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62 lines
1.2 KiB
C
62 lines
1.2 KiB
C
/*
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* The Python Imaging Library
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* $Id$
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*
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* offset an image in x and y directions
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*
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* history:
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* 96-07-22 fl: Created
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* 98-11-01 cgw@pgt.com: Fixed negative-array index bug
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*
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* Copyright (c) Fredrik Lundh 1996.
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* Copyright (c) Secret Labs AB 1997.
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*
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* See the README file for information on usage and redistribution.
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*/
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#include "Imaging.h"
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Imaging
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ImagingOffset(Imaging im, int xoffset, int yoffset)
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{
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int x, y;
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Imaging imOut;
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if (!im)
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return (Imaging) ImagingError_ModeError();
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imOut = ImagingNew(im->mode, im->xsize, im->ysize);
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if (!imOut)
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return NULL;
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ImagingCopyInfo(imOut, im);
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/* make offsets positive to avoid negative coordinates */
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xoffset %= im->xsize;
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xoffset = im->xsize - xoffset;
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if (xoffset < 0)
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xoffset += im->xsize;
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yoffset %= im->ysize;
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yoffset = im->ysize - yoffset;
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if (yoffset < 0)
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yoffset += im->ysize;
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#define OFFSET(image)\
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for (y = 0; y < im->ysize; y++)\
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for (x = 0; x < im->xsize; x++) {\
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int yi = (y + yoffset) % im->ysize;\
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int xi = (x + xoffset) % im->xsize;\
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imOut->image[y][x] = im->image[yi][xi];\
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}
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if (im->image8)
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OFFSET(image8)
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else
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OFFSET(image32)
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return imOut;
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}
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