--- ray/src/common/spec_rgb.c 1998/10/07 17:11:40 2.10 +++ ray/src/common/spec_rgb.c 2003/02/25 02:47:22 2.12 @@ -1,23 +1,32 @@ -/* Copyright (c) 1997 Regents of the University of California */ - #ifndef lint -static char SCCSid[] = "$SunId$ LBL"; +static const char RCSid[] = "$Id: spec_rgb.c,v 2.12 2003/02/25 02:47:22 greg Exp $"; #endif - /* * Convert colors and spectral ranges. + * Added von Kries white-balance calculations 10/01 (GW). + * + * Externals declared in color.h */ +#include "copyright.h" + #include "color.h" +#include -#define CEPS 1e-7 /* color epsilon */ +#define CEPS 1e-4 /* color epsilon */ +#define CEQ(v1,v2) ((v1) <= (v2)+CEPS && (v2) <= (v1)+CEPS) -RGBPRIMS stdprims = STDPRIMS; /* standard primary chromaticities */ +#define XYEQ(c1,c2) (CEQ((c1)[CIEX],(c2)[CIEX]) && CEQ((c1)[CIEY],(c2)[CIEY])) + +RGBPRIMS stdprims = STDPRIMS; /* standard primary chromaticities */ + COLOR cblack = BLKCOLOR; /* global black color */ COLOR cwhite = WHTCOLOR; /* global white color */ +float xyneu[2] = {1./3., 1./3.}; /* neutral xy chromaticities */ + /* * The following table contains the CIE tristimulus integrals * for X, Y, and Z. The table is cumulative, so that @@ -47,7 +56,7 @@ static BYTE chroma[3][NINC] = { } }; -COLORMAT xyz2rgbmat = { /* XYZ to RGB */ +COLORMAT xyz2rgbmat = { /* XYZ to RGB (no white balance) */ {(CIE_y_g - CIE_y_b - CIE_x_b*CIE_y_g + CIE_y_b*CIE_x_g)/CIE_C_rD, (CIE_x_b - CIE_x_g - CIE_x_b*CIE_y_g + CIE_x_g*CIE_y_b)/CIE_C_rD, (CIE_x_g*CIE_y_b - CIE_x_b*CIE_y_g)/CIE_C_rD}, @@ -59,7 +68,7 @@ COLORMAT xyz2rgbmat = { /* XYZ to RGB */ (CIE_x_r*CIE_y_g - CIE_x_g*CIE_y_r)/CIE_C_bD} }; -COLORMAT rgb2xyzmat = { /* RGB to XYZ */ +COLORMAT rgb2xyzmat = { /* RGB to XYZ (no white balance) */ {CIE_x_r*CIE_C_rD/CIE_D,CIE_x_g*CIE_C_gD/CIE_D,CIE_x_b*CIE_C_bD/CIE_D}, {CIE_y_r*CIE_C_rD/CIE_D,CIE_y_g*CIE_C_gD/CIE_D,CIE_y_b*CIE_C_bD/CIE_D}, {(1.-CIE_x_r-CIE_y_r)*CIE_C_rD/CIE_D, @@ -67,8 +76,20 @@ COLORMAT rgb2xyzmat = { /* RGB to XYZ */ (1.-CIE_x_b-CIE_y_b)*CIE_C_bD/CIE_D} }; +COLORMAT vkmat = { /* Sharp primary matrix */ + { 1.2694, -0.0988, -0.1706}, + {-0.8364, 1.8006, 0.0357}, + { 0.0297, -0.0315, 1.0018} +}; +COLORMAT ivkmat = { /* inverse Sharp primary matrix */ + { 0.8156, 0.0472, 0.1372}, + { 0.3791, 0.5769, 0.0440}, + {-0.0123, 0.0167, 0.9955} +}; + +void spec_rgb(col, s, e) /* compute RGB color from spectral range */ COLOR col; int s, e; @@ -80,6 +101,7 @@ int s, e; } +void spec_cie(col, s, e) /* compute a color from a spectral range */ COLOR col; /* returned color */ int s, e; /* starting and ending wavelengths */ @@ -114,8 +136,10 @@ int s, e; /* starting and ending wavelengths */ } +void cie_rgb(rgb, xyz) /* convert CIE color to standard RGB */ -COLOR rgb, xyz; +COLOR rgb; +COLOR xyz; { colortrans(rgb, xyz2rgbmat, xyz); clipgamut(rgb, xyz[CIEY], CGAMUT_LOWER, cblack, cwhite); @@ -168,9 +192,11 @@ COLOR lower, upper; } +void colortrans(c2, mat, c1) /* convert c1 by mat and put into c2 */ +register COLOR c2; register COLORMAT mat; -register COLOR c1, c2; +register COLOR c1; { COLOR cout; @@ -182,8 +208,10 @@ register COLOR c1, c2; } +void multcolormat(m3, m2, m1) /* multiply m1 by m2 and put into m3 */ -COLORMAT m1, m2, m3; /* m3 can be either m1 or m2 w/o harm */ +COLORMAT m3; /* m3 can be either m1 or m2 w/o harm */ +COLORMAT m2, m1; { COLORMAT mt; register int i, j; @@ -197,6 +225,7 @@ COLORMAT m1, m2, m3; /* m3 can be either m1 or m2 w/ } +void compxyz2rgbmat(mat, pr) /* compute conversion from CIE to RGB space */ COLORMAT mat; register RGBPRIMS pr; @@ -247,6 +276,7 @@ register RGBPRIMS pr; } +void comprgb2xyzmat(mat, pr) /* compute conversion from RGB to CIE space */ COLORMAT mat; register RGBPRIMS pr; @@ -284,6 +314,7 @@ register RGBPRIMS pr; } +void comprgb2rgbmat(mat, pr1, pr2) /* compute conversion from RGB1 to RGB2 */ COLORMAT mat; RGBPRIMS pr1, pr2; @@ -300,4 +331,84 @@ RGBPRIMS pr1, pr2; compxyz2rgbmat(xyztopr2, pr2); /* combine transforms */ multcolormat(mat, pr1toxyz, xyztopr2); +} + + +void +compxyzWBmat(mat, wht1, wht2) /* CIE von Kries transform from wht1 to wht2 */ +COLORMAT mat; +float wht1[2], wht2[2]; +{ + COLOR cw1, cw2; + if (XYEQ(wht1,wht2)) { + mat[0][0] = mat[1][1] = mat[2][2] = 1.0; + mat[0][1] = mat[0][2] = mat[1][0] = + mat[1][2] = mat[2][0] = mat[2][1] = 0.0; + return; + } + cw1[RED] = wht1[CIEX]/wht1[CIEY]; + cw1[GRN] = 1.; + cw1[BLU] = (1. - wht1[CIEX] - wht1[CIEY])/wht1[CIEY]; + colortrans(cw1, vkmat, cw1); + cw2[RED] = wht2[CIEX]/wht2[CIEY]; + cw2[GRN] = 1.; + cw2[BLU] = (1. - wht2[CIEX] - wht2[CIEY])/wht2[CIEY]; + colortrans(cw2, vkmat, cw2); + mat[0][0] = cw2[RED]/cw1[RED]; + mat[1][1] = cw2[GRN]/cw1[GRN]; + mat[2][2] = cw2[BLU]/cw1[BLU]; + mat[0][1] = mat[0][2] = mat[1][0] = + mat[1][2] = mat[2][0] = mat[2][1] = 0.0; + multcolormat(mat, vkmat, mat); + multcolormat(mat, mat, ivkmat); +} + + +void +compxyz2rgbWBmat(mat, pr) /* von Kries conversion from CIE to RGB space */ +COLORMAT mat; +RGBPRIMS pr; +{ + COLORMAT wbmat; + + compxyz2rgbmat(mat, pr); + if (XYEQ(pr[WHT],xyneu)) + return; + compxyzWBmat(wbmat, xyneu, pr[WHT]); + multcolormat(mat, wbmat, mat); +} + +void +comprgb2xyzWBmat(mat, pr) /* von Kries conversion from RGB to CIE space */ +COLORMAT mat; +RGBPRIMS pr; +{ + COLORMAT wbmat; + + comprgb2xyzmat(mat, pr); + if (XYEQ(pr[WHT],xyneu)) + return; + compxyzWBmat(wbmat, pr[WHT], xyneu); + multcolormat(mat, mat, wbmat); +} + +void +comprgb2rgbWBmat(mat, pr1, pr2) /* von Kries conversion from RGB1 to RGB2 */ +COLORMAT mat; +RGBPRIMS pr1, pr2; +{ + COLORMAT pr1toxyz, xyztopr2, wbmat; + + if (pr1 == pr2) { + mat[0][0] = mat[1][1] = mat[2][2] = 1.0; + mat[0][1] = mat[0][2] = mat[1][0] = + mat[1][2] = mat[2][0] = mat[2][1] = 0.0; + return; + } + comprgb2xyzmat(pr1toxyz, pr1); + compxyzWBmat(wbmat, pr1[WHT], pr2[WHT]); + compxyz2rgbmat(xyztopr2, pr2); + /* combine transforms */ + multcolormat(mat, pr1toxyz, wbmat); + multcolormat(mat, mat, xyztopr2); }