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Diffstat (limited to 'Imaging/libImaging/Filter.c')
| -rw-r--r-- | Imaging/libImaging/Filter.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/Imaging/libImaging/Filter.c b/Imaging/libImaging/Filter.c new file mode 100644 index 0000000..b73ca9f --- /dev/null +++ b/Imaging/libImaging/Filter.c @@ -0,0 +1,176 @@ +/* + * 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; +} + |