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/* Copyright (c) 1990 Regents of the University of California */ |
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/* Copyright (c) 1997 Regents of the University of California */ |
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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#include "color.h" |
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#define CEPS 1e-7 /* color epsilon */ |
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RGBPRIMS stdprims = STDPRIMS; /* standard primary chromaticities */ |
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COLOR cblack = BLKCOLOR; /* global black color */ |
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COLOR cwhite = WHTCOLOR; /* global white color */ |
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/* |
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* The following table contains the CIE tristimulus integrals |
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* for X, Y, and Z. The table is cumulative, so that |
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} |
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cie_rgb(rgb, xyz) /* convert CIE color to standard RGB */ |
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COLOR rgb, xyz; |
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{ |
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colortrans(rgb, xyz2rgbmat, xyz); |
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clipgamut(rgb, xyz[CIEY], CGAMUT_LOWER, cblack, cwhite); |
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} |
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int |
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clipgamut(col, brt, gamut, lower, upper) /* clip to gamut cube */ |
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COLOR col; |
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double brt; |
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int gamut; |
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COLOR lower, upper; |
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{ |
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int rflags = 0; |
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double brtmin, brtmax, v, vv; |
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COLOR cgry; |
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register int i; |
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/* check for no check */ |
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if (gamut == 0) return(0); |
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/* check brightness limits */ |
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brtmin = 1./3.*(lower[0]+lower[1]+lower[2]); |
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if (gamut & CGAMUT_LOWER && brt < brtmin) { |
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copycolor(col, lower); |
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return(CGAMUT_LOWER); |
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} |
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brtmax = 1./3.*(upper[0]+upper[1]+upper[2]); |
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if (gamut & CGAMUT_UPPER && brt > brtmax) { |
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copycolor(col, upper); |
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return(CGAMUT_UPPER); |
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} |
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/* compute equivalent grey */ |
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v = (brt - brtmin)/(brtmax - brtmin); |
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for (i = 0; i < 3; i++) |
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cgry[i] = v*upper[i] + (1.-v)*lower[i]; |
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vv = 1.; /* check each limit */ |
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for (i = 0; i < 3; i++) |
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if (gamut & CGAMUT_LOWER && col[i] < lower[i]) { |
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v = (lower[i]+CEPS - cgry[i])/(col[i] - cgry[i]); |
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if (v < vv) vv = v; |
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rflags |= CGAMUT_LOWER; |
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} else if (gamut & CGAMUT_UPPER && col[i] > upper[i]) { |
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v = (upper[i]-CEPS - cgry[i])/(col[i] - cgry[i]); |
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if (v < vv) vv = v; |
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rflags |= CGAMUT_UPPER; |
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} |
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if (rflags) /* desaturate to cube face */ |
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for (i = 0; i < 3; i++) |
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col[i] = vv*col[i] + (1.-vv)*cgry[i]; |
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return(rflags); |
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} |
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colortrans(c2, mat, c1) /* convert c1 by mat and put into c2 */ |
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register COLORMAT mat; |
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register COLOR c1, c2; |
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{ |
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static float cout[3]; |
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COLOR cout; |
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cout[0] = mat[0][0]*c1[0] + mat[0][1]*c1[1] + mat[0][2]*c1[2]; |
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cout[1] = mat[1][0]*c1[0] + mat[1][1]*c1[1] + mat[1][2]*c1[2]; |
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cout[2] = mat[2][0]*c1[0] + mat[2][1]*c1[1] + mat[2][2]*c1[2]; |
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if((c2[0] = cout[0]) < 0.) c2[0] = 0.; |
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if((c2[1] = cout[1]) < 0.) c2[1] = 0.; |
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if((c2[2] = cout[2]) < 0.) c2[2] = 0.; |
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copycolor(c2, cout); |
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} |
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