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 |
/* |
17 |
* The following table contains the CIE tristimulus integrals |
18 |
* for X, Y, and Z. The table is cumulative, so that |
19 |
* each color coordinate integrates to 1. |
20 |
*/ |
21 |
|
22 |
#define STARTWL 380 /* starting wavelength (nanometers) */ |
23 |
#define INCWL 10 /* wavelength increment */ |
24 |
#define NINC 40 /* # of values */ |
25 |
|
26 |
static BYTE chroma[3][NINC] = { |
27 |
{ /* X */ |
28 |
0, 0, 0, 2, 6, 13, 22, 30, 36, 41, |
29 |
42, 43, 43, 44, 46, 52, 60, 71, 87, 106, |
30 |
128, 153, 178, 200, 219, 233, 243, 249, 252, 254, |
31 |
255, 255, 255, 255, 255, 255, 255, 255, 255, 255 |
32 |
}, { /* Y */ |
33 |
0, 0, 0, 0, 0, 1, 2, 4, 7, 11, |
34 |
17, 24, 34, 48, 64, 84, 105, 127, 148, 169, |
35 |
188, 205, 220, 232, 240, 246, 250, 253, 254, 255, |
36 |
255, 255, 255, 255, 255, 255, 255, 255, 255, 255 |
37 |
}, { /* Z */ |
38 |
0, 0, 2, 10, 32, 66, 118, 153, 191, 220, |
39 |
237, 246, 251, 253, 254, 255, 255, 255, 255, 255, |
40 |
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, |
41 |
255, 255, 255, 255, 255, 255, 255, 255, 255, 255 |
42 |
} |
43 |
}; |
44 |
|
45 |
COLORMAT xyz2rgbmat = { /* XYZ to RGB */ |
46 |
{(CIE_y_g - CIE_y_b - CIE_x_b*CIE_y_g + CIE_y_b*CIE_x_g)/CIE_C_rD, |
47 |
(CIE_x_b - CIE_x_g - CIE_x_b*CIE_y_g + CIE_x_g*CIE_y_b)/CIE_C_rD, |
48 |
(CIE_x_g*CIE_y_b - CIE_x_b*CIE_y_g)/CIE_C_rD}, |
49 |
{(CIE_y_b - CIE_y_r - CIE_y_b*CIE_x_r + CIE_y_r*CIE_x_b)/CIE_C_gD, |
50 |
(CIE_x_r - CIE_x_b - CIE_x_r*CIE_y_b + CIE_x_b*CIE_y_r)/CIE_C_gD, |
51 |
(CIE_x_b*CIE_y_r - CIE_x_r*CIE_y_b)/CIE_C_gD}, |
52 |
{(CIE_y_r - CIE_y_g - CIE_y_r*CIE_x_g + CIE_y_g*CIE_x_r)/CIE_C_bD, |
53 |
(CIE_x_g - CIE_x_r - CIE_x_g*CIE_y_r + CIE_x_r*CIE_y_g)/CIE_C_bD, |
54 |
(CIE_x_r*CIE_y_g - CIE_x_g*CIE_y_r)/CIE_C_bD} |
55 |
}; |
56 |
|
57 |
COLORMAT rgb2xyzmat = { /* RGB to XYZ */ |
58 |
{CIE_x_r*CIE_C_rD/CIE_D,CIE_x_g*CIE_C_gD/CIE_D,CIE_x_b*CIE_C_bD/CIE_D}, |
59 |
{CIE_y_r*CIE_C_rD/CIE_D,CIE_y_g*CIE_C_gD/CIE_D,CIE_y_b*CIE_C_bD/CIE_D}, |
60 |
{(1.-CIE_x_r-CIE_y_r)*CIE_C_rD/CIE_D, |
61 |
(1.-CIE_x_g-CIE_y_g)*CIE_C_gD/CIE_D, |
62 |
(1.-CIE_x_b-CIE_y_b)*CIE_C_bD/CIE_D} |
63 |
}; |
64 |
|
65 |
|
66 |
|
67 |
spec_rgb(col, s, e) /* compute RGB color from spectral range */ |
68 |
COLOR col; |
69 |
int s, e; |
70 |
{ |
71 |
COLOR ciecolor; |
72 |
|
73 |
spec_cie(ciecolor, s, e); |
74 |
cie_rgb(col, ciecolor); |
75 |
} |
76 |
|
77 |
|
78 |
spec_cie(col, s, e) /* compute a color from a spectral range */ |
79 |
COLOR col; /* returned color */ |
80 |
int s, e; /* starting and ending wavelengths */ |
81 |
{ |
82 |
register int i, d, r; |
83 |
|
84 |
s -= STARTWL; |
85 |
if (s < 0) |
86 |
s = 0; |
87 |
|
88 |
e -= STARTWL; |
89 |
if (e <= s) { |
90 |
col[CIEX] = col[CIEY] = col[CIEZ] = 0.0; |
91 |
return; |
92 |
} |
93 |
if (e >= INCWL*(NINC - 1)) |
94 |
e = INCWL*(NINC - 1) - 1; |
95 |
|
96 |
d = e / INCWL; /* interpolate values */ |
97 |
r = e % INCWL; |
98 |
for (i = 0; i < 3; i++) |
99 |
col[i] = chroma[i][d]*(INCWL - r) + chroma[i][d + 1]*r; |
100 |
|
101 |
d = s / INCWL; |
102 |
r = s % INCWL; |
103 |
for (i = 0; i < 3; i++) |
104 |
col[i] -= chroma[i][d]*(INCWL - r) - chroma[i][d + 1]*r; |
105 |
|
106 |
col[CIEX] = (col[CIEX] + 0.5) * (1./(256*INCWL)); |
107 |
col[CIEY] = (col[CIEY] + 0.5) * (1./(256*INCWL)); |
108 |
col[CIEZ] = (col[CIEZ] + 0.5) * (1./(256*INCWL)); |
109 |
} |
110 |
|
111 |
|
112 |
colortrans(c2, mat, c1, noneg) /* convert c1 by mat and put into c2 */ |
113 |
register COLORMAT mat; |
114 |
register COLOR c1, c2; |
115 |
int noneg; |
116 |
{ |
117 |
static float cout[3]; |
118 |
|
119 |
cout[0] = mat[0][0]*c1[0] + mat[0][1]*c1[1] + mat[0][2]*c1[2]; |
120 |
cout[1] = mat[1][0]*c1[0] + mat[1][1]*c1[1] + mat[1][2]*c1[2]; |
121 |
cout[2] = mat[2][0]*c1[0] + mat[2][1]*c1[1] + mat[2][2]*c1[2]; |
122 |
if (!noneg) |
123 |
return; |
124 |
if ((c2[0] = cout[0]) < 0.) c2[0] = 0.; |
125 |
if ((c2[1] = cout[1]) < 0.) c2[1] = 0.; |
126 |
if ((c2[2] = cout[2]) < 0.) c2[2] = 0.; |
127 |
} |
128 |
|
129 |
|
130 |
multcolormat(m3, m2, m1) /* multiply m1 by m2 and put into m3 */ |
131 |
COLORMAT m1, m2, m3; /* m3 can be either m1 or m2 w/o harm */ |
132 |
{ |
133 |
COLORMAT mt; |
134 |
register int i, j; |
135 |
|
136 |
for (i = 0; i < 3; i++) |
137 |
for (j = 0; j < 3; j++) |
138 |
mt[i][j] = m1[i][0]*m2[0][j] + |
139 |
m1[i][1]*m2[1][j] + |
140 |
m1[i][2]*m2[2][j] ; |
141 |
cpcolormat(m3, mt); |
142 |
} |
143 |
|
144 |
|
145 |
compxyz2rgbmat(mat, pr) /* compute conversion from CIE to RGB space */ |
146 |
COLORMAT mat; |
147 |
register RGBPRIMS pr; |
148 |
{ |
149 |
double C_rD, C_gD, C_bD; |
150 |
|
151 |
if (pr == stdprims) { /* can use xyz2rgbmat */ |
152 |
cpcolormat(mat, xyz2rgbmat); |
153 |
return; |
154 |
} |
155 |
C_rD = (1./pr[WHT][CIEY]) * |
156 |
( pr[WHT][CIEX]*(pr[GRN][CIEY] - pr[BLU][CIEY]) - |
157 |
pr[WHT][CIEY]*(pr[GRN][CIEX] - pr[BLU][CIEX]) + |
158 |
pr[GRN][CIEX]*pr[BLU][CIEY] - pr[BLU][CIEX]*pr[GRN][CIEY] ) ; |
159 |
C_gD = (1./pr[WHT][CIEY]) * |
160 |
( pr[WHT][CIEX]*(pr[BLU][CIEY] - pr[RED][CIEY]) - |
161 |
pr[WHT][CIEY]*(pr[BLU][CIEX] - pr[RED][CIEX]) - |
162 |
pr[RED][CIEX]*pr[BLU][CIEY] + pr[BLU][CIEX]*pr[RED][CIEY] ) ; |
163 |
C_bD = (1./pr[WHT][CIEY]) * |
164 |
( pr[WHT][CIEX]*(pr[RED][CIEY] - pr[GRN][CIEY]) - |
165 |
pr[WHT][CIEY]*(pr[RED][CIEX] - pr[GRN][CIEX]) + |
166 |
pr[RED][CIEX]*pr[GRN][CIEY] - pr[GRN][CIEX]*pr[RED][CIEY] ) ; |
167 |
|
168 |
mat[0][0] = (pr[GRN][CIEY] - pr[BLU][CIEY] - |
169 |
pr[BLU][CIEX]*pr[GRN][CIEY] + |
170 |
pr[BLU][CIEY]*pr[GRN][CIEX])/C_rD ; |
171 |
mat[0][1] = (pr[BLU][CIEX] - pr[GRN][CIEX] - |
172 |
pr[BLU][CIEX]*pr[GRN][CIEY] + |
173 |
pr[GRN][CIEX]*pr[BLU][CIEY])/C_rD ; |
174 |
mat[0][2] = (pr[GRN][CIEX]*pr[BLU][CIEY] - |
175 |
pr[BLU][CIEX]*pr[GRN][CIEY])/C_rD ; |
176 |
mat[1][0] = (pr[BLU][CIEY] - pr[RED][CIEY] - |
177 |
pr[BLU][CIEY]*pr[RED][CIEX] + |
178 |
pr[RED][CIEY]*pr[BLU][CIEX])/C_gD ; |
179 |
mat[1][1] = (pr[RED][CIEX] - pr[BLU][CIEX] - |
180 |
pr[RED][CIEX]*pr[BLU][CIEY] + |
181 |
pr[BLU][CIEX]*pr[RED][CIEY])/C_gD ; |
182 |
mat[1][2] = (pr[BLU][CIEX]*pr[RED][CIEY] - |
183 |
pr[RED][CIEX]*pr[BLU][CIEY])/C_gD ; |
184 |
mat[2][0] = (pr[RED][CIEY] - pr[GRN][CIEY] - |
185 |
pr[RED][CIEY]*pr[GRN][CIEX] + |
186 |
pr[GRN][CIEY]*pr[RED][CIEX])/C_bD ; |
187 |
mat[2][1] = (pr[GRN][CIEX] - pr[RED][CIEX] - |
188 |
pr[GRN][CIEX]*pr[RED][CIEY] + |
189 |
pr[RED][CIEX]*pr[GRN][CIEY])/C_bD ; |
190 |
mat[2][2] = (pr[RED][CIEX]*pr[GRN][CIEY] - |
191 |
pr[GRN][CIEX]*pr[RED][CIEY])/C_bD ; |
192 |
} |
193 |
|
194 |
|
195 |
comprgb2xyzmat(mat, pr) /* compute conversion from RGB to CIE space */ |
196 |
COLORMAT mat; |
197 |
register RGBPRIMS pr; |
198 |
{ |
199 |
double C_rD, C_gD, C_bD, D; |
200 |
|
201 |
if (pr == stdprims) { /* can use rgb2xyzmat */ |
202 |
cpcolormat(mat, rgb2xyzmat); |
203 |
return; |
204 |
} |
205 |
C_rD = (1./pr[WHT][CIEY]) * |
206 |
( pr[WHT][CIEX]*(pr[GRN][CIEY] - pr[BLU][CIEY]) - |
207 |
pr[WHT][CIEY]*(pr[GRN][CIEX] - pr[BLU][CIEX]) + |
208 |
pr[GRN][CIEX]*pr[BLU][CIEY] - pr[BLU][CIEX]*pr[GRN][CIEY] ) ; |
209 |
C_gD = (1./pr[WHT][CIEY]) * |
210 |
( pr[WHT][CIEX]*(pr[BLU][CIEY] - pr[RED][CIEY]) - |
211 |
pr[WHT][CIEY]*(pr[BLU][CIEX] - pr[RED][CIEX]) - |
212 |
pr[RED][CIEX]*pr[BLU][CIEY] + pr[BLU][CIEX]*pr[RED][CIEY] ) ; |
213 |
C_bD = (1./pr[WHT][CIEY]) * |
214 |
( pr[WHT][CIEX]*(pr[RED][CIEY] - pr[GRN][CIEY]) - |
215 |
pr[WHT][CIEY]*(pr[RED][CIEX] - pr[GRN][CIEX]) + |
216 |
pr[RED][CIEX]*pr[GRN][CIEY] - pr[GRN][CIEX]*pr[RED][CIEY] ) ; |
217 |
D = pr[RED][CIEX]*(pr[GRN][CIEY] - pr[BLU][CIEY]) + |
218 |
pr[GRN][CIEX]*(pr[BLU][CIEY] - pr[RED][CIEY]) + |
219 |
pr[BLU][CIEX]*(pr[RED][CIEY] - pr[GRN][CIEY]) ; |
220 |
mat[0][0] = pr[RED][CIEX]*C_rD/D; |
221 |
mat[0][1] = pr[GRN][CIEX]*C_gD/D; |
222 |
mat[0][2] = pr[BLU][CIEX]*C_bD/D; |
223 |
mat[1][0] = pr[RED][CIEY]*C_rD/D; |
224 |
mat[1][1] = pr[GRN][CIEY]*C_gD/D; |
225 |
mat[1][2] = pr[BLU][CIEY]*C_bD/D; |
226 |
mat[2][0] = (1.-pr[RED][CIEX]-pr[RED][CIEY])*C_rD/D; |
227 |
mat[2][1] = (1.-pr[GRN][CIEX]-pr[GRN][CIEY])*C_gD/D; |
228 |
mat[2][2] = (1.-pr[BLU][CIEX]-pr[BLU][CIEY])*C_bD/D; |
229 |
} |
230 |
|
231 |
|
232 |
comprgb2rgbmat(mat, pr1, pr2) /* compute conversion from RGB1 to RGB2 */ |
233 |
COLORMAT mat; |
234 |
RGBPRIMS pr1, pr2; |
235 |
{ |
236 |
COLORMAT pr1toxyz, xyztopr2; |
237 |
|
238 |
if (pr1 == pr2) { |
239 |
mat[0][0] = mat[1][1] = mat[2][2] = 1.0; |
240 |
mat[0][1] = mat[0][2] = mat[1][0] = |
241 |
mat[1][2] = mat[2][0] = mat[2][1] = 0.0; |
242 |
return; |
243 |
} |
244 |
comprgb2xyzmat(pr1toxyz, pr1); |
245 |
compxyz2rgbmat(xyztopr2, pr2); |
246 |
/* combine transforms */ |
247 |
multcolormat(mat, pr1toxyz, xyztopr2); |
248 |
} |