2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
6 % SSSSS H H EEEEE AAA RRRR %
8 % SSS HHHHH EEE AAAAA RRRR %
10 % SSSSS H H EEEEE A A R R %
13 % MagickCore Methods to Shear or Rotate an Image by an Arbitrary Angle %
20 % Copyright 1999-2012 ImageMagick Studio LLC, a non-profit organization %
21 % dedicated to making software imaging solutions freely available. %
23 % You may not use this file except in compliance with the License. You may %
24 % obtain a copy of the License at %
26 % http://www.imagemagick.org/script/license.php %
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. %
34 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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.
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"
82 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
86 + C r o p T o F i t I m a g e %
90 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
92 % CropToFitImage() crops the sheared image as determined by the bounding box
93 % as defined by width and height and shearing angles.
95 % The format of the CropToFitImage method is:
97 % MagickBooleanType CropToFitImage(Image **image,
98 % const MagickRealType x_shear,const MagickRealType x_shear,
99 % const MagickRealType width,const MagickRealType height,
100 % const MagickBooleanType rotate,ExceptionInfo *exception)
102 % A description of each parameter follows.
104 % o image: the image.
106 % o x_shear, y_shear, width, height: Defines a region of the image to crop.
108 % o exception: return any errors or warnings in this structure.
111 static MagickBooleanType CropToFitImage(Image **image,
112 const MagickRealType x_shear,const MagickRealType y_shear,
113 const MagickRealType width,const MagickRealType height,
114 const MagickBooleanType rotate,ExceptionInfo *exception)
132 Calculate the rotated image size.
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++)
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;
153 for (i=1; i < 4; i++)
155 if (min.x > extent[i].x)
157 if (min.y > extent[i].y)
159 if (max.x < extent[i].x)
161 if (max.y < extent[i].y)
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);
169 (void) ParseAbsoluteGeometry("0x0+0+0",&(*image)->page);
170 crop_image=CropImage(*image,&geometry,exception);
171 if (crop_image == (Image *) NULL)
173 crop_image->page=page;
174 *image=DestroyImage(*image);
180 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
184 % D e s k e w I m a g e %
188 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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.
195 % The format of the DeskewImage method is:
197 % Image *DeskewImage(const Image *image,const double threshold,
198 % ExceptionInfo *exception)
200 % A description of each parameter follows:
202 % o image: the image.
204 % o threshold: separate background from foreground.
206 % o exception: return any errors or warnings in this structure.
210 typedef struct _RadonInfo
235 static RadonInfo *DestroyRadonInfo(RadonInfo *radon_info)
237 assert(radon_info != (RadonInfo *) NULL);
238 switch (radon_info->type)
242 if (radon_info->mapped == MagickFalse)
243 radon_info->cells=(unsigned short *) RelinquishMagickMemory(
246 radon_info->cells=(unsigned short *) UnmapBlob(radon_info->cells,
247 (size_t) radon_info->length);
248 RelinquishMagickResource(MemoryResource,radon_info->length);
253 radon_info->cells=(unsigned short *) UnmapBlob(radon_info->cells,(size_t)
255 RelinquishMagickResource(MapResource,radon_info->length);
259 if (radon_info->file != -1)
260 (void) close(radon_info->file);
261 (void) RelinquishUniqueFileResource(radon_info->path);
262 RelinquishMagickResource(DiskResource,radon_info->length);
268 return((RadonInfo *) RelinquishMagickMemory(radon_info));
271 static MagickBooleanType ResetRadonCells(RadonInfo *radon_info)
283 if (radon_info->type != DiskCache)
285 (void) ResetMagickMemory(radon_info->cells,0,(size_t) radon_info->length);
289 (void) lseek(radon_info->file,0,SEEK_SET);
290 for (y=0; y < (ssize_t) radon_info->height; y++)
292 for (x=0; x < (ssize_t) radon_info->width; x++)
294 count=write(radon_info->file,&value,sizeof(*radon_info->cells));
295 if (count != (ssize_t) sizeof(*radon_info->cells))
298 if (x < (ssize_t) radon_info->width)
301 return(y < (ssize_t) radon_info->height ? MagickFalse : MagickTrue);
304 static RadonInfo *AcquireRadonInfo(const Image *image,const size_t width,
305 const size_t height,ExceptionInfo *exception)
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)))
325 status=AcquireMagickResource(MemoryResource,radon_info->length);
326 if (status != MagickFalse)
328 radon_info->mapped=MagickFalse;
329 radon_info->cells=(unsigned short *) AcquireMagickMemory((size_t)
331 if (radon_info->cells == (unsigned short *) NULL)
333 radon_info->mapped=MagickTrue;
334 radon_info->cells=(unsigned short *) MapBlob(-1,IOMode,0,(size_t)
337 if (radon_info->cells == (unsigned short *) NULL)
338 RelinquishMagickResource(MemoryResource,radon_info->length);
341 radon_info->file=(-1);
342 if (radon_info->cells == (unsigned short *) NULL)
344 status=AcquireMagickResource(DiskResource,radon_info->length);
345 if (status == MagickFalse)
347 (void) ThrowMagickException(exception,GetMagickModule(),CacheError,
348 "CacheResourcesExhausted","`%s'",image->filename);
349 return(DestroyRadonInfo(radon_info));
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)
359 status=ResetRadonCells(radon_info);
360 if (status != MagickFalse)
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;
367 RelinquishMagickResource(MapResource,radon_info->length);
374 static inline size_t MagickMin(const size_t x,const size_t y)
381 static inline ssize_t ReadRadonCell(const RadonInfo *radon_info,
382 const MagickOffsetType offset,const size_t length,unsigned char *buffer)
390 #if !defined(MAGICKCORE_HAVE_PPREAD)
391 #if defined(MAGICKCORE_OPENMP_SUPPORT)
392 #pragma omp critical (MagickCore_ReadRadonCell)
396 if (lseek(radon_info->file,offset,SEEK_SET) >= 0)
400 for (i=0; i < (ssize_t) length; i+=count)
402 #if !defined(MAGICKCORE_HAVE_PPREAD)
403 count=read(radon_info->file,buffer+i,MagickMin(length-i,(size_t)
406 count=pread(radon_info->file,buffer+i,MagickMin(length-i,(size_t)
407 SSIZE_MAX),offset+i);
418 #if !defined(MAGICKCORE_HAVE_PPREAD)
425 static inline ssize_t WriteRadonCell(const RadonInfo *radon_info,
426 const MagickOffsetType offset,const size_t length,const unsigned char *buffer)
434 #if !defined(MAGICKCORE_HAVE_PWRITE)
435 #if defined(MAGICKCORE_OPENMP_SUPPORT)
436 #pragma omp critical (MagickCore_WriteRadonCell)
439 if (lseek(radon_info->file,offset,SEEK_SET) >= 0)
443 for (i=0; i < (ssize_t) length; i+=count)
445 #if !defined(MAGICKCORE_HAVE_PWRITE)
446 count=write(radon_info->file,buffer+i,MagickMin(length-i,(size_t)
449 count=pwrite(radon_info->file,buffer+i,MagickMin(length-i,(size_t)
450 SSIZE_MAX),offset+i);
461 #if !defined(MAGICKCORE_HAVE_PWRITE)
468 static inline unsigned short GetRadonCell(const RadonInfo *radon_info,
469 const ssize_t x,const ssize_t y)
477 i=(MagickOffsetType) radon_info->height*x+y;
479 ((MagickSizeType) (i*sizeof(*radon_info->cells)) >= radon_info->length))
481 if (radon_info->type != DiskCache)
482 return(radon_info->cells[i]);
484 (void) ReadRadonCell(radon_info,i*sizeof(*radon_info->cells),
485 sizeof(*radon_info->cells),(unsigned char *) &value);
489 static inline MagickBooleanType SetRadonCell(const RadonInfo *radon_info,
490 const ssize_t x,const ssize_t y,const unsigned short value)
498 i=(MagickOffsetType) radon_info->height*x+y;
500 ((MagickSizeType) (i*sizeof(*radon_info->cells)) >= radon_info->length))
502 if (radon_info->type != DiskCache)
504 radon_info->cells[i]=value;
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))
514 static void RadonProjection(RadonInfo *source_cells,
515 RadonInfo *destination_cells,const ssize_t sign,size_t *projection)
532 for (step=1; step < p->width; step*=2)
534 for (x=0; x < (ssize_t) p->width; x+=2*(ssize_t) step)
545 for (i=0; i < (ssize_t) step; i++)
547 for (y=0; y < (ssize_t) (p->height-i-1); y++)
549 cell=GetRadonCell(p,x+i,y);
550 (void) SetRadonCell(q,x+2*i,y,cell+GetRadonCell(p,x+i+(ssize_t)
552 (void) SetRadonCell(q,x+2*i+1,y,cell+GetRadonCell(p,x+i+(ssize_t)
555 for ( ; y < (ssize_t) (p->height-i); y++)
557 cell=GetRadonCell(p,x+i,y);
558 (void) SetRadonCell(q,x+2*i,y,cell+GetRadonCell(p,x+i+(ssize_t) step,
560 (void) SetRadonCell(q,x+2*i+1,y,cell);
562 for ( ; y < (ssize_t) p->height; y++)
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);
574 #if defined(MAGICKCORE_OPENMP_SUPPORT)
575 #pragma omp parallel for schedule(static,4)
577 for (x=0; x < (ssize_t) p->width; x++)
586 for (y=0; y < (ssize_t) (p->height-1); y++)
591 delta=GetRadonCell(p,x,y)-(ssize_t) GetRadonCell(p,x,y+1);
594 projection[p->width+sign*x-1]=sum;
598 static MagickBooleanType RadonTransform(const Image *image,
599 const double threshold,size_t *projection,ExceptionInfo *exception)
627 for (width=1; width < ((image->columns+7)/8); width<<=1) ;
628 source_cells=AcquireRadonInfo(image,width,image->rows,exception);
629 destination_cells=AcquireRadonInfo(image,width,image->rows,exception);
630 if ((source_cells == (RadonInfo *) NULL) ||
631 (destination_cells == (RadonInfo *) NULL))
633 if (destination_cells != (RadonInfo *) NULL)
634 destination_cells=DestroyRadonInfo(destination_cells);
635 if (source_cells != (RadonInfo *) NULL)
636 source_cells=DestroyRadonInfo(source_cells);
639 if (ResetRadonCells(source_cells) == MagickFalse)
641 destination_cells=DestroyRadonInfo(destination_cells);
642 source_cells=DestroyRadonInfo(source_cells);
645 for (i=0; i < 256; i++)
647 byte=(unsigned char) i;
648 for (count=0; byte != 0; byte>>=1)
650 bits[i]=(unsigned short) count;
653 image_view=AcquireVirtualCacheView(image,exception);
654 #if defined(MAGICKCORE_OPENMP_SUPPORT)
655 #pragma omp parallel for schedule(static,4) shared(status)
657 for (y=0; y < (ssize_t) image->rows; y++)
659 register const Quantum
670 if (status == MagickFalse)
672 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
673 if (p == (const Quantum *) NULL)
680 i=(ssize_t) (image->columns+7)/8;
681 for (x=0; x < (ssize_t) image->columns; x++)
684 if ((double) GetPixelIntensity(image,p) < threshold)
689 (void) SetRadonCell(source_cells,--i,y,bits[byte]);
693 p+=GetPixelChannels(image);
698 (void) SetRadonCell(source_cells,--i,y,bits[byte]);
701 RadonProjection(source_cells,destination_cells,-1,projection);
702 (void) ResetRadonCells(source_cells);
703 #if defined(MAGICKCORE_OPENMP_SUPPORT)
704 #pragma omp parallel for schedule(static,4) shared(status)
706 for (y=0; y < (ssize_t) image->rows; y++)
708 register const Quantum
719 if (status == MagickFalse)
721 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
722 if (p == (const Quantum *) NULL)
730 for (x=0; x < (ssize_t) image->columns; x++)
733 if ((double) GetPixelIntensity(image,p) < threshold)
738 (void) SetRadonCell(source_cells,i++,y,bits[byte]);
742 p+=GetPixelChannels(image);
747 (void) SetRadonCell(source_cells,i++,y,bits[byte]);
750 RadonProjection(source_cells,destination_cells,1,projection);
751 image_view=DestroyCacheView(image_view);
752 destination_cells=DestroyRadonInfo(destination_cells);
753 source_cells=DestroyRadonInfo(source_cells);
757 static void GetImageBackgroundColor(Image *image,const ssize_t offset,
758 ExceptionInfo *exception)
773 Compute average background color.
777 GetPixelInfo(image,&background);
779 image_view=AcquireVirtualCacheView(image,exception);
780 for (y=0; y < (ssize_t) image->rows; y++)
782 register const Quantum
788 if ((y >= offset) && (y < ((ssize_t) image->rows-offset)))
790 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
791 if (p == (const Quantum *) NULL)
793 for (x=0; x < (ssize_t) image->columns; x++)
795 if ((x >= offset) && (x < ((ssize_t) image->columns-offset)))
797 background.red+=QuantumScale*GetPixelRed(image,p);
798 background.green+=QuantumScale*GetPixelGreen(image,p);
799 background.blue+=QuantumScale*GetPixelBlue(image,p);
800 if ((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0)
801 background.alpha+=QuantumScale*GetPixelAlpha(image,p);
803 p+=GetPixelChannels(image);
806 image_view=DestroyCacheView(image_view);
807 image->background_color.red=(double) ClampToQuantum((MagickRealType)
808 QuantumRange*background.red/count);
809 image->background_color.green=(double) ClampToQuantum((MagickRealType)
810 QuantumRange*background.green/count);
811 image->background_color.blue=(double) ClampToQuantum((MagickRealType)
812 QuantumRange*background.blue/count);
813 if ((GetPixelAlphaTraits(image) & UpdatePixelTrait) != 0)
814 image->background_color.alpha=(double) ClampToQuantum((MagickRealType)
815 QuantumRange*background.alpha/count);
818 MagickExport Image *DeskewImage(const Image *image,const double threshold,
819 ExceptionInfo *exception)
854 Compute deskew angle.
856 for (width=1; width < ((image->columns+7)/8); width<<=1) ;
857 projection=(size_t *) AcquireQuantumMemory((size_t) (2*width-1),
858 sizeof(*projection));
859 if (projection == (size_t *) NULL)
860 ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
861 status=RadonTransform(image,threshold,projection,exception);
862 if (status == MagickFalse)
864 projection=(size_t *) RelinquishMagickMemory(projection);
865 ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
869 for (i=0; i < (ssize_t) (2*width-1); i++)
871 if (projection[i] > max_projection)
873 skew=i-(ssize_t) width+1;
874 max_projection=projection[i];
877 projection=(size_t *) RelinquishMagickMemory(projection);
881 clone_image=CloneImage(image,0,0,MagickTrue,exception);
882 if (clone_image == (Image *) NULL)
883 return((Image *) NULL);
884 (void) SetImageVirtualPixelMethod(clone_image,BackgroundVirtualPixelMethod,
886 degrees=RadiansToDegrees(-atan((double) skew/width/8));
887 if (image->debug != MagickFalse)
888 (void) LogMagickEvent(TransformEvent,GetMagickModule(),
889 " Deskew angle: %g",degrees);
890 affine_matrix.sx=cos(DegreesToRadians(fmod((double) degrees,360.0)));
891 affine_matrix.rx=sin(DegreesToRadians(fmod((double) degrees,360.0)));
892 affine_matrix.ry=(-sin(DegreesToRadians(fmod((double) degrees,360.0))));
893 affine_matrix.sy=cos(DegreesToRadians(fmod((double) degrees,360.0)));
894 affine_matrix.tx=0.0;
895 affine_matrix.ty=0.0;
896 artifact=GetImageArtifact(image,"deskew:auto-crop");
897 if (artifact == (const char *) NULL)
899 deskew_image=AffineTransformImage(clone_image,&affine_matrix,exception);
900 clone_image=DestroyImage(clone_image);
901 return(deskew_image);
906 GetImageBackgroundColor(clone_image,(ssize_t) StringToLong(artifact),
908 deskew_image=AffineTransformImage(clone_image,&affine_matrix,exception);
909 clone_image=DestroyImage(clone_image);
910 if (deskew_image == (Image *) NULL)
911 return((Image *) NULL);
912 median_image=StatisticImage(deskew_image,MedianStatistic,3,3,exception);
913 if (median_image == (Image *) NULL)
915 deskew_image=DestroyImage(deskew_image);
916 return((Image *) NULL);
918 geometry=GetImageBoundingBox(median_image,exception);
919 median_image=DestroyImage(median_image);
920 if (image->debug != MagickFalse)
921 (void) LogMagickEvent(TransformEvent,GetMagickModule()," Deskew geometry: "
922 "%.20gx%.20g%+.20g%+.20g",(double) geometry.width,(double)
923 geometry.height,(double) geometry.x,(double) geometry.y);
924 crop_image=CropImage(deskew_image,&geometry,exception);
925 deskew_image=DestroyImage(deskew_image);
930 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
934 % I n t e g r a l R o t a t e I m a g e %
938 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
940 % IntegralRotateImage() rotates the image an integral of 90 degrees. It
941 % allocates the memory necessary for the new Image structure and returns a
942 % pointer to the rotated image.
944 % The format of the IntegralRotateImage method is:
946 % Image *IntegralRotateImage(const Image *image,size_t rotations,
947 % ExceptionInfo *exception)
949 % A description of each parameter follows.
951 % o image: the image.
953 % o rotations: Specifies the number of 90 degree rotations.
956 MagickExport Image *IntegralRotateImage(const Image *image,size_t rotations,
957 ExceptionInfo *exception)
959 #define RotateImageTag "Rotate/Image"
981 Initialize rotated image attributes.
983 assert(image != (Image *) NULL);
987 return(CloneImage(image,0,0,MagickTrue,exception));
988 if ((rotations == 1) || (rotations == 3))
989 rotate_image=CloneImage(image,image->rows,image->columns,MagickTrue,
992 rotate_image=CloneImage(image,image->columns,image->rows,MagickTrue,
994 if (rotate_image == (Image *) NULL)
995 return((Image *) NULL);
997 Integral rotate the image.
1001 image_view=AcquireVirtualCacheView(image,exception);
1002 rotate_view=AcquireAuthenticCacheView(rotate_image,exception);
1024 GetPixelCacheTileSize(image,&tile_width,&tile_height);
1025 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1026 #pragma omp parallel for schedule(static,4) shared(progress,status)
1028 for (tile_y=0; tile_y < (ssize_t) image->rows; tile_y+=(ssize_t) tile_height)
1033 if (status == MagickFalse)
1036 for ( ; tile_x < (ssize_t) image->columns; tile_x+=(ssize_t) tile_width)
1041 register const Quantum
1055 if ((tile_x+(ssize_t) tile_width) > (ssize_t) image->columns)
1056 width=(size_t) (tile_width-(tile_x+tile_width-image->columns));
1058 if ((tile_y+(ssize_t) tile_height) > (ssize_t) image->rows)
1059 height=(size_t) (tile_height-(tile_y+tile_height-image->rows));
1060 p=GetCacheViewVirtualPixels(image_view,tile_x,tile_y,width,height,
1062 if (p == (const Quantum *) NULL)
1067 for (y=0; y < (ssize_t) width; y++)
1069 register const Quantum
1070 *restrict tile_pixels;
1075 if (status == MagickFalse)
1077 q=QueueCacheViewAuthenticPixels(rotate_view,(ssize_t)
1078 (rotate_image->columns-(tile_y+height)),y+tile_x,height,1,
1080 if (q == (Quantum *) NULL)
1085 tile_pixels=p+((height-1)*width+y)*GetPixelChannels(image);
1086 for (x=0; x < (ssize_t) height; x++)
1091 if (GetPixelMask(image,tile_pixels) != 0)
1093 tile_pixels-=width*GetPixelChannels(image);
1094 q+=GetPixelChannels(rotate_image);
1097 for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
1106 channel=GetPixelChannelMapChannel(image,i);
1107 traits=GetPixelChannelMapTraits(image,channel);
1108 rotate_traits=GetPixelChannelMapTraits(rotate_image,channel);
1109 if ((traits == UndefinedPixelTrait) ||
1110 (rotate_traits == UndefinedPixelTrait))
1112 SetPixelChannel(rotate_image,channel,tile_pixels[i],q);
1114 tile_pixels-=width*GetPixelChannels(image);
1115 q+=GetPixelChannels(rotate_image);
1117 sync=SyncCacheViewAuthenticPixels(rotate_view,exception);
1118 if (sync == MagickFalse)
1122 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1127 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1128 #pragma omp critical (MagickCore_IntegralRotateImage)
1130 proceed=SetImageProgress(image,RotateImageTag,progress+=tile_height,
1132 if (proceed == MagickFalse)
1136 (void) SetImageProgress(image,RotateImageTag,(MagickOffsetType)
1137 image->rows-1,image->rows);
1138 Swap(page.width,page.height);
1139 Swap(page.x,page.y);
1140 if (page.width != 0)
1141 page.x=(ssize_t) (page.width-rotate_image->columns-page.x);
1149 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1150 #pragma omp parallel for schedule(static) shared(progress,status)
1152 for (y=0; y < (ssize_t) image->rows; y++)
1157 register const Quantum
1166 if (status == MagickFalse)
1168 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
1169 q=QueueCacheViewAuthenticPixels(rotate_view,0,(ssize_t) (image->rows-y-
1170 1),image->columns,1,exception);
1171 if ((p == (const Quantum *) NULL) || (q == (Quantum *) NULL))
1176 q+=GetPixelChannels(rotate_image)*image->columns;
1177 for (x=0; x < (ssize_t) image->columns; x++)
1182 q-=GetPixelChannels(rotate_image);
1183 if (GetPixelMask(image,p) != 0)
1185 p+=GetPixelChannels(image);
1188 for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
1197 channel=GetPixelChannelMapChannel(image,i);
1198 traits=GetPixelChannelMapTraits(image,channel);
1199 rotate_traits=GetPixelChannelMapTraits(rotate_image,channel);
1200 if ((traits == UndefinedPixelTrait) ||
1201 (rotate_traits == UndefinedPixelTrait))
1203 SetPixelChannel(rotate_image,channel,p[i],q);
1205 p+=GetPixelChannels(image);
1207 sync=SyncCacheViewAuthenticPixels(rotate_view,exception);
1208 if (sync == MagickFalse)
1210 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1215 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1216 #pragma omp critical (MagickCore_IntegralRotateImage)
1218 proceed=SetImageProgress(image,RotateImageTag,progress++,
1220 if (proceed == MagickFalse)
1224 (void) SetImageProgress(image,RotateImageTag,(MagickOffsetType)
1225 image->rows-1,image->rows);
1226 Swap(page.width,page.height);
1227 Swap(page.x,page.y);
1228 if (page.width != 0)
1229 page.x=(ssize_t) (page.width-rotate_image->columns-page.x);
1244 GetPixelCacheTileSize(image,&tile_width,&tile_height);
1245 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1246 #pragma omp parallel for schedule(static,4) shared(progress,status)
1248 for (tile_y=0; tile_y < (ssize_t) image->rows; tile_y+=(ssize_t) tile_height)
1253 if (status == MagickFalse)
1256 for ( ; tile_x < (ssize_t) image->columns; tile_x+=(ssize_t) tile_width)
1261 register const Quantum
1275 if ((tile_x+(ssize_t) tile_width) > (ssize_t) image->columns)
1276 width=(size_t) (tile_width-(tile_x+tile_width-image->columns));
1278 if ((tile_y+(ssize_t) tile_height) > (ssize_t) image->rows)
1279 height=(size_t) (tile_height-(tile_y+tile_height-image->rows));
1280 p=GetCacheViewVirtualPixels(image_view,tile_x,tile_y,width,height,
1282 if (p == (const Quantum *) NULL)
1287 for (y=0; y < (ssize_t) width; y++)
1289 register const Quantum
1290 *restrict tile_pixels;
1295 if (status == MagickFalse)
1297 q=QueueCacheViewAuthenticPixels(rotate_view,tile_y,(ssize_t) (y+
1298 rotate_image->rows-(tile_x+width)),height,1,exception);
1299 if (q == (Quantum *) NULL)
1304 tile_pixels=p+((width-1)-y)*GetPixelChannels(image);
1305 for (x=0; x < (ssize_t) height; x++)
1310 if (GetPixelMask(image,tile_pixels) != 0)
1312 tile_pixels+=width*GetPixelChannels(image);
1313 q+=GetPixelChannels(rotate_image);
1316 for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
1325 channel=GetPixelChannelMapChannel(image,i);
1326 traits=GetPixelChannelMapTraits(image,channel);
1327 rotate_traits=GetPixelChannelMapTraits(rotate_image,channel);
1328 if ((traits == UndefinedPixelTrait) ||
1329 (rotate_traits == UndefinedPixelTrait))
1331 SetPixelChannel(rotate_image,channel,tile_pixels[i],q);
1333 tile_pixels+=width*GetPixelChannels(image);
1334 q+=GetPixelChannels(rotate_image);
1336 sync=SyncCacheViewAuthenticPixels(rotate_view,exception);
1337 if (sync == MagickFalse)
1341 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1346 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1347 #pragma omp critical (MagickCore_IntegralRotateImage)
1349 proceed=SetImageProgress(image,RotateImageTag,progress+=tile_height,
1351 if (proceed == MagickFalse)
1355 (void) SetImageProgress(image,RotateImageTag,(MagickOffsetType)
1356 image->rows-1,image->rows);
1357 Swap(page.width,page.height);
1358 Swap(page.x,page.y);
1359 if (page.width != 0)
1360 page.x=(ssize_t) (page.width-rotate_image->columns-page.x);
1364 rotate_view=DestroyCacheView(rotate_view);
1365 image_view=DestroyCacheView(image_view);
1366 rotate_image->type=image->type;
1367 rotate_image->page=page;
1368 if (status == MagickFalse)
1369 rotate_image=DestroyImage(rotate_image);
1370 return(rotate_image);
1374 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1378 + X S h e a r I m a g e %
1382 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1384 % XShearImage() shears the image in the X direction with a shear angle of
1385 % 'degrees'. Positive angles shear counter-clockwise (right-hand rule), and
1386 % negative angles shear clockwise. Angles are measured relative to a vertical
1387 % Y-axis. X shears will widen an image creating 'empty' triangles on the left
1388 % and right sides of the source image.
1390 % The format of the XShearImage method is:
1392 % MagickBooleanType XShearImage(Image *image,const MagickRealType degrees,
1393 % const size_t width,const size_t height,
1394 % const ssize_t x_offset,const ssize_t y_offset,ExceptionInfo *exception)
1396 % A description of each parameter follows.
1398 % o image: the image.
1400 % o degrees: A MagickRealType representing the shearing angle along the X
1403 % o width, height, x_offset, y_offset: Defines a region of the image
1406 % o exception: return any errors or warnings in this structure.
1409 static MagickBooleanType XShearImage(Image *image,const MagickRealType degrees,
1410 const size_t width,const size_t height,const ssize_t x_offset,
1411 const ssize_t y_offset,ExceptionInfo *exception)
1413 #define XShearImageTag "XShear/Image"
1439 assert(image != (Image *) NULL);
1440 assert(image->signature == MagickSignature);
1441 if (image->debug != MagickFalse)
1442 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1444 background=image->background_color;
1446 image_view=AcquireAuthenticCacheView(image,exception);
1447 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1448 #pragma omp parallel for schedule(static,4) shared(progress,status)
1450 for (y=0; y < (ssize_t) height; y++)
1474 if (status == MagickFalse)
1476 p=GetCacheViewAuthenticPixels(image_view,0,y_offset+y,image->columns,1,
1478 if (p == (Quantum *) NULL)
1483 p+=x_offset*GetPixelChannels(image);
1484 displacement=degrees*(MagickRealType) (y-height/2.0);
1485 if (displacement == 0.0)
1487 if (displacement > 0.0)
1491 displacement*=(-1.0);
1494 step=(ssize_t) floor((double) displacement);
1495 area=(MagickRealType) (displacement-step);
1498 GetPixelInfo(image,&source);
1499 GetPixelInfo(image,&destination);
1505 Transfer pixels left-to-right.
1507 if (step > x_offset)
1509 q=p-step*GetPixelChannels(image);
1510 for (i=0; i < (ssize_t) width; i++)
1512 if ((x_offset+i) < step)
1514 p+=GetPixelChannels(image);
1515 GetPixelInfoPixel(image,p,&pixel);
1516 q+=GetPixelChannels(image);
1519 GetPixelInfoPixel(image,p,&source);
1520 CompositePixelInfoAreaBlend(&pixel,(MagickRealType) pixel.alpha,
1521 &source,(MagickRealType) GetPixelAlpha(image,p),area,&destination);
1522 SetPixelInfoPixel(image,&destination,q);
1523 GetPixelInfoPixel(image,p,&pixel);
1524 p+=GetPixelChannels(image);
1525 q+=GetPixelChannels(image);
1527 CompositePixelInfoAreaBlend(&pixel,(MagickRealType) pixel.alpha,
1528 &background,(MagickRealType) background.alpha,area,&destination);
1529 SetPixelInfoPixel(image,&destination,q);
1530 q+=GetPixelChannels(image);
1531 for (i=0; i < (step-1); i++)
1533 SetPixelInfoPixel(image,&background,q);
1534 q+=GetPixelChannels(image);
1541 Transfer pixels right-to-left.
1543 p+=width*GetPixelChannels(image);
1544 q=p+step*GetPixelChannels(image);
1545 for (i=0; i < (ssize_t) width; i++)
1547 p-=GetPixelChannels(image);
1548 q-=GetPixelChannels(image);
1549 if ((size_t) (x_offset+width+step-i) >= image->columns)
1551 GetPixelInfoPixel(image,p,&source);
1552 CompositePixelInfoAreaBlend(&pixel,(MagickRealType) pixel.alpha,
1553 &source,(MagickRealType) GetPixelAlpha(image,p),area,&destination);
1554 SetPixelInfoPixel(image,&destination,q);
1555 GetPixelInfoPixel(image,p,&pixel);
1557 CompositePixelInfoAreaBlend(&pixel,(MagickRealType) pixel.alpha,
1558 &background,(MagickRealType) background.alpha,area,&destination);
1559 q-=GetPixelChannels(image);
1560 SetPixelInfoPixel(image,&destination,q);
1561 for (i=0; i < (step-1); i++)
1563 q-=GetPixelChannels(image);
1564 SetPixelInfoPixel(image,&background,q);
1569 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1571 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1576 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1577 #pragma omp critical (MagickCore_XShearImage)
1579 proceed=SetImageProgress(image,XShearImageTag,progress++,height);
1580 if (proceed == MagickFalse)
1584 image_view=DestroyCacheView(image_view);
1589 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1593 + Y S h e a r I m a g e %
1597 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1599 % YShearImage shears the image in the Y direction with a shear angle of
1600 % 'degrees'. Positive angles shear counter-clockwise (right-hand rule), and
1601 % negative angles shear clockwise. Angles are measured relative to a
1602 % horizontal X-axis. Y shears will increase the height of an image creating
1603 % 'empty' triangles on the top and bottom of the source image.
1605 % The format of the YShearImage method is:
1607 % MagickBooleanType YShearImage(Image *image,const MagickRealType degrees,
1608 % const size_t width,const size_t height,
1609 % const ssize_t x_offset,const ssize_t y_offset,ExceptionInfo *exception)
1611 % A description of each parameter follows.
1613 % o image: the image.
1615 % o degrees: A MagickRealType representing the shearing angle along the Y
1618 % o width, height, x_offset, y_offset: Defines a region of the image
1621 % o exception: return any errors or warnings in this structure.
1624 static MagickBooleanType YShearImage(Image *image,const MagickRealType degrees,
1625 const size_t width,const size_t height,const ssize_t x_offset,
1626 const ssize_t y_offset,ExceptionInfo *exception)
1628 #define YShearImageTag "YShear/Image"
1654 assert(image != (Image *) NULL);
1655 assert(image->signature == MagickSignature);
1656 if (image->debug != MagickFalse)
1657 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1660 background=image->background_color;
1661 image_view=AcquireAuthenticCacheView(image,exception);
1662 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1663 #pragma omp parallel for schedule(static,4) shared(progress,status)
1665 for (x=0; x < (ssize_t) width; x++)
1689 if (status == MagickFalse)
1691 p=GetCacheViewAuthenticPixels(image_view,x_offset+x,0,1,image->rows,
1693 if (p == (Quantum *) NULL)
1698 p+=y_offset*GetPixelChannels(image);
1699 displacement=degrees*(MagickRealType) (x-width/2.0);
1700 if (displacement == 0.0)
1702 if (displacement > 0.0)
1706 displacement*=(-1.0);
1709 step=(ssize_t) floor((double) displacement);
1710 area=(MagickRealType) (displacement-step);
1713 GetPixelInfo(image,&source);
1714 GetPixelInfo(image,&destination);
1720 Transfer pixels top-to-bottom.
1722 if (step > y_offset)
1724 q=p-step*GetPixelChannels(image);
1725 for (i=0; i < (ssize_t) height; i++)
1727 if ((y_offset+i) < step)
1729 p+=GetPixelChannels(image);
1730 GetPixelInfoPixel(image,p,&pixel);
1731 q+=GetPixelChannels(image);
1734 GetPixelInfoPixel(image,p,&source);
1735 CompositePixelInfoAreaBlend(&pixel,(MagickRealType) pixel.alpha,
1736 &source,(MagickRealType) GetPixelAlpha(image,p),area,
1738 SetPixelInfoPixel(image,&destination,q);
1739 GetPixelInfoPixel(image,p,&pixel);
1740 p+=GetPixelChannels(image);
1741 q+=GetPixelChannels(image);
1743 CompositePixelInfoAreaBlend(&pixel,(MagickRealType) pixel.alpha,
1744 &background,(MagickRealType) background.alpha,area,&destination);
1745 SetPixelInfoPixel(image,&destination,q);
1746 q+=GetPixelChannels(image);
1747 for (i=0; i < (step-1); i++)
1749 SetPixelInfoPixel(image,&background,q);
1750 q+=GetPixelChannels(image);
1757 Transfer pixels bottom-to-top.
1759 p+=height*GetPixelChannels(image);
1760 q=p+step*GetPixelChannels(image);
1761 for (i=0; i < (ssize_t) height; i++)
1763 p-=GetPixelChannels(image);
1764 q-=GetPixelChannels(image);
1765 if ((size_t) (y_offset+height+step-i) >= image->rows)
1767 GetPixelInfoPixel(image,p,&source);
1768 CompositePixelInfoAreaBlend(&pixel,(MagickRealType) pixel.alpha,
1769 &source,(MagickRealType) GetPixelAlpha(image,p),area,
1771 SetPixelInfoPixel(image,&destination,q);
1772 GetPixelInfoPixel(image,p,&pixel);
1774 CompositePixelInfoAreaBlend(&pixel,(MagickRealType) pixel.alpha,
1775 &background,(MagickRealType) background.alpha,area,&destination);
1776 q-=GetPixelChannels(image);
1777 SetPixelInfoPixel(image,&destination,q);
1778 for (i=0; i < (step-1); i++)
1780 q-=GetPixelChannels(image);
1781 SetPixelInfoPixel(image,&background,q);
1786 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1788 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1793 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1794 #pragma omp critical (MagickCore_YShearImage)
1796 proceed=SetImageProgress(image,YShearImageTag,progress++,image->rows);
1797 if (proceed == MagickFalse)
1801 image_view=DestroyCacheView(image_view);
1806 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1810 % S h e a r I m a g e %
1814 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1816 % ShearImage() creates a new image that is a shear_image copy of an existing
1817 % one. Shearing slides one edge of an image along the X or Y axis, creating
1818 % a parallelogram. An X direction shear slides an edge along the X axis,
1819 % while a Y direction shear slides an edge along the Y axis. The amount of
1820 % the shear is controlled by a shear angle. For X direction shears, x_shear
1821 % is measured relative to the Y axis, and similarly, for Y direction shears
1822 % y_shear is measured relative to the X axis. Empty triangles left over from
1823 % shearing the image are filled with the background color defined by member
1824 % 'background_color' of the image.. ShearImage() allocates the memory
1825 % necessary for the new Image structure and returns a pointer to the new image.
1827 % ShearImage() is based on the paper "A Fast Algorithm for General Raster
1828 % Rotatation" by Alan W. Paeth.
1830 % The format of the ShearImage method is:
1832 % Image *ShearImage(const Image *image,const double x_shear,
1833 % const double y_shear,ExceptionInfo *exception)
1835 % A description of each parameter follows.
1837 % o image: the image.
1839 % o x_shear, y_shear: Specifies the number of degrees to shear the image.
1841 % o exception: return any errors or warnings in this structure.
1844 MagickExport Image *ShearImage(const Image *image,const double x_shear,
1845 const double y_shear,ExceptionInfo *exception)
1867 assert(image != (Image *) NULL);
1868 assert(image->signature == MagickSignature);
1869 if (image->debug != MagickFalse)
1870 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1871 assert(exception != (ExceptionInfo *) NULL);
1872 assert(exception->signature == MagickSignature);
1873 if ((x_shear != 0.0) && (fmod(x_shear,90.0) == 0.0))
1874 ThrowImageException(ImageError,"AngleIsDiscontinuous");
1875 if ((y_shear != 0.0) && (fmod(y_shear,90.0) == 0.0))
1876 ThrowImageException(ImageError,"AngleIsDiscontinuous");
1878 Initialize shear angle.
1880 integral_image=CloneImage(image,0,0,MagickTrue,exception);
1881 if (integral_image == (Image *) NULL)
1882 ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
1883 shear.x=(-tan(DegreesToRadians(fmod(x_shear,360.0))));
1884 shear.y=tan(DegreesToRadians(fmod(y_shear,360.0)));
1885 if ((shear.x == 0.0) && (shear.y == 0.0))
1886 return(integral_image);
1887 if (SetImageStorageClass(integral_image,DirectClass,exception) == MagickFalse)
1889 integral_image=DestroyImage(integral_image);
1890 return(integral_image);
1892 if (integral_image->matte == MagickFalse)
1893 (void) SetImageAlphaChannel(integral_image,OpaqueAlphaChannel,exception);
1897 y_width=image->columns+(ssize_t) floor(fabs(shear.x)*image->rows+0.5);
1898 x_offset=(ssize_t) ceil((double) image->columns+((fabs(shear.x)*image->rows)-
1899 image->columns)/2.0-0.5);
1900 y_offset=(ssize_t) ceil((double) image->rows+((fabs(shear.y)*y_width)-
1901 image->rows)/2.0-0.5);
1903 Surround image with border.
1905 integral_image->border_color=integral_image->background_color;
1906 integral_image->compose=CopyCompositeOp;
1907 border_info.width=(size_t) x_offset;
1908 border_info.height=(size_t) y_offset;
1909 shear_image=BorderImage(integral_image,&border_info,image->compose,exception);
1910 integral_image=DestroyImage(integral_image);
1911 if (shear_image == (Image *) NULL)
1912 ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
1916 if (shear_image->matte == MagickFalse)
1917 (void) SetImageAlphaChannel(shear_image,OpaqueAlphaChannel,exception);
1918 status=XShearImage(shear_image,shear.x,image->columns,image->rows,x_offset,
1919 (ssize_t) (shear_image->rows-image->rows)/2,exception);
1920 if (status == MagickFalse)
1922 shear_image=DestroyImage(shear_image);
1923 return((Image *) NULL);
1925 status=YShearImage(shear_image,shear.y,y_width,image->rows,(ssize_t)
1926 (shear_image->columns-y_width)/2,y_offset,exception);
1927 if (status == MagickFalse)
1929 shear_image=DestroyImage(shear_image);
1930 return((Image *) NULL);
1932 status=CropToFitImage(&shear_image,shear.x,shear.y,(MagickRealType)
1933 image->columns,(MagickRealType) image->rows,MagickFalse,exception);
1934 if (status == MagickFalse)
1936 shear_image=DestroyImage(shear_image);
1937 return((Image *) NULL);
1939 shear_image->compose=image->compose;
1940 shear_image->page.width=0;
1941 shear_image->page.height=0;
1942 return(shear_image);
1946 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1950 % S h e a r R o t a t e I m a g e %
1954 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1956 % ShearRotateImage() creates a new image that is a rotated copy of an existing
1957 % one. Positive angles rotate counter-clockwise (right-hand rule), while
1958 % negative angles rotate clockwise. Rotated images are usually larger than
1959 % the originals and have 'empty' triangular corners. X axis. Empty
1960 % triangles left over from shearing the image are filled with the background
1961 % color defined by member 'background_color' of the image. ShearRotateImage
1962 % allocates the memory necessary for the new Image structure and returns a
1963 % pointer to the new image.
1965 % ShearRotateImage() is based on the paper "A Fast Algorithm for General
1966 % Raster Rotatation" by Alan W. Paeth. ShearRotateImage is adapted from a
1967 % similar method based on the Paeth paper written by Michael Halle of the
1968 % Spatial Imaging Group, MIT Media Lab.
1970 % The format of the ShearRotateImage method is:
1972 % Image *ShearRotateImage(const Image *image,const double degrees,
1973 % ExceptionInfo *exception)
1975 % A description of each parameter follows.
1977 % o image: the image.
1979 % o degrees: Specifies the number of degrees to rotate the image.
1981 % o exception: return any errors or warnings in this structure.
1984 MagickExport Image *ShearRotateImage(const Image *image,const double degrees,
1985 ExceptionInfo *exception)
2014 Adjust rotation angle.
2016 assert(image != (Image *) NULL);
2017 assert(image->signature == MagickSignature);
2018 if (image->debug != MagickFalse)
2019 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2020 assert(exception != (ExceptionInfo *) NULL);
2021 assert(exception->signature == MagickSignature);
2023 while (angle < -45.0)
2025 for (rotations=0; angle > 45.0; rotations++)
2029 Calculate shear equations.
2031 integral_image=IntegralRotateImage(image,rotations,exception);
2032 if (integral_image == (Image *) NULL)
2033 ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
2034 shear.x=(-tan((double) DegreesToRadians(angle)/2.0));
2035 shear.y=sin((double) DegreesToRadians(angle));
2036 if ((shear.x == 0.0) && (shear.y == 0.0))
2037 return(integral_image);
2038 if (SetImageStorageClass(integral_image,DirectClass,exception) == MagickFalse)
2040 integral_image=DestroyImage(integral_image);
2041 return(integral_image);
2043 if (integral_image->matte == MagickFalse)
2044 (void) SetImageAlphaChannel(integral_image,OpaqueAlphaChannel,exception);
2048 width=image->columns;
2050 if ((rotations == 1) || (rotations == 3))
2053 height=image->columns;
2055 y_width=width+(ssize_t) floor(fabs(shear.x)*height+0.5);
2056 x_offset=(ssize_t) ceil((double) width+((fabs(shear.y)*height)-width)/2.0-
2058 y_offset=(ssize_t) ceil((double) height+((fabs(shear.y)*y_width)-height)/2.0-
2061 Surround image with a border.
2063 integral_image->border_color=integral_image->background_color;
2064 integral_image->compose=CopyCompositeOp;
2065 border_info.width=(size_t) x_offset;
2066 border_info.height=(size_t) y_offset;
2067 rotate_image=BorderImage(integral_image,&border_info,image->compose,
2069 integral_image=DestroyImage(integral_image);
2070 if (rotate_image == (Image *) NULL)
2071 ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
2075 status=XShearImage(rotate_image,shear.x,width,height,x_offset,(ssize_t)
2076 (rotate_image->rows-height)/2,exception);
2077 if (status == MagickFalse)
2079 rotate_image=DestroyImage(rotate_image);
2080 return((Image *) NULL);
2082 status=YShearImage(rotate_image,shear.y,y_width,height,(ssize_t)
2083 (rotate_image->columns-y_width)/2,y_offset,exception);
2084 if (status == MagickFalse)
2086 rotate_image=DestroyImage(rotate_image);
2087 return((Image *) NULL);
2089 status=XShearImage(rotate_image,shear.x,y_width,rotate_image->rows,(ssize_t)
2090 (rotate_image->columns-y_width)/2,0,exception);
2091 if (status == MagickFalse)
2093 rotate_image=DestroyImage(rotate_image);
2094 return((Image *) NULL);
2096 status=CropToFitImage(&rotate_image,shear.x,shear.y,(MagickRealType) width,
2097 (MagickRealType) height,MagickTrue,exception);
2098 if (status == MagickFalse)
2100 rotate_image=DestroyImage(rotate_image);
2101 return((Image *) NULL);
2103 rotate_image->compose=image->compose;
2104 rotate_image->page.width=0;
2105 rotate_image->page.height=0;
2106 return(rotate_image);