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imagemagick/magick/shear.c

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Import Upstream version 6.9.11.60
2023-02-03 21:16:55 +08:00
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% SSSSS H H EEEEE AAA RRRR %
% SS H H E A A R R %
% SSS HHHHH EEE AAAAA RRRR %
% SS H H E A A R R %
% SSSSS H H EEEEE A A R R %
% %
% %
% MagickCore Methods to Shear or Rotate an Image by an Arbitrary Angle %
% %
% Software Design %
% Cristy %
% July 1992 %
% %
% %
% Copyright 1999-2021 ImageMagick Studio LLC, a non-profit organization %
% dedicated to making software imaging solutions freely available. %
% %
% You may not use this file except in compliance with the License. You may %
% obtain a copy of the License at %
% %
% https://imagemagick.org/script/license.php %
% %
% Unless required by applicable law or agreed to in writing, software %
% distributed under the License is distributed on an "AS IS" BASIS, %
% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. %
% See the License for the specific language governing permissions and %
% limitations under the License. %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% The XShearImage() and YShearImage() methods are based on the paper "A Fast
% Algorithm for General Raster Rotation" by Alan W. Paeth, Graphics
% Interface '86 (Vancouver). ShearRotateImage() is adapted from a similar
% method based on the Paeth paper written by Michael Halle of the Spatial
% Imaging Group, MIT Media Lab.
%
*/
/*
Include declarations.
*/
#include "magick/studio.h"
#include "magick/artifact.h"
#include "magick/attribute.h"
#include "magick/blob-private.h"
#include "magick/cache-private.h"
#include "magick/channel.h"
#include "magick/color-private.h"
#include "magick/colorspace-private.h"
#include "magick/composite.h"
#include "magick/composite-private.h"
#include "magick/decorate.h"
#include "magick/distort.h"
#include "magick/draw.h"
#include "magick/exception.h"
#include "magick/exception-private.h"
#include "magick/gem.h"
#include "magick/geometry.h"
#include "magick/image.h"
#include "magick/image-private.h"
#include "magick/memory_.h"
#include "magick/list.h"
#include "magick/matrix.h"
#include "magick/monitor.h"
#include "magick/monitor-private.h"
#include "magick/nt-base-private.h"
#include "magick/pixel-private.h"
#include "magick/quantum.h"
#include "magick/resource_.h"
#include "magick/shear.h"
#include "magick/statistic.h"
#include "magick/string_.h"
#include "magick/string-private.h"
#include "magick/thread-private.h"
#include "magick/threshold.h"
#include "magick/token.h"
#include "magick/transform.h"
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
+ C r o p T o F i t I m a g e %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% CropToFitImage() crops the sheared image as determined by the bounding box
% as defined by width and height and shearing angles.
%
% The format of the CropToFitImage method is:
%
% MagickBooleanType CropToFitImage(Image **image,
% const MagickRealType x_shear,const MagickRealType x_shear,
% const MagickRealType width,const MagickRealType height,
% const MagickBooleanType rotate,ExceptionInfo *exception)
%
% A description of each parameter follows.
%
% o image: the image.
%
% o x_shear, y_shear, width, height: Defines a region of the image to crop.
%
% o exception: return any errors or warnings in this structure.
%
*/
static MagickBooleanType CropToFitImage(Image **image,
const MagickRealType x_shear,const MagickRealType y_shear,
const MagickRealType width,const MagickRealType height,
const MagickBooleanType rotate,ExceptionInfo *exception)
{
Image
*crop_image;
PointInfo
extent[4],
min,
max;
RectangleInfo
geometry,
page;
ssize_t
i;
/*
Calculate the rotated image size.
*/
extent[0].x=(double) (-width/2.0);
extent[0].y=(double) (-height/2.0);
extent[1].x=(double) width/2.0;
extent[1].y=(double) (-height/2.0);
extent[2].x=(double) (-width/2.0);
extent[2].y=(double) height/2.0;
extent[3].x=(double) width/2.0;
extent[3].y=(double) height/2.0;
for (i=0; i < 4; i++)
{
extent[i].x+=x_shear*extent[i].y;
extent[i].y+=y_shear*extent[i].x;
if (rotate != MagickFalse)
extent[i].x+=x_shear*extent[i].y;
extent[i].x+=(double) (*image)->columns/2.0;
extent[i].y+=(double) (*image)->rows/2.0;
}
min=extent[0];
max=extent[0];
for (i=1; i < 4; i++)
{
if (min.x > extent[i].x)
min.x=extent[i].x;
if (min.y > extent[i].y)
min.y=extent[i].y;
if (max.x < extent[i].x)
max.x=extent[i].x;
if (max.y < extent[i].y)
max.y=extent[i].y;
}
geometry.x=CastDoubleToLong(ceil(min.x-0.5));
geometry.y=CastDoubleToLong(ceil(min.y-0.5));
geometry.width=(size_t) floor(max.x-min.x+0.5);
geometry.height=(size_t) floor(max.y-min.y+0.5);
page=(*image)->page;
(void) ParseAbsoluteGeometry("0x0+0+0",&(*image)->page);
crop_image=CropImage(*image,&geometry,exception);
if (crop_image == (Image *) NULL)
return(MagickFalse);
crop_image->page=page;
*image=DestroyImage(*image);
*image=crop_image;
return(MagickTrue);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% D e s k e w I m a g e %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% DeskewImage() removes skew from the image. Skew is an artifact that
% occurs in scanned images because of the camera being misaligned,
% imperfections in the scanning or surface, or simply because the paper was
% not placed completely flat when scanned.
%
% The amount of rotation calculated to deskew the image is saved in the
% artifact "deskew:angle".
%
% If the artifact "deskew:auto-crop" is given the image will be automatically
% cropped of the excess background.
%
% The format of the DeskewImage method is:
%
% Image *DeskewImage(const Image *image,const double threshold,
% ExceptionInfo *exception)
%
% A description of each parameter follows:
%
% o image: the image.
%
% o threshold: separate background from foreground.
%
% o exception: return any errors or warnings in this structure.
%
*/
static void RadonProjection(const Image *image,MatrixInfo *source_matrix,
MatrixInfo *destination_matrix,const ssize_t sign,size_t *projection)
{
MatrixInfo
*swap;
MatrixInfo
*p,
*q;
ssize_t
x;
size_t
step;
p=source_matrix;
q=destination_matrix;
for (step=1; step < GetMatrixColumns(p); step*=2)
{
for (x=0; x < (ssize_t) GetMatrixColumns(p); x+=2*(ssize_t) step)
{
ssize_t
i;
ssize_t
y;
unsigned short
element,
neighbor;
for (i=0; i < (ssize_t) step; i++)
{
for (y=0; y < (ssize_t) (GetMatrixRows(p)-i-1); y++)
{
if (GetMatrixElement(p,x+i,y,&element) == MagickFalse)
continue;
if (GetMatrixElement(p,x+i+step,y+i,&neighbor) == MagickFalse)
continue;
neighbor+=element;
if (SetMatrixElement(q,x+2*i,y,&neighbor) == MagickFalse)
continue;
if (GetMatrixElement(p,x+i+step,y+i+1,&neighbor) == MagickFalse)
continue;
neighbor+=element;
if (SetMatrixElement(q,x+2*i+1,y,&neighbor) == MagickFalse)
continue;
}
for ( ; y < (ssize_t) (GetMatrixRows(p)-i); y++)
{
if (GetMatrixElement(p,x+i,y,&element) == MagickFalse)
continue;
if (GetMatrixElement(p,x+i+step,y+i,&neighbor) == MagickFalse)
continue;
neighbor+=element;
if (SetMatrixElement(q,x+2*i,y,&neighbor) == MagickFalse)
continue;
if (SetMatrixElement(q,x+2*i+1,y,&element) == MagickFalse)
continue;
}
for ( ; y < (ssize_t) GetMatrixRows(p); y++)
{
if (GetMatrixElement(p,x+i,y,&element) == MagickFalse)
continue;
if (SetMatrixElement(q,x+2*i,y,&element) == MagickFalse)
continue;
if (SetMatrixElement(q,x+2*i+1,y,&element) == MagickFalse)
continue;
}
}
}
swap=p;
p=q;
q=swap;
}
#if defined(MAGICKCORE_OPENMP_SUPPORT)
#pragma omp parallel for schedule(static) \
magick_number_threads(image,image,GetMatrixColumns(p),1)
#endif
for (x=0; x < (ssize_t) GetMatrixColumns(p); x++)
{
ssize_t
y;
size_t
sum;
sum=0;
for (y=0; y < (ssize_t) (GetMatrixRows(p)-1); y++)
{
ssize_t
delta;
unsigned short
element,
neighbor;
if (GetMatrixElement(p,x,y,&element) == MagickFalse)
continue;
if (GetMatrixElement(p,x,y+1,&neighbor) == MagickFalse)
continue;
delta=(ssize_t) element-(ssize_t) neighbor;
sum+=delta*delta;
}
projection[GetMatrixColumns(p)+sign*x-1]=sum;
}
}
static MagickBooleanType RadonTransform(const Image *image,
const double threshold,size_t *projection,ExceptionInfo *exception)
{
CacheView
*image_view;
MatrixInfo
*destination_matrix,
*source_matrix;
MagickBooleanType
status;
ssize_t
i;
size_t
count,
width;
ssize_t
y;
unsigned char
byte;
unsigned short
bits[256];
for (width=1; width < ((image->columns+7)/8); width<<=1) ;
source_matrix=AcquireMatrixInfo(width,image->rows,sizeof(unsigned short),
exception);
destination_matrix=AcquireMatrixInfo(width,image->rows,sizeof(unsigned short),
exception);
if ((source_matrix == (MatrixInfo *) NULL) ||
(destination_matrix == (MatrixInfo *) NULL))
{
if (destination_matrix != (MatrixInfo *) NULL)
destination_matrix=DestroyMatrixInfo(destination_matrix);
if (source_matrix != (MatrixInfo *) NULL)
source_matrix=DestroyMatrixInfo(source_matrix);
return(MagickFalse);
}
if (NullMatrix(source_matrix) == MagickFalse)
{
destination_matrix=DestroyMatrixInfo(destination_matrix);
source_matrix=DestroyMatrixInfo(source_matrix);
return(MagickFalse);
}
for (i=0; i < 256; i++)
{
byte=(unsigned char) i;
for (count=0; byte != 0; byte>>=1)
count+=byte & 0x01;
bits[i]=(unsigned short) count;
}
status=MagickTrue;
image_view=AcquireVirtualCacheView(image,exception);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
#pragma omp parallel for schedule(static) shared(status) \
magick_number_threads(image,image,image->rows,1)
#endif
for (y=0; y < (ssize_t) image->rows; y++)
{
const PixelPacket
*magick_restrict p;
ssize_t
i,
x;
size_t
bit,
byte;
unsigned short
value;
if (status == MagickFalse)
continue;
p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
if (p == (const PixelPacket *) NULL)
{
status=MagickFalse;
continue;
}
bit=0;
byte=0;
i=(ssize_t) (image->columns+7)/8;
for (x=0; x < (ssize_t) image->columns; x++)
{
byte<<=1;
if (((MagickRealType) GetPixelRed(p) < threshold) ||
((MagickRealType) GetPixelGreen(p) < threshold) ||
((MagickRealType) GetPixelBlue(p) < threshold))
byte|=0x01;
bit++;
if (bit == 8)
{
value=bits[byte];
(void) SetMatrixElement(source_matrix,--i,y,&value);
bit=0;
byte=0;
}
p++;
}
if (bit != 0)
{
byte<<=(8-bit);
value=bits[byte];
(void) SetMatrixElement(source_matrix,--i,y,&value);
}
}
RadonProjection(image,source_matrix,destination_matrix,-1,projection);
(void) NullMatrix(source_matrix);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
#pragma omp parallel for schedule(static) shared(status) \
magick_number_threads(image,image,image->rows,1)
#endif
for (y=0; y < (ssize_t) image->rows; y++)
{
const PixelPacket
*magick_restrict p;
ssize_t
i,
x;
size_t
bit,
byte;
unsigned short
value;
if (status == MagickFalse)
continue;
p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
if (p == (const PixelPacket *) NULL)
{
status=MagickFalse;
continue;
}
bit=0;
byte=0;
i=0;
for (x=0; x < (ssize_t) image->columns; x++)
{
byte<<=1;
if (((MagickRealType) GetPixelRed(p) < threshold) ||
((MagickRealType) GetPixelGreen(p) < threshold) ||
((MagickRealType) GetPixelBlue(p) < threshold))
byte|=0x01;
bit++;
if (bit == 8)
{
value=bits[byte];
(void) SetMatrixElement(source_matrix,i++,y,&value);
bit=0;
byte=0;
}
p++;
}
if (bit != 0)
{
byte<<=(8-bit);
value=bits[byte];
(void) SetMatrixElement(source_matrix,i++,y,&value);
}
}
RadonProjection(image,source_matrix,destination_matrix,1,projection);
image_view=DestroyCacheView(image_view);
destination_matrix=DestroyMatrixInfo(destination_matrix);
source_matrix=DestroyMatrixInfo(source_matrix);
return(MagickTrue);
}
static void GetImageBackgroundColor(Image *image,const ssize_t offset,
ExceptionInfo *exception)
{
CacheView
*image_view;
MagickPixelPacket
background;
MagickRealType
count;
ssize_t
y;
/*
Compute average background color.
*/
if (offset <= 0)
return;
GetMagickPixelPacket(image,&background);
count=0.0;
image_view=AcquireVirtualCacheView(image,exception);
for (y=0; y < (ssize_t) image->rows; y++)
{
const PixelPacket
*magick_restrict p;
ssize_t
x;
if ((y >= offset) && (y < ((ssize_t) image->rows-offset)))
continue;
p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,exception);
if (p == (const PixelPacket *) NULL)
continue;
for (x=0; x < (ssize_t) image->columns; x++)
{
if ((x >= offset) && (x < ((ssize_t) image->columns-offset)))
continue;
background.red+=QuantumScale*GetPixelRed(p);
background.green+=QuantumScale*GetPixelGreen(p);
background.blue+=QuantumScale*GetPixelBlue(p);
background.opacity+=QuantumScale*GetPixelOpacity(p);
count++;
p++;
}
}
image_view=DestroyCacheView(image_view);
image->background_color.red=ClampToQuantum((MagickRealType) QuantumRange*
background.red/count);
image->background_color.green=ClampToQuantum((MagickRealType) QuantumRange*
background.green/count);
image->background_color.blue=ClampToQuantum((MagickRealType) QuantumRange*
background.blue/count);
image->background_color.opacity=ClampToQuantum((MagickRealType) QuantumRange*
background.opacity/count);
}
MagickExport Image *DeskewImage(const Image *image,const double threshold,
ExceptionInfo *exception)
{
AffineMatrix
affine_matrix;
const char
*artifact;
double
degrees;
Image
*clone_image,
*crop_image,
*deskew_image,
*median_image;
MagickBooleanType
status;
RectangleInfo
geometry;
ssize_t
i;
size_t
max_projection,
*projection,
width;
ssize_t
skew;
/*
Compute deskew angle.
*/
for (width=1; width < ((image->columns+7)/8); width<<=1) ;
projection=(size_t *) AcquireQuantumMemory((size_t) (2*width-1),
sizeof(*projection));
if (projection == (size_t *) NULL)
ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
status=RadonTransform(image,threshold,projection,exception);
if (status == MagickFalse)
{
projection=(size_t *) RelinquishMagickMemory(projection);
ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
}
max_projection=0;
skew=0;
for (i=0; i < (ssize_t) (2*width-1); i++)
{
if (projection[i] > max_projection)
{
skew=i-(ssize_t) width+1;
max_projection=projection[i];
}
}
projection=(size_t *) RelinquishMagickMemory(projection);
degrees=RadiansToDegrees(-atan((double) skew/width/8));
if (image->debug != MagickFalse)
(void) LogMagickEvent(TransformEvent,GetMagickModule(),
" Deskew angle: %g",degrees);
/*
Deskew image.
*/
clone_image=CloneImage(image,0,0,MagickTrue,exception);
if (clone_image == (Image *) NULL)
return((Image *) NULL);
{
char
angle[MaxTextExtent];
(void) FormatLocaleString(angle,MaxTextExtent,"%g",degrees);
(void) SetImageArtifact(clone_image,"deskew:angle",angle);
}
(void) SetImageVirtualPixelMethod(clone_image,BackgroundVirtualPixelMethod);
affine_matrix.sx=cos(DegreesToRadians(fmod((double) degrees,360.0)));
affine_matrix.rx=sin(DegreesToRadians(fmod((double) degrees,360.0)));
affine_matrix.ry=(-sin(DegreesToRadians(fmod((double) degrees,360.0))));
affine_matrix.sy=cos(DegreesToRadians(fmod((double) degrees,360.0)));
affine_matrix.tx=0.0;
affine_matrix.ty=0.0;
artifact=GetImageArtifact(image,"deskew:auto-crop");
if (IsMagickTrue(artifact) == MagickFalse)
{
deskew_image=AffineTransformImage(clone_image,&affine_matrix,exception);
clone_image=DestroyImage(clone_image);
return(deskew_image);
}
/*
Auto-crop image.
*/
GetImageBackgroundColor(clone_image,(ssize_t) StringToLong(artifact),
exception);
deskew_image=AffineTransformImage(clone_image,&affine_matrix,exception);
clone_image=DestroyImage(clone_image);
if (deskew_image == (Image *) NULL)
return((Image *) NULL);
median_image=StatisticImage(deskew_image,MedianStatistic,3,3,exception);
if (median_image == (Image *) NULL)
{
deskew_image=DestroyImage(deskew_image);
return((Image *) NULL);
}
geometry=GetImageBoundingBox(median_image,exception);
median_image=DestroyImage(median_image);
if (image->debug != MagickFalse)
(void) LogMagickEvent(TransformEvent,GetMagickModule()," Deskew geometry: "
"%.20gx%.20g%+.20g%+.20g",(double) geometry.width,(double)
geometry.height,(double) geometry.x,(double) geometry.y);
crop_image=CropImage(deskew_image,&geometry,exception);
deskew_image=DestroyImage(deskew_image);
return(crop_image);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% I n t e g r a l R o t a t e I m a g e %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% IntegralRotateImage() rotates the image an integral of 90 degrees. It
% allocates the memory necessary for the new Image structure and returns a
% pointer to the rotated image.
%
% The format of the IntegralRotateImage method is:
%
% Image *IntegralRotateImage(const Image *image,size_t rotations,
% ExceptionInfo *exception)
%
% A description of each parameter follows.
%
% o image: the image.
%
% o rotations: Specifies the number of 90 degree rotations.
%
*/
MagickExport Image *IntegralRotateImage(const Image *image,size_t rotations,
ExceptionInfo *exception)
{
#define RotateImageTag "Rotate/Image"
CacheView
*image_view,
*rotate_view;
Image
*rotate_image;
MagickBooleanType
status;
MagickOffsetType
progress;
RectangleInfo
page;
ssize_t
y;
/*
Initialize rotated image attributes.
*/
assert(image != (Image *) NULL);
page=image->page;
rotations%=4;
rotate_image=(Image *) NULL;
rotate_view=(CacheView *) NULL;
switch (rotations)
{
case 0:
default:
{
rotate_image=CloneImage(image,0,0,MagickTrue,exception);
break;
}
case 2:
{
rotate_image=CloneImage(image,image->columns,image->rows,MagickTrue,
exception);
break;
}
case 1:
case 3:
{
rotate_image=CloneImage(image,image->rows,image->columns,MagickTrue,
exception);
break;
}
}
if (rotate_image == (Image *) NULL)
return((Image *) NULL);
if (rotations == 0)
return(rotate_image);
/*
Integral rotate the image.
*/
status=MagickTrue;
progress=0;
image_view=AcquireVirtualCacheView(image,exception);
rotate_view=AcquireAuthenticCacheView(rotate_image,exception);
switch (rotations)
{
case 1:
{
size_t
tile_height,
tile_width;
ssize_t
tile_y;
/*
Rotate 90 degrees.
*/
GetPixelCacheTileSize(image,&tile_width,&tile_height);
tile_width=image->columns;
#if defined(MAGICKCORE_OPENMP_SUPPORT)
#pragma omp parallel for schedule(static) shared(status) \
magick_number_threads(image,rotate_image,image->rows/tile_height,1)
#endif
for (tile_y=0; tile_y < (ssize_t) image->rows; tile_y+=(ssize_t) tile_height)
{
ssize_t
tile_x;
if (status == MagickFalse)
continue;
for (tile_x=0; tile_x < (ssize_t) image->columns; tile_x+=(ssize_t) tile_width)
{
MagickBooleanType
sync;
const IndexPacket
*magick_restrict indexes;
const PixelPacket
*magick_restrict p;
IndexPacket
*magick_restrict rotate_indexes;
PixelPacket
*magick_restrict q;
ssize_t
y;
size_t
height,
width;
width=tile_width;
if ((tile_x+(ssize_t) tile_width) > (ssize_t) image->columns)
width=(size_t) (tile_width-(tile_x+tile_width-image->columns));
height=tile_height;
if ((tile_y+(ssize_t) tile_height) > (ssize_t) image->rows)
height=(size_t) (tile_height-(tile_y+tile_height-image->rows));
p=GetCacheViewVirtualPixels(image_view,tile_x,tile_y,width,height,
exception);
if (p == (const PixelPacket *) NULL)
{
status=MagickFalse;
break;
}
indexes=GetCacheViewVirtualIndexQueue(image_view);
for (y=0; y < (ssize_t) width; y++)
{
const PixelPacket
*magick_restrict tile_pixels;
ssize_t
x;
if (status == MagickFalse)
continue;
q=QueueCacheViewAuthenticPixels(rotate_view,(ssize_t)
(rotate_image->columns-(tile_y+height)),y+tile_x,height,1,
exception);
if (q == (PixelPacket *) NULL)
{
status=MagickFalse;
continue;
}
tile_pixels=p+(height-1)*width+y;
for (x=0; x < (ssize_t) height; x++)
{
*q++=(*tile_pixels);
tile_pixels-=width;
}
rotate_indexes=GetCacheViewAuthenticIndexQueue(rotate_view);
if ((indexes != (IndexPacket *) NULL) &&
(rotate_indexes != (IndexPacket *) NULL))
{
const IndexPacket
*magick_restrict tile_indexes;
tile_indexes=indexes+(height-1)*width+y;
for (x=0; x < (ssize_t) height; x++)
{
*rotate_indexes++=(*tile_indexes);
tile_indexes-=width;
}
}
sync=SyncCacheViewAuthenticPixels(rotate_view,exception);
if (sync == MagickFalse)
status=MagickFalse;
}
}
if (image->progress_monitor != (MagickProgressMonitor) NULL)
{
MagickBooleanType
proceed;
proceed=SetImageProgress(image,RotateImageTag,progress+=tile_height,
image->rows);
if (proceed == MagickFalse)
status=MagickFalse;
}
}
(void) SetImageProgress(image,RotateImageTag,(MagickOffsetType)
image->rows-1,image->rows);
Swap(page.width,page.height);
Swap(page.x,page.y);
if (page.width != 0)
page.x=(ssize_t) (page.width-rotate_image->columns-page.x);
break;
}
case 2:
{
/*
Rotate 180 degrees.
*/
#if defined(MAGICKCORE_OPENMP_SUPPORT)
#pragma omp parallel for schedule(static) shared(status) \
magick_number_threads(image,rotate_image,image->rows,1)
#endif
for (y=0; y < (ssize_t) image->rows; y++)
{
MagickBooleanType
sync;
const IndexPacket
*magick_restrict indexes;
const PixelPacket
*magick_restrict p;
IndexPacket
*magick_restrict rotate_indexes;
PixelPacket
*magick_restrict q;
ssize_t
x;
if (status == MagickFalse)
continue;
p=GetCacheViewVirtualPixels(image_view,0,y,image->columns,1,
exception);
q=QueueCacheViewAuthenticPixels(rotate_view,0,(ssize_t) (image->rows-y-
1),image->columns,1,exception);
if ((p == (const PixelPacket *) NULL) || (q == (PixelPacket *) NULL))
{
status=MagickFalse;
continue;
}
indexes=GetCacheViewVirtualIndexQueue(image_view);
rotate_indexes=GetCacheViewAuthenticIndexQueue(rotate_view);
q+=image->columns;
for (x=0; x < (ssize_t) image->columns; x++)
*--q=(*p++);
if ((indexes != (IndexPacket *) NULL) &&
(rotate_indexes != (IndexPacket *) NULL))
for (x=0; x < (ssize_t) image->columns; x++)
SetPixelIndex(rotate_indexes+image->columns-x-1,
GetPixelIndex(indexes+x));
sync=SyncCacheViewAuthenticPixels(rotate_view,exception);
if (sync == MagickFalse)
status=MagickFalse;
if (image->progress_monitor != (MagickProgressMonitor) NULL)
{
MagickBooleanType
proceed;
#if defined(MAGICKCORE_OPENMP_SUPPORT)
#pragma omp atomic
#endif
progress++;
proceed=SetImageProgress(image,RotateImageTag,progress,image->rows);
if (proceed == MagickFalse)
status=MagickFalse;
}
}
if (page.width != 0)
page.x=(ssize_t) (page.width-rotate_image->columns-page.x);
if (page.height != 0)
page.y=(ssize_t) (page.height-rotate_image->rows-page.y);
break;
}
case 3:
{
size_t
tile_height,
tile_width;
ssize_t
tile_y;
/*
Rotate 270 degrees.
*/
GetPixelCacheTileSize(image,&tile_width,&tile_height);
tile_width=image->columns;
#if defined(MAGICKCORE_OPENMP_SUPPORT)
#pragma omp parallel for schedule(static) shared(status) \
magick_number_threads(image,rotate_image,image->rows/tile_height,1)
#endif
for (tile_y=0; tile_y < (ssize_t) image->rows; tile_y+=(ssize_t) tile_height)
{
ssize_t
tile_x;
if (status == MagickFalse)
continue;
for (tile_x=0; tile_x < (ssize_t) image->columns; tile_x+=(ssize_t) tile_width)
{
MagickBooleanType
sync;
const IndexPacket
*magick_restrict indexes;
const PixelPacket
*magick_restrict p;
IndexPacket
*magick_restrict rotate_indexes;
PixelPacket
*magick_restrict q;
ssize_t
y;
size_t
height,
width;
width=tile_width;
if ((tile_x+(ssize_t) tile_width) > (ssize_t) image->columns)
width=(size_t) (tile_width-(tile_x+tile_width-image->columns));
height=tile_height;
if ((tile_y+(ssize_t) tile_height) > (ssize_t) image->rows)
height=(size_t) (tile_height-(tile_y+tile_height-image->rows));
p=GetCacheViewVirtualPixels(image_view,tile_x,tile_y,width,height,
exception);
if (p == (const PixelPacket *) NULL)
{
status=MagickFalse;
break;
}
indexes=GetCacheViewVirtualIndexQueue(image_view);
for (y=0; y < (ssize_t) width; y++)
{
const PixelPacket
*magick_restrict tile_pixels;
ssize_t
x;
if (status == MagickFalse)
continue;
q=QueueCacheViewAuthenticPixels(rotate_view,tile_y,(ssize_t) (y+
rotate_image->rows-(tile_x+width)),height,1,exception);
if (q == (PixelPacket *) NULL)
{
status=MagickFalse;
continue;
}
tile_pixels=p+(width-1)-y;
for (x=0; x < (ssize_t) height; x++)
{
*q++=(*tile_pixels);
tile_pixels+=width;
}
rotate_indexes=GetCacheViewAuthenticIndexQueue(rotate_view);
if ((indexes != (IndexPacket *) NULL) &&
(rotate_indexes != (IndexPacket *) NULL))
{
const IndexPacket
*magick_restrict tile_indexes;
tile_indexes=indexes+(width-1)-y;
for (x=0; x < (ssize_t) height; x++)
{
*rotate_indexes++=(*tile_indexes);
tile_indexes+=width;
}
}
sync=SyncCacheViewAuthenticPixels(rotate_view,exception);
if (sync == MagickFalse)
status=MagickFalse;
}
}
if (image->progress_monitor != (MagickProgressMonitor) NULL)
{
MagickBooleanType
proceed;
proceed=SetImageProgress(image,RotateImageTag,progress+=tile_height,
image->rows);
if (proceed == MagickFalse)
status=MagickFalse;
}
}
(void) SetImageProgress(image,RotateImageTag,(MagickOffsetType)
image->rows-1,image->rows);
Swap(page.width,page.height);
Swap(page.x,page.y);
if (page.height != 0)
page.y=(ssize_t) (page.height-rotate_image->rows-page.y);
break;
}
default:
break;
}
rotate_view=DestroyCacheView(rotate_view);
image_view=DestroyCacheView(image_view);
rotate_image->type=image->type;
rotate_image->page=page;
if (status == MagickFalse)
rotate_image=DestroyImage(rotate_image);
return(rotate_image);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
+ X S h e a r I m a g e %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% XShearImage() shears the image in the X direction with a shear angle of
% 'degrees'. Positive angles shear counter-clockwise (right-hand rule), and
% negative angles shear clockwise. Angles are measured relative to a vertical
% Y-axis. X shears will widen an image creating 'empty' triangles on the left
% and right sides of the source image.
%
% The format of the XShearImage method is:
%
% MagickBooleanType XShearImage(Image *image,const MagickRealType degrees,
% const size_t width,const size_t height,
% const ssize_t x_offset,const ssize_t y_offset,ExceptionInfo *exception)
%
% A description of each parameter follows.
%
% o image: the image.
%
% o degrees: A MagickRealType representing the shearing angle along the X
% axis.
%
% o width, height, x_offset, y_offset: Defines a region of the image
% to shear.
%
% o exception: return any errors or warnings in this structure.
%
*/
static MagickBooleanType XShearImage(Image *image,const MagickRealType degrees,
const size_t width,const size_t height,const ssize_t x_offset,
const ssize_t y_offset,ExceptionInfo *exception)
{
#define XShearImageTag "XShear/Image"
typedef enum
{
LEFT,
RIGHT
} ShearDirection;
CacheView
*image_view;
MagickBooleanType
status;
MagickOffsetType
progress;
MagickPixelPacket
background;
ssize_t
y;
assert(image != (Image *) NULL);
assert(image->signature == MagickCoreSignature);
if (image->debug != MagickFalse)
(void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
GetMagickPixelPacket(image,&background);
SetMagickPixelPacket(image,&image->background_color,(IndexPacket *) NULL,
&background);
if (image->colorspace == CMYKColorspace)
ConvertRGBToCMYK(&background);
/*
X shear image.
*/
status=MagickTrue;
progress=0;
image_view=AcquireAuthenticCacheView(image,exception);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
#pragma omp parallel for schedule(static) shared(progress,status) \
magick_number_threads(image,image,height,1)
#endif
for (y=0; y < (ssize_t) height; y++)
{
MagickPixelPacket
pixel,
source,
destination;
MagickRealType
area,
displacement;
IndexPacket
*magick_restrict indexes,
*magick_restrict shear_indexes;
PixelPacket
*magick_restrict p,
*magick_restrict q;
ssize_t
i;
ShearDirection
direction;
ssize_t
step;
if (status == MagickFalse)
continue;
p=GetCacheViewAuthenticPixels(image_view,0,y_offset+y,image->columns,1,
exception);
if (p == (PixelPacket *) NULL)
{
status=MagickFalse;
continue;
}
indexes=GetCacheViewAuthenticIndexQueue(image_view);
p+=x_offset;
indexes+=x_offset;
displacement=degrees*(MagickRealType) (y-height/2.0);
if (displacement == 0.0)
continue;
if (displacement > 0.0)
direction=RIGHT;
else
{
displacement*=(-1.0);
direction=LEFT;
}
step=CastDoubleToLong(floor((double) displacement));
area=(MagickRealType) (displacement-step);
step++;
pixel=background;
GetMagickPixelPacket(image,&source);
GetMagickPixelPacket(image,&destination);
switch (direction)
{
case LEFT:
{
/*
Transfer pixels left-to-right.
*/
if (step > x_offset)
break;
q=p-step;
shear_indexes=indexes-step;
for (i=0; i < (ssize_t) width; i++)
{
if ((x_offset+i) < step)
{
SetMagickPixelPacket(image,++p,++indexes,&pixel);
q++;
shear_indexes++;
continue;
}
SetMagickPixelPacket(image,p,indexes,&source);
MagickPixelCompositeAreaBlend(&pixel,(MagickRealType) pixel.opacity,
&source,(MagickRealType) GetPixelOpacity(p),area,&destination);
SetPixelPacket(image,&destination,q++,shear_indexes++);
SetMagickPixelPacket(image,p++,indexes++,&pixel);
}
MagickPixelCompositeAreaBlend(&pixel,(MagickRealType) pixel.opacity,
&background,(MagickRealType) background.opacity,area,&destination);
SetPixelPacket(image,&destination,q++,shear_indexes++);
for (i=0; i < (step-1); i++)
SetPixelPacket(image,&background,q++,shear_indexes++);
break;
}
case RIGHT:
{
/*
Transfer pixels right-to-left.
*/
p+=width;
indexes+=width;
q=p+step;
shear_indexes=indexes+step;
for (i=0; i < (ssize_t) width; i++)
{
p--;
indexes--;
q--;
shear_indexes--;
if ((size_t) (x_offset+width+step-i) > image->columns)
continue;
SetMagickPixelPacket(image,p,indexes,&source);
MagickPixelCompositeAreaBlend(&pixel,(MagickRealType) pixel.opacity,
&source,(MagickRealType) GetPixelOpacity(p),area,&destination);
SetPixelPacket(image,&destination,q,shear_indexes);
SetMagickPixelPacket(image,p,indexes,&pixel);
}
MagickPixelCompositeAreaBlend(&pixel,(MagickRealType) pixel.opacity,
&background,(MagickRealType) background.opacity,area,&destination);
SetPixelPacket(image,&destination,--q,--shear_indexes);
for (i=0; i < (step-1); i++)
SetPixelPacket(image,&background,--q,--shear_indexes);
break;
}
}
if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
status=MagickFalse;
if (image->progress_monitor != (MagickProgressMonitor) NULL)
{
MagickBooleanType
proceed;
#if defined(MAGICKCORE_OPENMP_SUPPORT)
#pragma omp atomic
#endif
progress++;
proceed=SetImageProgress(image,XShearImageTag,progress,height);
if (proceed == MagickFalse)
status=MagickFalse;
}
}
image_view=DestroyCacheView(image_view);
return(status);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
+ Y S h e a r I m a g e %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% YShearImage shears the image in the Y direction with a shear angle of
% 'degrees'. Positive angles shear counter-clockwise (right-hand rule), and
% negative angles shear clockwise. Angles are measured relative to a
% horizontal X-axis. Y shears will increase the height of an image creating
% 'empty' triangles on the top and bottom of the source image.
%
% The format of the YShearImage method is:
%
% MagickBooleanType YShearImage(Image *image,const MagickRealType degrees,
% const size_t width,const size_t height,
% const ssize_t x_offset,const ssize_t y_offset,ExceptionInfo *exception)
%
% A description of each parameter follows.
%
% o image: the image.
%
% o degrees: A MagickRealType representing the shearing angle along the Y
% axis.
%
% o width, height, x_offset, y_offset: Defines a region of the image
% to shear.
%
% o exception: return any errors or warnings in this structure.
%
*/
static MagickBooleanType YShearImage(Image *image,const MagickRealType degrees,
const size_t width,const size_t height,const ssize_t x_offset,
const ssize_t y_offset,ExceptionInfo *exception)
{
#define YShearImageTag "YShear/Image"
typedef enum
{
UP,
DOWN
} ShearDirection;
CacheView
*image_view;
MagickBooleanType
status;
MagickOffsetType
progress;
MagickPixelPacket
background;
ssize_t
x;
assert(image != (Image *) NULL);
assert(image->signature == MagickCoreSignature);
if (image->debug != MagickFalse)
(void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
GetMagickPixelPacket(image,&background);
SetMagickPixelPacket(image,&image->background_color,(IndexPacket *) NULL,
&background);
if (image->colorspace == CMYKColorspace)
ConvertRGBToCMYK(&background);
/*
Y Shear image.
*/
status=MagickTrue;
progress=0;
image_view=AcquireAuthenticCacheView(image,exception);
#if defined(MAGICKCORE_OPENMP_SUPPORT)
#pragma omp parallel for schedule(static) shared(progress,status) \
magick_number_threads(image,image,width,1)
#endif
for (x=0; x < (ssize_t) width; x++)
{
MagickPixelPacket
pixel,
source,
destination;
MagickRealType
area,
displacement;
IndexPacket
*magick_restrict indexes,
*magick_restrict shear_indexes;
ssize_t
i;
PixelPacket
*magick_restrict p,
*magick_restrict q;
ShearDirection
direction;
ssize_t
step;
if (status == MagickFalse)
continue;
p=GetCacheViewAuthenticPixels(image_view,x_offset+x,0,1,image->rows,
exception);
if (p == (PixelPacket *) NULL)
{
status=MagickFalse;
continue;
}
indexes=GetCacheViewAuthenticIndexQueue(image_view);
p+=y_offset;
indexes+=y_offset;
displacement=degrees*(MagickRealType) (x-width/2.0);
if (displacement == 0.0)
continue;
if (displacement > 0.0)
direction=DOWN;
else
{
displacement*=(-1.0);
direction=UP;
}
step=CastDoubleToLong(floor((double) displacement));
area=(MagickRealType) (displacement-step);
step++;
pixel=background;
GetMagickPixelPacket(image,&source);
GetMagickPixelPacket(image,&destination);
switch (direction)
{
case UP:
{
/*
Transfer pixels top-to-bottom.
*/
if (step > y_offset)
break;
q=p-step;
shear_indexes=indexes-step;
for (i=0; i < (ssize_t) height; i++)
{
if ((y_offset+i) < step)
{
SetMagickPixelPacket(image,++p,++indexes,&pixel);
q++;
shear_indexes++;
continue;
}
SetMagickPixelPacket(image,p,indexes,&source);
MagickPixelCompositeAreaBlend(&pixel,(MagickRealType) pixel.opacity,
&source,(MagickRealType) GetPixelOpacity(p),area,&destination);
SetPixelPacket(image,&destination,q++,shear_indexes++);
SetMagickPixelPacket(image,p++,indexes++,&pixel);
}
MagickPixelCompositeAreaBlend(&pixel,(MagickRealType) pixel.opacity,
&background,(MagickRealType) background.opacity,area,&destination);
SetPixelPacket(image,&destination,q++,shear_indexes++);
for (i=0; i < (step-1); i++)
SetPixelPacket(image,&background,q++,shear_indexes++);
break;
}
case DOWN:
{
/*
Transfer pixels bottom-to-top.
*/
p+=height;
indexes+=height;
q=p+step;
shear_indexes=indexes+step;
for (i=0; i < (ssize_t) height; i++)
{
p--;
indexes--;
q--;
shear_indexes--;
if ((size_t) (y_offset+height+step-i) > image->rows)
continue;
SetMagickPixelPacket(image,p,indexes,&source);
MagickPixelCompositeAreaBlend(&pixel,(MagickRealType) pixel.opacity,
&source,(MagickRealType) GetPixelOpacity(p),area,&destination);
SetPixelPacket(image,&destination,q,shear_indexes);
SetMagickPixelPacket(image,p,indexes,&pixel);
}
MagickPixelCompositeAreaBlend(&pixel,(MagickRealType) pixel.opacity,
&background,(MagickRealType) background.opacity,area,&destination);
SetPixelPacket(image,&destination,--q,--shear_indexes);
for (i=0; i < (step-1); i++)
SetPixelPacket(image,&background,--q,--shear_indexes);
break;
}
}
if (SyncCacheViewAuthenticPixels(image_view,exception) == MagickFalse)
status=MagickFalse;
if (image->progress_monitor != (MagickProgressMonitor) NULL)
{
MagickBooleanType
proceed;
#if defined(MAGICKCORE_OPENMP_SUPPORT)
#pragma omp atomic
#endif
progress++;
proceed=SetImageProgress(image,YShearImageTag,progress,image->rows);
if (proceed == MagickFalse)
status=MagickFalse;
}
}
image_view=DestroyCacheView(image_view);
return(status);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% S h e a r I m a g e %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% ShearImage() creates a new image that is a shear_image copy of an existing
% one. Shearing slides one edge of an image along the X or Y axis, creating
% a parallelogram. An X direction shear slides an edge along the X axis,
% while a Y direction shear slides an edge along the Y axis. The amount of
% the shear is controlled by a shear angle. For X direction shears, x_shear
% is measured relative to the Y axis, and similarly, for Y direction shears
% y_shear is measured relative to the X axis. Empty triangles left over from
% shearing the image are filled with the background color defined by member
% 'background_color' of the image.. ShearImage() allocates the memory
% necessary for the new Image structure and returns a pointer to the new image.
%
% ShearImage() is based on the paper "A Fast Algorithm for General Raster
% Rotatation" by Alan W. Paeth.
%
% The format of the ShearImage method is:
%
% Image *ShearImage(const Image *image,const double x_shear,
% const double y_shear,ExceptionInfo *exception)
%
% A description of each parameter follows.
%
% o image: the image.
%
% o x_shear, y_shear: Specifies the number of degrees to shear the image.
%
% o exception: return any errors or warnings in this structure.
%
*/
MagickExport Image *ShearImage(const Image *image,const double x_shear,
const double y_shear,ExceptionInfo *exception)
{
Image
*integral_image,
*shear_image;
MagickBooleanType
status;
PointInfo
shear;
RectangleInfo
border_info,
bounds;
assert(image != (Image *) NULL);
assert(image->signature == MagickCoreSignature);
if (image->debug != MagickFalse)
(void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
assert(exception != (ExceptionInfo *) NULL);
assert(exception->signature == MagickCoreSignature);
if ((x_shear != 0.0) && (fmod(x_shear,90.0) == 0.0))
ThrowImageException(ImageError,"AngleIsDiscontinuous");
if ((y_shear != 0.0) && (fmod(y_shear,90.0) == 0.0))
ThrowImageException(ImageError,"AngleIsDiscontinuous");
/*
Initialize shear angle.
*/
integral_image=CloneImage(image,0,0,MagickTrue,exception);
if (integral_image == (Image *) NULL)
ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
shear.x=(-tan(DegreesToRadians(fmod(x_shear,360.0))));
shear.y=tan(DegreesToRadians(fmod(y_shear,360.0)));
if ((shear.x == 0.0) && (shear.y == 0.0))
return(integral_image);
if (SetImageStorageClass(integral_image,DirectClass) == MagickFalse)
{
InheritException(exception,&integral_image->exception);
integral_image=DestroyImage(integral_image);
return(integral_image);
}
if (integral_image->matte == MagickFalse)
(void) SetImageAlphaChannel(integral_image,OpaqueAlphaChannel);
/*
Compute image size.
*/
bounds.width=image->columns+CastDoubleToLong(floor(fabs(shear.x)*
image->rows+0.5));
bounds.x=CastDoubleToLong(ceil((double) image->columns+((fabs(shear.x)*
image->rows)-image->columns)/2.0-0.5));
bounds.y=CastDoubleToLong(ceil((double) image->rows+((fabs(shear.y)*
bounds.width)-image->rows)/2.0-0.5));
/*
Surround image with border.
*/
integral_image->border_color=integral_image->background_color;
integral_image->compose=CopyCompositeOp;
border_info.width=(size_t) bounds.x;
border_info.height=(size_t) bounds.y;
shear_image=BorderImage(integral_image,&border_info,exception);
integral_image=DestroyImage(integral_image);
if (shear_image == (Image *) NULL)
ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
/*
Shear the image.
*/
if (shear_image->matte == MagickFalse)
(void) SetImageAlphaChannel(shear_image,OpaqueAlphaChannel);
status=XShearImage(shear_image,shear.x,image->columns,image->rows,bounds.x,
(ssize_t) (shear_image->rows-image->rows)/2,exception);
if (status == MagickFalse)
{
shear_image=DestroyImage(shear_image);
return((Image *) NULL);
}
status=YShearImage(shear_image,shear.y,bounds.width,image->rows,(ssize_t)
(shear_image->columns-bounds.width)/2,bounds.y,exception);
if (status == MagickFalse)
{
shear_image=DestroyImage(shear_image);
return((Image *) NULL);
}
status=CropToFitImage(&shear_image,shear.x,shear.y,(MagickRealType)
image->columns,(MagickRealType) image->rows,MagickFalse,exception);
shear_image->matte=image->matte;
shear_image->compose=image->compose;
shear_image->page.width=0;
shear_image->page.height=0;
if (status == MagickFalse)
shear_image=DestroyImage(shear_image);
return(shear_image);
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% S h e a r R o t a t e I m a g e %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% ShearRotateImage() creates a new image that is a rotated copy of an existing
% one. Positive angles rotate counter-clockwise (right-hand rule), while
% negative angles rotate clockwise. Rotated images are usually larger than
% the originals and have 'empty' triangular corners. X axis. Empty
% triangles left over from shearing the image are filled with the background
% color defined by member 'background_color' of the image. ShearRotateImage
% allocates the memory necessary for the new Image structure and returns a
% pointer to the new image.
%
% ShearRotateImage() is based on the paper "A Fast Algorithm for General
% Raster Rotatation" by Alan W. Paeth. ShearRotateImage is adapted from a
% similar method based on the Paeth paper written by Michael Halle of the
% Spatial Imaging Group, MIT Media Lab.
%
% The format of the ShearRotateImage method is:
%
% Image *ShearRotateImage(const Image *image,const double degrees,
% ExceptionInfo *exception)
%
% A description of each parameter follows.
%
% o image: the image.
%
% o degrees: Specifies the number of degrees to rotate the image.
%
% o exception: return any errors or warnings in this structure.
%
*/
MagickExport Image *ShearRotateImage(const Image *image,const double degrees,
ExceptionInfo *exception)
{
Image
*integral_image,
*rotate_image;
MagickBooleanType
status;
MagickRealType
angle;
PointInfo
shear;
RectangleInfo
border_info,
bounds;
size_t
height,
rotations,
shear_width,
width;
/*
Adjust rotation angle.
*/
assert(image != (Image *) NULL);
assert(image->signature == MagickCoreSignature);
if (image->debug != MagickFalse)
(void) LogMagickEvent(TraceEvent,GetMagickModule(),"%s",image->filename);
assert(exception != (ExceptionInfo *) NULL);
assert(exception->signature == MagickCoreSignature);
angle=fmod(degrees,360.0);
if (angle < -45.0)
angle+=360.0;
for (rotations=0; angle > 45.0; rotations++)
angle-=90.0;
rotations%=4;
/*
Calculate shear equations.
*/
integral_image=IntegralRotateImage(image,rotations,exception);
if (integral_image == (Image *) NULL)
ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
shear.x=(-tan((double) DegreesToRadians(angle)/2.0));
shear.y=sin((double) DegreesToRadians(angle));
if ((shear.x == 0.0) && (shear.y == 0.0))
return(integral_image);
if (SetImageStorageClass(integral_image,DirectClass) == MagickFalse)
{
InheritException(exception,&integral_image->exception);
integral_image=DestroyImage(integral_image);
return(integral_image);
}
if (integral_image->matte == MagickFalse)
(void) SetImageAlphaChannel(integral_image,OpaqueAlphaChannel);
/*
Compute maximum bounds for 3 shear operations.
*/
width=integral_image->columns;
height=integral_image->rows;
bounds.width=(size_t) floor(fabs((double) height*shear.x)+width+0.5);
bounds.height=(size_t) floor(fabs((double) bounds.width*shear.y)+height+0.5);
shear_width=(size_t) floor(fabs((double) bounds.height*shear.x)+
bounds.width+0.5);
bounds.x=CastDoubleToLong(floor((double) ((shear_width > bounds.width) ?
width : bounds.width-shear_width+2)/2.0+0.5));
bounds.y=CastDoubleToLong(floor(((double) bounds.height-height+2)/2.0+0.5));
/*
Surround image with a border.
*/
integral_image->border_color=integral_image->background_color;
integral_image->compose=CopyCompositeOp;
border_info.width=(size_t) bounds.x;
border_info.height=(size_t) bounds.y;
rotate_image=BorderImage(integral_image,&border_info,exception);
integral_image=DestroyImage(integral_image);
if (rotate_image == (Image *) NULL)
ThrowImageException(ResourceLimitError,"MemoryAllocationFailed");
/*
Rotate the image.
*/
status=XShearImage(rotate_image,shear.x,width,height,bounds.x,(ssize_t)
(rotate_image->rows-height)/2,exception);
if (status == MagickFalse)
{
rotate_image=DestroyImage(rotate_image);
return((Image *) NULL);
}
status=YShearImage(rotate_image,shear.y,bounds.width,height,(ssize_t)
(rotate_image->columns-bounds.width)/2,bounds.y,exception);
if (status == MagickFalse)
{
rotate_image=DestroyImage(rotate_image);
return((Image *) NULL);
}
status=XShearImage(rotate_image,shear.x,bounds.width,bounds.height,(ssize_t)
(rotate_image->columns-bounds.width)/2,(ssize_t) (rotate_image->rows-
bounds.height)/2,exception);
if (status == MagickFalse)
{
rotate_image=DestroyImage(rotate_image);
return((Image *) NULL);
}
status=CropToFitImage(&rotate_image,shear.x,shear.y,(MagickRealType) width,
(MagickRealType) height,MagickTrue,exception);
rotate_image->matte=image->matte;
rotate_image->compose=image->compose;
rotate_image->page.width=0;
rotate_image->page.height=0;
if (status == MagickFalse)
rotate_image=DestroyImage(rotate_image);
return(rotate_image);
}