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#ifndef lint |
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static const char RCSid[] = "$Id: ccyrgb.c,v 3.1 2011/02/18 00:40:25 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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|
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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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|
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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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|
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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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|
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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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|
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return(xyz[CIEY]); |
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} |
