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#ifndef lint
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static const char RCSid[] = "$Id: biq.c,v 2.5 2004/03/28 20:33:13 schorsch 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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#include <string.h>
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#include "standard.h"
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#include "ciq.h"
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static void draw_grey(colormap ocm);
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void
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biq(
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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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picreadcm(ocm); /* read original picture's colormap (usually identity)*/
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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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picwritecm(color);
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draw_grey(ocm);
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memcpy((void *)cm,(void *)color,sizeof color);
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}
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/*----------------------------------------------------------------------*/
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static void
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draw_grey(
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colormap ocm
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)
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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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linin = line3alloc(xmax);
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linout = linealloc(xmax);
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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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}
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