QuantumRange;
 670          else
 671            noise=(double) pixel;
 672       break;
 673     }
 674     case LaplacianNoise:
 675     {
 676       if (alpha <= 0.5)
 677         {
 678           if (alpha <= NoiseEpsilon)
 679             noise=(double) pixel-(double) QuantumRange;
 680           else
 681             noise=(double) pixel+ScaleCharToQuantum((unsigned char)
 682               (SigmaLaplacian*log((2.0*alpha))+0.5));
 683           break;
 684         }
 685       beta=1.0-alpha;
 686       if (beta <= (0.5*NoiseEpsilon))
 687         noise=(double) (pixel+QuantumRange);
 688       else
 689         noise=(double) pixel-ScaleCharToQuantum((unsigned char)
 690           (SigmaLaplacian*log((2.0*beta))+0.5));
 691       break;
 692     }
 693     case PoissonNoise:
 694     {
 695       double
 696         poisson;
 697
 698       register long
 699         i;
 700
 701       poisson=exp(-SigmaPoisson*ScaleQuantumToChar(pixel));
 702       for (i=0; alpha > poisson; i++)
 703       {
 704         beta=GetPseudoRandomValue(random_info);
 705         alpha*=beta;
 706       }
 707       noise=(double) ScaleCharToQuantum((unsigned char) (i/SigmaPoisson));
 708       break;
 709     }
 710     case RandomNoise:
 711     {
 712       noise=(double) QuantumRange*GetPseudoRandomValue(random_info);
 713       break;
 714     }
 715   }
 716   return(noise);
 717 }
 718 \f
 719 /*
 720 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 721 %                                                                             %
 722 %                                                                             %
 723 %                                                                             %
 724 %   G e t O p t i m a l K e r n e l W i d t h                                 %
 725 %                                                                             %
 726 %                                                                             %
 727 %                                                                             %
 728 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 729 %
 730 %  GetOptimalKernelWidth() computes the optimal kernel radius for a convolution
 731 %  filter.  Start with the minimum value of 3 pixels and walk out until we drop
 732 %  below the threshold of one pixel numerical accuracy.
 733 %
 734 %  The format of the GetOptimalKernelWidth method is:
 735 %
 736 %      unsigned long GetOptimalKernelWidth(const double radius,
 737 %        const double sigma)
 738 %
 739 %  A description of each parameter follows:
 740 %
 741 %    o width: Method GetOptimalKernelWidth returns the optimal width of
 742 %      a convolution kernel.
 743 %
 744 %    o radius: the radius of the Gaussian, in pixels, not counting the center
 745 %      pixel.
 746 %
 747 %    o sigma: the standard deviation of the Gaussian, in pixels.
 748 %
 749 */
 750 MagickExport unsigned long GetOptimalKernelWidth1D(const double radius,
 751   const double sigma)
 752 {
 753   long
 754     width;
 755
 756   MagickRealType
 757     normalize,
 758     value;
 759
 760   register long
 761     u;
 762
 763   (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
 764   if (radius > 0.0)
 765     return((unsigned long) (2.0*ceil(radius)+1.0));
 766   if (fabs(sigma) <= MagickEpsilon)
 767     return(1);
 768   for (width=5; ; )
 769   {
 770     normalize=0.0;
 771     for (u=(-width/2); u <= (width/2); u++)
 772       normalize+=exp(-((double) u*u)/(2.0*sigma*sigma))/(MagickSQ2PI*sigma);
 773     u=width/2;
 774     value=exp(-((double) u*u)/(2.0*sigma*sigma))/(MagickSQ2PI*sigma)/normalize;
 775     if ((long) (QuantumRange*value) <= 0L)
 776       break;
 777     width+=2;
 778   }
 779   return((unsigned long) (width-2));
 780 }
 781
 782 MagickExport unsigned long GetOptimalKernelWidth2D(const double radius,
 783   const double sigma)
 784 {
 785
 786   long
 787     width;
 788
 789   MagickRealType
 790     alpha,
 791     normalize,
 792     value;
 793
 794   register long
 795     u,
 796     v;
 797
 798   (void) LogMagickEvent(TraceEvent,GetMagickModule(),"...");
 799   if (radius > 0.0)
 800     return((unsigned long) (2.0*ceil(radius)+1.0));
 801   if (fabs(sigma) <= MagickEpsilon)
 802     return(1);
 803   for (width=5; ; )
 804   {
 805     normalize=0.0;
 806     for (v=(-width/2); v <= (width/2); v++)
 807     {
 808       for (u=(-width/2); u <= (width/2); u++)
 809       {
 810         alpha=exp(-((double) u*u+v*v)/(2.0*sigma*sigma));
 811         normalize+=alpha/(2.0*MagickPI*sigma*sigma);
 812       }
 813     }
 814     v=width/2;
 815     value=exp(-((double) v*v)/(2.0*sigma*sigma))/normalize;
 816     if ((long) (QuantumRange*value) <= 0L)
 817       break;
 818     width+=2;
 819   }
 820   return((unsigned long) (width-2));
 821 }
 822
 823 MagickExport unsigned long  GetOptimalKernelWidth(const double radius,
 824   const double sigma)
 825 {
 826   return(GetOptimalKernelWidth1D(radius,sigma));
 827 }