granicus.if.org Git - imagemagick/blob - MagickCore/shear.c

   1 /*
   2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   3 %                                                                             %
   4 %                                                                             %
   5 %                                                                             %
   6 %                      SSSSS  H   H  EEEEE   AAA    RRRR                      %
   7 %                      SS     H   H  E      A   A   R   R                     %
   8 %                       SSS   HHHHH  EEE    AAAAA   RRRR                      %
   9 %                         SS  H   H  E      A   A   R R                       %
  10 %                      SSSSS  H   H  EEEEE  A   A   R  R                      %
  11 %                                                                             %
  12 %                                                                             %
  13 %    MagickCore Methods to Shear or Rotate an Image by an Arbitrary Angle     %
  14 %                                                                             %
  15 %                               Software Design                               %
  16 %                                 John Cristy                                 %
  17 %                                  July 1992                                  %
  18 %                                                                             %
  19 %                                                                             %
  20 %  Copyright 1999-2012 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 %  The XShearImage() and YShearImage() methods are based on the paper "A Fast
  37 %  Algorithm for General Raster Rotatation" by Alan W. Paeth, Graphics
  38 %  Interface '86 (Vancouver).  ShearRotateImage() is adapted from a similar
  39 %  method based on the Paeth paper written by Michael Halle of the Spatial
  40 %  Imaging Group, MIT Media Lab.
  41 %
  42 */
  43 \f
  44 /*
  45   Include declarations.
  46 */
  47 #include "MagickCore/studio.h"
  48 #include "MagickCore/artifact.h"
  49 #include "MagickCore/attribute.h"
  50 #include "MagickCore/blob-private.h"
  51 #include "MagickCore/cache-private.h"
  52 #include "MagickCore/color-private.h"
  53 #include "MagickCore/colorspace-private.h"
  54 #include "MagickCore/composite.h"
  55 #include "MagickCore/composite-private.h"
  56 #include "MagickCore/decorate.h"
  57 #include "MagickCore/distort.h"
  58 #include "MagickCore/draw.h"
  59 #include "MagickCore/exception.h"
  60 #include "MagickCore/exception-private.h"
  61 #include "MagickCore/gem.h"
  62 #include "MagickCore/geometry.h"
  63 #include "MagickCore/image.h"
  64 #include "MagickCore/image-private.h"
  65 #include "MagickCore/memory_.h"
  66 #include "MagickCore/list.h"
  67 #include "MagickCore/monitor.h"
  68 #include "MagickCore/monitor-private.h"
  69 #include "MagickCore/nt-base-private.h"
  70 #include "MagickCore/pixel-accessor.h"
  71 #include "MagickCore/quantum.h"
  72 #include "MagickCore/resource_.h"
  73 #include "MagickCore/shear.h"
  74 #include "MagickCore/statistic.h"
  75 #include "MagickCore/string_.h"
  76 #include "MagickCore/string-private.h"
  77 #include "MagickCore/thread-private.h"
  78 #include "MagickCore/threshold.h"
  79 #include "MagickCore/transform.h"
  80 \f
  81 /*
  82 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  83 %                                                                             %
  84 %                                                                             %
  85 %                                                                             %
  86 +   C r o p T o F i t I m a g e                                               %
  87 %                                                                             %
  88 %                                                                             %
  89 %                                                                             %
  90 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  91 %
  92 %  CropToFitImage() crops the sheared image as determined by the bounding box
  93 %  as defined by width and height and shearing angles.
  94 %
  95 %  The format of the CropToFitImage method is:
  96 %
  97 %      MagickBooleanType CropToFitImage(Image **image,
  98 %        const double x_shear,const double x_shear,
  99 %        const double width,const double height,
 100 %        const MagickBooleanType rotate,ExceptionInfo *exception)
 101 %
 102 %  A description of each parameter follows.
 103 %
 104 %    o image: the image.
 105 %
 106 %    o x_shear, y_shear, width, height: Defines a region of the image to crop.
 107 %
 108 %    o exception: return any errors or warnings in this structure.
 109 %
 110 */
 111 static MagickBooleanType CropToFitImage(Image **image,
 112   const double x_shear,const double y_shear,
 113   const double width,const double height,
 114   const MagickBooleanType rotate,ExceptionInfo *exception)
 115 {
 116   Image
 117     *crop_image;
 118
 119   PointInfo
 120     extent[4],
 121     min,
 122     max;
 123
 124   RectangleInfo
 125     geometry,
 126     page;
 127
 128   register ssize_t
 129     i;
 130
 131   /*
 132     Calculate the rotated image size.
 133   */
 134   extent[0].x=(double) (-width/2.0);
 135   extent[0].y=(double) (-height/2.0);
 136   extent[1].x=(double) width/2.0;
 137   extent[1].y=(double) (-height/2.0);
 138   extent[2].x=(double) (-width/2.0);
 139   extent[2].y=(double) height/2.0;
 140   extent[3].x=(double) width/2.0;
 141   extent[3].y=(double) height/2.0;
 142   for (i=0; i < 4; i++)
 143   {
 144     extent[i].x+=x_shear*extent[i].y;
 145     extent[i].y+=y_shear*extent[i].x;
 146     if (rotate != MagickFalse)
 147       extent[i].x+=x_shear*extent[i].y;
 148     extent[i].x+=(double) (*image)->columns/2.0;
 149     extent[i].y+=(double) (*image)->rows/2.0;
 150   }
 151   min=extent[0];
 152   max=extent[0];
 153   for (i=1; i < 4; i++)
 154   {
 155     if (min.x > extent[i].x)
 156       min.x=extent[i].x;
 157     if (min.y > extent[i].y)
 158       min.y=extent[i].y;
 159     if (max.x < extent[i].x)
 160       max.x=extent[i].x;
 161     if (max.y < extent[i].y)
 162       max.y=extent[i].y;
 163   }
 164   geometry.x=(ssize_t) ceil(min.x-0.5);
 165   geometry.y=(ssize_t) ceil(min.y-0.5);
 166   geometry.width=(size_t) floor(max.x-min.x+0.5);
 167   geometry.height=(size_t) floor(max.y-min.y+0.5);
 168   page=(*image)->page;
 169   (void) ParseAbsoluteGeometry("0x0+0+0",&(*image)->page);
 170   crop_image=CropImage(*image,&geometry,exception);
 171   if (crop_image == (Image *) NULL)
 172     return(MagickFalse);
 173   crop_image->page=page;
 174   *image=DestroyImage(*image);
 175   *image=crop_image;
 176   return(MagickTrue);
 177 }
 178 \f
 179 /*
 180 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 181 %                                                                             %
 182 %                                                                             %
 183 %                                                                             %
 184 %     D e s k e w I m a g e                                                   %
 185 %                                                                             %
 186 %                                                                             %
 187 %                                                                             %
 188 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 189 %
 190 %  DeskewImage() removes skew from the image.  Skew is an artifact that
 191 %  occurs in scanned images because of the camera being misaligned,
 192 %  imperfections in the scanning or surface, or simply because the paper was
 193 %  not placed completely flat when scanned.
 194 %
 195 %  The format of the DeskewImage method is:
 196 %
 197 %      Image *DeskewImage(const Image *image,const double threshold,
 198 %        ExceptionInfo *exception)
 199 %
 200 %  A description of each parameter follows:
 201 %
 202 %    o image: the image.
 203 %
 204 %    o threshold: separate background from foreground.
 205 %
 206 %    o exception: return any errors or warnings in this structure.
 207 %
 208 */
 209
 210 typedef struct _RadonInfo
 211 {
 212   CacheType
 213     type;
 214
 215   size_t
 216     width,
 217     height;
 218
 219   MagickSizeType
 220     length;
 221
 222   MagickBooleanType
 223     mapped;
 224
 225   char
 226     path[MaxTextExtent];
 227
 228   int
 229     file;
 230
 231   unsigned short
 232     *cells;
 233 } RadonInfo;
 234
 235 static RadonInfo *DestroyRadonInfo(RadonInfo *radon_info)
 236 {
 237   assert(radon_info != (RadonInfo *) NULL);
 238   switch (radon_info->type)
 239   {
 240     case MemoryCache:
 241     {
 242       if (radon_info->mapped == MagickFalse)
 243         radon_info->cells=(unsigned short *) RelinquishMagickMemory(
 244           radon_info->cells);
 245       else
 246         radon_info->cells=(unsigned short *) UnmapBlob(radon_info->cells,
 247           (size_t) radon_info->length);
 248       RelinquishMagickResource(MemoryResource,radon_info->length);
 249       break;
 250     }
 251     case MapCache:
 252     {
 253       radon_info->cells=(unsigned short *) UnmapBlob(radon_info->cells,(size_t)
 254         radon_info->length);
 255       RelinquishMagickResource(MapResource,radon_info->length);
 256     }
 257     case DiskCache:
 258     {
 259       if (radon_info->file != -1)
 260         (void) close(radon_info->file);
 261       (void) RelinquishUniqueFileResource(radon_info->path);
 262       RelinquishMagickResource(DiskResource,radon_info->length);
 263       break;
 264     }
 265     default:
 266       break;
 267   }
 268   return((RadonInfo *) RelinquishMagickMemory(radon_info));
 269 }
 270
 271 static MagickBooleanType ResetRadonCells(RadonInfo *radon_info)
 272 {
 273   register ssize_t
 274     x;
 275
 276   ssize_t
 277     count,
 278     y;
 279
 280   unsigned short
 281     value;
 282
 283   if (radon_info->type != DiskCache)
 284     {
 285       (void) ResetMagickMemory(radon_info->cells,0,(size_t) radon_info->length);
 286       return(MagickTrue);
 287     }
 288   value=0;
 289   (void) lseek(radon_info->file,0,SEEK_SET);
 290   for (y=0; y < (ssize_t) radon_info->height; y++)
 291   {
 292     for (x=0; x < (ssize_t) radon_info->width; x++)
 293     {
 294       count=write(radon_info->file,&value,sizeof(*radon_info->cells));
 295       if (count != (ssize_t) sizeof(*radon_info->cells))
 296         break;
 297     }
 298     if (x < (ssize_t) radon_info->width)
 299       break;
 300   }
 301   return(y < (ssize_t) radon_info->height ? MagickFalse : MagickTrue);
 302 }
 303
 304 static RadonInfo *AcquireRadonInfo(const Image *image,const size_t width,
 305   const size_t height,ExceptionInfo *exception)
 306 {
 307   MagickBooleanType
 308     status;
 309
 310   RadonInfo
 311     *radon_info;
 312
 313   radon_info=(RadonInfo *) AcquireMagickMemory(sizeof(*radon_info));
 314   if (radon_info == (RadonInfo *) NULL)
 315     return((RadonInfo *) NULL);
 316   (void) ResetMagickMemory(radon_info,0,sizeof(*radon_info));
 317   radon_info->width=width;
 318   radon_info->height=height;
 319   radon_info->length=(MagickSizeType) width*height*sizeof(*radon_info->cells);
 320   radon_info->type=MemoryCache;
 321   status=AcquireMagickResource(AreaResource,radon_info->length);
 322   if ((status != MagickFalse) &&
 323       (radon_info->length == (MagickSizeType) ((size_t) radon_info->length)))
 324     {
 325       status=AcquireMagickResource(MemoryResource,radon_info->length);
 326       if (status != MagickFalse)
 327         {
 328           radon_info->mapped=MagickFalse;
 329           radon_info->cells=(unsigned short *) AcquireMagickMemory((size_t)
 330             radon_info->length);
 331           if (radon_info->cells == (unsigned short *) NULL)
 332             {
 333               radon_info->mapped=MagickTrue;
 334               radon_info->cells=(unsigned short *) MapBlob(-1,IOMode,0,(size_t)
 335                 radon_info->length);
 336             }
 337           if (radon_info->cells == (unsigned short *) NULL)
 338             RelinquishMagickResource(MemoryResource,radon_info->length);
 339         }
 340     }
 341   radon_info->file=(-1);
 342   if (radon_info->cells == (unsigned short *) NULL)
 343     {
 344       status=AcquireMagickResource(DiskResource,radon_info->length);
 345       if (status == MagickFalse)
 346         {
 347           (void) ThrowMagickException(exception,GetMagickModule(),CacheError,
 348             "CacheResourcesExhausted","'%s'",image->filename);
 349           return(DestroyRadonInfo(radon_info));
 350         }
 351       radon_info->type=DiskCache;
 352       (void) AcquireMagickResource(MemoryResource,radon_info->length);
 353       radon_info->file=AcquireUniqueFileResource(radon_info->path);
 354       if (radon_info->file == -1)
 355         return(DestroyRadonInfo(radon_info));
 356       status=AcquireMagickResource(MapResource,radon_info->length);
 357       if (status != MagickFalse)
 358         {
 359           status=ResetRadonCells(radon_info);
 360           if (status != MagickFalse)
 361             {
 362               radon_info->cells=(unsigned short *) MapBlob(radon_info->file,
 363                 IOMode,0,(size_t) radon_info->length);
 364               if (radon_info->cells != (unsigned short *) NULL)
 365                 radon_info->type=MapCache;
 366               else
 367                 RelinquishMagickResource(MapResource,radon_info->length);
 368             }
 369         }
 370     }
 371   return(radon_info);
 372 }
 373
 374 static inline size_t MagickMin(const size_t x,const size_t y)
 375 {
 376   if (x < y)
 377     return(x);
 378   return(y);
 379 }
 380
 381 static inline ssize_t ReadRadonCell(const RadonInfo *radon_info,
 382   const MagickOffsetType offset,const size_t length,unsigned char *buffer)
 383 {
 384   register ssize_t
 385     i;
 386
 387   ssize_t
 388     count;
 389
 390 #if !defined(MAGICKCORE_HAVE_PPREAD)
 391 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 392   #pragma omp critical (MagickCore_ReadRadonCell)
 393 #endif
 394   {
 395     i=(-1);
 396     if (lseek(radon_info->file,offset,SEEK_SET) >= 0)
 397       {
 398 #endif
 399         count=0;
 400         for (i=0; i < (ssize_t) length; i+=count)
 401         {
 402 #if !defined(MAGICKCORE_HAVE_PPREAD)
 403           count=read(radon_info->file,buffer+i,MagickMin(length-i,(size_t)
 404             SSIZE_MAX));
 405 #else
 406           count=pread(radon_info->file,buffer+i,MagickMin(length-i,(size_t)
 407             SSIZE_MAX),offset+i);
 408 #endif
 409           if (count > 0)
 410             continue;
 411           count=0;
 412           if (errno != EINTR)
 413             {
 414               i=(-1);
 415               break;
 416             }
 417         }
 418 #if !defined(MAGICKCORE_HAVE_PPREAD)
 419       }
 420   }
 421 #endif
 422   return(i);
 423 }
 424
 425 static inline ssize_t WriteRadonCell(const RadonInfo *radon_info,
 426   const MagickOffsetType offset,const size_t length,const unsigned char *buffer)
 427 {
 428   register ssize_t
 429     i;
 430
 431   ssize_t
 432     count;
 433
 434 #if !defined(MAGICKCORE_HAVE_PWRITE)
 435 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 436   #pragma omp critical (MagickCore_WriteRadonCell)
 437 #endif
 438   {
 439     if (lseek(radon_info->file,offset,SEEK_SET) >= 0)
 440       {
 441 #endif
 442         count=0;
 443         for (i=0; i < (ssize_t) length; i+=count)
 444         {
 445 #if !defined(MAGICKCORE_HAVE_PWRITE)
 446           count=write(radon_info->file,buffer+i,MagickMin(length-i,(size_t)
 447             SSIZE_MAX));
 448 #else
 449           count=pwrite(radon_info->file,buffer+i,MagickMin(length-i,(size_t)
 450             SSIZE_MAX),offset+i);
 451 #endif
 452           if (count > 0)
 453             continue;
 454           count=0;
 455           if (errno != EINTR)
 456             {
 457               i=(-1);
 458               break;
 459             }
 460         }
 461 #if !defined(MAGICKCORE_HAVE_PWRITE)
 462       }
 463   }
 464 #endif
 465   return(i);
 466 }
 467
 468 static inline unsigned short GetRadonCell(const RadonInfo *radon_info,
 469   const ssize_t x,const ssize_t y)
 470 {
 471   MagickOffsetType
 472     i;
 473
 474   unsigned short
 475     value;
 476
 477   i=(MagickOffsetType) radon_info->height*x+y;
 478   if ((i < 0) ||
 479       ((MagickSizeType) (i*sizeof(*radon_info->cells)) >= radon_info->length))
 480     return(0);
 481   if (radon_info->type != DiskCache)
 482     return(radon_info->cells[i]);
 483   value=0;
 484   (void) ReadRadonCell(radon_info,i*sizeof(*radon_info->cells),
 485     sizeof(*radon_info->cells),(unsigned char *) &value);
 486   return(value);
 487 }
 488
 489 static inline MagickBooleanType SetRadonCell(const RadonInfo *radon_info,
 490   const ssize_t x,const ssize_t y,const unsigned short value)
 491 {
 492   MagickOffsetType
 493     i;
 494
 495   ssize_t
 496     count;
 497
 498   i=(MagickOffsetType) radon_info->height*x+y;
 499   if ((i < 0) ||
 500       ((MagickSizeType) (i*sizeof(*radon_info->cells)) >= radon_info->length))
 501     return(MagickFalse);
 502   if (radon_info->type != DiskCache)
 503     {
 504       radon_info->cells[i]=value;
 505       return(MagickTrue);
 506     }
 507   count=WriteRadonCell(radon_info,i*sizeof(*radon_info->cells),
 508     sizeof(*radon_info->cells),(const unsigned char *) &value);
 509   if (count != (ssize_t) sizeof(*radon_info->cells))
 510     return(MagickFalse);
 511   return(MagickTrue);
 512 }
 513
 514 static void RadonProjection(const Image *image,RadonInfo *source_cells,
 515   RadonInfo *destination_cells,const ssize_t sign,size_t *projection)
 516 {
 517   RadonInfo
 518     *swap;
 519
 520   register ssize_t
 521     x;
 522
 523   register RadonInfo
 524     *p,
 525     *q;
 526
 527   size_t
 528     step;
 529
 530   p=source_cells;
 531   q=destination_cells;
 532   for (step=1; step < p->width; step*=2)
 533   {
 534     for (x=0; x < (ssize_t) p->width; x+=2*(ssize_t) step)
 535     {
 536       register ssize_t
 537         i;
 538
 539       ssize_t
 540         y;
 541
 542       unsigned short
 543         cell;
 544
 545       for (i=0; i < (ssize_t) step; i++)
 546       {
 547         for (y=0; y < (ssize_t) (p->height-i-1); y++)
 548         {
 549           cell=GetRadonCell(p,x+i,y);
 550           (void) SetRadonCell(q,x+2*i,y,cell+GetRadonCell(p,x+i+(ssize_t)
 551             step,y+i));
 552           (void) SetRadonCell(q,x+2*i+1,y,cell+GetRadonCell(p,x+i+(ssize_t)
 553             step,y+i+1));
 554         }
 555         for ( ; y < (ssize_t) (p->height-i); y++)
 556         {
 557           cell=GetRadonCell(p,x+i,y);
 558           (void) SetRadonCell(q,x+2*i,y,cell+GetRadonCell(p,x+i+(ssize_t) step,
 559             y+i));
 560           (void) SetRadonCell(q,x+2*i+1,y,cell);
 561         }
 562         for ( ; y < (ssize_t) p->height; y++)
 563         {
 564           cell=GetRadonCell(p,x+i,y);
 565           (void) SetRadonCell(q,x+2*i,y,cell);
 566           (void) SetRadonCell(q,x+2*i+1,y,cell);
 567         }
 568       }
 569     }
 570     swap=p;
 571     p=q;
 572     q=swap;
 573   }
 574 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 575   #pragma omp parallel for schedule(static,4) \
 576     dynamic_number_threads(image,p->width,p->height,1)
 577 #endif
 578   for (x=0; x < (ssize_t) p->width; x++)
 579   {
 580     register ssize_t
 581       y;
 582
 583     size_t
 584       sum;
 585
 586     sum=0;
 587     for (y=0; y < (ssize_t) (p->height-1); y++)
 588     {
 589       ssize_t
 590         delta;
 591
 592       delta=GetRadonCell(p,x,y)-(ssize_t) GetRadonCell(p,x,y+1);
 593       sum+=delta*delta;
 594     }
 595     projection[p->width+sign*x-1]=sum;
 596   }
 597 }
 598
 599 static MagickBooleanType RadonTransform(const Image *image,
 600   const double threshold,size_t *projection,ExceptionInfo *exception)
 601 {
 602   CacheView
 603     *image_view;
 604
 605   MagickBooleanType
 606     status;
 607
 608   RadonInfo
 609     *destination_cells,
 610     *source_cells;
 611
 612   register ssize_t
 613     i;
 614
 615   size_t
 616     count,
 617     width;
 618
 619   ssize_t
 620     y;
 621
 622   unsigned char
 623     byte;
 624
 625   unsigned short
 626     bits[256];
 627
 628   for (width=1; width < ((image->columns+7)/8); width<<=1) ;
 629   source_cells=AcquireRadonInfo(image,width,image->rows,exception);
 630   destination_cells=AcquireRadonInfo(image,width,image->rows,exception);
 631   if ((source_cells == (RadonInfo *) NULL) ||
 632       (destination_cells == (RadonInfo *) NULL))
 633     {
 634       if (destination_cells != (RadonInfo *) NULL)
 635         destination_cells=DestroyRadonInfo(destination_cells);
 636       if (source_cells != (RadonInfo *) NULL)
 637         source_cells=DestroyRadonInfo(source_cells);
 638       return(MagickFalse);
 639     }
 640   if (ResetRadonCells(source_cells) == MagickFalse)
 641     {
 642       destination_cells=DestroyRadonInfo(destination_cells);
 643       source_cells=DestroyRadonInfo(source_cells);
 644       return(MagickFalse);
 645     }
 646   for (i=0; i < 256; i++)
 647   {
 648     byte=(unsigned char) i;
 649     for (count=0; byte != 0; byte>>=1)
 650       count+=byte & 0x01;
 651     bits[i]=(unsigned short) count;
 652   }
 653   status=MagickTrue;
 654   image_view=AcquireVirtualCacheView(image,exception);
 655 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 656   #pragma omp parallel for schedule(static,4) shared(status) \
 657     dynamic_number_threads(image,image->columns,image->rows,1)
 658 #endif
 659   for (y=0; y < (ssize_t) image->rows; y++)
 660   {
 661     register const Quantum
 662       *restrict p;
 663
 664     register ssize_t
 665       i,
 666       x;
 667
 668     size_t
 669       bit,
 670       byte;
 671
 672     if (status == MagickFalse)
 673       continue;
 674     p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
 675     if (p == (const Quantum *) NULL)
 676       {
 677         status=MagickFalse;
 678         continue;
 679       }
 680     bit=0;
 681     byte=0;
 682     i=(ssize_t) (image->columns+7)/8;
 683     for (x=0; x < (ssize_t) image->columns; x++)
 684     {
 685       byte<<=1;
 686       if (GetPixelIntensity(image,p) < threshold)
 687         byte|=0x01;
 688       bit++;
 689       if (bit == 8)
 690         {
 691           (void) SetRadonCell(source_cells,--i,y,bits[byte]);
 692           bit=0;
 693           byte=0;
 694         }
 695       p+=GetPixelChannels(image);
 696     }
 697     if (bit != 0)
 698       {
 699         byte<<=(8-bit);
 700         (void) SetRadonCell(source_cells,--i,y,bits[byte]);
 701       }
 702   }
 703   RadonProjection(image,source_cells,destination_cells,-1,projection);
 704   (void) ResetRadonCells(source_cells);
 705 #if defined(MAGICKCORE_OPENMP_SUPPORT)
 706   #pragma omp parallel for schedule(static,4) shared(status) \
 707     dynamic_number_threads(image,image->columns,image->rows,1)
 708 #endif
 709   for (y=0; y < (ssize_t) image->rows; y++)
 710   {
 711     register const Quantum
 712       *restrict p;
 713
 714     register ssize_t
 715       i,
 716       x;
 717
 718     size_t
 719       bit,
 720       byte;
 721
 722     if (status == MagickFalse)
 723       continue;
 724     p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
 725     if (p == (const Quantum *) NULL)
 726       {
 727         status=MagickFalse;
 728         continue;
 729       }
 730     bit=0;
 731     byte=0;
 732     i=0;
 733     for (x=0; x < (ssize_t) image->columns; x++)
 734     {
 735       byte<<=1;
 736       if (GetPixelIntensity(image,p) < threshold)
 737         byte|=0x01;
 738       bit++;
 739       if (bit == 8)
 740         {
 741           (void) SetRadonCell(source_cells,i++,y,bits[byte]);
 742           bit=0;
 743           byte=0;
 744         }
 745       p+=GetPixelChannels(image);
 746     }
 747     if (bit != 0)
 748       {
 749         byte<<=(8-bit);
 750         (void) SetRadonCell(source_cells,i++,y,bits[byte]);
 751       }
 752   }
 753   RadonProjection(image,source_cells,destination_cells,1,projection);
 754   image_view=DestroyCacheView(image_view);
 755   destination_cells=DestroyRadonInfo(destination_cells);
 756   source_cells=DestroyRadonInfo(source_cells);
 757   return(MagickTrue);
 758 }
 759
 760 static void GetImageBackgroundColor(Image *image,const ssize_t offset,
 761   ExceptionInfo *exception)
 762 {
 763   CacheView
 764     *image_view;
 765
 766   PixelInfo
 767     background;
 768
 769   double
 770     count;
 771
 772   ssize_t
 773     y;
 774
 775   /*
 776     Compute average background color.
 777   */
 778   if (offset <= 0)
 779     return;
 780   GetPixelInfo(image,&background);
 781   count=0.0;
 782   image_view=AcquireVirtualCacheView(image,exception);
 783   for (y=0; y < (ssize_t) image->rows; y++)
 784   {
 785     register const Quantum
 786       *restrict p;
 787
 788     register ssize_t
 789       x;
 790
 791     if ((y >= offset) && (y < ((ssize_t) image->rows-offset)))
 792       continue;
 793     p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
 794     if (p == (const Quantum *) NULL)
 795       continue;
 796     for (x=0; x < (ssize_t) image->columns; x++)
 797     {
 798       if ((x >= offset) && (x < ((ssize_t) image->columns-offset)))
 799         continue;
 800       background.red+=QuantumScale*GetPixelRed(image,p);
 801       background.green+=QuantumScale*GetPixelGreen(image,p);
 802       background.blue+=QuantumScale*GetPixelBlue(image,p);
 803       if ((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0)
 804         background.alpha+=QuantumScale*GetPixelAlpha(image,p);
 805       count++;
 806       p+=GetPixelChannels(image);
 807     }
 808   }
 809   image_view=DestroyCacheView(image_view);
 810   image->background_color.red=(double) ClampToQuantum(QuantumRange*
 811     background.red/count);
 812   image->background_color.green=(double) ClampToQuantum(QuantumRange*
 813     background.green/count);
 814   image->background_color.blue=(double) ClampToQuantum(QuantumRange*
 815     background.blue/count);
 816   if ((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0)
 817     image->background_color.alpha=(double) ClampToQuantum(QuantumRange*
 818       background.alpha/count);
 819 }
 820
 821 MagickExport Image *DeskewImage(const Image *image,const double threshold,
 822   ExceptionInfo *exception)
 823 {
 824   AffineMatrix
 825     affine_matrix;
 826
 827   const char
 828     *artifact;
 829
 830   double
 831     degrees;
 832
 833   Image
 834     *clone_image,
 835     *crop_image,
 836     *deskew_image,
 837     *median_image;
 838
 839   MagickBooleanType
 840     status;
 841
 842   RectangleInfo
 843     geometry;
 844
 845   register ssize_t
 846     i;
 847
 848   size_t
 849     max_projection,
 850     *projection,
 851     width;
 852
 853   ssize_t
 854     skew;
 855
 856   /*
 857     Compute deskew angle.
 858   */
 859   for (width=1; width < ((image->columns+7)/8); width<<=1) ;
 860   projection=(size_t *) AcquireQuantumMemory((size_t) (2*width-1),
 861     sizeof(*projection));
 862   if (projection == (size_t *) NULL)
 863     ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
 864   status=RadonTransform(image,threshold,projection,exception);
 865   if (status == MagickFalse)
 866     {
 867       projection=(size_t *) RelinquishMagickMemory(projection);
 868       ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
 869     }
 870   max_projection=0;
 871   skew=0;
 872   for (i=0; i < (ssize_t) (2*width-1); i++)
 873   {
 874     if (projection[i] > max_projection)
 875       {
 876         skew=i-(ssize_t) width+1;
 877         max_projection=projection[i];
 878       }
 879   }
 880   projection=(size_t *) RelinquishMagickMemory(projection);
 881   /*
 882     Deskew image.
 883   */
 884   clone_image=CloneImage(image,0,0,MagickTrue,exception);
 885   if (clone_image == (Image *) NULL)
 886     return((Image *) NULL);
 887   (void) SetImageVirtualPixelMethod(clone_image,BackgroundVirtualPixelMethod,
 888     exception);
 889   degrees=RadiansToDegrees(-atan((double) skew/width/8));
 890   if (image->debug != MagickFalse)
 891     (void) LogMagickEvent(TransformEvent,GetMagickModule(),
 892       "  Deskew angle: %g",degrees);
 893   affine_matrix.sx=cos(DegreesToRadians(fmod((double) degrees,360.0)));
 894   affine_matrix.rx=sin(DegreesToRadians(fmod((double) degrees,360.0)));
 895   affine_matrix.ry=(-sin(DegreesToRadians(fmod((double) degrees,360.0))));
 896   affine_matrix.sy=cos(DegreesToRadians(fmod((double) degrees,360.0)));
 897   affine_matrix.tx=0.0;
 898   affine_matrix.ty=0.0;
 899   artifact=GetImageArtifact(image,"deskew:auto-crop");
 900   if (artifact == (const char *) NULL)
 901     {
 902       deskew_image=AffineTransformImage(clone_image,&affine_matrix,exception);
 903       clone_image=DestroyImage(clone_image);
 904       return(deskew_image);
 905     }
 906   /*
 907     Auto-crop image.
 908   */
 909   GetImageBackgroundColor(clone_image,(ssize_t) StringToLong(artifact),
 910     exception);
 911   deskew_image=AffineTransformImage(clone_image,&affine_matrix,exception);
 912   clone_image=DestroyImage(clone_image);
 913   if (deskew_image == (Image *) NULL)
 914     return((Image *) NULL);
 915   median_image=StatisticImage(deskew_image,MedianStatistic,3,3,exception);
 916   if (median_image == (Image *) NULL)
 917     {
 918       deskew_image=DestroyImage(deskew_image);
 919       return((Image *) NULL);
 920     }
 921   geometry=GetImageBoundingBox(median_image,exception);
 922   median_image=DestroyImage(median_image);
 923   if (image->debug != MagickFalse)
 924     (void) LogMagickEvent(TransformEvent,GetMagickModule(),"  Deskew geometry: "
 925       "%.20gx%.20g%+.20g%+.20g",(double) geometry.width,(double)
 926       geometry.height,(double) geometry.x,(double) geometry.y);
 927   crop_image=CropImage(deskew_image,&geometry,exception);
 928   deskew_image=DestroyImage(deskew_image);
 929   return(crop_image);
 930 }
 931 \f
 932 /*
 933 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 934 %                                                                             %
 935 %                                                                             %
 936 %                                                                             %
 937 %   I n t e g r a l R o t a t e I m a g e                                     %
 938 %                                                                             %
 939 %                                                                             %
 940 %                                                                             %
 941 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 942 %
 943 %  IntegralRotateImage() rotates the image an integral of 90 degrees.  It
 944 %  allocates the memory necessary for the new Image structure and returns a
 945 %  pointer to the rotated image.
 946 %
 947 %  The format of the IntegralRotateImage method is:
 948 %
 949 %      Image *IntegralRotateImage(const Image *image,size_t rotations,
 950 %        ExceptionInfo *exception)
 951 %
 952 %  A description of each parameter follows.
 953 %
 954 %    o image: the image.
 955 %
 956 %    o rotations: Specifies the number of 90 degree rotations.
 957 %
 958 */
 959 MagickExport Image *IntegralRotateImage(const Image *image,size_t rotations,
 960   ExceptionInfo *exception)
 961 {
 962 #define RotateImageTag  "Rotate/Image"
 963
 964   CacheView
 965     *image_view,
 966     *rotate_view;
 967
 968   Image
 969     *rotate_image;
 970
 971   MagickBooleanType
 972     status;
 973
 974   MagickOffsetType
 975     progress;
 976
 977   RectangleInfo
 978     page;
 979
 980   ssize_t
 981     y;
 982
 983   /*
 984     Initialize rotated image attributes.
 985   */
 986   assert(image != (Image *) NULL);
 987   page=image->page;
 988   rotations%=4;
 989   if (rotations == 0)
 990     return(CloneImage(image,0,0,MagickTrue,exception));
 991   if ((rotations == 1) || (rotations == 3))
 992     rotate_image=CloneImage(image,image->rows,image->columns,MagickTrue,
 993       exception);
 994   else
 995     rotate_image=CloneImage(image,image->columns,image->rows,MagickTrue,
 996       exception);
 997   if (rotate_image == (Image *) NULL)
 998     return((Image *) NULL);
 999   /*
1000     Integral rotate the image.
1001   */
1002   status=MagickTrue;
1003   progress=0;
1004   image_view=AcquireVirtualCacheView(image,exception);
1005   rotate_view=AcquireAuthenticCacheView(rotate_image,exception);
1006   switch (rotations)
1007   {
1008     case 0:
1009     {
1010       /*
1011         Rotate 0 degrees.
1012       */
1013       break;
1014     }
1015     case 1:
1016     {
1017       size_t
1018         tile_height,
1019         tile_width;
1020
1021       ssize_t
1022         tile_y;
1023
1024       /*
1025         Rotate 90 degrees.
1026       */
1027       GetPixelCacheTileSize(image,&tile_width,&tile_height);
1028 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1029       #pragma omp parallel for schedule(static,4) shared(progress,status) \
1030         dynamic_number_threads(image,image->columns,image->rows,1)
1031 #endif
1032       for (tile_y=0; tile_y < (ssize_t) image->rows; tile_y+=(ssize_t) tile_height)
1033       {
1034         register ssize_t
1035           tile_x;
1036
1037         if (status == MagickFalse)
1038           continue;
1039         tile_x=0;
1040         for ( ; tile_x < (ssize_t) image->columns; tile_x+=(ssize_t) tile_width)
1041         {
1042           MagickBooleanType
1043             sync;
1044
1045           register const Quantum
1046             *restrict p;
1047
1048           register Quantum
1049             *restrict q;
1050
1051           register ssize_t
1052             y;
1053
1054           size_t
1055             height,
1056             width;
1057
1058           width=tile_width;
1059           if ((tile_x+(ssize_t) tile_width) > (ssize_t) image->columns)
1060             width=(size_t) (tile_width-(tile_x+tile_width-image->columns));
1061           height=tile_height;
1062           if ((tile_y+(ssize_t) tile_height) > (ssize_t) image->rows)
1063             height=(size_t) (tile_height-(tile_y+tile_height-image->rows));
1064           p=GetCacheViewVirtualPixels(image_view,tile_x,tile_y,width,height,
1065             exception);
1066           if (p == (const Quantum *) NULL)
1067             {
1068               status=MagickFalse;
1069               break;
1070             }
1071           for (y=0; y < (ssize_t) width; y++)
1072           {
1073             register const Quantum
1074               *restrict tile_pixels;
1075
1076             register ssize_t
1077               x;
1078
1079             if (status == MagickFalse)
1080               continue;
1081             q=QueueCacheViewAuthenticPixels(rotate_view,(ssize_t)
1082               (rotate_image->columns-(tile_y+height)),y+tile_x,height,1,
1083               exception);
1084             if (q == (Quantum *) NULL)
1085               {
1086                 status=MagickFalse;
1087                 continue;
1088               }
1089             tile_pixels=p+((height-1)*width+y)*GetPixelChannels(image);
1090             for (x=0; x < (ssize_t) height; x++)
1091             {
1092               register ssize_t
1093                 i;
1094
1095               if (GetPixelMask(image,tile_pixels) != 0)
1096                 {
1097                   tile_pixels-=width*GetPixelChannels(image);
1098                   q+=GetPixelChannels(rotate_image);
1099                   continue;
1100                 }
1101               for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
1102               {
1103                 PixelChannel
1104                   channel;
1105
1106                 PixelTrait
1107                   rotate_traits,
1108                   traits;
1109
1110                 channel=GetPixelChannelChannel(image,i);
1111                 traits=GetPixelChannelTraits(image,channel);
1112                 rotate_traits=GetPixelChannelTraits(rotate_image,channel);
1113                 if ((traits == UndefinedPixelTrait) ||
1114                     (rotate_traits == UndefinedPixelTrait))
1115                   continue;
1116                 SetPixelChannel(rotate_image,channel,tile_pixels[i],q);
1117               }
1118               tile_pixels-=width*GetPixelChannels(image);
1119               q+=GetPixelChannels(rotate_image);
1120             }
1121             sync=SyncCacheViewAuthenticPixels(rotate_view,exception);
1122             if (sync == MagickFalse)
1123               status=MagickFalse;
1124           }
1125         }
1126         if (image->progress_monitor != (MagickProgressMonitor) NULL)
1127           {
1128             MagickBooleanType
1129               proceed;
1130
1131 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1132             #pragma omp critical (MagickCore_IntegralRotateImage)
1133 #endif
1134             proceed=SetImageProgress(image,RotateImageTag,progress+=tile_height,
1135               image->rows);
1136             if (proceed == MagickFalse)
1137               status=MagickFalse;
1138           }
1139       }
1140       (void) SetImageProgress(image,RotateImageTag,(MagickOffsetType)
1141         image->rows-1,image->rows);
1142       Swap(page.width,page.height);
1143       Swap(page.x,page.y);
1144       if (page.width != 0)
1145         page.x=(ssize_t) (page.width-rotate_image->columns-page.x);
1146       break;
1147     }
1148     case 2:
1149     {
1150       /*
1151         Rotate 180 degrees.
1152       */
1153 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1154       #pragma omp parallel for schedule(static) shared(progress,status) \
1155         dynamic_number_threads(image,image->columns,image->rows,1)
1156 #endif
1157       for (y=0; y < (ssize_t) image->rows; y++)
1158       {
1159         MagickBooleanType
1160           sync;
1161
1162         register const Quantum
1163           *restrict p;
1164
1165         register Quantum
1166           *restrict q;
1167
1168         register ssize_t
1169           x;
1170
1171         if (status == MagickFalse)
1172           continue;
1173         p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
1174         q=QueueCacheViewAuthenticPixels(rotate_view,0,(ssize_t) (image->rows-y-
1175           1),image->columns,1,exception);
1176         if ((p == (const Quantum *) NULL) || (q == (Quantum *) NULL))
1177           {
1178             status=MagickFalse;
1179             continue;
1180           }
1181         q+=GetPixelChannels(rotate_image)*image->columns;
1182         for (x=0; x < (ssize_t) image->columns; x++)
1183         {
1184           register ssize_t
1185             i;
1186
1187           q-=GetPixelChannels(rotate_image);
1188           if (GetPixelMask(image,p) != 0)
1189             {
1190               p+=GetPixelChannels(image);
1191               continue;
1192             }
1193           for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
1194           {
1195             PixelChannel
1196               channel;
1197
1198             PixelTrait
1199               rotate_traits,
1200               traits;
1201
1202             channel=GetPixelChannelChannel(image,i);
1203             traits=GetPixelChannelTraits(image,channel);
1204             rotate_traits=GetPixelChannelTraits(rotate_image,channel);
1205             if ((traits == UndefinedPixelTrait) ||
1206                 (rotate_traits == UndefinedPixelTrait))
1207               continue;
1208             SetPixelChannel(rotate_image,channel,p[i],q);
1209           }
1210           p+=GetPixelChannels(image);
1211         }
1212         sync=SyncCacheViewAuthenticPixels(rotate_view,exception);
1213         if (sync == MagickFalse)
1214           status=MagickFalse;
1215         if (image->progress_monitor != (MagickProgressMonitor) NULL)
1216           {
1217             MagickBooleanType
1218               proceed;
1219
1220 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1221             #pragma omp critical (MagickCore_IntegralRotateImage)
1222 #endif
1223             proceed=SetImageProgress(image,RotateImageTag,progress++,
1224               image->rows);
1225             if (proceed == MagickFalse)
1226               status=MagickFalse;
1227           }
1228       }
1229       (void) SetImageProgress(image,RotateImageTag,(MagickOffsetType)
1230         image->rows-1,image->rows);
1231       Swap(page.width,page.height);
1232       Swap(page.x,page.y);
1233       if (page.width != 0)
1234         page.x=(ssize_t) (page.width-rotate_image->columns-page.x);
1235       break;
1236     }
1237     case 3:
1238     {
1239       size_t
1240         tile_height,
1241         tile_width;
1242
1243       ssize_t
1244         tile_y;
1245
1246       /*
1247         Rotate 270 degrees.
1248       */
1249       GetPixelCacheTileSize(image,&tile_width,&tile_height);
1250 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1251       #pragma omp parallel for schedule(static,4) shared(progress,status) \
1252         dynamic_number_threads(image,image->columns,image->rows,1)
1253 #endif
1254       for (tile_y=0; tile_y < (ssize_t) image->rows; tile_y+=(ssize_t) tile_height)
1255       {
1256         register ssize_t
1257           tile_x;
1258
1259         if (status == MagickFalse)
1260           continue;
1261         tile_x=0;
1262         for ( ; tile_x < (ssize_t) image->columns; tile_x+=(ssize_t) tile_width)
1263         {
1264           MagickBooleanType
1265             sync;
1266
1267           register const Quantum
1268             *restrict p;
1269
1270           register Quantum
1271             *restrict q;
1272
1273           register ssize_t
1274             y;
1275
1276           size_t
1277             height,
1278             width;
1279
1280           width=tile_width;
1281           if ((tile_x+(ssize_t) tile_width) > (ssize_t) image->columns)
1282             width=(size_t) (tile_width-(tile_x+tile_width-image->columns));
1283           height=tile_height;
1284           if ((tile_y+(ssize_t) tile_height) > (ssize_t) image->rows)
1285             height=(size_t) (tile_height-(tile_y+tile_height-image->rows));
1286           p=GetCacheViewVirtualPixels(image_view,tile_x,tile_y,width,height,
1287             exception);
1288           if (p == (const Quantum *) NULL)
1289             {
1290               status=MagickFalse;
1291               break;
1292             }
1293           for (y=0; y < (ssize_t) width; y++)
1294           {
1295             register const Quantum
1296               *restrict tile_pixels;
1297
1298             register ssize_t
1299               x;
1300
1301             if (status == MagickFalse)
1302               continue;
1303             q=QueueCacheViewAuthenticPixels(rotate_view,tile_y,(ssize_t) (y+
1304               rotate_image->rows-(tile_x+width)),height,1,exception);
1305             if (q == (Quantum *) NULL)
1306               {
1307                 status=MagickFalse;
1308                 continue;
1309               }
1310             tile_pixels=p+((width-1)-y)*GetPixelChannels(image);
1311             for (x=0; x < (ssize_t) height; x++)
1312             {
1313               register ssize_t
1314                 i;
1315
1316               if (GetPixelMask(image,tile_pixels) != 0)
1317                 {
1318                   tile_pixels+=width*GetPixelChannels(image);
1319                   q+=GetPixelChannels(rotate_image);
1320                   continue;
1321                 }
1322               for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
1323               {
1324                 PixelChannel
1325                   channel;
1326
1327                 PixelTrait
1328                   rotate_traits,
1329                   traits;
1330
1331                 channel=GetPixelChannelChannel(image,i);
1332                 traits=GetPixelChannelTraits(image,channel);
1333                 rotate_traits=GetPixelChannelTraits(rotate_image,channel);
1334                 if ((traits == UndefinedPixelTrait) ||
1335                     (rotate_traits == UndefinedPixelTrait))
1336                   continue;
1337                 SetPixelChannel(rotate_image,channel,tile_pixels[i],q);
1338               }
1339               tile_pixels+=width*GetPixelChannels(image);
1340               q+=GetPixelChannels(rotate_image);
1341             }
1342             sync=SyncCacheViewAuthenticPixels(rotate_view,exception);
1343             if (sync == MagickFalse)
1344               status=MagickFalse;
1345           }
1346         }
1347         if (image->progress_monitor != (MagickProgressMonitor) NULL)
1348           {
1349             MagickBooleanType
1350               proceed;
1351
1352 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1353             #pragma omp critical (MagickCore_IntegralRotateImage)
1354 #endif
1355             proceed=SetImageProgress(image,RotateImageTag,progress+=tile_height,
1356               image->rows);
1357             if (proceed == MagickFalse)
1358               status=MagickFalse;
1359           }
1360       }
1361       (void) SetImageProgress(image,RotateImageTag,(MagickOffsetType)
1362         image->rows-1,image->rows);
1363       Swap(page.width,page.height);
1364       Swap(page.x,page.y);
1365       if (page.width != 0)
1366         page.x=(ssize_t) (page.width-rotate_image->columns-page.x);
1367       break;
1368     }
1369   }
1370   rotate_view=DestroyCacheView(rotate_view);
1371   image_view=DestroyCacheView(image_view);
1372   rotate_image->type=image->type;
1373   rotate_image->page=page;
1374   if (status == MagickFalse)
1375     rotate_image=DestroyImage(rotate_image);
1376   return(rotate_image);
1377 }
1378 \f
1379 /*
1380 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1381 %                                                                             %
1382 %                                                                             %
1383 %                                                                             %
1384 +   X S h e a r I m a g e                                                     %
1385 %                                                                             %
1386 %                                                                             %
1387 %                                                                             %
1388 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1389 %
1390 %  XShearImage() shears the image in the X direction with a shear angle of
1391 %  'degrees'.  Positive angles shear counter-clockwise (right-hand rule), and
1392 %  negative angles shear clockwise.  Angles are measured relative to a vertical
1393 %  Y-axis.  X shears will widen an image creating 'empty' triangles on the left
1394 %  and right sides of the source image.
1395 %
1396 %  The format of the XShearImage method is:
1397 %
1398 %      MagickBooleanType XShearImage(Image *image,const double degrees,
1399 %        const size_t width,const size_t height,
1400 %        const ssize_t x_offset,const ssize_t y_offset,ExceptionInfo *exception)
1401 %
1402 %  A description of each parameter follows.
1403 %
1404 %    o image: the image.
1405 %
1406 %    o degrees: A double representing the shearing angle along the X
1407 %      axis.
1408 %
1409 %    o width, height, x_offset, y_offset: Defines a region of the image
1410 %      to shear.
1411 %
1412 %    o exception: return any errors or warnings in this structure.
1413 %
1414 */
1415 static MagickBooleanType XShearImage(Image *image,const double degrees,
1416   const size_t width,const size_t height,const ssize_t x_offset,
1417   const ssize_t y_offset,ExceptionInfo *exception)
1418 {
1419 #define XShearImageTag  "XShear/Image"
1420
1421   typedef enum
1422   {
1423     LEFT,
1424     RIGHT
1425   } ShearDirection;
1426
1427   CacheView
1428     *image_view;
1429
1430   MagickBooleanType
1431     status;
1432
1433   MagickOffsetType
1434     progress;
1435
1436   PixelInfo
1437     background;
1438
1439   ssize_t
1440     y;
1441
1442   /*
1443     X shear image.
1444   */
1445   assert(image != (Image *) NULL);
1446   assert(image->signature == MagickSignature);
1447   if (image->debug != MagickFalse)
1448     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1449   status=MagickTrue;
1450   background=image->background_color;
1451   progress=0;
1452   image_view=AcquireAuthenticCacheView(image,exception);
1453 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1454   #pragma omp parallel for schedule(static,4) shared(progress,status) \
1455     dynamic_number_threads(image,width,height,1)
1456 #endif
1457   for (y=0; y < (ssize_t) height; y++)
1458   {
1459     PixelInfo
1460       pixel,
1461       source,
1462       destination;
1463
1464     double
1465       area,
1466       displacement;
1467
1468     register Quantum
1469       *restrict p,
1470       *restrict q;
1471
1472     register ssize_t
1473       i;
1474
1475     ShearDirection
1476       direction;
1477
1478     ssize_t
1479       step;
1480
1481     if (status == MagickFalse)
1482       continue;
1483     p=GetCacheViewAuthenticPixels(image_view,0,y_offset+y,image->columns,1,
1484       exception);
1485     if (p == (Quantum *) NULL)
1486       {
1487         status=MagickFalse;
1488         continue;
1489       }
1490     p+=x_offset*GetPixelChannels(image);
1491     displacement=degrees*(double) (y-height/2.0);
1492     if (displacement == 0.0)
1493       continue;
1494     if (displacement > 0.0)
1495       direction=RIGHT;
1496     else
1497       {
1498         displacement*=(-1.0);
1499         direction=LEFT;
1500       }
1501     step=(ssize_t) floor((double) displacement);
1502     area=(double) (displacement-step);
1503     step++;
1504     pixel=background;
1505     GetPixelInfo(image,&source);
1506     GetPixelInfo(image,&destination);
1507     switch (direction)
1508     {
1509       case LEFT:
1510       {
1511         /*
1512           Transfer pixels left-to-right.
1513         */
1514         if (step > x_offset)
1515           break;
1516         q=p-step*GetPixelChannels(image);
1517         for (i=0; i < (ssize_t) width; i++)
1518         {
1519           if ((x_offset+i) < step)
1520             {
1521               p+=GetPixelChannels(image);
1522               GetPixelInfoPixel(image,p,&pixel);
1523               q+=GetPixelChannels(image);
1524               continue;
1525             }
1526           GetPixelInfoPixel(image,p,&source);
1527           CompositePixelInfoAreaBlend(&pixel,(double) pixel.alpha,
1528             &source,(double) GetPixelAlpha(image,p),area,&destination);
1529           SetPixelInfoPixel(image,&destination,q);
1530           GetPixelInfoPixel(image,p,&pixel);
1531           p+=GetPixelChannels(image);
1532           q+=GetPixelChannels(image);
1533         }
1534         CompositePixelInfoAreaBlend(&pixel,(double) pixel.alpha,
1535           &background,(double) background.alpha,area,&destination);
1536         SetPixelInfoPixel(image,&destination,q);
1537         q+=GetPixelChannels(image);
1538         for (i=0; i < (step-1); i++)
1539         {
1540           SetPixelInfoPixel(image,&background,q);
1541           q+=GetPixelChannels(image);
1542         }
1543         break;
1544       }
1545       case RIGHT:
1546       {
1547         /*
1548           Transfer pixels right-to-left.
1549         */
1550         p+=width*GetPixelChannels(image);
1551         q=p+step*GetPixelChannels(image);
1552         for (i=0; i < (ssize_t) width; i++)
1553         {
1554           p-=GetPixelChannels(image);
1555           q-=GetPixelChannels(image);
1556           if ((size_t) (x_offset+width+step-i) >= image->columns)
1557             continue;
1558           GetPixelInfoPixel(image,p,&source);
1559           CompositePixelInfoAreaBlend(&pixel,(double) pixel.alpha,
1560             &source,(double) GetPixelAlpha(image,p),area,&destination);
1561           SetPixelInfoPixel(image,&destination,q);
1562           GetPixelInfoPixel(image,p,&pixel);
1563         }
1564         CompositePixelInfoAreaBlend(&pixel,(double) pixel.alpha,
1565           &background,(double) background.alpha,area,&destination);
1566         q-=GetPixelChannels(image);
1567         SetPixelInfoPixel(image,&destination,q);
1568         for (i=0; i < (step-1); i++)
1569         {
1570           q-=GetPixelChannels(image);
1571           SetPixelInfoPixel(image,&background,q);
1572         }
1573         break;
1574       }
1575     }
1576     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1577       status=MagickFalse;
1578     if (image->progress_monitor != (MagickProgressMonitor) NULL)
1579       {
1580         MagickBooleanType
1581           proceed;
1582
1583 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1584         #pragma omp critical (MagickCore_XShearImage)
1585 #endif
1586         proceed=SetImageProgress(image,XShearImageTag,progress++,height);
1587         if (proceed == MagickFalse)
1588           status=MagickFalse;
1589       }
1590   }
1591   image_view=DestroyCacheView(image_view);
1592   return(status);
1593 }
1594 \f
1595 /*
1596 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1597 %                                                                             %
1598 %                                                                             %
1599 %                                                                             %
1600 +   Y S h e a r I m a g e                                                     %
1601 %                                                                             %
1602 %                                                                             %
1603 %                                                                             %
1604 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1605 %
1606 %  YShearImage shears the image in the Y direction with a shear angle of
1607 %  'degrees'.  Positive angles shear counter-clockwise (right-hand rule), and
1608 %  negative angles shear clockwise.  Angles are measured relative to a
1609 %  horizontal X-axis.  Y shears will increase the height of an image creating
1610 %  'empty' triangles on the top and bottom of the source image.
1611 %
1612 %  The format of the YShearImage method is:
1613 %
1614 %      MagickBooleanType YShearImage(Image *image,const double degrees,
1615 %        const size_t width,const size_t height,
1616 %        const ssize_t x_offset,const ssize_t y_offset,ExceptionInfo *exception)
1617 %
1618 %  A description of each parameter follows.
1619 %
1620 %    o image: the image.
1621 %
1622 %    o degrees: A double representing the shearing angle along the Y
1623 %      axis.
1624 %
1625 %    o width, height, x_offset, y_offset: Defines a region of the image
1626 %      to shear.
1627 %
1628 %    o exception: return any errors or warnings in this structure.
1629 %
1630 */
1631 static MagickBooleanType YShearImage(Image *image,const double degrees,
1632   const size_t width,const size_t height,const ssize_t x_offset,
1633   const ssize_t y_offset,ExceptionInfo *exception)
1634 {
1635 #define YShearImageTag  "YShear/Image"
1636
1637   typedef enum
1638   {
1639     UP,
1640     DOWN
1641   } ShearDirection;
1642
1643   CacheView
1644     *image_view;
1645
1646   MagickBooleanType
1647     status;
1648
1649   MagickOffsetType
1650     progress;
1651
1652   PixelInfo
1653     background;
1654
1655   ssize_t
1656     x;
1657
1658   /*
1659     Y Shear image.
1660   */
1661   assert(image != (Image *) NULL);
1662   assert(image->signature == MagickSignature);
1663   if (image->debug != MagickFalse)
1664     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1665   status=MagickTrue;
1666   progress=0;
1667   background=image->background_color;
1668   image_view=AcquireAuthenticCacheView(image,exception);
1669 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1670   #pragma omp parallel for schedule(static,4) shared(progress,status) \
1671     dynamic_number_threads(image,width,height,1)
1672 #endif
1673   for (x=0; x < (ssize_t) width; x++)
1674   {
1675     ssize_t
1676       step;
1677
1678     double
1679       area,
1680       displacement;
1681
1682     PixelInfo
1683       pixel,
1684       source,
1685       destination;
1686
1687     register Quantum
1688       *restrict p,
1689       *restrict q;
1690
1691     register ssize_t
1692       i;
1693
1694     ShearDirection
1695       direction;
1696
1697     if (status == MagickFalse)
1698       continue;
1699     p=GetCacheViewAuthenticPixels(image_view,x_offset+x,0,1,image->rows,
1700       exception);
1701     if (p == (Quantum *) NULL)
1702       {
1703         status=MagickFalse;
1704         continue;
1705       }
1706     p+=y_offset*GetPixelChannels(image);
1707     displacement=degrees*(double) (x-width/2.0);
1708     if (displacement == 0.0)
1709       continue;
1710     if (displacement > 0.0)
1711       direction=DOWN;
1712     else
1713       {
1714         displacement*=(-1.0);
1715         direction=UP;
1716       }
1717     step=(ssize_t) floor((double) displacement);
1718     area=(double) (displacement-step);
1719     step++;
1720     pixel=background;
1721     GetPixelInfo(image,&source);
1722     GetPixelInfo(image,&destination);
1723     switch (direction)
1724     {
1725       case UP:
1726       {
1727         /*
1728           Transfer pixels top-to-bottom.
1729         */
1730         if (step > y_offset)
1731           break;
1732         q=p-step*GetPixelChannels(image);
1733         for (i=0; i < (ssize_t) height; i++)
1734         {
1735           if ((y_offset+i) < step)
1736             {
1737               p+=GetPixelChannels(image);
1738               GetPixelInfoPixel(image,p,&pixel);
1739               q+=GetPixelChannels(image);
1740               continue;
1741             }
1742           GetPixelInfoPixel(image,p,&source);
1743           CompositePixelInfoAreaBlend(&pixel,(double) pixel.alpha,
1744             &source,(double) GetPixelAlpha(image,p),area,
1745             &destination);
1746           SetPixelInfoPixel(image,&destination,q);
1747           GetPixelInfoPixel(image,p,&pixel);
1748           p+=GetPixelChannels(image);
1749           q+=GetPixelChannels(image);
1750         }
1751         CompositePixelInfoAreaBlend(&pixel,(double) pixel.alpha,
1752           &background,(double) background.alpha,area,&destination);
1753         SetPixelInfoPixel(image,&destination,q);
1754         q+=GetPixelChannels(image);
1755         for (i=0; i < (step-1); i++)
1756         {
1757           SetPixelInfoPixel(image,&background,q);
1758           q+=GetPixelChannels(image);
1759         }
1760         break;
1761       }
1762       case DOWN:
1763       {
1764         /*
1765           Transfer pixels bottom-to-top.
1766         */
1767         p+=height*GetPixelChannels(image);
1768         q=p+step*GetPixelChannels(image);
1769         for (i=0; i < (ssize_t) height; i++)
1770         {
1771           p-=GetPixelChannels(image);
1772           q-=GetPixelChannels(image);
1773           if ((size_t) (y_offset+height+step-i) >= image->rows)
1774             continue;
1775           GetPixelInfoPixel(image,p,&source);
1776           CompositePixelInfoAreaBlend(&pixel,(double) pixel.alpha,
1777             &source,(double) GetPixelAlpha(image,p),area,
1778             &destination);
1779           SetPixelInfoPixel(image,&destination,q);
1780           GetPixelInfoPixel(image,p,&pixel);
1781         }
1782         CompositePixelInfoAreaBlend(&pixel,(double) pixel.alpha,
1783           &background,(double) background.alpha,area,&destination);
1784         q-=GetPixelChannels(image);
1785         SetPixelInfoPixel(image,&destination,q);
1786         for (i=0; i < (step-1); i++)
1787         {
1788           q-=GetPixelChannels(image);
1789           SetPixelInfoPixel(image,&background,q);
1790         }
1791         break;
1792       }
1793     }
1794     if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1795       status=MagickFalse;
1796     if (image->progress_monitor != (MagickProgressMonitor) NULL)
1797       {
1798         MagickBooleanType
1799           proceed;
1800
1801 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1802         #pragma omp critical (MagickCore_YShearImage)
1803 #endif
1804         proceed=SetImageProgress(image,YShearImageTag,progress++,image->rows);
1805         if (proceed == MagickFalse)
1806           status=MagickFalse;
1807       }
1808   }
1809   image_view=DestroyCacheView(image_view);
1810   return(status);
1811 }
1812 \f
1813 /*
1814 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1815 %                                                                             %
1816 %                                                                             %
1817 %                                                                             %
1818 %   S h e a r I m a g e                                                       %
1819 %                                                                             %
1820 %                                                                             %
1821 %                                                                             %
1822 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1823 %
1824 %  ShearImage() creates a new image that is a shear_image copy of an existing
1825 %  one.  Shearing slides one edge of an image along the X or Y axis, creating
1826 %  a parallelogram.  An X direction shear slides an edge along the X axis,
1827 %  while a Y direction shear slides an edge along the Y axis.  The amount of
1828 %  the shear is controlled by a shear angle.  For X direction shears, x_shear
1829 %  is measured relative to the Y axis, and similarly, for Y direction shears
1830 %  y_shear is measured relative to the X axis.  Empty triangles left over from
1831 %  shearing the image are filled with the background color defined by member
1832 %  'background_color' of the image..  ShearImage() allocates the memory
1833 %  necessary for the new Image structure and returns a pointer to the new image.
1834 %
1835 %  ShearImage() is based on the paper "A Fast Algorithm for General Raster
1836 %  Rotatation" by Alan W. Paeth.
1837 %
1838 %  The format of the ShearImage method is:
1839 %
1840 %      Image *ShearImage(const Image *image,const double x_shear,
1841 %        const double y_shear,ExceptionInfo *exception)
1842 %
1843 %  A description of each parameter follows.
1844 %
1845 %    o image: the image.
1846 %
1847 %    o x_shear, y_shear: Specifies the number of degrees to shear the image.
1848 %
1849 %    o exception: return any errors or warnings in this structure.
1850 %
1851 */
1852 MagickExport Image *ShearImage(const Image *image,const double x_shear,
1853   const double y_shear,ExceptionInfo *exception)
1854 {
1855   Image
1856     *integral_image,
1857     *shear_image;
1858
1859   ssize_t
1860     x_offset,
1861     y_offset;
1862
1863   MagickBooleanType
1864     status;
1865
1866   PointInfo
1867     shear;
1868
1869   RectangleInfo
1870     border_info;
1871
1872   size_t
1873     y_width;
1874
1875   assert(image != (Image *) NULL);
1876   assert(image->signature == MagickSignature);
1877   if (image->debug != MagickFalse)
1878     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1879   assert(exception != (ExceptionInfo *) NULL);
1880   assert(exception->signature == MagickSignature);
1881   if ((x_shear != 0.0) && (fmod(x_shear,90.0) == 0.0))
1882     ThrowImageException(ImageError,"AngleIsDiscontinuous");
1883   if ((y_shear != 0.0) && (fmod(y_shear,90.0) == 0.0))
1884     ThrowImageException(ImageError,"AngleIsDiscontinuous");
1885   /*
1886     Initialize shear angle.
1887   */
1888   integral_image=CloneImage(image,0,0,MagickTrue,exception);
1889   if (integral_image == (Image *) NULL)
1890     ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
1891   shear.x=(-tan(DegreesToRadians(fmod(x_shear,360.0))));
1892   shear.y=tan(DegreesToRadians(fmod(y_shear,360.0)));
1893   if ((shear.x == 0.0) && (shear.y == 0.0))
1894     return(integral_image);
1895   if (SetImageStorageClass(integral_image,DirectClass,exception) == MagickFalse)
1896     {
1897       integral_image=DestroyImage(integral_image);
1898       return(integral_image);
1899     }
1900   if (integral_image->alpha_trait != BlendPixelTrait)
1901     (void) SetImageAlphaChannel(integral_image,OpaqueAlphaChannel,exception);
1902   /*
1903     Compute image size.
1904   */
1905   y_width=image->columns+(ssize_t) floor(fabs(shear.x)*image->rows+0.5);
1906   x_offset=(ssize_t) ceil((double) image->columns+((fabs(shear.x)*image->rows)-
1907     image->columns)/2.0-0.5);
1908   y_offset=(ssize_t) ceil((double) image->rows+((fabs(shear.y)*y_width)-
1909     image->rows)/2.0-0.5);
1910   /*
1911     Surround image with border.
1912   */
1913   integral_image->border_color=integral_image->background_color;
1914   integral_image->compose=CopyCompositeOp;
1915   border_info.width=(size_t) x_offset;
1916   border_info.height=(size_t) y_offset;
1917   shear_image=BorderImage(integral_image,&border_info,image->compose,exception);
1918   integral_image=DestroyImage(integral_image);
1919   if (shear_image == (Image *) NULL)
1920     ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
1921   /*
1922     Shear the image.
1923   */
1924   if (shear_image->alpha_trait != BlendPixelTrait)
1925     (void) SetImageAlphaChannel(shear_image,OpaqueAlphaChannel,exception);
1926   status=XShearImage(shear_image,shear.x,image->columns,image->rows,x_offset,
1927     (ssize_t) (shear_image->rows-image->rows)/2,exception);
1928   if (status == MagickFalse)
1929     {
1930       shear_image=DestroyImage(shear_image);
1931       return((Image *) NULL);
1932     }
1933   status=YShearImage(shear_image,shear.y,y_width,image->rows,(ssize_t)
1934     (shear_image->columns-y_width)/2,y_offset,exception);
1935   if (status == MagickFalse)
1936     {
1937       shear_image=DestroyImage(shear_image);
1938       return((Image *) NULL);
1939     }
1940   status=CropToFitImage(&shear_image,shear.x,shear.y,(double)
1941     image->columns,(double) image->rows,MagickFalse,exception);
1942   if (status == MagickFalse)
1943     {
1944       shear_image=DestroyImage(shear_image);
1945       return((Image *) NULL);
1946     }
1947   shear_image->compose=image->compose;
1948   shear_image->page.width=0;
1949   shear_image->page.height=0;
1950   return(shear_image);
1951 }
1952 \f
1953 /*
1954 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1955 %                                                                             %
1956 %                                                                             %
1957 %                                                                             %
1958 %   S h e a r R o t a t e I m a g e                                           %
1959 %                                                                             %
1960 %                                                                             %
1961 %                                                                             %
1962 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1963 %
1964 %  ShearRotateImage() creates a new image that is a rotated copy of an existing
1965 %  one.  Positive angles rotate counter-clockwise (right-hand rule), while
1966 %  negative angles rotate clockwise.  Rotated images are usually larger than
1967 %  the originals and have 'empty' triangular corners.  X axis.  Empty
1968 %  triangles left over from shearing the image are filled with the background
1969 %  color defined by member 'background_color' of the image.  ShearRotateImage
1970 %  allocates the memory necessary for the new Image structure and returns a
1971 %  pointer to the new image.
1972 %
1973 %  ShearRotateImage() is based on the paper "A Fast Algorithm for General
1974 %  Raster Rotatation" by Alan W. Paeth.  ShearRotateImage is adapted from a
1975 %  similar method based on the Paeth paper written by Michael Halle of the
1976 %  Spatial Imaging Group, MIT Media Lab.
1977 %
1978 %  The format of the ShearRotateImage method is:
1979 %
1980 %      Image *ShearRotateImage(const Image *image,const double degrees,
1981 %        ExceptionInfo *exception)
1982 %
1983 %  A description of each parameter follows.
1984 %
1985 %    o image: the image.
1986 %
1987 %    o degrees: Specifies the number of degrees to rotate the image.
1988 %
1989 %    o exception: return any errors or warnings in this structure.
1990 %
1991 */
1992 MagickExport Image *ShearRotateImage(const Image *image,const double degrees,
1993   ExceptionInfo *exception)
1994 {
1995   Image
1996     *integral_image,
1997     *rotate_image;
1998
1999   MagickBooleanType
2000     status;
2001
2002   double
2003     angle;
2004
2005   PointInfo
2006     shear;
2007
2008   RectangleInfo
2009     border_info;
2010
2011   size_t
2012     height,
2013     rotations,
2014     width,
2015     y_width;
2016
2017   ssize_t
2018     x_offset,
2019     y_offset;
2020
2021   /*
2022     Adjust rotation angle.
2023   */
2024   assert(image != (Image *) NULL);
2025   assert(image->signature == MagickSignature);
2026   if (image->debug != MagickFalse)
2027     (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2028   assert(exception != (ExceptionInfo *) NULL);
2029   assert(exception->signature == MagickSignature);
2030   angle=degrees;
2031   while (angle < -45.0)
2032     angle+=360.0;
2033   for (rotations=0; angle > 45.0; rotations++)
2034     angle-=90.0;
2035   rotations%=4;
2036   /*
2037     Calculate shear equations.
2038   */
2039   integral_image=IntegralRotateImage(image,rotations,exception);
2040   if (integral_image == (Image *) NULL)
2041     ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
2042   shear.x=(-tan((double) DegreesToRadians(angle)/2.0));
2043   shear.y=sin((double) DegreesToRadians(angle));
2044   if ((shear.x == 0.0) && (shear.y == 0.0))
2045     return(integral_image);
2046   if (SetImageStorageClass(integral_image,DirectClass,exception) == MagickFalse)
2047     {
2048       integral_image=DestroyImage(integral_image);
2049       return(integral_image);
2050     }
2051   if (integral_image->alpha_trait != BlendPixelTrait)
2052     (void) SetImageAlphaChannel(integral_image,OpaqueAlphaChannel,exception);
2053   /*
2054     Compute image size.
2055   */
2056   width=image->columns;
2057   height=image->rows;
2058   if ((rotations == 1) || (rotations == 3))
2059     {
2060       width=image->rows;
2061       height=image->columns;
2062     }
2063   y_width=width+(ssize_t) floor(fabs(shear.x)*height+0.5);
2064   x_offset=(ssize_t) ceil((double) width+((fabs(shear.y)*height)-width)/2.0-
2065     0.5);
2066   y_offset=(ssize_t) ceil((double) height+((fabs(shear.y)*y_width)-height)/2.0-
2067     0.5);
2068   /*
2069     Surround image with a border.
2070   */
2071   integral_image->border_color=integral_image->background_color;
2072   integral_image->compose=CopyCompositeOp;
2073   border_info.width=(size_t) x_offset;
2074   border_info.height=(size_t) y_offset;
2075   rotate_image=BorderImage(integral_image,&border_info,image->compose,
2076     exception);
2077   integral_image=DestroyImage(integral_image);
2078   if (rotate_image == (Image *) NULL)
2079     ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
2080   /*
2081     Rotate the image.
2082   */
2083   status=XShearImage(rotate_image,shear.x,width,height,x_offset,(ssize_t)
2084     (rotate_image->rows-height)/2,exception);
2085   if (status == MagickFalse)
2086     {
2087       rotate_image=DestroyImage(rotate_image);
2088       return((Image *) NULL);
2089     }
2090   status=YShearImage(rotate_image,shear.y,y_width,height,(ssize_t)
2091     (rotate_image->columns-y_width)/2,y_offset,exception);
2092   if (status == MagickFalse)
2093     {
2094       rotate_image=DestroyImage(rotate_image);
2095       return((Image *) NULL);
2096     }
2097   status=XShearImage(rotate_image,shear.x,y_width,rotate_image->rows,(ssize_t)
2098     (rotate_image->columns-y_width)/2,0,exception);
2099   if (status == MagickFalse)
2100     {
2101       rotate_image=DestroyImage(rotate_image);
2102       return((Image *) NULL);
2103     }
2104   status=CropToFitImage(&rotate_image,shear.x,shear.y,(double) width,
2105     (double) height,MagickTrue,exception);
2106   if (status == MagickFalse)
2107     {
2108       rotate_image=DestroyImage(rotate_image);
2109       return((Image *) NULL);
2110     }
2111   rotate_image->compose=image->compose;
2112   rotate_image->page.width=0;
2113   rotate_image->page.height=0;
2114   return(rotate_image);
2115 }