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 1999-2011 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(dynamic,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=AcquireCacheView(image);
654 #if defined(MAGICKCORE_OPENMP_SUPPORT)
655 #pragma omp parallel for schedule(dynamic,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(dynamic,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=AcquireCacheView(image);
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);
885 degrees=RadiansToDegrees(-atan((double) skew/width/8));
886 if (image->debug != MagickFalse)
887 (void) LogMagickEvent(TransformEvent,GetMagickModule(),
888 " Deskew angle: %g",degrees);
889 affine_matrix.sx=cos(DegreesToRadians(fmod((double) degrees,360.0)));
890 affine_matrix.rx=sin(DegreesToRadians(fmod((double) degrees,360.0)));
891 affine_matrix.ry=(-sin(DegreesToRadians(fmod((double) degrees,360.0))));
892 affine_matrix.sy=cos(DegreesToRadians(fmod((double) degrees,360.0)));
893 affine_matrix.tx=0.0;
894 affine_matrix.ty=0.0;
895 artifact=GetImageArtifact(image,"deskew:auto-crop");
896 if (artifact == (const char *) NULL)
898 deskew_image=AffineTransformImage(clone_image,&affine_matrix,exception);
899 clone_image=DestroyImage(clone_image);
900 return(deskew_image);
905 GetImageBackgroundColor(clone_image,(ssize_t) StringToLong(artifact),
907 deskew_image=AffineTransformImage(clone_image,&affine_matrix,exception);
908 clone_image=DestroyImage(clone_image);
909 if (deskew_image == (Image *) NULL)
910 return((Image *) NULL);
911 median_image=StatisticImage(deskew_image,MedianStatistic,3,3,exception);
912 if (median_image == (Image *) NULL)
914 deskew_image=DestroyImage(deskew_image);
915 return((Image *) NULL);
917 geometry=GetImageBoundingBox(median_image,exception);
918 median_image=DestroyImage(median_image);
919 if (image->debug != MagickFalse)
920 (void) LogMagickEvent(TransformEvent,GetMagickModule()," Deskew geometry: "
921 "%.20gx%.20g%+.20g%+.20g",(double) geometry.width,(double)
922 geometry.height,(double) geometry.x,(double) geometry.y);
923 crop_image=CropImage(deskew_image,&geometry,exception);
924 deskew_image=DestroyImage(deskew_image);
929 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
933 % I n t e g r a l R o t a t e I m a g e %
937 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
939 % IntegralRotateImage() rotates the image an integral of 90 degrees. It
940 % allocates the memory necessary for the new Image structure and returns a
941 % pointer to the rotated image.
943 % The format of the IntegralRotateImage method is:
945 % Image *IntegralRotateImage(const Image *image,size_t rotations,
946 % ExceptionInfo *exception)
948 % A description of each parameter follows.
950 % o image: the image.
952 % o rotations: Specifies the number of 90 degree rotations.
955 MagickExport Image *IntegralRotateImage(const Image *image,size_t rotations,
956 ExceptionInfo *exception)
958 #define RotateImageTag "Rotate/Image"
980 Initialize rotated image attributes.
982 assert(image != (Image *) NULL);
986 return(CloneImage(image,0,0,MagickTrue,exception));
987 if ((rotations == 1) || (rotations == 3))
988 rotate_image=CloneImage(image,image->rows,image->columns,MagickTrue,
991 rotate_image=CloneImage(image,image->columns,image->rows,MagickTrue,
993 if (rotate_image == (Image *) NULL)
994 return((Image *) NULL);
996 Integral rotate the image.
1000 image_view=AcquireCacheView(image);
1001 rotate_view=AcquireCacheView(rotate_image);
1023 GetPixelCacheTileSize(image,&tile_width,&tile_height);
1024 tile_width=image->columns;
1025 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1026 #pragma omp parallel for schedule(dynamic,4) shared(progress, status) omp_throttle(1)
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 for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
1100 channel=GetPixelChannelMapChannel(image,i);
1101 traits=GetPixelChannelMapTraits(image,channel);
1102 rotate_traits=GetPixelChannelMapTraits(rotate_image,channel);
1103 if ((traits == UndefinedPixelTrait) ||
1104 (rotate_traits == UndefinedPixelTrait))
1106 SetPixelChannel(rotate_image,channel,tile_pixels[i],q);
1108 tile_pixels-=width*GetPixelChannels(image);
1109 q+=GetPixelChannels(rotate_image);
1111 sync=SyncCacheViewAuthenticPixels(rotate_view,exception);
1112 if (sync == MagickFalse)
1116 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1121 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1122 #pragma omp critical (MagickCore_IntegralRotateImage)
1124 proceed=SetImageProgress(image,RotateImageTag,progress+=tile_height,
1126 if (proceed == MagickFalse)
1130 (void) SetImageProgress(image,RotateImageTag,(MagickOffsetType)
1131 image->rows-1,image->rows);
1132 Swap(page.width,page.height);
1133 Swap(page.x,page.y);
1134 if (page.width != 0)
1135 page.x=(ssize_t) (page.width-rotate_image->columns-page.x);
1143 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1144 #pragma omp parallel for schedule(dynamic,4) shared(progress,status) omp_throttle(1)
1146 for (y=0; y < (ssize_t) image->rows; y++)
1151 register const Quantum
1160 if (status == MagickFalse)
1162 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
1163 q=QueueCacheViewAuthenticPixels(rotate_view,0,(ssize_t) (image->rows-y-
1164 1),image->columns,1,exception);
1165 if ((p == (const Quantum *) NULL) || (q == (Quantum *) NULL))
1170 q+=GetPixelChannels(rotate_image)*image->columns;
1171 for (x=0; x < (ssize_t) image->columns; x++)
1176 q-=GetPixelChannels(rotate_image);
1177 for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
1186 channel=GetPixelChannelMapChannel(image,i);
1187 traits=GetPixelChannelMapTraits(image,channel);
1188 rotate_traits=GetPixelChannelMapTraits(rotate_image,channel);
1189 if ((traits == UndefinedPixelTrait) ||
1190 (rotate_traits == UndefinedPixelTrait))
1192 SetPixelChannel(rotate_image,channel,p[i],q);
1194 p+=GetPixelChannels(image);
1196 sync=SyncCacheViewAuthenticPixels(rotate_view,exception);
1197 if (sync == MagickFalse)
1199 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1204 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1205 #pragma omp critical (MagickCore_IntegralRotateImage)
1207 proceed=SetImageProgress(image,RotateImageTag,progress++,
1209 if (proceed == MagickFalse)
1213 (void) SetImageProgress(image,RotateImageTag,(MagickOffsetType)
1214 image->rows-1,image->rows);
1215 Swap(page.width,page.height);
1216 Swap(page.x,page.y);
1217 if (page.width != 0)
1218 page.x=(ssize_t) (page.width-rotate_image->columns-page.x);
1233 GetPixelCacheTileSize(image,&tile_width,&tile_height);
1234 tile_width=image->columns;
1235 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1236 #pragma omp parallel for schedule(dynamic,4) shared(progress,status) omp_throttle(1)
1238 for (tile_y=0; tile_y < (ssize_t) image->rows; tile_y+=(ssize_t) tile_height)
1243 if (status == MagickFalse)
1246 for ( ; tile_x < (ssize_t) image->columns; tile_x+=(ssize_t) tile_width)
1251 register const Quantum
1265 if ((tile_x+(ssize_t) tile_width) > (ssize_t) image->columns)
1266 width=(size_t) (tile_width-(tile_x+tile_width-image->columns));
1268 if ((tile_y+(ssize_t) tile_height) > (ssize_t) image->rows)
1269 height=(size_t) (tile_height-(tile_y+tile_height-image->rows));
1270 p=GetCacheViewVirtualPixels(image_view,tile_x,tile_y,width,height,
1272 if (p == (const Quantum *) NULL)
1277 for (y=0; y < (ssize_t) width; y++)
1279 register const Quantum
1280 *restrict tile_pixels;
1285 if (status == MagickFalse)
1287 q=QueueCacheViewAuthenticPixels(rotate_view,tile_y,(ssize_t) (y+
1288 rotate_image->rows-(tile_x+width)),height,1,exception);
1289 if (q == (Quantum *) NULL)
1294 tile_pixels=p+((width-1)-y)*GetPixelChannels(image);
1295 for (x=0; x < (ssize_t) height; x++)
1300 for (i=0; i < (ssize_t) GetPixelChannels(image); i++)
1309 channel=GetPixelChannelMapChannel(image,i);
1310 traits=GetPixelChannelMapTraits(image,channel);
1311 rotate_traits=GetPixelChannelMapTraits(rotate_image,channel);
1312 if ((traits == UndefinedPixelTrait) ||
1313 (rotate_traits == UndefinedPixelTrait))
1315 SetPixelChannel(rotate_image,channel,tile_pixels[i],q);
1317 tile_pixels+=width*GetPixelChannels(image);
1318 q+=GetPixelChannels(rotate_image);
1320 sync=SyncCacheViewAuthenticPixels(rotate_view,exception);
1321 if (sync == MagickFalse)
1325 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1330 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1331 #pragma omp critical (MagickCore_IntegralRotateImage)
1333 proceed=SetImageProgress(image,RotateImageTag,progress+=tile_height,
1335 if (proceed == MagickFalse)
1339 (void) SetImageProgress(image,RotateImageTag,(MagickOffsetType)
1340 image->rows-1,image->rows);
1341 Swap(page.width,page.height);
1342 Swap(page.x,page.y);
1343 if (page.width != 0)
1344 page.x=(ssize_t) (page.width-rotate_image->columns-page.x);
1348 rotate_view=DestroyCacheView(rotate_view);
1349 image_view=DestroyCacheView(image_view);
1350 rotate_image->type=image->type;
1351 rotate_image->page=page;
1352 if (status == MagickFalse)
1353 rotate_image=DestroyImage(rotate_image);
1354 return(rotate_image);
1358 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1362 + X S h e a r I m a g e %
1366 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1368 % XShearImage() shears the image in the X direction with a shear angle of
1369 % 'degrees'. Positive angles shear counter-clockwise (right-hand rule), and
1370 % negative angles shear clockwise. Angles are measured relative to a vertical
1371 % Y-axis. X shears will widen an image creating 'empty' triangles on the left
1372 % and right sides of the source image.
1374 % The format of the XShearImage method is:
1376 % MagickBooleanType XShearImage(Image *image,const MagickRealType degrees,
1377 % const size_t width,const size_t height,
1378 % const ssize_t x_offset,const ssize_t y_offset,ExceptionInfo *exception)
1380 % A description of each parameter follows.
1382 % o image: the image.
1384 % o degrees: A MagickRealType representing the shearing angle along the X
1387 % o width, height, x_offset, y_offset: Defines a region of the image
1390 % o exception: return any errors or warnings in this structure.
1393 static MagickBooleanType XShearImage(Image *image,const MagickRealType degrees,
1394 const size_t width,const size_t height,const ssize_t x_offset,
1395 const ssize_t y_offset,ExceptionInfo *exception)
1397 #define XShearImageTag "XShear/Image"
1423 assert(image != (Image *) NULL);
1424 assert(image->signature == MagickSignature);
1425 if (image->debug != MagickFalse)
1426 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1428 background=image->background_color;
1430 image_view=AcquireCacheView(image);
1431 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1432 #pragma omp parallel for schedule(dynamic,4) shared(progress, status)
1434 for (y=0; y < (ssize_t) height; y++)
1458 if (status == MagickFalse)
1460 p=GetCacheViewAuthenticPixels(image_view,0,y_offset+y,image->columns,1,
1462 if (p == (Quantum *) NULL)
1467 p+=x_offset*GetPixelChannels(image);
1468 displacement=degrees*(MagickRealType) (y-height/2.0);
1469 if (displacement == 0.0)
1471 if (displacement > 0.0)
1475 displacement*=(-1.0);
1478 step=(ssize_t) floor((double) displacement);
1479 area=(MagickRealType) (displacement-step);
1482 GetPixelInfo(image,&source);
1483 GetPixelInfo(image,&destination);
1489 Transfer pixels left-to-right.
1491 if (step > x_offset)
1493 q=p-step*GetPixelChannels(image);
1494 for (i=0; i < (ssize_t) width; i++)
1496 if ((x_offset+i) < step)
1498 p+=GetPixelChannels(image);
1499 GetPixelInfoPixel(image,p,&pixel);
1500 q+=GetPixelChannels(image);
1503 GetPixelInfoPixel(image,p,&source);
1504 CompositePixelInfoAreaBlend(&pixel,(MagickRealType) pixel.alpha,
1505 &source,(MagickRealType) GetPixelAlpha(image,p),area,&destination);
1506 SetPixelInfoPixel(image,&destination,q);
1507 GetPixelInfoPixel(image,p,&pixel);
1508 p+=GetPixelChannels(image);
1509 q+=GetPixelChannels(image);
1511 CompositePixelInfoAreaBlend(&pixel,(MagickRealType) pixel.alpha,
1512 &background,(MagickRealType) background.alpha,area,&destination);
1513 SetPixelInfoPixel(image,&destination,q);
1514 q+=GetPixelChannels(image);
1515 for (i=0; i < (step-1); i++)
1517 SetPixelInfoPixel(image,&background,q);
1518 q+=GetPixelChannels(image);
1525 Transfer pixels right-to-left.
1527 p+=width*GetPixelChannels(image);
1528 q=p+step*GetPixelChannels(image);
1529 for (i=0; i < (ssize_t) width; i++)
1531 p-=GetPixelChannels(image);
1532 q-=GetPixelChannels(image);
1533 if ((size_t) (x_offset+width+step-i) >= image->columns)
1535 GetPixelInfoPixel(image,p,&source);
1536 CompositePixelInfoAreaBlend(&pixel,(MagickRealType) pixel.alpha,
1537 &source,(MagickRealType) GetPixelAlpha(image,p),area,&destination);
1538 SetPixelInfoPixel(image,&destination,q);
1539 GetPixelInfoPixel(image,p,&pixel);
1541 CompositePixelInfoAreaBlend(&pixel,(MagickRealType) pixel.alpha,
1542 &background,(MagickRealType) background.alpha,area,&destination);
1543 q-=GetPixelChannels(image);
1544 SetPixelInfoPixel(image,&destination,q);
1545 for (i=0; i < (step-1); i++)
1547 q-=GetPixelChannels(image);
1548 SetPixelInfoPixel(image,&background,q);
1553 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1555 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1560 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1561 #pragma omp critical (MagickCore_XShearImage)
1563 proceed=SetImageProgress(image,XShearImageTag,progress++,height);
1564 if (proceed == MagickFalse)
1568 image_view=DestroyCacheView(image_view);
1573 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1577 + Y S h e a r I m a g e %
1581 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1583 % YShearImage shears the image in the Y direction with a shear angle of
1584 % 'degrees'. Positive angles shear counter-clockwise (right-hand rule), and
1585 % negative angles shear clockwise. Angles are measured relative to a
1586 % horizontal X-axis. Y shears will increase the height of an image creating
1587 % 'empty' triangles on the top and bottom of the source image.
1589 % The format of the YShearImage method is:
1591 % MagickBooleanType YShearImage(Image *image,const MagickRealType degrees,
1592 % const size_t width,const size_t height,
1593 % const ssize_t x_offset,const ssize_t y_offset,ExceptionInfo *exception)
1595 % A description of each parameter follows.
1597 % o image: the image.
1599 % o degrees: A MagickRealType representing the shearing angle along the Y
1602 % o width, height, x_offset, y_offset: Defines a region of the image
1605 % o exception: return any errors or warnings in this structure.
1608 static MagickBooleanType YShearImage(Image *image,const MagickRealType degrees,
1609 const size_t width,const size_t height,const ssize_t x_offset,
1610 const ssize_t y_offset,ExceptionInfo *exception)
1612 #define YShearImageTag "YShear/Image"
1638 assert(image != (Image *) NULL);
1639 assert(image->signature == MagickSignature);
1640 if (image->debug != MagickFalse)
1641 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1644 background=image->background_color;
1645 image_view=AcquireCacheView(image);
1646 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1647 #pragma omp parallel for schedule(dynamic,4) shared(progress, status)
1649 for (x=0; x < (ssize_t) width; x++)
1673 if (status == MagickFalse)
1675 p=GetCacheViewAuthenticPixels(image_view,x_offset+x,0,1,image->rows,
1677 if (p == (Quantum *) NULL)
1682 p+=y_offset*GetPixelChannels(image);
1683 displacement=degrees*(MagickRealType) (x-width/2.0);
1684 if (displacement == 0.0)
1686 if (displacement > 0.0)
1690 displacement*=(-1.0);
1693 step=(ssize_t) floor((double) displacement);
1694 area=(MagickRealType) (displacement-step);
1697 GetPixelInfo(image,&source);
1698 GetPixelInfo(image,&destination);
1704 Transfer pixels top-to-bottom.
1706 if (step > y_offset)
1708 q=p-step*GetPixelChannels(image);
1709 for (i=0; i < (ssize_t) height; i++)
1711 if ((y_offset+i) < step)
1713 p+=GetPixelChannels(image);
1714 GetPixelInfoPixel(image,p,&pixel);
1715 q+=GetPixelChannels(image);
1718 GetPixelInfoPixel(image,p,&source);
1719 CompositePixelInfoAreaBlend(&pixel,(MagickRealType) pixel.alpha,
1720 &source,(MagickRealType) GetPixelAlpha(image,p),area,
1722 SetPixelInfoPixel(image,&destination,q);
1723 GetPixelInfoPixel(image,p,&pixel);
1724 p+=GetPixelChannels(image);
1725 q+=GetPixelChannels(image);
1727 CompositePixelInfoAreaBlend(&pixel,(MagickRealType) pixel.alpha,
1728 &background,(MagickRealType) background.alpha,area,&destination);
1729 SetPixelInfoPixel(image,&destination,q);
1730 q+=GetPixelChannels(image);
1731 for (i=0; i < (step-1); i++)
1733 SetPixelInfoPixel(image,&background,q);
1734 q+=GetPixelChannels(image);
1741 Transfer pixels bottom-to-top.
1743 p+=height*GetPixelChannels(image);
1744 q=p+step*GetPixelChannels(image);
1745 for (i=0; i < (ssize_t) height; i++)
1747 p-=GetPixelChannels(image);
1748 q-=GetPixelChannels(image);
1749 if ((size_t) (y_offset+height+step-i) >= image->rows)
1751 GetPixelInfoPixel(image,p,&source);
1752 CompositePixelInfoAreaBlend(&pixel,(MagickRealType) pixel.alpha,
1753 &source,(MagickRealType) GetPixelAlpha(image,p),area,
1755 SetPixelInfoPixel(image,&destination,q);
1756 GetPixelInfoPixel(image,p,&pixel);
1758 CompositePixelInfoAreaBlend(&pixel,(MagickRealType) pixel.alpha,
1759 &background,(MagickRealType) background.alpha,area,&destination);
1760 q-=GetPixelChannels(image);
1761 SetPixelInfoPixel(image,&destination,q);
1762 for (i=0; i < (step-1); i++)
1764 q-=GetPixelChannels(image);
1765 SetPixelInfoPixel(image,&background,q);
1770 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1772 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1777 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1778 #pragma omp critical (MagickCore_YShearImage)
1780 proceed=SetImageProgress(image,YShearImageTag,progress++,image->rows);
1781 if (proceed == MagickFalse)
1785 image_view=DestroyCacheView(image_view);
1790 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1794 % S h e a r I m a g e %
1798 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1800 % ShearImage() creates a new image that is a shear_image copy of an existing
1801 % one. Shearing slides one edge of an image along the X or Y axis, creating
1802 % a parallelogram. An X direction shear slides an edge along the X axis,
1803 % while a Y direction shear slides an edge along the Y axis. The amount of
1804 % the shear is controlled by a shear angle. For X direction shears, x_shear
1805 % is measured relative to the Y axis, and similarly, for Y direction shears
1806 % y_shear is measured relative to the X axis. Empty triangles left over from
1807 % shearing the image are filled with the background color defined by member
1808 % 'background_color' of the image.. ShearImage() allocates the memory
1809 % necessary for the new Image structure and returns a pointer to the new image.
1811 % ShearImage() is based on the paper "A Fast Algorithm for General Raster
1812 % Rotatation" by Alan W. Paeth.
1814 % The format of the ShearImage method is:
1816 % Image *ShearImage(const Image *image,const double x_shear,
1817 % const double y_shear,ExceptionInfo *exception)
1819 % A description of each parameter follows.
1821 % o image: the image.
1823 % o x_shear, y_shear: Specifies the number of degrees to shear the image.
1825 % o exception: return any errors or warnings in this structure.
1828 MagickExport Image *ShearImage(const Image *image,const double x_shear,
1829 const double y_shear,ExceptionInfo *exception)
1851 assert(image != (Image *) NULL);
1852 assert(image->signature == MagickSignature);
1853 if (image->debug != MagickFalse)
1854 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1855 assert(exception != (ExceptionInfo *) NULL);
1856 assert(exception->signature == MagickSignature);
1857 if ((x_shear != 0.0) && (fmod(x_shear,90.0) == 0.0))
1858 ThrowImageException(ImageError,"AngleIsDiscontinuous");
1859 if ((y_shear != 0.0) && (fmod(y_shear,90.0) == 0.0))
1860 ThrowImageException(ImageError,"AngleIsDiscontinuous");
1862 Initialize shear angle.
1864 integral_image=CloneImage(image,0,0,MagickTrue,exception);
1865 if (integral_image == (Image *) NULL)
1866 ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
1867 shear.x=(-tan(DegreesToRadians(fmod(x_shear,360.0))));
1868 shear.y=tan(DegreesToRadians(fmod(y_shear,360.0)));
1869 if ((shear.x == 0.0) && (shear.y == 0.0))
1870 return(integral_image);
1871 if (SetImageStorageClass(integral_image,DirectClass,exception) == MagickFalse)
1873 integral_image=DestroyImage(integral_image);
1874 return(integral_image);
1876 if (integral_image->matte == MagickFalse)
1877 (void) SetImageAlphaChannel(integral_image,OpaqueAlphaChannel,exception);
1881 y_width=image->columns+(ssize_t) floor(fabs(shear.x)*image->rows+0.5);
1882 x_offset=(ssize_t) ceil((double) image->columns+((fabs(shear.x)*image->rows)-
1883 image->columns)/2.0-0.5);
1884 y_offset=(ssize_t) ceil((double) image->rows+((fabs(shear.y)*y_width)-
1885 image->rows)/2.0-0.5);
1887 Surround image with border.
1889 integral_image->border_color=integral_image->background_color;
1890 integral_image->compose=CopyCompositeOp;
1891 border_info.width=(size_t) x_offset;
1892 border_info.height=(size_t) y_offset;
1893 shear_image=BorderImage(integral_image,&border_info,image->compose,exception);
1894 integral_image=DestroyImage(integral_image);
1895 if (shear_image == (Image *) NULL)
1896 ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
1900 if (shear_image->matte == MagickFalse)
1901 (void) SetImageAlphaChannel(shear_image,OpaqueAlphaChannel,exception);
1902 status=XShearImage(shear_image,shear.x,image->columns,image->rows,x_offset,
1903 (ssize_t) (shear_image->rows-image->rows)/2,exception);
1904 if (status == MagickFalse)
1906 shear_image=DestroyImage(shear_image);
1907 return((Image *) NULL);
1909 status=YShearImage(shear_image,shear.y,y_width,image->rows,(ssize_t)
1910 (shear_image->columns-y_width)/2,y_offset,exception);
1911 if (status == MagickFalse)
1913 shear_image=DestroyImage(shear_image);
1914 return((Image *) NULL);
1916 status=CropToFitImage(&shear_image,shear.x,shear.y,(MagickRealType)
1917 image->columns,(MagickRealType) image->rows,MagickFalse,exception);
1918 if (status == MagickFalse)
1920 shear_image=DestroyImage(shear_image);
1921 return((Image *) NULL);
1923 shear_image->compose=image->compose;
1924 shear_image->page.width=0;
1925 shear_image->page.height=0;
1926 return(shear_image);
1930 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1934 % S h e a r R o t a t e I m a g e %
1938 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1940 % ShearRotateImage() creates a new image that is a rotated copy of an existing
1941 % one. Positive angles rotate counter-clockwise (right-hand rule), while
1942 % negative angles rotate clockwise. Rotated images are usually larger than
1943 % the originals and have 'empty' triangular corners. X axis. Empty
1944 % triangles left over from shearing the image are filled with the background
1945 % color defined by member 'background_color' of the image. ShearRotateImage
1946 % allocates the memory necessary for the new Image structure and returns a
1947 % pointer to the new image.
1949 % ShearRotateImage() is based on the paper "A Fast Algorithm for General
1950 % Raster Rotatation" by Alan W. Paeth. ShearRotateImage is adapted from a
1951 % similar method based on the Paeth paper written by Michael Halle of the
1952 % Spatial Imaging Group, MIT Media Lab.
1954 % The format of the ShearRotateImage method is:
1956 % Image *ShearRotateImage(const Image *image,const double degrees,
1957 % ExceptionInfo *exception)
1959 % A description of each parameter follows.
1961 % o image: the image.
1963 % o degrees: Specifies the number of degrees to rotate the image.
1965 % o exception: return any errors or warnings in this structure.
1968 MagickExport Image *ShearRotateImage(const Image *image,const double degrees,
1969 ExceptionInfo *exception)
1998 Adjust rotation angle.
2000 assert(image != (Image *) NULL);
2001 assert(image->signature == MagickSignature);
2002 if (image->debug != MagickFalse)
2003 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2004 assert(exception != (ExceptionInfo *) NULL);
2005 assert(exception->signature == MagickSignature);
2007 while (angle < -45.0)
2009 for (rotations=0; angle > 45.0; rotations++)
2013 Calculate shear equations.
2015 integral_image=IntegralRotateImage(image,rotations,exception);
2016 if (integral_image == (Image *) NULL)
2017 ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
2018 shear.x=(-tan((double) DegreesToRadians(angle)/2.0));
2019 shear.y=sin((double) DegreesToRadians(angle));
2020 if ((shear.x == 0.0) && (shear.y == 0.0))
2021 return(integral_image);
2022 if (SetImageStorageClass(integral_image,DirectClass,exception) == MagickFalse)
2024 integral_image=DestroyImage(integral_image);
2025 return(integral_image);
2027 if (integral_image->matte == MagickFalse)
2028 (void) SetImageAlphaChannel(integral_image,OpaqueAlphaChannel,exception);
2032 width=image->columns;
2034 if ((rotations == 1) || (rotations == 3))
2037 height=image->columns;
2039 y_width=width+(ssize_t) floor(fabs(shear.x)*height+0.5);
2040 x_offset=(ssize_t) ceil((double) width+((fabs(shear.y)*height)-width)/2.0-
2042 y_offset=(ssize_t) ceil((double) height+((fabs(shear.y)*y_width)-height)/2.0-
2045 Surround image with a border.
2047 integral_image->border_color=integral_image->background_color;
2048 integral_image->compose=CopyCompositeOp;
2049 border_info.width=(size_t) x_offset;
2050 border_info.height=(size_t) y_offset;
2051 rotate_image=BorderImage(integral_image,&border_info,image->compose,
2053 integral_image=DestroyImage(integral_image);
2054 if (rotate_image == (Image *) NULL)
2055 ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
2059 status=XShearImage(rotate_image,shear.x,width,height,x_offset,(ssize_t)
2060 (rotate_image->rows-height)/2,exception);
2061 if (status == MagickFalse)
2063 rotate_image=DestroyImage(rotate_image);
2064 return((Image *) NULL);
2066 status=YShearImage(rotate_image,shear.y,y_width,height,(ssize_t)
2067 (rotate_image->columns-y_width)/2,y_offset,exception);
2068 if (status == MagickFalse)
2070 rotate_image=DestroyImage(rotate_image);
2071 return((Image *) NULL);
2073 status=XShearImage(rotate_image,shear.x,y_width,rotate_image->rows,(ssize_t)
2074 (rotate_image->columns-y_width)/2,0,exception);
2075 if (status == MagickFalse)
2077 rotate_image=DestroyImage(rotate_image);
2078 return((Image *) NULL);
2080 status=CropToFitImage(&rotate_image,shear.x,shear.y,(MagickRealType) width,
2081 (MagickRealType) height,MagickTrue,exception);
2082 if (status == MagickFalse)
2084 rotate_image=DestroyImage(rotate_image);
2085 return((Image *) NULL);
2087 rotate_image->compose=image->compose;
2088 rotate_image->page.width=0;
2089 rotate_image->page.height=0;
2090 return(rotate_image);