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#ifndef lint |
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static const char RCSid[] = "$Id: biq.c,v 2.3 2003/05/13 17:58:33 greg Exp $"; |
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#endif |
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/* |
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* biq.c - simple greyscale quantization. |
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* |
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* 9/19/88 |
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*/ |
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|
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#include <string.h> |
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|
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#include "standard.h" |
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#include "ciq.h" |
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|
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|
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biq(dith,nw,synth,cm) |
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int dith; /* is dithering desired? 0=no, 1=yes */ |
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int nw; /* number of colors wanted in output image */ |
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int synth; /* synthesize colormap? 0=no, 1=yes */ |
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colormap cm; /* quantization colormap */ |
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/* read if synth=0; always written */ |
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{ |
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colormap ocm; |
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|
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picreadcm(ocm); /* read original picture's colormap (usually identity)*/ |
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|
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for (n = 0; n < nw; n++) /* also sets n to nw */ |
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color[0][n] = color[1][n] = color[2][n] = (n*256L+128)/nw; |
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|
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picwritecm(color); |
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|
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draw_grey(ocm); |
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|
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memcpy((void *)cm,(void *)color,sizeof color); |
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} |
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|
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/*----------------------------------------------------------------------*/ |
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|
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draw_grey(ocm) |
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colormap ocm; |
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{ |
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register rgbpixel *linin; |
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register pixel *linout; |
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rgbpixel intmp; |
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int outtmp; |
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int y; |
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register int x; |
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|
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linin = line3alloc(xmax); |
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linout = linealloc(xmax); |
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|
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for (y = 0; y < ymax; y++) { |
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picreadline3(y, linin); |
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for (x = 0; x < xmax; x++) { |
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intmp.r = ocm[0][linin[x].r]; |
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intmp.g = ocm[1][linin[x].g]; |
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intmp.b = ocm[2][linin[x].b]; |
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outtmp = rgb_bright(&intmp); |
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linout[x] = (outtmp*n+n/2)/256; |
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} |
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picwriteline(y, linout); |
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} |
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free((void *)linin); |
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free((void *)linout); |
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} |
