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 1999-2010 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 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.
48 #include "magick/studio.h"
49 #include "magick/artifact.h"
50 #include "magick/attribute.h"
51 #include "magick/blob-private.h"
52 #include "magick/cache-private.h"
53 #include "magick/color-private.h"
54 #include "magick/colorspace-private.h"
55 #include "magick/composite.h"
56 #include "magick/composite-private.h"
57 #include "magick/decorate.h"
58 #include "magick/distort.h"
59 #include "magick/draw.h"
60 #include "magick/exception.h"
61 #include "magick/exception-private.h"
62 #include "magick/gem.h"
63 #include "magick/geometry.h"
64 #include "magick/image.h"
65 #include "magick/image-private.h"
66 #include "magick/memory_.h"
67 #include "magick/list.h"
68 #include "magick/monitor.h"
69 #include "magick/monitor-private.h"
70 #include "magick/pixel-private.h"
71 #include "magick/quantum.h"
72 #include "magick/resource_.h"
73 #include "magick/shear.h"
74 #include "magick/statistic.h"
75 #include "magick/string_.h"
76 #include "magick/string-private.h"
77 #include "magick/threshold.h"
78 #include "magick/transform.h"
81 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
85 % A f f i n e T r a n s f o r m I m a g e %
89 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
91 % AffineTransformImage() transforms an image as dictated by the affine matrix.
92 % It allocates the memory necessary for the new Image structure and returns
93 % a pointer to the new image.
95 % The format of the AffineTransformImage method is:
97 % Image *AffineTransformImage(const Image *image,
98 % AffineMatrix *affine_matrix,ExceptionInfo *exception)
100 % A description of each parameter follows:
102 % o image: the image.
104 % o affine_matrix: the affine matrix.
106 % o exception: return any errors or warnings in this structure.
109 MagickExport Image *AffineTransformImage(const Image *image,
110 const AffineMatrix *affine_matrix,ExceptionInfo *exception)
119 Affine transform image.
121 assert(image->signature == MagickSignature);
122 if (image->debug != MagickFalse)
123 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
124 assert(affine_matrix != (AffineMatrix *) NULL);
125 assert(exception != (ExceptionInfo *) NULL);
126 assert(exception->signature == MagickSignature);
127 distort[0]=affine_matrix->sx;
128 distort[1]=affine_matrix->rx;
129 distort[2]=affine_matrix->ry;
130 distort[3]=affine_matrix->sy;
131 distort[4]=affine_matrix->tx;
132 distort[5]=affine_matrix->ty;
133 deskew_image=DistortImage(image,AffineProjectionDistortion,6,distort,
134 MagickTrue,exception);
135 return(deskew_image);
139 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
143 + C r o p T o F i t I m a g e %
147 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
149 % CropToFitImage() crops the sheared image as determined by the bounding box
150 % as defined by width and height and shearing angles.
152 % The format of the CropToFitImage method is:
154 % MagickBooleanType CropToFitImage(Image **image,
155 % const MagickRealType x_shear,const MagickRealType x_shear,
156 % const MagickRealType width,const MagickRealType height,
157 % const MagickBooleanType rotate,ExceptionInfo *exception)
159 % A description of each parameter follows.
161 % o image: the image.
163 % o x_shear, y_shear, width, height: Defines a region of the image to crop.
165 % o exception: return any errors or warnings in this structure.
168 static MagickBooleanType CropToFitImage(Image **image,
169 const MagickRealType x_shear,const MagickRealType y_shear,
170 const MagickRealType width,const MagickRealType height,
171 const MagickBooleanType rotate,ExceptionInfo *exception)
189 Calculate the rotated image size.
191 extent[0].x=(double) (-width/2.0);
192 extent[0].y=(double) (-height/2.0);
193 extent[1].x=(double) width/2.0;
194 extent[1].y=(double) (-height/2.0);
195 extent[2].x=(double) (-width/2.0);
196 extent[2].y=(double) height/2.0;
197 extent[3].x=(double) width/2.0;
198 extent[3].y=(double) height/2.0;
199 for (i=0; i < 4; i++)
201 extent[i].x+=x_shear*extent[i].y;
202 extent[i].y+=y_shear*extent[i].x;
203 if (rotate != MagickFalse)
204 extent[i].x+=x_shear*extent[i].y;
205 extent[i].x+=(double) (*image)->columns/2.0;
206 extent[i].y+=(double) (*image)->rows/2.0;
210 for (i=1; i < 4; i++)
212 if (min.x > extent[i].x)
214 if (min.y > extent[i].y)
216 if (max.x < extent[i].x)
218 if (max.y < extent[i].y)
221 geometry.x=(ssize_t) ceil(min.x-0.5);
222 geometry.y=(ssize_t) ceil(min.y-0.5);
223 geometry.width=(size_t) floor(max.x-min.x+0.5);
224 geometry.height=(size_t) floor(max.y-min.y+0.5);
226 (void) ParseAbsoluteGeometry("0x0+0+0",&(*image)->page);
227 crop_image=CropImage(*image,&geometry,exception);
228 if (crop_image == (Image *) NULL)
230 crop_image->page=page;
231 *image=DestroyImage(*image);
237 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
241 % D e s k e w I m a g e %
245 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
247 % DeskewImage() removes skew from the image. Skew is an artifact that
248 % occurs in scanned images because of the camera being misaligned,
249 % imperfections in the scanning or surface, or simply because the paper was
250 % not placed completely flat when scanned.
252 % The format of the DeskewImage method is:
254 % Image *DeskewImage(const Image *image,const double threshold,
255 % ExceptionInfo *exception)
257 % A description of each parameter follows:
259 % o image: the image.
261 % o threshold: separate background from foreground.
263 % o exception: return any errors or warnings in this structure.
267 typedef struct _RadonInfo
292 static RadonInfo *DestroyRadonInfo(RadonInfo *radon_info)
294 assert(radon_info != (RadonInfo *) NULL);
295 switch (radon_info->type)
299 if (radon_info->mapped == MagickFalse)
300 radon_info->cells=(unsigned short *) RelinquishMagickMemory(
303 radon_info->cells=(unsigned short *) UnmapBlob(radon_info->cells,
304 (size_t) radon_info->length);
305 RelinquishMagickResource(MemoryResource,radon_info->length);
310 radon_info->cells=(unsigned short *) UnmapBlob(radon_info->cells,(size_t)
312 RelinquishMagickResource(MapResource,radon_info->length);
316 if (radon_info->file != -1)
317 (void) close(radon_info->file);
318 (void) RelinquishUniqueFileResource(radon_info->path);
319 RelinquishMagickResource(DiskResource,radon_info->length);
325 return((RadonInfo *) RelinquishMagickMemory(radon_info));
328 static MagickBooleanType ResetRadonCells(RadonInfo *radon_info)
342 if (radon_info->type != DiskCache)
344 (void) ResetMagickMemory(radon_info->cells,0,(size_t) radon_info->length);
348 (void) MagickSeek(radon_info->file,0,SEEK_SET);
349 for (y=0; y < (ssize_t) radon_info->height; y++)
351 for (x=0; x < (ssize_t) radon_info->width; x++)
353 count=write(radon_info->file,&value,sizeof(*radon_info->cells));
354 if (count != (ssize_t) sizeof(*radon_info->cells))
357 if (x < (ssize_t) radon_info->width)
360 return(y < (ssize_t) radon_info->height ? MagickFalse : MagickTrue);
363 static RadonInfo *AcquireRadonInfo(const Image *image,const size_t width,
364 const size_t height,ExceptionInfo *exception)
372 radon_info=(RadonInfo *) AcquireMagickMemory(sizeof(*radon_info));
373 if (radon_info == (RadonInfo *) NULL)
374 return((RadonInfo *) NULL);
375 (void) ResetMagickMemory(radon_info,0,sizeof(*radon_info));
376 radon_info->width=width;
377 radon_info->height=height;
378 radon_info->length=(MagickSizeType) width*height*sizeof(*radon_info->cells);
379 radon_info->type=MemoryCache;
380 status=AcquireMagickResource(AreaResource,radon_info->length);
381 if ((status != MagickFalse) &&
382 (radon_info->length == (MagickSizeType) ((size_t) radon_info->length)))
384 status=AcquireMagickResource(MemoryResource,radon_info->length);
385 if (status != MagickFalse)
387 radon_info->mapped=MagickFalse;
388 radon_info->cells=(unsigned short *) AcquireMagickMemory((size_t)
390 if (radon_info->cells == (unsigned short *) NULL)
392 radon_info->mapped=MagickTrue;
393 radon_info->cells=(unsigned short *) MapBlob(-1,IOMode,0,(size_t)
396 if (radon_info->cells == (unsigned short *) NULL)
397 RelinquishMagickResource(MemoryResource,radon_info->length);
400 radon_info->file=(-1);
401 if (radon_info->cells == (unsigned short *) NULL)
403 status=AcquireMagickResource(DiskResource,radon_info->length);
404 if (status == MagickFalse)
406 (void) ThrowMagickException(exception,GetMagickModule(),CacheError,
407 "CacheResourcesExhausted","`%s'",image->filename);
408 return(DestroyRadonInfo(radon_info));
410 radon_info->type=DiskCache;
411 (void) AcquireMagickResource(MemoryResource,radon_info->length);
412 radon_info->file=AcquireUniqueFileResource(radon_info->path);
413 if (radon_info->file == -1)
414 return(DestroyRadonInfo(radon_info));
415 status=AcquireMagickResource(MapResource,radon_info->length);
416 if (status != MagickFalse)
418 status=ResetRadonCells(radon_info);
419 if (status != MagickFalse)
421 radon_info->cells=(unsigned short *) MapBlob(radon_info->file,
422 IOMode,0,(size_t) radon_info->length);
423 if (radon_info->cells != (unsigned short *) NULL)
424 radon_info->type=MapCache;
426 RelinquishMagickResource(MapResource,radon_info->length);
433 static inline size_t MagickMin(const size_t x,const size_t y)
440 static inline ssize_t ReadRadonCell(const RadonInfo *radon_info,
441 const off_t offset,const size_t length,unsigned char *buffer)
449 #if !defined(MAGICKCORE_HAVE_PPREAD)
450 #if defined(MAGICKCORE_OPENMP_SUPPORT)
451 #pragma omp critical (MagickCore_ReadRadonCell)
455 if (MagickSeek(radon_info->file,offset,SEEK_SET) >= 0)
459 for (i=0; i < (ssize_t) length; i+=count)
461 #if !defined(MAGICKCORE_HAVE_PPREAD)
462 count=read(radon_info->file,buffer+i,MagickMin(length-i,(size_t)
465 count=pread(radon_info->file,buffer+i,MagickMin(length-i,(size_t)
466 SSIZE_MAX),(off_t) (offset+i));
477 #if !defined(MAGICKCORE_HAVE_PPREAD)
484 static inline ssize_t WriteRadonCell(const RadonInfo *radon_info,
485 const off_t offset,const size_t length,const unsigned char *buffer)
493 #if !defined(MAGICKCORE_HAVE_PWRITE)
494 #if defined(MAGICKCORE_OPENMP_SUPPORT)
495 #pragma omp critical (MagickCore_WriteRadonCell)
498 if (MagickSeek(radon_info->file,offset,SEEK_SET) >= 0)
502 for (i=0; i < (ssize_t) length; i+=count)
504 #if !defined(MAGICKCORE_HAVE_PWRITE)
505 count=write(radon_info->file,buffer+i,MagickMin(length-i,(size_t)
508 count=pwrite(radon_info->file,buffer+i,MagickMin(length-i,(size_t)
509 SSIZE_MAX),(off_t) (offset+i));
520 #if !defined(MAGICKCORE_HAVE_PWRITE)
527 static inline unsigned short GetRadonCell(const RadonInfo *radon_info,
528 const ssize_t x,const ssize_t y)
536 i=(off_t) radon_info->height*x+y;
538 ((MagickSizeType) (i*sizeof(*radon_info->cells)) >= radon_info->length))
540 if (radon_info->type != DiskCache)
541 return(radon_info->cells[i]);
543 (void) ReadRadonCell(radon_info,i*sizeof(*radon_info->cells),
544 sizeof(*radon_info->cells),(unsigned char *) &value);
548 static inline MagickBooleanType SetRadonCell(const RadonInfo *radon_info,
549 const ssize_t x,const ssize_t y,const unsigned short value)
557 i=(off_t) radon_info->height*x+y;
559 ((MagickSizeType) (i*sizeof(*radon_info->cells)) >= radon_info->length))
561 if (radon_info->type != DiskCache)
563 radon_info->cells[i]=value;
566 count=WriteRadonCell(radon_info,i*sizeof(*radon_info->cells),
567 sizeof(*radon_info->cells),(const unsigned char *) &value);
568 if (count != (ssize_t) sizeof(*radon_info->cells))
573 static void RadonProjection(RadonInfo *source_cells,
574 RadonInfo *destination_cells,const ssize_t sign,size_t *projection)
591 for (step=1; step < p->width; step*=2)
593 for (x=0; x < (ssize_t) p->width; x+=2*(ssize_t) step)
604 for (i=0; i < (ssize_t) step; i++)
606 for (y=0; y < (ssize_t) (p->height-i-1); y++)
608 cell=GetRadonCell(p,x+i,y);
609 (void) SetRadonCell(q,x+2*i,y,cell+GetRadonCell(p,x+i+(ssize_t)
611 (void) SetRadonCell(q,x+2*i+1,y,cell+GetRadonCell(p,x+i+(ssize_t)
614 for ( ; y < (ssize_t) (p->height-i); y++)
616 cell=GetRadonCell(p,x+i,y);
617 (void) SetRadonCell(q,x+2*i,y,cell+GetRadonCell(p,x+i+(ssize_t) step,
619 (void) SetRadonCell(q,x+2*i+1,y,cell);
621 for ( ; y < (ssize_t) p->height; y++)
623 cell=GetRadonCell(p,x+i,y);
624 (void) SetRadonCell(q,x+2*i,y,cell);
625 (void) SetRadonCell(q,x+2*i+1,y,cell);
633 #if defined(MAGICKCORE_OPENMP_SUPPORT)
634 #pragma omp parallel for schedule(dynamic,4)
636 for (x=0; x < (ssize_t) p->width; x++)
645 for (y=0; y < (ssize_t) (p->height-1); y++)
650 delta=GetRadonCell(p,x,y)-(ssize_t) GetRadonCell(p,x,y+1);
653 projection[p->width+sign*x-1]=sum;
657 static MagickBooleanType RadonTransform(const Image *image,
658 const double threshold,size_t *projection,ExceptionInfo *exception)
686 for (width=1; width < ((image->columns+7)/8); width<<=1) ;
687 source_cells=AcquireRadonInfo(image,width,image->rows,exception);
688 destination_cells=AcquireRadonInfo(image,width,image->rows,exception);
689 if ((source_cells == (RadonInfo *) NULL) ||
690 (destination_cells == (RadonInfo *) NULL))
692 if (destination_cells != (RadonInfo *) NULL)
693 destination_cells=DestroyRadonInfo(destination_cells);
694 if (source_cells != (RadonInfo *) NULL)
695 source_cells=DestroyRadonInfo(source_cells);
698 if (ResetRadonCells(source_cells) == MagickFalse)
700 destination_cells=DestroyRadonInfo(destination_cells);
701 source_cells=DestroyRadonInfo(source_cells);
704 for (i=0; i < 256; i++)
706 byte=(unsigned char) i;
707 for (count=0; byte != 0; byte>>=1)
709 bits[i]=(unsigned short) count;
712 image_view=AcquireCacheView(image);
713 #if defined(MAGICKCORE_OPENMP_SUPPORT)
714 #pragma omp parallel for schedule(dynamic,4) shared(status)
716 for (y=0; y < (ssize_t) image->rows; y++)
718 register const PixelPacket
729 if (status == MagickFalse)
731 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
732 if (p == (const PixelPacket *) NULL)
739 i=(ssize_t) (image->columns+7)/8;
740 for (x=0; x < (ssize_t) image->columns; x++)
743 if (((MagickRealType) p->red < threshold) ||
744 ((MagickRealType) p->green < threshold) ||
745 ((MagickRealType) p->blue < threshold))
750 (void) SetRadonCell(source_cells,--i,y,bits[byte]);
759 (void) SetRadonCell(source_cells,--i,y,bits[byte]);
762 RadonProjection(source_cells,destination_cells,-1,projection);
763 (void) ResetRadonCells(source_cells);
764 #if defined(MAGICKCORE_OPENMP_SUPPORT)
765 #pragma omp parallel for schedule(dynamic,4) shared(status)
767 for (y=0; y < (ssize_t) image->rows; y++)
769 register const PixelPacket
780 if (status == MagickFalse)
782 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
783 if (p == (const PixelPacket *) NULL)
791 for (x=0; x < (ssize_t) image->columns; x++)
794 if (((MagickRealType) p->red < threshold) ||
795 ((MagickRealType) p->green < threshold) ||
796 ((MagickRealType) p->blue < threshold))
801 (void) SetRadonCell(source_cells,i++,y,bits[byte]);
810 (void) SetRadonCell(source_cells,i++,y,bits[byte]);
813 RadonProjection(source_cells,destination_cells,1,projection);
814 image_view=DestroyCacheView(image_view);
815 destination_cells=DestroyRadonInfo(destination_cells);
816 source_cells=DestroyRadonInfo(source_cells);
820 static void GetImageBackgroundColor(Image *image,const ssize_t offset,
821 ExceptionInfo *exception)
836 Compute average background color.
840 GetMagickPixelPacket(image,&background);
842 image_view=AcquireCacheView(image);
843 for (y=0; y < (ssize_t) image->rows; y++)
845 register const PixelPacket
851 if ((y >= offset) && (y < ((ssize_t) image->rows-offset)))
853 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
854 if (p == (const PixelPacket *) NULL)
856 for (x=0; x < (ssize_t) image->columns; x++)
858 if ((x >= offset) && (x < ((ssize_t) image->columns-offset)))
860 background.red+=QuantumScale*GetRedPixelComponent(p);
861 background.green+=QuantumScale*GetGreenPixelComponent(p);
862 background.blue+=QuantumScale*GetBluePixelComponent(p);
863 background.opacity+=QuantumScale*GetOpacityPixelComponent(p);
868 image_view=DestroyCacheView(image_view);
869 image->background_color.red=ClampToQuantum((MagickRealType) QuantumRange*
870 background.red/count);
871 image->background_color.green=ClampToQuantum((MagickRealType) QuantumRange*
872 background.green/count);
873 image->background_color.blue=ClampToQuantum((MagickRealType) QuantumRange*
874 background.blue/count);
875 image->background_color.opacity=ClampToQuantum((MagickRealType) QuantumRange*
876 background.opacity/count);
879 MagickExport Image *DeskewImage(const Image *image,const double threshold,
880 ExceptionInfo *exception)
915 Compute deskew angle.
917 for (width=1; width < ((image->columns+7)/8); width<<=1) ;
918 projection=(size_t *) AcquireQuantumMemory((size_t) (2*width-1),
919 sizeof(*projection));
920 if (projection == (size_t *) NULL)
921 ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
922 status=RadonTransform(image,threshold,projection,exception);
923 if (status == MagickFalse)
925 projection=(size_t *) RelinquishMagickMemory(projection);
926 ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
930 for (i=0; i < (ssize_t) (2*width-1); i++)
932 if (projection[i] > max_projection)
934 skew=i-(ssize_t) width+1;
935 max_projection=projection[i];
938 projection=(size_t *) RelinquishMagickMemory(projection);
942 clone_image=CloneImage(image,0,0,MagickTrue,exception);
943 if (clone_image == (Image *) NULL)
944 return((Image *) NULL);
945 (void) SetImageVirtualPixelMethod(clone_image,BackgroundVirtualPixelMethod);
946 degrees=RadiansToDegrees(-atan((double) skew/width/8));
947 if (image->debug != MagickFalse)
948 (void) LogMagickEvent(TransformEvent,GetMagickModule(),
949 " Deskew angle: %g",degrees);
950 affine_matrix.sx=cos(DegreesToRadians(fmod((double) degrees,360.0)));
951 affine_matrix.rx=sin(DegreesToRadians(fmod((double) degrees,360.0)));
952 affine_matrix.ry=(-sin(DegreesToRadians(fmod((double) degrees,360.0))));
953 affine_matrix.sy=cos(DegreesToRadians(fmod((double) degrees,360.0)));
954 affine_matrix.tx=0.0;
955 affine_matrix.ty=0.0;
956 artifact=GetImageArtifact(image,"deskew:auto-crop");
957 if (artifact == (const char *) NULL)
959 deskew_image=AffineTransformImage(clone_image,&affine_matrix,exception);
960 clone_image=DestroyImage(clone_image);
961 return(deskew_image);
966 GetImageBackgroundColor(clone_image,(ssize_t) StringToLong(artifact),
968 deskew_image=AffineTransformImage(clone_image,&affine_matrix,exception);
969 clone_image=DestroyImage(clone_image);
970 if (deskew_image == (Image *) NULL)
971 return((Image *) NULL);
972 median_image=MedianFilterImage(deskew_image,0.0,exception);
973 if (median_image == (Image *) NULL)
975 deskew_image=DestroyImage(deskew_image);
976 return((Image *) NULL);
978 geometry=GetImageBoundingBox(median_image,exception);
979 median_image=DestroyImage(median_image);
980 if (image->debug != MagickFalse)
981 (void) LogMagickEvent(TransformEvent,GetMagickModule()," Deskew geometry: "
982 "%.20gx%.20g%+.20g%+.20g",(double) geometry.width,(double)
983 geometry.height,(double) geometry.x,(double) geometry.y);
984 crop_image=CropImage(deskew_image,&geometry,exception);
985 deskew_image=DestroyImage(deskew_image);
990 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
994 + I n t e g r a l R o t a t e I m a g e %
998 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1000 % IntegralRotateImage() rotates the image an integral of 90 degrees. It
1001 % allocates the memory necessary for the new Image structure and returns a
1002 % pointer to the rotated image.
1004 % The format of the IntegralRotateImage method is:
1006 % Image *IntegralRotateImage(const Image *image,size_t rotations,
1007 % ExceptionInfo *exception)
1009 % A description of each parameter follows.
1011 % o image: the image.
1013 % o rotations: Specifies the number of 90 degree rotations.
1016 static Image *IntegralRotateImage(const Image *image,size_t rotations,
1017 ExceptionInfo *exception)
1019 #define RotateImageTag "Rotate/Image"
1041 Initialize rotated image attributes.
1043 assert(image != (Image *) NULL);
1047 return(CloneImage(image,0,0,MagickTrue,exception));
1048 if ((rotations == 1) || (rotations == 3))
1049 rotate_image=CloneImage(image,image->rows,image->columns,MagickTrue,
1052 rotate_image=CloneImage(image,image->columns,image->rows,MagickTrue,
1054 if (rotate_image == (Image *) NULL)
1055 return((Image *) NULL);
1057 Integral rotate the image.
1061 image_view=AcquireCacheView(image);
1062 rotate_view=AcquireCacheView(rotate_image);
1084 GetPixelCacheTileSize(image,&tile_width,&tile_height);
1085 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1086 #pragma omp parallel for schedule(static,1) shared(progress, status)
1088 for (tile_y=0; tile_y < (ssize_t) image->rows; tile_y+=(ssize_t) tile_height)
1093 if (status == MagickFalse)
1095 for (tile_x=0; tile_x < (ssize_t) image->columns; tile_x+=(ssize_t) tile_width)
1100 register const IndexPacket
1103 register const PixelPacket
1106 register IndexPacket
1107 *restrict rotate_indexes;
1112 register PixelPacket
1120 if ((tile_x+(ssize_t) tile_width) > (ssize_t) image->columns)
1121 width=(size_t) (tile_width-(tile_x+tile_width-
1124 if ((tile_y+(ssize_t) tile_height) > (ssize_t) image->rows)
1125 height=(size_t) (tile_height-(tile_y+tile_height-
1127 p=GetCacheViewVirtualPixels(image_view,tile_x,tile_y,width,height,
1129 if (p == (const PixelPacket *) NULL)
1134 indexes=GetCacheViewVirtualIndexQueue(image_view);
1135 for (y=0; y < (ssize_t) width; y++)
1137 register const PixelPacket
1138 *restrict tile_pixels;
1143 q=QueueCacheViewAuthenticPixels(rotate_view,(ssize_t)
1144 (rotate_image->columns-(tile_y+height)),y+tile_x,height,
1146 if (q == (PixelPacket *) NULL)
1151 tile_pixels=p+(height-1)*width+y;
1152 for (x=0; x < (ssize_t) height; x++)
1154 *q++=(*tile_pixels);
1157 rotate_indexes=GetCacheViewAuthenticIndexQueue(rotate_view);
1158 if ((indexes != (IndexPacket *) NULL) &&
1159 (rotate_indexes != (IndexPacket *) NULL))
1161 register const IndexPacket
1162 *restrict tile_indexes;
1164 tile_indexes=indexes+(height-1)*width+y;
1165 for (x=0; x < (ssize_t) height; x++)
1167 *rotate_indexes++=(*tile_indexes);
1168 tile_indexes-=width;
1171 sync=SyncCacheViewAuthenticPixels(rotate_view,exception);
1172 if (sync == MagickFalse)
1176 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1181 proceed=SetImageProgress(image,RotateImageTag,progress+=tile_height,
1183 if (proceed == MagickFalse)
1187 (void) SetImageProgress(image,RotateImageTag,(MagickOffsetType)
1188 image->rows-1,image->rows);
1189 Swap(page.width,page.height);
1190 Swap(page.x,page.y);
1191 if (page.width != 0)
1192 page.x=(ssize_t) (page.width-rotate_image->columns-page.x);
1200 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1201 #pragma omp parallel for schedule(static,8) shared(progress,status)
1203 for (y=0; y < (ssize_t) image->rows; y++)
1208 register const IndexPacket
1211 register const PixelPacket
1214 register IndexPacket
1215 *restrict rotate_indexes;
1220 register PixelPacket
1223 if (status == MagickFalse)
1225 p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,
1227 q=QueueCacheViewAuthenticPixels(rotate_view,0,(ssize_t) (image->rows-
1228 y-1),image->columns,1,exception);
1229 if ((p == (const PixelPacket *) NULL) || (q == (PixelPacket *) NULL))
1234 indexes=GetCacheViewVirtualIndexQueue(image_view);
1235 rotate_indexes=GetCacheViewAuthenticIndexQueue(rotate_view);
1237 for (x=0; x < (ssize_t) image->columns; x++)
1239 if ((indexes != (IndexPacket *) NULL) &&
1240 (rotate_indexes != (IndexPacket *) NULL))
1241 for (x=0; x < (ssize_t) image->columns; x++)
1242 rotate_indexes[image->columns-x-1]=indexes[x];
1243 sync=SyncCacheViewAuthenticPixels(rotate_view,exception);
1244 if (sync == MagickFalse)
1246 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1251 proceed=SetImageProgress(image,RotateImageTag,progress++,
1253 if (proceed == MagickFalse)
1257 if (page.width != 0)
1258 page.x=(ssize_t) (page.width-rotate_image->columns-page.x);
1259 if (page.height != 0)
1260 page.y=(ssize_t) (page.height-rotate_image->rows-page.y);
1275 GetPixelCacheTileSize(image,&tile_width,&tile_height);
1276 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1277 #pragma omp parallel for schedule(static,1) shared(progress,status)
1279 for (tile_y=0; tile_y < (ssize_t) image->rows; tile_y+=(ssize_t) tile_height)
1284 if (status == MagickFalse)
1286 for (tile_x=0; tile_x < (ssize_t) image->columns; tile_x+=(ssize_t) tile_width)
1291 register const IndexPacket
1294 register const PixelPacket
1297 register IndexPacket
1298 *restrict rotate_indexes;
1303 register PixelPacket
1311 if ((tile_x+(ssize_t) tile_width) > (ssize_t) image->columns)
1312 width=(size_t) (tile_width-(tile_x+tile_width-
1315 if ((tile_y+(ssize_t) tile_height) > (ssize_t) image->rows)
1316 height=(size_t) (tile_height-(tile_y+tile_height-
1318 p=GetCacheViewVirtualPixels(image_view,tile_x,tile_y,width,
1320 if (p == (const PixelPacket *) NULL)
1325 indexes=GetCacheViewVirtualIndexQueue(image_view);
1326 for (y=0; y < (ssize_t) width; y++)
1328 register const PixelPacket
1329 *restrict tile_pixels;
1334 q=QueueCacheViewAuthenticPixels(rotate_view,tile_y,(ssize_t)
1335 (y+rotate_image->rows-(tile_x+width)),height,1,exception);
1336 if (q == (PixelPacket *) NULL)
1341 tile_pixels=p+(width-1)-y;
1342 for (x=0; x < (ssize_t) height; x++)
1344 *q++=(*tile_pixels);
1347 rotate_indexes=GetCacheViewAuthenticIndexQueue(rotate_view);
1348 if ((indexes != (IndexPacket *) NULL) &&
1349 (rotate_indexes != (IndexPacket *) NULL))
1351 register const IndexPacket
1352 *restrict tile_indexes;
1354 tile_indexes=indexes+(width-1)-y;
1355 for (x=0; x < (ssize_t) height; x++)
1357 *rotate_indexes++=(*tile_indexes);
1358 tile_indexes+=width;
1361 sync=SyncCacheViewAuthenticPixels(rotate_view,exception);
1362 if (sync == MagickFalse)
1366 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1371 proceed=SetImageProgress(image,RotateImageTag,progress+=tile_height,
1373 if (proceed == MagickFalse)
1377 (void) SetImageProgress(image,RotateImageTag,(MagickOffsetType)
1378 image->rows-1,image->rows);
1379 Swap(page.width,page.height);
1380 Swap(page.x,page.y);
1381 if (page.height != 0)
1382 page.y=(ssize_t) (page.height-rotate_image->rows-page.y);
1386 rotate_view=DestroyCacheView(rotate_view);
1387 image_view=DestroyCacheView(image_view);
1388 rotate_image->type=image->type;
1389 rotate_image->page=page;
1390 if (status == MagickFalse)
1391 rotate_image=DestroyImage(rotate_image);
1392 return(rotate_image);
1396 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1400 + X S h e a r I m a g e %
1404 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1406 % XShearImage() shears the image in the X direction with a shear angle of
1407 % 'degrees'. Positive angles shear counter-clockwise (right-hand rule), and
1408 % negative angles shear clockwise. Angles are measured relative to a vertical
1409 % Y-axis. X shears will widen an image creating 'empty' triangles on the left
1410 % and right sides of the source image.
1412 % The format of the XShearImage method is:
1414 % MagickBooleanType XShearImage(Image *image,const MagickRealType degrees,
1415 % const size_t width,const size_t height,
1416 % const ssize_t x_offset,const ssize_t y_offset,ExceptionInfo *exception)
1418 % A description of each parameter follows.
1420 % o image: the image.
1422 % o degrees: A MagickRealType representing the shearing angle along the X
1425 % o width, height, x_offset, y_offset: Defines a region of the image
1428 % o exception: return any errors or warnings in this structure.
1431 static MagickBooleanType XShearImage(Image *image,const MagickRealType degrees,
1432 const size_t width,const size_t height,const ssize_t x_offset,
1433 const ssize_t y_offset,ExceptionInfo *exception)
1435 #define XShearImageTag "XShear/Image"
1458 assert(image != (Image *) NULL);
1459 assert(image->signature == MagickSignature);
1460 if (image->debug != MagickFalse)
1461 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1462 GetMagickPixelPacket(image,&background);
1463 SetMagickPixelPacket(image,&image->background_color,(IndexPacket *) NULL,
1465 if (image->colorspace == CMYKColorspace)
1466 ConvertRGBToCMYK(&background);
1472 image_view=AcquireCacheView(image);
1473 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1474 #pragma omp parallel for schedule(dynamic,4) shared(progress, status)
1476 for (y=0; y < (ssize_t) height; y++)
1493 register IndexPacket
1495 *restrict shear_indexes;
1497 register PixelPacket
1504 if (status == MagickFalse)
1506 p=GetCacheViewAuthenticPixels(image_view,0,y_offset+y,image->columns,1,
1508 if (p == (PixelPacket *) NULL)
1513 indexes=GetCacheViewAuthenticIndexQueue(image_view);
1516 displacement=degrees*(MagickRealType) (y-height/2.0);
1517 if (displacement == 0.0)
1519 if (displacement > 0.0)
1523 displacement*=(-1.0);
1526 step=(ssize_t) floor((double) displacement);
1527 area=(MagickRealType) (displacement-step);
1530 GetMagickPixelPacket(image,&source);
1531 GetMagickPixelPacket(image,&destination);
1537 Transfer pixels left-to-right.
1539 if (step > x_offset)
1542 shear_indexes=indexes-step;
1543 for (i=0; i < (ssize_t) width; i++)
1545 if ((x_offset+i) < step)
1547 SetMagickPixelPacket(image,++p,++indexes,&pixel);
1552 SetMagickPixelPacket(image,p,indexes,&source);
1553 MagickPixelCompositeAreaBlend(&pixel,(MagickRealType) pixel.opacity,
1554 &source,(MagickRealType) p->opacity,area,&destination);
1555 SetPixelPacket(image,&destination,q++,shear_indexes++);
1556 SetMagickPixelPacket(image,p++,indexes++,&pixel);
1558 MagickPixelCompositeAreaBlend(&pixel,(MagickRealType) pixel.opacity,
1559 &background,(MagickRealType) background.opacity,area,&destination);
1560 SetPixelPacket(image,&destination,q++,shear_indexes++);
1561 for (i=0; i < (step-1); i++)
1562 SetPixelPacket(image,&background,q++,shear_indexes++);
1568 Transfer pixels right-to-left.
1573 shear_indexes=indexes+step;
1574 for (i=0; i < (ssize_t) width; i++)
1580 if ((size_t) (x_offset+width+step-i) >= image->columns)
1582 SetMagickPixelPacket(image,p,indexes,&source);
1583 MagickPixelCompositeAreaBlend(&pixel,(MagickRealType) pixel.opacity,
1584 &source,(MagickRealType) p->opacity,area,&destination);
1585 SetPixelPacket(image,&destination,q,shear_indexes);
1586 SetMagickPixelPacket(image,p,indexes,&pixel);
1588 MagickPixelCompositeAreaBlend(&pixel,(MagickRealType) pixel.opacity,
1589 &background,(MagickRealType) background.opacity,area,&destination);
1590 SetPixelPacket(image,&destination,--q,--shear_indexes);
1591 for (i=0; i < (step-1); i++)
1592 SetPixelPacket(image,&background,--q,--shear_indexes);
1596 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1598 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1603 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1604 #pragma omp critical (MagickCore_XShearImage)
1606 proceed=SetImageProgress(image,XShearImageTag,progress++,height);
1607 if (proceed == MagickFalse)
1611 image_view=DestroyCacheView(image_view);
1616 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1620 + Y S h e a r I m a g e %
1624 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1626 % YShearImage shears the image in the Y direction with a shear angle of
1627 % 'degrees'. Positive angles shear counter-clockwise (right-hand rule), and
1628 % negative angles shear clockwise. Angles are measured relative to a
1629 % horizontal X-axis. Y shears will increase the height of an image creating
1630 % 'empty' triangles on the top and bottom of the source image.
1632 % The format of the YShearImage method is:
1634 % MagickBooleanType YShearImage(Image *image,const MagickRealType degrees,
1635 % const size_t width,const size_t height,
1636 % const ssize_t x_offset,const ssize_t y_offset,ExceptionInfo *exception)
1638 % A description of each parameter follows.
1640 % o image: the image.
1642 % o degrees: A MagickRealType representing the shearing angle along the Y
1645 % o width, height, x_offset, y_offset: Defines a region of the image
1648 % o exception: return any errors or warnings in this structure.
1651 static MagickBooleanType YShearImage(Image *image,const MagickRealType degrees,
1652 const size_t width,const size_t height,const ssize_t x_offset,
1653 const ssize_t y_offset,ExceptionInfo *exception)
1655 #define YShearImageTag "YShear/Image"
1678 assert(image != (Image *) NULL);
1679 assert(image->signature == MagickSignature);
1680 if (image->debug != MagickFalse)
1681 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1682 GetMagickPixelPacket(image,&background);
1683 SetMagickPixelPacket(image,&image->background_color,(IndexPacket *) NULL,
1685 if (image->colorspace == CMYKColorspace)
1686 ConvertRGBToCMYK(&background);
1692 image_view=AcquireCacheView(image);
1693 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1694 #pragma omp parallel for schedule(dynamic,4) shared(progress, status)
1696 for (x=0; x < (ssize_t) width; x++)
1710 register IndexPacket
1712 *restrict shear_indexes;
1717 register PixelPacket
1724 if (status == MagickFalse)
1726 p=GetCacheViewAuthenticPixels(image_view,x_offset+x,0,1,image->rows,
1728 if (p == (PixelPacket *) NULL)
1733 indexes=GetCacheViewAuthenticIndexQueue(image_view);
1736 displacement=degrees*(MagickRealType) (x-width/2.0);
1737 if (displacement == 0.0)
1739 if (displacement > 0.0)
1743 displacement*=(-1.0);
1746 step=(ssize_t) floor((double) displacement);
1747 area=(MagickRealType) (displacement-step);
1750 GetMagickPixelPacket(image,&source);
1751 GetMagickPixelPacket(image,&destination);
1757 Transfer pixels top-to-bottom.
1759 if (step > y_offset)
1762 shear_indexes=indexes-step;
1763 for (i=0; i < (ssize_t) height; i++)
1765 if ((y_offset+i) < step)
1767 SetMagickPixelPacket(image,++p,++indexes,&pixel);
1772 SetMagickPixelPacket(image,p,indexes,&source);
1773 MagickPixelCompositeAreaBlend(&pixel,(MagickRealType) pixel.opacity,
1774 &source,(MagickRealType) p->opacity,area,&destination);
1775 SetPixelPacket(image,&destination,q++,shear_indexes++);
1776 SetMagickPixelPacket(image,p++,indexes++,&pixel);
1778 MagickPixelCompositeAreaBlend(&pixel,(MagickRealType) pixel.opacity,
1779 &background,(MagickRealType) background.opacity,area,&destination);
1780 SetPixelPacket(image,&destination,q++,shear_indexes++);
1781 for (i=0; i < (step-1); i++)
1782 SetPixelPacket(image,&background,q++,shear_indexes++);
1788 Transfer pixels bottom-to-top.
1793 shear_indexes=indexes+step;
1794 for (i=0; i < (ssize_t) height; i++)
1800 if ((size_t) (y_offset+height+step-i) >= image->rows)
1802 SetMagickPixelPacket(image,p,indexes,&source);
1803 MagickPixelCompositeAreaBlend(&pixel,(MagickRealType) pixel.opacity,
1804 &source,(MagickRealType) p->opacity,area,&destination);
1805 SetPixelPacket(image,&destination,q,shear_indexes);
1806 SetMagickPixelPacket(image,p,indexes,&pixel);
1808 MagickPixelCompositeAreaBlend(&pixel,(MagickRealType) pixel.opacity,
1809 &background,(MagickRealType) background.opacity,area,&destination);
1810 SetPixelPacket(image,&destination,--q,--shear_indexes);
1811 for (i=0; i < (step-1); i++)
1812 SetPixelPacket(image,&background,--q,--shear_indexes);
1816 if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
1818 if (image->progress_monitor != (MagickProgressMonitor) NULL)
1823 #if defined(MAGICKCORE_OPENMP_SUPPORT)
1824 #pragma omp critical (MagickCore_YShearImage)
1826 proceed=SetImageProgress(image,YShearImageTag,progress++,image->rows);
1827 if (proceed == MagickFalse)
1831 image_view=DestroyCacheView(image_view);
1836 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1840 % R o t a t e I m a g e %
1844 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1846 % RotateImage() creates a new image that is a rotated copy of an existing
1847 % one. Positive angles rotate counter-clockwise (right-hand rule), while
1848 % negative angles rotate clockwise. Rotated images are usually larger than
1849 % the originals and have 'empty' triangular corners. X axis. Empty
1850 % triangles left over from shearing the image are filled with the background
1851 % color defined by member 'background_color' of the image. RotateImage
1852 % allocates the memory necessary for the new Image structure and returns a
1853 % pointer to the new image.
1855 % RotateImage() is based on the paper "A Fast Algorithm for General
1856 % Raster Rotatation" by Alan W. Paeth. RotateImage is adapted from a similar
1857 % method based on the Paeth paper written by Michael Halle of the Spatial
1858 % Imaging Group, MIT Media Lab.
1860 % The format of the RotateImage method is:
1862 % Image *RotateImage(const Image *image,const double degrees,
1863 % ExceptionInfo *exception)
1865 % A description of each parameter follows.
1867 % o image: the image.
1869 % o degrees: Specifies the number of degrees to rotate the image.
1871 % o exception: return any errors or warnings in this structure.
1874 MagickExport Image *RotateImage(const Image *image,const double degrees,
1875 ExceptionInfo *exception)
1904 Adjust rotation angle.
1906 assert(image != (Image *) NULL);
1907 assert(image->signature == MagickSignature);
1908 if (image->debug != MagickFalse)
1909 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
1910 assert(exception != (ExceptionInfo *) NULL);
1911 assert(exception->signature == MagickSignature);
1913 while (angle < -45.0)
1915 for (rotations=0; angle > 45.0; rotations++)
1919 Calculate shear equations.
1921 integral_image=IntegralRotateImage(image,rotations,exception);
1922 if (integral_image == (Image *) NULL)
1923 ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
1924 shear.x=(-tan((double) DegreesToRadians(angle)/2.0));
1925 shear.y=sin((double) DegreesToRadians(angle));
1926 if ((shear.x == 0.0) && (shear.y == 0.0))
1927 return(integral_image);
1928 if (SetImageStorageClass(integral_image,DirectClass) == MagickFalse)
1930 InheritException(exception,&integral_image->exception);
1931 integral_image=DestroyImage(integral_image);
1932 return(integral_image);
1934 if (integral_image->matte == MagickFalse)
1935 (void) SetImageAlphaChannel(integral_image,OpaqueAlphaChannel);
1939 width=image->columns;
1941 if ((rotations == 1) || (rotations == 3))
1944 height=image->columns;
1946 y_width=width+(ssize_t) floor(fabs(shear.x)*height+0.5);
1947 x_offset=(ssize_t) ceil((double) width+((fabs(shear.y)*height)-width)/2.0-
1949 y_offset=(ssize_t) ceil((double) height+((fabs(shear.y)*y_width)-height)/2.0-
1952 Surround image with a border.
1954 integral_image->border_color=integral_image->background_color;
1955 integral_image->compose=CopyCompositeOp;
1956 border_info.width=(size_t) x_offset;
1957 border_info.height=(size_t) y_offset;
1958 rotate_image=BorderImage(integral_image,&border_info,exception);
1959 integral_image=DestroyImage(integral_image);
1960 if (rotate_image == (Image *) NULL)
1961 ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
1965 status=XShearImage(rotate_image,shear.x,width,height,x_offset,(ssize_t)
1966 (rotate_image->rows-height)/2,exception);
1967 if (status == MagickFalse)
1969 rotate_image=DestroyImage(rotate_image);
1970 return((Image *) NULL);
1972 status=YShearImage(rotate_image,shear.y,y_width,height,(ssize_t)
1973 (rotate_image->columns-y_width)/2,y_offset,exception);
1974 if (status == MagickFalse)
1976 rotate_image=DestroyImage(rotate_image);
1977 return((Image *) NULL);
1979 status=XShearImage(rotate_image,shear.x,y_width,rotate_image->rows,(ssize_t)
1980 (rotate_image->columns-y_width)/2,0,exception);
1981 if (status == MagickFalse)
1983 rotate_image=DestroyImage(rotate_image);
1984 return((Image *) NULL);
1986 status=CropToFitImage(&rotate_image,shear.x,shear.y,(MagickRealType) width,
1987 (MagickRealType) height,MagickTrue,exception);
1988 if (status == MagickFalse)
1990 rotate_image=DestroyImage(rotate_image);
1991 return((Image *) NULL);
1993 rotate_image->compose=image->compose;
1994 rotate_image->page.width=0;
1995 rotate_image->page.height=0;
1996 return(rotate_image);
2000 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2004 % S h e a r I m a g e %
2008 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2010 % ShearImage() creates a new image that is a shear_image copy of an existing
2011 % one. Shearing slides one edge of an image along the X or Y axis, creating
2012 % a parallelogram. An X direction shear slides an edge along the X axis,
2013 % while a Y direction shear slides an edge along the Y axis. The amount of
2014 % the shear is controlled by a shear angle. For X direction shears, x_shear
2015 % is measured relative to the Y axis, and similarly, for Y direction shears
2016 % y_shear is measured relative to the X axis. Empty triangles left over from
2017 % shearing the image are filled with the background color defined by member
2018 % 'background_color' of the image.. ShearImage() allocates the memory
2019 % necessary for the new Image structure and returns a pointer to the new image.
2021 % ShearImage() is based on the paper "A Fast Algorithm for General Raster
2022 % Rotatation" by Alan W. Paeth.
2024 % The format of the ShearImage method is:
2026 % Image *ShearImage(const Image *image,const double x_shear,
2027 % const double y_shear,ExceptionInfo *exception)
2029 % A description of each parameter follows.
2031 % o image: the image.
2033 % o x_shear, y_shear: Specifies the number of degrees to shear the image.
2035 % o exception: return any errors or warnings in this structure.
2038 MagickExport Image *ShearImage(const Image *image,const double x_shear,
2039 const double y_shear,ExceptionInfo *exception)
2061 assert(image != (Image *) NULL);
2062 assert(image->signature == MagickSignature);
2063 if (image->debug != MagickFalse)
2064 (void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
2065 assert(exception != (ExceptionInfo *) NULL);
2066 assert(exception->signature == MagickSignature);
2067 if ((x_shear != 0.0) && (fmod(x_shear,90.0) == 0.0))
2068 ThrowImageException(ImageError,"AngleIsDiscontinuous");
2069 if ((y_shear != 0.0) && (fmod(y_shear,90.0) == 0.0))
2070 ThrowImageException(ImageError,"AngleIsDiscontinuous");
2072 Initialize shear angle.
2074 integral_image=CloneImage(image,0,0,MagickTrue,exception);
2075 if (integral_image == (Image *) NULL)
2076 ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
2077 shear.x=(-tan(DegreesToRadians(fmod(x_shear,360.0))));
2078 shear.y=tan(DegreesToRadians(fmod(y_shear,360.0)));
2079 if ((shear.x == 0.0) && (shear.y == 0.0))
2080 return(integral_image);
2081 if (SetImageStorageClass(integral_image,DirectClass) == MagickFalse)
2083 InheritException(exception,&integral_image->exception);
2084 integral_image=DestroyImage(integral_image);
2085 return(integral_image);
2087 if (integral_image->matte == MagickFalse)
2088 (void) SetImageAlphaChannel(integral_image,OpaqueAlphaChannel);
2092 y_width=image->columns+(ssize_t) floor(fabs(shear.x)*image->rows+0.5);
2093 x_offset=(ssize_t) ceil((double) image->columns+((fabs(shear.x)*image->rows)-
2094 image->columns)/2.0-0.5);
2095 y_offset=(ssize_t) ceil((double) image->rows+((fabs(shear.y)*y_width)-
2096 image->rows)/2.0-0.5);
2098 Surround image with border.
2100 integral_image->border_color=integral_image->background_color;
2101 integral_image->compose=CopyCompositeOp;
2102 border_info.width=(size_t) x_offset;
2103 border_info.height=(size_t) y_offset;
2104 shear_image=BorderImage(integral_image,&border_info,exception);
2105 integral_image=DestroyImage(integral_image);
2106 if (shear_image == (Image *) NULL)
2107 ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
2111 if (shear_image->matte == MagickFalse)
2112 (void) SetImageAlphaChannel(shear_image,OpaqueAlphaChannel);
2113 status=XShearImage(shear_image,shear.x,image->columns,image->rows,x_offset,
2114 (ssize_t) (shear_image->rows-image->rows)/2,exception);
2115 if (status == MagickFalse)
2117 shear_image=DestroyImage(shear_image);
2118 return((Image *) NULL);
2120 status=YShearImage(shear_image,shear.y,y_width,image->rows,(ssize_t)
2121 (shear_image->columns-y_width)/2,y_offset,exception);
2122 if (status == MagickFalse)
2124 shear_image=DestroyImage(shear_image);
2125 return((Image *) NULL);
2127 status=CropToFitImage(&shear_image,shear.x,shear.y,(MagickRealType)
2128 image->columns,(MagickRealType) image->rows,MagickFalse,exception);
2129 if (status == MagickFalse)
2131 shear_image=DestroyImage(shear_image);
2132 return((Image *) NULL);
2134 shear_image->compose=image->compose;
2135 shear_image->page.width=0;
2136 shear_image->page.height=0;
2137 return(shear_image);