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