1 |
#ifndef lint |
2 |
static const char RCSid[] = "$Id: ccolor.c,v 3.1 2011/02/18 00:40:25 greg Exp $"; |
3 |
#endif |
4 |
/* |
5 |
* Spectral color handling routines |
6 |
*/ |
7 |
|
8 |
#include <stdio.h> |
9 |
#include <math.h> |
10 |
#include "ccolor.h" |
11 |
|
12 |
|
13 |
C_COLOR c_dfcolor = C_DEFCOLOR; |
14 |
|
15 |
/* CIE 1931 Standard Observer curves */ |
16 |
static const C_COLOR cie_xf = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF, |
17 |
{14,42,143,435,1344,2839,3483,3362,2908,1954,956, |
18 |
320,49,93,633,1655,2904,4334,5945,7621,9163,10263, |
19 |
10622,10026,8544,6424,4479,2835,1649,874,468,227, |
20 |
114,58,29,14,7,3,2,1,0}, 106836L, .467, .368, 362.230 |
21 |
}; |
22 |
static const C_COLOR cie_yf = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF, |
23 |
{0,1,4,12,40,116,230,380,600,910,1390,2080,3230, |
24 |
5030,7100,8620,9540,9950,9950,9520,8700,7570,6310, |
25 |
5030,3810,2650,1750,1070,610,320,170,82,41,21,10, |
26 |
5,2,1,1,0,0}, 106856L, .398, .542, 493.525 |
27 |
}; |
28 |
static const C_COLOR cie_zf = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF, |
29 |
{65,201,679,2074,6456,13856,17471,17721,16692, |
30 |
12876,8130,4652,2720,1582,782,422,203,87,39,21,17, |
31 |
11,8,3,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, |
32 |
106770L, .147, .077, 54.363 |
33 |
}; |
34 |
/* Derived CIE 1931 Primaries (imaginary) */ |
35 |
static const C_COLOR cie_xp = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY, |
36 |
{-174,-198,-195,-197,-202,-213,-235,-272,-333, |
37 |
-444,-688,-1232,-2393,-4497,-6876,-6758,-5256, |
38 |
-3100,-815,1320,3200,4782,5998,6861,7408,7754, |
39 |
7980,8120,8199,8240,8271,8292,8309,8283,8469, |
40 |
8336,8336,8336,8336,8336,8336}, |
41 |
127424L, 1., .0, |
42 |
}; |
43 |
static const C_COLOR cie_yp = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY, |
44 |
{-451,-431,-431,-430,-427,-417,-399,-366,-312, |
45 |
-204,57,691,2142,4990,8810,9871,9122,7321,5145, |
46 |
3023,1123,-473,-1704,-2572,-3127,-3474,-3704, |
47 |
-3846,-3927,-3968,-3999,-4021,-4038,-4012,-4201, |
48 |
-4066,-4066,-4066,-4066,-4066,-4066}, |
49 |
-23035L, .0, 1., |
50 |
}; |
51 |
static const C_COLOR cie_zp = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY, |
52 |
{4051,4054,4052,4053,4054,4056,4059,4064,4071, |
53 |
4074,4056,3967,3677,2933,1492,313,-440,-795, |
54 |
-904,-918,-898,-884,-869,-863,-855,-855,-851, |
55 |
-848,-847,-846,-846,-846,-845,-846,-843,-845, |
56 |
-845,-845,-845,-845,-845}, |
57 |
36057L, .0, .0, |
58 |
}; |
59 |
|
60 |
/* Sharp primary matrix */ |
61 |
static const float toSharp[3][3] = { |
62 |
{ 1.2694, -0.0988, -0.1706}, |
63 |
{-0.8364, 1.8006, 0.0357}, |
64 |
{ 0.0297, -0.0315, 1.0018} |
65 |
}; |
66 |
/* inverse Sharp primary matrix */ |
67 |
static const float fromSharp[3][3] = { |
68 |
{ 0.8156, 0.0472, 0.1372}, |
69 |
{ 0.3791, 0.5769, 0.0440}, |
70 |
{-0.0123, 0.0167, 0.9955} |
71 |
}; |
72 |
|
73 |
static void |
74 |
c_toSharpRGB(C_COLOR *cin, double cieY, float cout[3]) |
75 |
{ |
76 |
double xyz[3]; |
77 |
|
78 |
c_ccvt(cin, C_CSXY); |
79 |
|
80 |
xyz[0] = cin->cx/cin->cy * cieY; |
81 |
xyz[1] = cieY; |
82 |
xyz[2] = (1. - cin->cx - cin->cy)/cin->cy * cieY; |
83 |
|
84 |
cout[0] = toSharp[0][0]*xyz[0] + toSharp[0][1]*xyz[1] + |
85 |
toSharp[0][2]*xyz[2]; |
86 |
cout[1] = toSharp[1][0]*xyz[0] + toSharp[1][1]*xyz[1] + |
87 |
toSharp[1][2]*xyz[2]; |
88 |
cout[2] = toSharp[2][0]*xyz[0] + toSharp[2][1]*xyz[1] + |
89 |
toSharp[2][2]*xyz[2]; |
90 |
} |
91 |
|
92 |
static double |
93 |
c_fromSharpRGB(float cin[3], C_COLOR *cout) |
94 |
{ |
95 |
double xyz[3], sf; |
96 |
|
97 |
xyz[0] = fromSharp[0][0]*cin[0] + fromSharp[0][1]*cin[1] + |
98 |
fromSharp[0][2]*cin[2]; |
99 |
xyz[1] = fromSharp[1][0]*cin[0] + fromSharp[1][1]*cin[1] + |
100 |
fromSharp[1][2]*cin[2]; |
101 |
xyz[2] = fromSharp[2][0]*cin[0] + fromSharp[2][1]*cin[1] + |
102 |
fromSharp[2][2]*cin[2]; |
103 |
|
104 |
sf = 1./(xyz[0] + xyz[1] + xyz[2]); |
105 |
|
106 |
cout->cx = xyz[0] * sf; |
107 |
cout->cy = xyz[1] * sf; |
108 |
cout->flags = C_CDXY|C_CSXY; |
109 |
|
110 |
return(xyz[1]); |
111 |
} |
112 |
|
113 |
/* check if color is grey */ |
114 |
int |
115 |
c_isgrey(C_COLOR *clr) |
116 |
{ |
117 |
if (!(clr->flags & (C_CSXY|C_CSSPEC))) |
118 |
return(1); /* no settings == grey */ |
119 |
|
120 |
c_ccvt(clr, C_CSXY); |
121 |
|
122 |
return(clr->cx >= .323 && clr->cx <= .343 && |
123 |
clr->cy >= .323 && clr->cy <= .343); |
124 |
} |
125 |
|
126 |
/* convert color representations */ |
127 |
void |
128 |
c_ccvt(C_COLOR *clr, int fl) |
129 |
{ |
130 |
double x, y, z; |
131 |
int i; |
132 |
|
133 |
fl &= ~clr->flags; /* ignore what's done */ |
134 |
if (!fl) /* everything's done! */ |
135 |
return; |
136 |
if (!(clr->flags & (C_CSXY|C_CSSPEC))) { |
137 |
*clr = c_dfcolor; /* nothing was set! */ |
138 |
return; |
139 |
} |
140 |
if (fl & C_CSXY) { /* cspec -> cxy */ |
141 |
x = y = z = 0.; |
142 |
for (i = 0; i < C_CNSS; i++) { |
143 |
x += cie_xf.ssamp[i] * clr->ssamp[i]; |
144 |
y += cie_yf.ssamp[i] * clr->ssamp[i]; |
145 |
z += cie_zf.ssamp[i] * clr->ssamp[i]; |
146 |
} |
147 |
x /= (double)cie_xf.ssum; |
148 |
y /= (double)cie_yf.ssum; |
149 |
z /= (double)cie_zf.ssum; |
150 |
z += x + y; |
151 |
clr->cx = x / z; |
152 |
clr->cy = y / z; |
153 |
clr->flags |= C_CSXY; |
154 |
} else if (fl & C_CSSPEC) { /* cxy -> cspec */ |
155 |
x = clr->cx; |
156 |
y = clr->cy; |
157 |
z = 1. - x - y; |
158 |
clr->ssum = 0; |
159 |
for (i = 0; i < C_CNSS; i++) { |
160 |
clr->ssamp[i] = x*cie_xp.ssamp[i] + y*cie_yp.ssamp[i] |
161 |
+ z*cie_zp.ssamp[i] + .5; |
162 |
if (clr->ssamp[i] < 0) /* out of gamut! */ |
163 |
clr->ssamp[i] = 0; |
164 |
else |
165 |
clr->ssum += clr->ssamp[i]; |
166 |
} |
167 |
clr->flags |= C_CSSPEC; |
168 |
} |
169 |
if (fl & C_CSEFF) { /* compute efficacy */ |
170 |
if (clr->flags & C_CSSPEC) { /* from spectrum */ |
171 |
y = 0.; |
172 |
for (i = 0; i < C_CNSS; i++) |
173 |
y += cie_yf.ssamp[i] * clr->ssamp[i]; |
174 |
clr->eff = C_CLPWM * y / clr->ssum; |
175 |
} else /* clr->flags & C_CSXY */ { /* from (x,y) */ |
176 |
clr->eff = clr->cx*cie_xf.eff + clr->cy*cie_yf.eff + |
177 |
(1. - clr->cx - clr->cy)*cie_zf.eff; |
178 |
} |
179 |
clr->flags |= C_CSEFF; |
180 |
} |
181 |
} |
182 |
|
183 |
/* mix two colors according to weights given -- cres may be c1 or c2 */ |
184 |
void |
185 |
c_cmix(C_COLOR *cres, double w1, C_COLOR *c1, double w2, C_COLOR *c2) |
186 |
{ |
187 |
double scale; |
188 |
int i; |
189 |
|
190 |
if ((c1->flags|c2->flags) & C_CDSPEC) { /* spectral mixing */ |
191 |
float cmix[C_CNSS]; |
192 |
|
193 |
c_ccvt(c1, C_CSSPEC|C_CSEFF); |
194 |
c_ccvt(c2, C_CSSPEC|C_CSEFF); |
195 |
w1 /= c1->eff*c1->ssum; |
196 |
w2 /= c2->eff*c2->ssum; |
197 |
scale = 0.; |
198 |
for (i = 0; i < C_CNSS; i++) { |
199 |
cmix[i] = w1*c1->ssamp[i] + w2*c2->ssamp[i]; |
200 |
if (cmix[i] > scale) |
201 |
scale = cmix[i]; |
202 |
} |
203 |
scale = C_CMAXV / scale; |
204 |
cres->ssum = 0; |
205 |
for (i = 0; i < C_CNSS; i++) |
206 |
cres->ssum += cres->ssamp[i] = scale*cmix[i] + .5; |
207 |
cres->flags = C_CDSPEC|C_CSSPEC; |
208 |
} else { /* CIE xy mixing */ |
209 |
c_ccvt(c1, C_CSXY); |
210 |
c_ccvt(c2, C_CSXY); |
211 |
w1 *= c2->cy; |
212 |
w2 *= c1->cy; |
213 |
scale = w1 + w2; |
214 |
if (scale == 0.) { |
215 |
*cres = c_dfcolor; |
216 |
return; |
217 |
} |
218 |
scale = 1. / scale; |
219 |
cres->cx = (w1*c1->cx + w2*c2->cx) * scale; |
220 |
cres->cy = (w1*c1->cy + w2*c2->cy) * scale; |
221 |
cres->flags = C_CDXY|C_CSXY; |
222 |
} |
223 |
} |
224 |
|
225 |
/* multiply two colors -- cres may be c1 or c2 */ |
226 |
double |
227 |
c_cmult(C_COLOR *cres, C_COLOR *c1, double y1, C_COLOR *c2, double y2) |
228 |
{ |
229 |
double yres; |
230 |
int i; |
231 |
|
232 |
if ((c1->flags|c2->flags) & C_CDSPEC) { |
233 |
long cmix[C_CNSS], cmax = 0; /* spectral multiply */ |
234 |
|
235 |
c_ccvt(c1, C_CSSPEC|C_CSEFF); |
236 |
c_ccvt(c2, C_CSSPEC|C_CSEFF); |
237 |
for (i = 0; i < C_CNSS; i++) { |
238 |
cmix[i] = c1->ssamp[i] * c2->ssamp[i]; |
239 |
if (cmix[i] > cmax) |
240 |
cmax = cmix[i]; |
241 |
} |
242 |
cmax /= C_CMAXV; |
243 |
if (!cmax) { |
244 |
*cres = c_dfcolor; |
245 |
return(0.); |
246 |
} |
247 |
cres->ssum = 0; |
248 |
for (i = 0; i < C_CNSS; i++) |
249 |
cres->ssum += cres->ssamp[i] = cmix[i] / cmax; |
250 |
cres->flags = C_CDSPEC|C_CSSPEC; |
251 |
|
252 |
c_ccvt(cres, C_CSEFF); /* nasty, but true */ |
253 |
yres = (y1 * y2 * cie_yf.ssum * C_CLPWM) / |
254 |
(c1->eff*c1->ssum * c2->eff*c2->ssum) * |
255 |
cres->eff*( cres->ssum*(double)cmax + |
256 |
C_CNSS/2.0*(cmax-1) ); |
257 |
} else { |
258 |
float rgb1[3], rgb2[3]; /* CIE xy multiply */ |
259 |
|
260 |
c_toSharpRGB(c1, y1, rgb1); |
261 |
c_toSharpRGB(c2, y2, rgb2); |
262 |
|
263 |
rgb2[0] *= rgb1[0]; rgb2[1] *= rgb1[1]; rgb2[2] *= rgb1[2]; |
264 |
|
265 |
yres = c_fromSharpRGB(rgb2, cres); |
266 |
} |
267 |
return(yres); |
268 |
} |
269 |
|
270 |
#define C1 3.741832e-16 /* W-m^2 */ |
271 |
#define C2 1.4388e-2 /* m-K */ |
272 |
|
273 |
#define bbsp(l,t) (C1/((l)*(l)*(l)*(l)*(l)*(exp(C2/((t)*(l)))-1.))) |
274 |
#define bblm(t) (C2*0.2/(t)) |
275 |
|
276 |
/* set black body spectrum */ |
277 |
int |
278 |
c_bbtemp(C_COLOR *clr, double tk) |
279 |
{ |
280 |
double sf, wl; |
281 |
int i; |
282 |
|
283 |
if (tk < 1000) |
284 |
return(0); |
285 |
wl = bblm(tk); /* scalefactor based on peak */ |
286 |
if (wl < C_CMINWL*1e-9) |
287 |
wl = C_CMINWL*1e-9; |
288 |
else if (wl > C_CMAXWL*1e-9) |
289 |
wl = C_CMAXWL*1e-9; |
290 |
sf = C_CMAXV/bbsp(wl,tk); |
291 |
clr->ssum = 0; |
292 |
for (i = 0; i < C_CNSS; i++) { |
293 |
wl = (C_CMINWL + i*C_CWLI)*1e-9; |
294 |
clr->ssum += clr->ssamp[i] = sf*bbsp(wl,tk) + .5; |
295 |
} |
296 |
clr->flags = C_CDSPEC|C_CSSPEC; |
297 |
return(1); |
298 |
} |
299 |
|
300 |
#undef C1 |
301 |
#undef C2 |
302 |
#undef bbsp |
303 |
#undef bblm |