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#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <wand/MagickWand.h>
static MagickBooleanType SigmoidalContrast(WandView *contrast_view,
const ssize_t y,const int id,void *context)
{
#define QuantumScale ((MagickRealType) 1.0/(MagickRealType) QuantumRange)
#define SigmoidalContrast(x) \
(QuantumRange*(1.0/(1+exp(10.0*(0.5-QuantumScale*x)))-0.0066928509)*1.0092503)
RectangleInfo
extent;
MagickPixelPacket
pixel;
PixelWand
**pixels;
register ssize_t
x;
extent=GetWandViewExtent(contrast_view);
pixels=GetWandViewPixels(contrast_view);
for (x=0; x < (ssize_t) (extent.width-extent.x); x++)
{
PixelGetMagickColor(pixels[x],&pixel);
pixel.red=SigmoidalContrast(pixel.red);
pixel.green=SigmoidalContrast(pixel.green);
pixel.blue=SigmoidalContrast(pixel.blue);
pixel.index=SigmoidalContrast(pixel.index);
PixelSetMagickColor(pixels[x],&pixel);
}
return(MagickTrue);
}
int main(int argc,char **argv)
{
#define ThrowViewException(view) \
{ \
description=GetWandViewException(view,&severity); \
(void) fprintf(stderr,"%s %s %lu %s\n",GetMagickModule(),description); \
description=(char *) MagickRelinquishMemory(description); \
exit(-1); \
}
#define ThrowWandException(wand) \
{ \
description=MagickGetException(wand,&severity); \
(void) fprintf(stderr,"%s %s %lu %s\n",GetMagickModule(),description); \
description=(char *) MagickRelinquishMemory(description); \
exit(-1); \
}
char
*description;
ExceptionType
severity;
MagickBooleanType
status;
MagickPixelPacket
pixel;
MagickWand
*contrast_wand;
WandView
*contrast_view;
if (argc != 3)
{
(void) fprintf(stdout,"Usage: %s image sigmoidal-image\n",argv[0]);
exit(0);
}
/*
Read an image.
*/
MagickWandGenesis();
contrast_wand=NewMagickWand();
status=MagickReadImage(contrast_wand,argv[1]);
if (status == MagickFalse)
ThrowWandException(contrast_wand);
/*
Sigmoidal non-linearity contrast control.
*/
contrast_view=NewWandView(contrast_wand);
if (contrast_view == (WandView *) NULL)
ThrowWandException(contrast_wand);
status=UpdateWandViewIterator(contrast_view,SigmoidalContrast,(void *) NULL);
if (status == MagickFalse)
ThrowWandException(contrast_wand);
contrast_view=DestroyWandView(contrast_view);
/*
Write the image then destroy it.
*/
status=MagickWriteImages(contrast_wand,argv[2],MagickTrue);
if (status == MagickFalse)
ThrowWandException(contrast_wand);
contrast_wand=DestroyMagickWand(contrast_wand);
MagickWandTerminus();
return(0);
}