// C code for Image::Filter::Sharpen
// Simple Black & White Sharpen
// (c) 2002 - Hendrik Van Belleghem
// hendrik@quickndirty.org
// Released under the GPL
#include <math.h>
#include <stdio.h>
#include "gd.h"
gdImagePtr sharpen (gdImagePtr imageptr)
{ gdImagePtr imsharp;
int dimx = 0;
int dimy = 0;
int w = 0;
int h = 0;
int index = 0;
int newrcolor = 0;
int newgcolor = 0;
int newbcolor = 0;
dimx = gdImageSX(imageptr);
dimy = gdImageSY(imageptr);
imsharp = gdImageCreateTrueColor(dimx,dimy);
for (w = 0; w < dimx ; w++)
{ for (h = 0; h < dimy ; h++)
{ newrcolor = (
5*gdImageRed(imageptr,gdImageGetPixel(imageptr,w,h))-
gdImageRed(imageptr,gdImageGetPixel(imageptr,w-1,h))+
gdImageRed(imageptr,gdImageGetPixel(imageptr,w,h-1))+
gdImageRed(imageptr,gdImageGetPixel(imageptr,w,h+1))+
gdImageRed(imageptr,gdImageGetPixel(imageptr,w+1,h)) );
newgcolor = (
5*gdImageGreen(imageptr,gdImageGetPixel(imageptr,w,h))-
gdImageGreen(imageptr,gdImageGetPixel(imageptr,w-1,h))+
gdImageGreen(imageptr,gdImageGetPixel(imageptr,w,h-1))+
gdImageGreen(imageptr,gdImageGetPixel(imageptr,w,h+1))+
gdImageGreen(imageptr,gdImageGetPixel(imageptr,w+1,h)) );
newbcolor = (
5*gdImageBlue(imageptr,gdImageGetPixel(imageptr,w,h))-
gdImageBlue(imageptr,gdImageGetPixel(imageptr,w-1,h))+
gdImageBlue(imageptr,gdImageGetPixel(imageptr,w,h-1))+
gdImageBlue(imageptr,gdImageGetPixel(imageptr,w,h+1))+
gdImageBlue(imageptr,gdImageGetPixel(imageptr,w+1,h)) );
newrcolor = newrcolor > 255 ? 255 : (newrcolor < 0 ? 0 : newrcolor);
newgcolor = newgcolor > 255 ? 255 : (newgcolor < 0 ? 0 : newgcolor);
newbcolor = newbcolor > 255 ? 255 : (newbcolor < 0 ? 0 : newbcolor);
index = gdImageColorExact(imsharp,newrcolor,newgcolor,newbcolor);
if (index == -1) { index = gdImageColorAllocate(imsharp,newrcolor,newgcolor,newbcolor); }
gdImageSetPixel(imsharp,w,h,index);
}
}
return imsharp;
}