| 1 |
/* Copyright (c) 1997 Regents of the University of California */ |
| 2 |
|
| 3 |
#ifndef lint |
| 4 |
static char SCCSid[] = "$SunId$ LBL"; |
| 5 |
#endif |
| 6 |
|
| 7 |
/* |
| 8 |
* Convert colors and spectral ranges. |
| 9 |
*/ |
| 10 |
|
| 11 |
#include "color.h" |
| 12 |
|
| 13 |
|
| 14 |
RGBPRIMS stdprims = STDPRIMS; /* standard primary chromaticities */ |
| 15 |
|
| 16 |
COLOR cblack = BLKCOLOR; /* global black color */ |
| 17 |
COLOR cwhite = WHTCOLOR; /* global white color */ |
| 18 |
|
| 19 |
/* |
| 20 |
* The following table contains the CIE tristimulus integrals |
| 21 |
* for X, Y, and Z. The table is cumulative, so that |
| 22 |
* each color coordinate integrates to 1. |
| 23 |
*/ |
| 24 |
|
| 25 |
#define STARTWL 380 /* starting wavelength (nanometers) */ |
| 26 |
#define INCWL 10 /* wavelength increment */ |
| 27 |
#define NINC 40 /* # of values */ |
| 28 |
|
| 29 |
static BYTE chroma[3][NINC] = { |
| 30 |
{ /* X */ |
| 31 |
0, 0, 0, 2, 6, 13, 22, 30, 36, 41, |
| 32 |
42, 43, 43, 44, 46, 52, 60, 71, 87, 106, |
| 33 |
128, 153, 178, 200, 219, 233, 243, 249, 252, 254, |
| 34 |
255, 255, 255, 255, 255, 255, 255, 255, 255, 255 |
| 35 |
}, { /* Y */ |
| 36 |
0, 0, 0, 0, 0, 1, 2, 4, 7, 11, |
| 37 |
17, 24, 34, 48, 64, 84, 105, 127, 148, 169, |
| 38 |
188, 205, 220, 232, 240, 246, 250, 253, 254, 255, |
| 39 |
255, 255, 255, 255, 255, 255, 255, 255, 255, 255 |
| 40 |
}, { /* Z */ |
| 41 |
0, 0, 2, 10, 32, 66, 118, 153, 191, 220, |
| 42 |
237, 246, 251, 253, 254, 255, 255, 255, 255, 255, |
| 43 |
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, |
| 44 |
255, 255, 255, 255, 255, 255, 255, 255, 255, 255 |
| 45 |
} |
| 46 |
}; |
| 47 |
|
| 48 |
COLORMAT xyz2rgbmat = { /* XYZ to RGB */ |
| 49 |
{(CIE_y_g - CIE_y_b - CIE_x_b*CIE_y_g + CIE_y_b*CIE_x_g)/CIE_C_rD, |
| 50 |
(CIE_x_b - CIE_x_g - CIE_x_b*CIE_y_g + CIE_x_g*CIE_y_b)/CIE_C_rD, |
| 51 |
(CIE_x_g*CIE_y_b - CIE_x_b*CIE_y_g)/CIE_C_rD}, |
| 52 |
{(CIE_y_b - CIE_y_r - CIE_y_b*CIE_x_r + CIE_y_r*CIE_x_b)/CIE_C_gD, |
| 53 |
(CIE_x_r - CIE_x_b - CIE_x_r*CIE_y_b + CIE_x_b*CIE_y_r)/CIE_C_gD, |
| 54 |
(CIE_x_b*CIE_y_r - CIE_x_r*CIE_y_b)/CIE_C_gD}, |
| 55 |
{(CIE_y_r - CIE_y_g - CIE_y_r*CIE_x_g + CIE_y_g*CIE_x_r)/CIE_C_bD, |
| 56 |
(CIE_x_g - CIE_x_r - CIE_x_g*CIE_y_r + CIE_x_r*CIE_y_g)/CIE_C_bD, |
| 57 |
(CIE_x_r*CIE_y_g - CIE_x_g*CIE_y_r)/CIE_C_bD} |
| 58 |
}; |
| 59 |
|
| 60 |
COLORMAT rgb2xyzmat = { /* RGB to XYZ */ |
| 61 |
{CIE_x_r*CIE_C_rD/CIE_D,CIE_x_g*CIE_C_gD/CIE_D,CIE_x_b*CIE_C_bD/CIE_D}, |
| 62 |
{CIE_y_r*CIE_C_rD/CIE_D,CIE_y_g*CIE_C_gD/CIE_D,CIE_y_b*CIE_C_bD/CIE_D}, |
| 63 |
{(1.-CIE_x_r-CIE_y_r)*CIE_C_rD/CIE_D, |
| 64 |
(1.-CIE_x_g-CIE_y_g)*CIE_C_gD/CIE_D, |
| 65 |
(1.-CIE_x_b-CIE_y_b)*CIE_C_bD/CIE_D} |
| 66 |
}; |
| 67 |
|
| 68 |
|
| 69 |
|
| 70 |
spec_rgb(col, s, e) /* compute RGB color from spectral range */ |
| 71 |
COLOR col; |
| 72 |
int s, e; |
| 73 |
{ |
| 74 |
COLOR ciecolor; |
| 75 |
|
| 76 |
spec_cie(ciecolor, s, e); |
| 77 |
cie_rgb(col, ciecolor); |
| 78 |
} |
| 79 |
|
| 80 |
|
| 81 |
spec_cie(col, s, e) /* compute a color from a spectral range */ |
| 82 |
COLOR col; /* returned color */ |
| 83 |
int s, e; /* starting and ending wavelengths */ |
| 84 |
{ |
| 85 |
register int i, d, r; |
| 86 |
|
| 87 |
s -= STARTWL; |
| 88 |
if (s < 0) |
| 89 |
s = 0; |
| 90 |
|
| 91 |
e -= STARTWL; |
| 92 |
if (e <= s) { |
| 93 |
col[CIEX] = col[CIEY] = col[CIEZ] = 0.0; |
| 94 |
return; |
| 95 |
} |
| 96 |
if (e >= INCWL*(NINC - 1)) |
| 97 |
e = INCWL*(NINC - 1) - 1; |
| 98 |
|
| 99 |
d = e / INCWL; /* interpolate values */ |
| 100 |
r = e % INCWL; |
| 101 |
for (i = 0; i < 3; i++) |
| 102 |
col[i] = chroma[i][d]*(INCWL - r) + chroma[i][d + 1]*r; |
| 103 |
|
| 104 |
d = s / INCWL; |
| 105 |
r = s % INCWL; |
| 106 |
for (i = 0; i < 3; i++) |
| 107 |
col[i] -= chroma[i][d]*(INCWL - r) - chroma[i][d + 1]*r; |
| 108 |
|
| 109 |
col[CIEX] = (col[CIEX] + 0.5) * (1./(256*INCWL)); |
| 110 |
col[CIEY] = (col[CIEY] + 0.5) * (1./(256*INCWL)); |
| 111 |
col[CIEZ] = (col[CIEZ] + 0.5) * (1./(256*INCWL)); |
| 112 |
} |
| 113 |
|
| 114 |
|
| 115 |
cie_rgb(rgb, xyz) /* convert CIE color to standard RGB */ |
| 116 |
COLOR rgb, xyz; |
| 117 |
{ |
| 118 |
colortrans(rgb, xyz2rgbmat, xyz); |
| 119 |
clipgamut(rgb, xyz[CIEY], CGAMUT_LOWER, cblack, cwhite); |
| 120 |
} |
| 121 |
|
| 122 |
|
| 123 |
int |
| 124 |
clipgamut(col, brt, gamut, lower, upper) /* clip to gamut cube */ |
| 125 |
COLOR col; |
| 126 |
double brt; |
| 127 |
int gamut; |
| 128 |
COLOR lower, upper; |
| 129 |
{ |
| 130 |
int rflags = 0; |
| 131 |
double brtmin, brtmax, v, vv; |
| 132 |
COLOR cgry; |
| 133 |
register int i; |
| 134 |
/* check for no check */ |
| 135 |
if (gamut == 0) return(0); |
| 136 |
/* check brightness limits */ |
| 137 |
brtmin = 1./3.*(lower[0]+lower[1]+lower[2]); |
| 138 |
if (gamut & CGAMUT_LOWER && brt < brtmin) { |
| 139 |
copycolor(col, lower); |
| 140 |
return(CGAMUT_LOWER); |
| 141 |
} |
| 142 |
brtmax = 1./3.*(upper[0]+upper[1]+upper[2]); |
| 143 |
if (gamut & CGAMUT_UPPER && brt > brtmax) { |
| 144 |
copycolor(col, upper); |
| 145 |
return(CGAMUT_UPPER); |
| 146 |
} |
| 147 |
/* compute equivalent grey */ |
| 148 |
v = (brt - brtmin)/(brtmax - brtmin); |
| 149 |
for (i = 0; i < 3; i++) |
| 150 |
cgry[i] = v*upper[i] + (1.-v)*lower[i]; |
| 151 |
vv = 1.; /* check each limit */ |
| 152 |
for (i = 0; i < 3; i++) |
| 153 |
if (gamut & CGAMUT_LOWER && col[i] < lower[i]) { |
| 154 |
v = (lower[i] - cgry[i])/(col[i] - cgry[i]); |
| 155 |
if (v < vv) vv = v; |
| 156 |
rflags |= CGAMUT_LOWER; |
| 157 |
} else if (gamut & CGAMUT_UPPER && col[i] > upper[i]) { |
| 158 |
v = (upper[i] - cgry[i])/(col[i] - cgry[i]); |
| 159 |
if (v < vv) vv = v; |
| 160 |
rflags |= CGAMUT_UPPER; |
| 161 |
} |
| 162 |
if (rflags) /* desaturate to cube face */ |
| 163 |
for (i = 0; i < 3; i++) |
| 164 |
col[i] = vv*col[i] + (1.-vv)*cgry[i]; |
| 165 |
return(rflags); |
| 166 |
} |
| 167 |
|
| 168 |
|
| 169 |
colortrans(c2, mat, c1) /* convert c1 by mat and put into c2 */ |
| 170 |
register COLORMAT mat; |
| 171 |
register COLOR c1, c2; |
| 172 |
{ |
| 173 |
c2[0] = mat[0][0]*c1[0] + mat[0][1]*c1[1] + mat[0][2]*c1[2]; |
| 174 |
c2[1] = mat[1][0]*c1[0] + mat[1][1]*c1[1] + mat[1][2]*c1[2]; |
| 175 |
c2[2] = mat[2][0]*c1[0] + mat[2][1]*c1[1] + mat[2][2]*c1[2]; |
| 176 |
} |
| 177 |
|
| 178 |
|
| 179 |
multcolormat(m3, m2, m1) /* multiply m1 by m2 and put into m3 */ |
| 180 |
COLORMAT m1, m2, m3; /* m3 can be either m1 or m2 w/o harm */ |
| 181 |
{ |
| 182 |
COLORMAT mt; |
| 183 |
register int i, j; |
| 184 |
|
| 185 |
for (i = 0; i < 3; i++) |
| 186 |
for (j = 0; j < 3; j++) |
| 187 |
mt[i][j] = m1[i][0]*m2[0][j] + |
| 188 |
m1[i][1]*m2[1][j] + |
| 189 |
m1[i][2]*m2[2][j] ; |
| 190 |
cpcolormat(m3, mt); |
| 191 |
} |
| 192 |
|
| 193 |
|
| 194 |
compxyz2rgbmat(mat, pr) /* compute conversion from CIE to RGB space */ |
| 195 |
COLORMAT mat; |
| 196 |
register RGBPRIMS pr; |
| 197 |
{ |
| 198 |
double C_rD, C_gD, C_bD; |
| 199 |
|
| 200 |
if (pr == stdprims) { /* can use xyz2rgbmat */ |
| 201 |
cpcolormat(mat, xyz2rgbmat); |
| 202 |
return; |
| 203 |
} |
| 204 |
C_rD = (1./pr[WHT][CIEY]) * |
| 205 |
( pr[WHT][CIEX]*(pr[GRN][CIEY] - pr[BLU][CIEY]) - |
| 206 |
pr[WHT][CIEY]*(pr[GRN][CIEX] - pr[BLU][CIEX]) + |
| 207 |
pr[GRN][CIEX]*pr[BLU][CIEY] - pr[BLU][CIEX]*pr[GRN][CIEY] ) ; |
| 208 |
C_gD = (1./pr[WHT][CIEY]) * |
| 209 |
( pr[WHT][CIEX]*(pr[BLU][CIEY] - pr[RED][CIEY]) - |
| 210 |
pr[WHT][CIEY]*(pr[BLU][CIEX] - pr[RED][CIEX]) - |
| 211 |
pr[RED][CIEX]*pr[BLU][CIEY] + pr[BLU][CIEX]*pr[RED][CIEY] ) ; |
| 212 |
C_bD = (1./pr[WHT][CIEY]) * |
| 213 |
( pr[WHT][CIEX]*(pr[RED][CIEY] - pr[GRN][CIEY]) - |
| 214 |
pr[WHT][CIEY]*(pr[RED][CIEX] - pr[GRN][CIEX]) + |
| 215 |
pr[RED][CIEX]*pr[GRN][CIEY] - pr[GRN][CIEX]*pr[RED][CIEY] ) ; |
| 216 |
|
| 217 |
mat[0][0] = (pr[GRN][CIEY] - pr[BLU][CIEY] - |
| 218 |
pr[BLU][CIEX]*pr[GRN][CIEY] + |
| 219 |
pr[BLU][CIEY]*pr[GRN][CIEX])/C_rD ; |
| 220 |
mat[0][1] = (pr[BLU][CIEX] - pr[GRN][CIEX] - |
| 221 |
pr[BLU][CIEX]*pr[GRN][CIEY] + |
| 222 |
pr[GRN][CIEX]*pr[BLU][CIEY])/C_rD ; |
| 223 |
mat[0][2] = (pr[GRN][CIEX]*pr[BLU][CIEY] - |
| 224 |
pr[BLU][CIEX]*pr[GRN][CIEY])/C_rD ; |
| 225 |
mat[1][0] = (pr[BLU][CIEY] - pr[RED][CIEY] - |
| 226 |
pr[BLU][CIEY]*pr[RED][CIEX] + |
| 227 |
pr[RED][CIEY]*pr[BLU][CIEX])/C_gD ; |
| 228 |
mat[1][1] = (pr[RED][CIEX] - pr[BLU][CIEX] - |
| 229 |
pr[RED][CIEX]*pr[BLU][CIEY] + |
| 230 |
pr[BLU][CIEX]*pr[RED][CIEY])/C_gD ; |
| 231 |
mat[1][2] = (pr[BLU][CIEX]*pr[RED][CIEY] - |
| 232 |
pr[RED][CIEX]*pr[BLU][CIEY])/C_gD ; |
| 233 |
mat[2][0] = (pr[RED][CIEY] - pr[GRN][CIEY] - |
| 234 |
pr[RED][CIEY]*pr[GRN][CIEX] + |
| 235 |
pr[GRN][CIEY]*pr[RED][CIEX])/C_bD ; |
| 236 |
mat[2][1] = (pr[GRN][CIEX] - pr[RED][CIEX] - |
| 237 |
pr[GRN][CIEX]*pr[RED][CIEY] + |
| 238 |
pr[RED][CIEX]*pr[GRN][CIEY])/C_bD ; |
| 239 |
mat[2][2] = (pr[RED][CIEX]*pr[GRN][CIEY] - |
| 240 |
pr[GRN][CIEX]*pr[RED][CIEY])/C_bD ; |
| 241 |
} |
| 242 |
|
| 243 |
|
| 244 |
comprgb2xyzmat(mat, pr) /* compute conversion from RGB to CIE space */ |
| 245 |
COLORMAT mat; |
| 246 |
register RGBPRIMS pr; |
| 247 |
{ |
| 248 |
double C_rD, C_gD, C_bD, D; |
| 249 |
|
| 250 |
if (pr == stdprims) { /* can use rgb2xyzmat */ |
| 251 |
cpcolormat(mat, rgb2xyzmat); |
| 252 |
return; |
| 253 |
} |
| 254 |
C_rD = (1./pr[WHT][CIEY]) * |
| 255 |
( pr[WHT][CIEX]*(pr[GRN][CIEY] - pr[BLU][CIEY]) - |
| 256 |
pr[WHT][CIEY]*(pr[GRN][CIEX] - pr[BLU][CIEX]) + |
| 257 |
pr[GRN][CIEX]*pr[BLU][CIEY] - pr[BLU][CIEX]*pr[GRN][CIEY] ) ; |
| 258 |
C_gD = (1./pr[WHT][CIEY]) * |
| 259 |
( pr[WHT][CIEX]*(pr[BLU][CIEY] - pr[RED][CIEY]) - |
| 260 |
pr[WHT][CIEY]*(pr[BLU][CIEX] - pr[RED][CIEX]) - |
| 261 |
pr[RED][CIEX]*pr[BLU][CIEY] + pr[BLU][CIEX]*pr[RED][CIEY] ) ; |
| 262 |
C_bD = (1./pr[WHT][CIEY]) * |
| 263 |
( pr[WHT][CIEX]*(pr[RED][CIEY] - pr[GRN][CIEY]) - |
| 264 |
pr[WHT][CIEY]*(pr[RED][CIEX] - pr[GRN][CIEX]) + |
| 265 |
pr[RED][CIEX]*pr[GRN][CIEY] - pr[GRN][CIEX]*pr[RED][CIEY] ) ; |
| 266 |
D = pr[RED][CIEX]*(pr[GRN][CIEY] - pr[BLU][CIEY]) + |
| 267 |
pr[GRN][CIEX]*(pr[BLU][CIEY] - pr[RED][CIEY]) + |
| 268 |
pr[BLU][CIEX]*(pr[RED][CIEY] - pr[GRN][CIEY]) ; |
| 269 |
mat[0][0] = pr[RED][CIEX]*C_rD/D; |
| 270 |
mat[0][1] = pr[GRN][CIEX]*C_gD/D; |
| 271 |
mat[0][2] = pr[BLU][CIEX]*C_bD/D; |
| 272 |
mat[1][0] = pr[RED][CIEY]*C_rD/D; |
| 273 |
mat[1][1] = pr[GRN][CIEY]*C_gD/D; |
| 274 |
mat[1][2] = pr[BLU][CIEY]*C_bD/D; |
| 275 |
mat[2][0] = (1.-pr[RED][CIEX]-pr[RED][CIEY])*C_rD/D; |
| 276 |
mat[2][1] = (1.-pr[GRN][CIEX]-pr[GRN][CIEY])*C_gD/D; |
| 277 |
mat[2][2] = (1.-pr[BLU][CIEX]-pr[BLU][CIEY])*C_bD/D; |
| 278 |
} |
| 279 |
|
| 280 |
|
| 281 |
comprgb2rgbmat(mat, pr1, pr2) /* compute conversion from RGB1 to RGB2 */ |
| 282 |
COLORMAT mat; |
| 283 |
RGBPRIMS pr1, pr2; |
| 284 |
{ |
| 285 |
COLORMAT pr1toxyz, xyztopr2; |
| 286 |
|
| 287 |
if (pr1 == pr2) { |
| 288 |
mat[0][0] = mat[1][1] = mat[2][2] = 1.0; |
| 289 |
mat[0][1] = mat[0][2] = mat[1][0] = |
| 290 |
mat[1][2] = mat[2][0] = mat[2][1] = 0.0; |
| 291 |
return; |
| 292 |
} |
| 293 |
comprgb2xyzmat(pr1toxyz, pr1); |
| 294 |
compxyz2rgbmat(xyztopr2, pr2); |
| 295 |
/* combine transforms */ |
| 296 |
multcolormat(mat, pr1toxyz, xyztopr2); |
| 297 |
} |
