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/*
* The Python Imaging Library
* $Id: Filter.c 2134 2004-10-06 08:55:20Z fredrik $
*
* apply convolution kernel to image
*
* history:
* 1995-11-26 fl Created, supports 3x3 kernels
* 1995-11-27 fl Added 5x5 kernels, copy border
* 1999-07-26 fl Eliminated a few compiler warnings
* 2002-06-09 fl Moved kernel definitions to Python
* 2002-06-11 fl Support floating point kernels
* 2003-09-15 fl Added ImagingExpand helper
*
* Copyright (c) Secret Labs AB 1997-2002. All rights reserved.
* Copyright (c) Fredrik Lundh 1995.
*
* See the README file for information on usage and redistribution.
*/
/*
* FIXME: Support RGB and RGBA/CMYK modes as well
* FIXME: Expand image border (current version leaves border as is)
* FIXME: Implement image processing gradient filters
*/
#include "Imaging.h"
Imaging
ImagingExpand(Imaging imIn, int xmargin, int ymargin, int mode)
{
Imaging imOut;
int x, y;
if (xmargin < 0 && ymargin < 0)
return (Imaging) ImagingError_ValueError("bad kernel size");
imOut = ImagingNew(
imIn->mode, imIn->xsize+2*xmargin, imIn->ysize+2*ymargin
);
if (!imOut)
return NULL;
#define EXPAND_LINE(type, image, yin, yout) {\
for (x = 0; x < xmargin; x++)\
imOut->image[yout][x] = imIn->image[yin][0];\
for (x = 0; x < imIn->xsize; x++)\
imOut->image[yout][x+xmargin] = imIn->image[yin][x];\
for (x = 0; x < xmargin; x++)\
imOut->image[yout][xmargin+imIn->xsize+x] =\
imIn->image[yin][imIn->xsize-1];\
}
#define EXPAND(type, image) {\
for (y = 0; y < ymargin; y++)\
EXPAND_LINE(type, image, 0, y);\
for (y = 0; y < imIn->ysize; y++)\
EXPAND_LINE(type, image, y, y+ymargin);\
for (y = 0; y < ymargin; y++)\
EXPAND_LINE(type, image, imIn->ysize-1, ymargin+imIn->ysize+y);\
}
if (imIn->image8) {
EXPAND(UINT8, image8);
} else {
EXPAND(INT32, image32);
}
ImagingCopyInfo(imOut, imIn);
return imOut;
}
Imaging
ImagingFilter(Imaging im, int xsize, int ysize, const FLOAT32* kernel,
FLOAT32 offset, FLOAT32 divisor)
{
Imaging imOut;
int x, y;
FLOAT32 sum;
if (!im || strcmp(im->mode, "L") != 0)
return (Imaging) ImagingError_ModeError();
if ((xsize != 3 && xsize != 5) || xsize != ysize)
return (Imaging) ImagingError_ValueError("bad kernel size");
imOut = ImagingNew(im->mode, im->xsize, im->ysize);
if (!imOut)
return NULL;
/* brute force kernel implementations */
#define KERNEL3x3(image, kernel, d) ( \
(int) image[y+1][x-d] * kernel[0] + \
(int) image[y+1][x] * kernel[1] + \
(int) image[y+1][x+d] * kernel[2] + \
(int) image[y][x-d] * kernel[3] + \
(int) image[y][x] * kernel[4] + \
(int) image[y][x+d] * kernel[5] + \
(int) image[y-1][x-d] * kernel[6] + \
(int) image[y-1][x] * kernel[7] + \
(int) image[y-1][x+d] * kernel[8])
#define KERNEL5x5(image, kernel, d) ( \
(int) image[y+2][x-d-d] * kernel[0] + \
(int) image[y+2][x-d] * kernel[1] + \
(int) image[y+2][x] * kernel[2] + \
(int) image[y+2][x+d] * kernel[3] + \
(int) image[y+2][x+d+d] * kernel[4] + \
(int) image[y+1][x-d-d] * kernel[5] + \
(int) image[y+1][x-d] * kernel[6] + \
(int) image[y+1][x] * kernel[7] + \
(int) image[y+1][x+d] * kernel[8] + \
(int) image[y+1][x+d+d] * kernel[9] + \
(int) image[y][x-d-d] * kernel[10] + \
(int) image[y][x-d] * kernel[11] + \
(int) image[y][x] * kernel[12] + \
(int) image[y][x+d] * kernel[13] + \
(int) image[y][x+d+d] * kernel[14] + \
(int) image[y-1][x-d-d] * kernel[15] + \
(int) image[y-1][x-d] * kernel[16] + \
(int) image[y-1][x] * kernel[17] + \
(int) image[y-1][x+d] * kernel[18] + \
(int) image[y-1][x+d+d] * kernel[19] + \
(int) image[y-2][x-d-d] * kernel[20] + \
(int) image[y-2][x-d] * kernel[21] + \
(int) image[y-2][x] * kernel[22] + \
(int) image[y-2][x+d] * kernel[23] + \
(int) image[y-2][x+d+d] * kernel[24])
if (xsize == 3) {
/* 3x3 kernel. */
for (x = 0; x < im->xsize; x++)
imOut->image[0][x] = im->image8[0][x];
for (y = 1; y < im->ysize-1; y++) {
imOut->image[y][0] = im->image8[y][0];
for (x = 1; x < im->xsize-1; x++) {
sum = KERNEL3x3(im->image8, kernel, 1) / divisor + offset;
if (sum <= 0)
imOut->image8[y][x] = 0;
else if (sum >= 255)
imOut->image8[y][x] = 255;
else
imOut->image8[y][x] = (UINT8) sum;
}
imOut->image8[y][x] = im->image8[y][x];
}
for (x = 0; x < im->xsize; x++)
imOut->image8[y][x] = im->image8[y][x];
} else {
/* 5x5 kernel. */
for (y = 0; y < 2; y++)
for (x = 0; x < im->xsize; x++)
imOut->image8[y][x] = im->image8[y][x];
for (; y < im->ysize-2; y++) {
for (x = 0; x < 2; x++)
imOut->image8[y][x] = im->image8[y][x];
for (; x < im->xsize-2; x++) {
sum = KERNEL5x5(im->image8, kernel, 1) / divisor + offset;
if (sum <= 0)
imOut->image8[y][x] = 0;
else if (sum >= 255)
imOut->image8[y][x] = 255;
else
imOut->image8[y][x] = (UINT8) sum;
}
for (; x < im->xsize; x++)
imOut->image8[y][x] = im->image8[y][x];
}
for (; y < im->ysize; y++)
for (x = 0; x < im->xsize; x++)
imOut->image8[y][x] = im->image8[y][x];
}
return imOut;
}
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