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#ifndef lint
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static const char RCSid[] = "$Id: ccyrgb.c,v 3.3 2012/05/17 17:10:23 greg Exp $";
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#endif
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/*
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* Convert MGF color to RGB representation
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*/
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#include <stdio.h>
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#include "color.h"
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#include "ccolor.h"
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void
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ccy2rgb( /* convert MGF color to RGB */
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C_COLOR *cin, /* input MGF chrominance */
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double cieY, /* input luminance or reflectance */
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COLOR cout /* output RGB color */
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)
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{
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double d;
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COLOR xyz;
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/* get CIE XYZ representation */
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c_ccvt(cin, C_CSXY);
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d = cin->cx/cin->cy;
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xyz[CIEX] = d * cieY;
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xyz[CIEY] = cieY;
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xyz[CIEZ] = (1./cin->cy - d - 1.) * cieY;
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cie_rgb(cout, xyz);
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}
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/* Convert RGB to MGF color and value */
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double
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rgb2ccy(COLOR cin, C_COLOR *cout)
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{
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COLOR xyz;
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double df;
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rgb_cie(xyz, cin);
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*cout = c_dfcolor;
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df = xyz[CIEX] + xyz[CIEY] + xyz[CIEZ];
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if (df <= .0)
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return(.0);
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df = 1./df;
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cout->cx = xyz[CIEX]*df;
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cout->cy = xyz[CIEZ]*df;
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cout->flags = (C_CSXY|C_CDXY);
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return(xyz[CIEY]);
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}
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