| 1 |
#ifndef lint |
| 2 |
static const char RCSid[] = "$Id: cvrgb.c,v 1.3 2003/11/15 17:54:06 schorsch Exp $"; |
| 3 |
#endif |
| 4 |
/* |
| 5 |
* Convert MGF color to RGB representation |
| 6 |
*/ |
| 7 |
|
| 8 |
#include <stdio.h> |
| 9 |
#include "color.h" |
| 10 |
#include "ccolor.h" |
| 11 |
|
| 12 |
void |
| 13 |
ccy2rgb( /* convert MGF color to RGB */ |
| 14 |
C_COLOR *cin, /* input MGF chrominance */ |
| 15 |
double cieY, /* input luminance or reflectance */ |
| 16 |
COLOR cout /* output RGB color */ |
| 17 |
) |
| 18 |
{ |
| 19 |
double d; |
| 20 |
COLOR xyz; |
| 21 |
/* get CIE XYZ representation */ |
| 22 |
c_ccvt(cin, C_CSXY); |
| 23 |
d = cin->cx/cin->cy; |
| 24 |
xyz[CIEX] = d * cieY; |
| 25 |
xyz[CIEY] = cieY; |
| 26 |
xyz[CIEZ] = (1./cin->cy - d - 1.) * cieY; |
| 27 |
cie_rgb(cout, xyz); |
| 28 |
} |
| 29 |
|
| 30 |
/* Convert RGB to MGF color and value */ |
| 31 |
double |
| 32 |
rgb2ccy(COLOR cin, C_COLOR *cout) |
| 33 |
{ |
| 34 |
COLOR xyz; |
| 35 |
double df; |
| 36 |
|
| 37 |
rgb_cie(xyz, cin); |
| 38 |
*cout = c_dfcolor; |
| 39 |
df = xyz[CIEX] + xyz[CIEY] + xyz[CIEZ]; |
| 40 |
if (df <= .0) |
| 41 |
return; |
| 42 |
df = 1./df; |
| 43 |
cout->cx = xyz[CIEX]*df; |
| 44 |
cout->cy = xyz[CIEZ]*df; |
| 45 |
cout->flags = (C_CSXY|C_CDXY); |
| 46 |
|
| 47 |
return(xyz[CIEY]); |
| 48 |
} |
