| 1 |
#ifndef lint |
| 2 |
static const char RCSid[] = "$Id: ccolor.c,v 3.7 2015/03/26 15:57:19 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 |
/* Sharp primary matrix */ |
| 13 |
float XYZtoSharp[3][3] = { |
| 14 |
{ 1.2694, -0.0988, -0.1706}, |
| 15 |
{-0.8364, 1.8006, 0.0357}, |
| 16 |
{ 0.0297, -0.0315, 1.0018} |
| 17 |
}; |
| 18 |
/* inverse Sharp primary matrix */ |
| 19 |
float XYZfromSharp[3][3] = { |
| 20 |
{ 0.8156, 0.0472, 0.1372}, |
| 21 |
{ 0.3791, 0.5769, 0.0440}, |
| 22 |
{-0.0123, 0.0167, 0.9955} |
| 23 |
}; |
| 24 |
|
| 25 |
const C_COLOR c_dfcolor = C_DEFCOLOR; |
| 26 |
|
| 27 |
/* CIE 1931 Standard Observer curves */ |
| 28 |
const C_COLOR c_x31 = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF, |
| 29 |
{14,42,143,435,1344,2839,3483,3362,2908,1954,956, |
| 30 |
320,49,93,633,1655,2904,4334,5945,7621,9163,10263, |
| 31 |
10622,10026,8544,6424,4479,2835,1649,874,468,227, |
| 32 |
114,58,29,14,7,3,2,1,0}, 106836L, .467, .368, 362.230 |
| 33 |
}; |
| 34 |
const C_COLOR c_y31 = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF, |
| 35 |
{0,1,4,12,40,116,230,380,600,910,1390,2080,3230, |
| 36 |
5030,7100,8620,9540,9950,9950,9520,8700,7570,6310, |
| 37 |
5030,3810,2650,1750,1070,610,320,170,82,41,21,10, |
| 38 |
5,2,1,1,0,0}, 106856L, .398, .542, 493.525 |
| 39 |
}; |
| 40 |
const C_COLOR c_z31 = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF, |
| 41 |
{65,201,679,2074,6456,13856,17471,17721,16692, |
| 42 |
12876,8130,4652,2720,1582,782,422,203,87,39,21,17, |
| 43 |
11,8,3,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}, |
| 44 |
106770L, .147, .077, 54.363 |
| 45 |
}; |
| 46 |
/* Derived CIE 1931 Primaries (imaginary) */ |
| 47 |
static const C_COLOR cie_xp = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY, |
| 48 |
{-174,-198,-195,-197,-202,-213,-235,-272,-333, |
| 49 |
-444,-688,-1232,-2393,-4497,-6876,-6758,-5256, |
| 50 |
-3100,-815,1320,3200,4782,5998,6861,7408,7754, |
| 51 |
7980,8120,8199,8240,8271,8292,8309,8283,8469, |
| 52 |
8336,8336,8336,8336,8336,8336}, |
| 53 |
127424L, 1., .0, |
| 54 |
}; |
| 55 |
static const C_COLOR cie_yp = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY, |
| 56 |
{-451,-431,-431,-430,-427,-417,-399,-366,-312, |
| 57 |
-204,57,691,2142,4990,8810,9871,9122,7321,5145, |
| 58 |
3023,1123,-473,-1704,-2572,-3127,-3474,-3704, |
| 59 |
-3846,-3927,-3968,-3999,-4021,-4038,-4012,-4201, |
| 60 |
-4066,-4066,-4066,-4066,-4066,-4066}, |
| 61 |
-23035L, .0, 1., |
| 62 |
}; |
| 63 |
static const C_COLOR cie_zp = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY, |
| 64 |
{4051,4054,4052,4053,4054,4056,4059,4064,4071, |
| 65 |
4074,4056,3967,3677,2933,1492,313,-440,-795, |
| 66 |
-904,-918,-898,-884,-869,-863,-855,-855,-851, |
| 67 |
-848,-847,-846,-846,-846,-845,-846,-843,-845, |
| 68 |
-845,-845,-845,-845,-845}, |
| 69 |
36057L, .0, .0, |
| 70 |
}; |
| 71 |
|
| 72 |
|
| 73 |
/* convert to sharpened RGB color for low-error operations */ |
| 74 |
void |
| 75 |
c_toSharpRGB(C_COLOR *cin, double cieY, float cout[3]) |
| 76 |
{ |
| 77 |
double xyz[3]; |
| 78 |
|
| 79 |
c_ccvt(cin, C_CSXY); |
| 80 |
|
| 81 |
xyz[0] = cin->cx/cin->cy * cieY; |
| 82 |
xyz[1] = cieY; |
| 83 |
xyz[2] = (1. - cin->cx - cin->cy)/cin->cy * cieY; |
| 84 |
|
| 85 |
cout[0] = XYZtoSharp[0][0]*xyz[0] + XYZtoSharp[0][1]*xyz[1] + |
| 86 |
XYZtoSharp[0][2]*xyz[2]; |
| 87 |
cout[1] = XYZtoSharp[1][0]*xyz[0] + XYZtoSharp[1][1]*xyz[1] + |
| 88 |
XYZtoSharp[1][2]*xyz[2]; |
| 89 |
cout[2] = XYZtoSharp[2][0]*xyz[0] + XYZtoSharp[2][1]*xyz[1] + |
| 90 |
XYZtoSharp[2][2]*xyz[2]; |
| 91 |
} |
| 92 |
|
| 93 |
/* convert back from sharpened RGB color */ |
| 94 |
double |
| 95 |
c_fromSharpRGB(float cin[3], C_COLOR *cout) |
| 96 |
{ |
| 97 |
double xyz[3], sf; |
| 98 |
|
| 99 |
xyz[1] = XYZfromSharp[1][0]*cin[0] + XYZfromSharp[1][1]*cin[1] + |
| 100 |
XYZfromSharp[1][2]*cin[2]; |
| 101 |
if (xyz[1] <= 1e-6) { |
| 102 |
*cout = c_dfcolor; /* punting, here... */ |
| 103 |
return xyz[1]; |
| 104 |
} |
| 105 |
xyz[0] = XYZfromSharp[0][0]*cin[0] + XYZfromSharp[0][1]*cin[1] + |
| 106 |
XYZfromSharp[0][2]*cin[2]; |
| 107 |
xyz[2] = XYZfromSharp[2][0]*cin[0] + XYZfromSharp[2][1]*cin[1] + |
| 108 |
XYZfromSharp[2][2]*cin[2]; |
| 109 |
|
| 110 |
sf = 1./(xyz[0] + xyz[1] + xyz[2]); |
| 111 |
|
| 112 |
cout->cx = xyz[0] * sf; |
| 113 |
cout->cy = xyz[1] * sf; |
| 114 |
cout->flags = C_CDXY|C_CSXY; |
| 115 |
|
| 116 |
return(xyz[1]); |
| 117 |
} |
| 118 |
|
| 119 |
/* assign arbitrary spectrum and return Y value */ |
| 120 |
double |
| 121 |
c_sset(C_COLOR *clr, double wlmin, double wlmax, const float spec[], int nwl) |
| 122 |
{ |
| 123 |
double yval, scale; |
| 124 |
float va[C_CNSS]; |
| 125 |
int i, pos, n, imax, wl; |
| 126 |
double wl0, wlstep; |
| 127 |
double boxpos, boxstep; |
| 128 |
/* check arguments */ |
| 129 |
if ((nwl <= 1) | (spec == NULL) | (wlmin >= C_CMAXWL) | |
| 130 |
(wlmax <= C_CMINWL) | (wlmin >= wlmax)) |
| 131 |
return(0.); |
| 132 |
wlstep = (wlmax - wlmin)/(nwl-1); |
| 133 |
while (wlmin < C_CMINWL) { |
| 134 |
wlmin += wlstep; |
| 135 |
--nwl; ++spec; |
| 136 |
} |
| 137 |
while (wlmax > C_CMAXWL) { |
| 138 |
wlmax -= wlstep; |
| 139 |
--nwl; |
| 140 |
} |
| 141 |
if ((nwl <= 1) | (wlmin >= wlmax)) |
| 142 |
return(0.); |
| 143 |
imax = nwl; /* box filter if necessary */ |
| 144 |
boxpos = 0; |
| 145 |
boxstep = 1; |
| 146 |
if (wlstep < C_CWLI) { |
| 147 |
imax = (wlmax - wlmin)/C_CWLI + 1e-7; |
| 148 |
boxpos = (wlmin - C_CMINWL)/C_CWLI; |
| 149 |
boxstep = wlstep/C_CWLI; |
| 150 |
wlstep = C_CWLI; |
| 151 |
} |
| 152 |
scale = 0.; /* get values and maximum */ |
| 153 |
yval = 0.; |
| 154 |
pos = 0; |
| 155 |
for (i = 0; i < imax; i++) { |
| 156 |
va[i] = 0.; n = 0; |
| 157 |
while (boxpos < i+.5 && pos < nwl) { |
| 158 |
va[i] += spec[pos++]; |
| 159 |
n++; |
| 160 |
boxpos += boxstep; |
| 161 |
} |
| 162 |
if (n > 1) |
| 163 |
va[i] /= (double)n; |
| 164 |
if (va[i] > scale) |
| 165 |
scale = va[i]; |
| 166 |
else if (va[i] < -scale) |
| 167 |
scale = -va[i]; |
| 168 |
yval += va[i] * c_y31.ssamp[i]; |
| 169 |
} |
| 170 |
if (scale <= 1e-7) |
| 171 |
return(0.); |
| 172 |
yval /= (double)c_y31.ssum; |
| 173 |
scale = C_CMAXV / scale; |
| 174 |
clr->ssum = 0; /* convert to our spacing */ |
| 175 |
wl0 = wlmin; |
| 176 |
pos = 0; |
| 177 |
for (i = 0, wl = C_CMINWL; i < C_CNSS; i++, wl += C_CWLI) |
| 178 |
if ((wl < wlmin) | (wl > wlmax)) |
| 179 |
clr->ssamp[i] = 0; |
| 180 |
else { |
| 181 |
while (wl0 + wlstep < wl+1e-7) { |
| 182 |
wl0 += wlstep; |
| 183 |
pos++; |
| 184 |
} |
| 185 |
if ((wl+1e-7 >= wl0) & (wl-1e-7 <= wl0)) |
| 186 |
clr->ssamp[i] = scale*va[pos] + .5; |
| 187 |
else /* interpolate if necessary */ |
| 188 |
clr->ssamp[i] = .5 + scale / wlstep * |
| 189 |
( va[pos]*(wl0+wlstep - wl) + |
| 190 |
va[pos+1]*(wl - wl0) ); |
| 191 |
clr->ssum += clr->ssamp[i]; |
| 192 |
} |
| 193 |
clr->flags = C_CDSPEC|C_CSSPEC; |
| 194 |
return(yval); |
| 195 |
} |
| 196 |
|
| 197 |
/* check if color is grey */ |
| 198 |
int |
| 199 |
c_isgrey(C_COLOR *clr) |
| 200 |
{ |
| 201 |
if (!(clr->flags & (C_CSXY|C_CSSPEC))) |
| 202 |
return(1); /* no settings == grey */ |
| 203 |
|
| 204 |
c_ccvt(clr, C_CSXY); |
| 205 |
|
| 206 |
return(clr->cx >= .323 && clr->cx <= .343 && |
| 207 |
clr->cy >= .323 && clr->cy <= .343); |
| 208 |
} |
| 209 |
|
| 210 |
/* convert color representations */ |
| 211 |
void |
| 212 |
c_ccvt(C_COLOR *clr, int fl) |
| 213 |
{ |
| 214 |
double x, y, z; |
| 215 |
int i; |
| 216 |
|
| 217 |
fl &= ~clr->flags; /* ignore what's done */ |
| 218 |
if (!fl) /* everything's done! */ |
| 219 |
return; |
| 220 |
if (!(clr->flags & (C_CSXY|C_CSSPEC))) { |
| 221 |
*clr = c_dfcolor; /* nothing was set! */ |
| 222 |
return; |
| 223 |
} |
| 224 |
if (fl & C_CSXY) { /* cspec -> cxy */ |
| 225 |
x = y = z = 0.; |
| 226 |
for (i = 0; i < C_CNSS; i++) { |
| 227 |
x += c_x31.ssamp[i] * clr->ssamp[i]; |
| 228 |
y += c_y31.ssamp[i] * clr->ssamp[i]; |
| 229 |
z += c_z31.ssamp[i] * clr->ssamp[i]; |
| 230 |
} |
| 231 |
x /= (double)c_x31.ssum; |
| 232 |
y /= (double)c_y31.ssum; |
| 233 |
z /= (double)c_z31.ssum; |
| 234 |
z += x + y; |
| 235 |
clr->cx = x / z; |
| 236 |
clr->cy = y / z; |
| 237 |
clr->flags |= C_CSXY; |
| 238 |
} |
| 239 |
if (fl & C_CSSPEC) { /* cxy -> cspec */ |
| 240 |
x = clr->cx; |
| 241 |
y = clr->cy; |
| 242 |
z = 1. - x - y; |
| 243 |
clr->ssum = 0; |
| 244 |
for (i = 0; i < C_CNSS; i++) { |
| 245 |
clr->ssamp[i] = x*cie_xp.ssamp[i] + y*cie_yp.ssamp[i] |
| 246 |
+ z*cie_zp.ssamp[i] + .5; |
| 247 |
if (clr->ssamp[i] < 0) /* out of gamut! */ |
| 248 |
clr->ssamp[i] = 0; |
| 249 |
else |
| 250 |
clr->ssum += clr->ssamp[i]; |
| 251 |
} |
| 252 |
clr->flags |= C_CSSPEC; |
| 253 |
} |
| 254 |
if (fl & C_CSEFF) { /* compute efficacy */ |
| 255 |
if (clr->flags & C_CSSPEC) { /* from spectrum */ |
| 256 |
y = 0.; |
| 257 |
for (i = 0; i < C_CNSS; i++) |
| 258 |
y += c_y31.ssamp[i] * clr->ssamp[i]; |
| 259 |
clr->eff = C_CLPWM * y / clr->ssum; |
| 260 |
} else /* clr->flags & C_CSXY */ { /* from (x,y) */ |
| 261 |
clr->eff = clr->cx*c_x31.eff + clr->cy*c_y31.eff + |
| 262 |
(1. - clr->cx - clr->cy)*c_z31.eff; |
| 263 |
} |
| 264 |
clr->flags |= C_CSEFF; |
| 265 |
} |
| 266 |
} |
| 267 |
|
| 268 |
/* mix two colors according to weights given -- cres may be c1 or c2 */ |
| 269 |
void |
| 270 |
c_cmix(C_COLOR *cres, double w1, C_COLOR *c1, double w2, C_COLOR *c2) |
| 271 |
{ |
| 272 |
double scale; |
| 273 |
int i; |
| 274 |
|
| 275 |
if ((c1->flags|c2->flags) & C_CDSPEC) { /* spectral mixing */ |
| 276 |
float cmix[C_CNSS]; |
| 277 |
|
| 278 |
c_ccvt(c1, C_CSSPEC|C_CSEFF); |
| 279 |
c_ccvt(c2, C_CSSPEC|C_CSEFF); |
| 280 |
w1 /= c1->eff*c1->ssum; |
| 281 |
w2 /= c2->eff*c2->ssum; |
| 282 |
scale = 0.; |
| 283 |
for (i = 0; i < C_CNSS; i++) { |
| 284 |
cmix[i] = w1*c1->ssamp[i] + w2*c2->ssamp[i]; |
| 285 |
if (cmix[i] > scale) |
| 286 |
scale = cmix[i]; |
| 287 |
else if (cmix[i] < -scale) |
| 288 |
scale = -cmix[i]; |
| 289 |
} |
| 290 |
scale = C_CMAXV / scale; |
| 291 |
cres->ssum = 0; |
| 292 |
for (i = 0; i < C_CNSS; i++) |
| 293 |
cres->ssum += cres->ssamp[i] = scale*cmix[i] + .5; |
| 294 |
cres->flags = C_CDSPEC|C_CSSPEC; |
| 295 |
} else { /* CIE xy mixing */ |
| 296 |
c_ccvt(c1, C_CSXY); |
| 297 |
c_ccvt(c2, C_CSXY); |
| 298 |
w1 *= c2->cy; |
| 299 |
w2 *= c1->cy; |
| 300 |
scale = w1 + w2; |
| 301 |
if (scale == 0.) { |
| 302 |
*cres = c_dfcolor; |
| 303 |
return; |
| 304 |
} |
| 305 |
scale = 1. / scale; |
| 306 |
cres->cx = (w1*c1->cx + w2*c2->cx) * scale; |
| 307 |
cres->cy = (w1*c1->cy + w2*c2->cy) * scale; |
| 308 |
cres->flags = C_CDXY|C_CSXY; |
| 309 |
} |
| 310 |
} |
| 311 |
|
| 312 |
/* multiply two colors -- cres may be c1 or c2 */ |
| 313 |
double |
| 314 |
c_cmult(C_COLOR *cres, C_COLOR *c1, double y1, C_COLOR *c2, double y2) |
| 315 |
{ |
| 316 |
double yres; |
| 317 |
int i; |
| 318 |
|
| 319 |
if ((c1->flags|c2->flags) & C_CDSPEC) { |
| 320 |
long cmix[C_CNSS], cmax = 0; /* spectral multiply */ |
| 321 |
|
| 322 |
c_ccvt(c1, C_CSSPEC|C_CSEFF); |
| 323 |
c_ccvt(c2, C_CSSPEC|C_CSEFF); |
| 324 |
for (i = 0; i < C_CNSS; i++) { |
| 325 |
cmix[i] = c1->ssamp[i] * c2->ssamp[i]; |
| 326 |
if (cmix[i] > cmax) |
| 327 |
cmax = cmix[i]; |
| 328 |
else if (cmix[i] < -cmax) |
| 329 |
cmax = -cmix[i]; |
| 330 |
} |
| 331 |
cmax /= C_CMAXV; |
| 332 |
if (!cmax) { |
| 333 |
*cres = c_dfcolor; |
| 334 |
return(0.); |
| 335 |
} |
| 336 |
cres->ssum = 0; |
| 337 |
for (i = 0; i < C_CNSS; i++) |
| 338 |
cres->ssum += cres->ssamp[i] = cmix[i] / cmax; |
| 339 |
cres->flags = C_CDSPEC|C_CSSPEC; |
| 340 |
|
| 341 |
c_ccvt(cres, C_CSEFF); /* below is correct */ |
| 342 |
yres = y1 * y2 * c_y31.ssum * C_CLPWM / |
| 343 |
(c1->eff*c1->ssum * c2->eff*c2->ssum) * |
| 344 |
cres->eff*( cres->ssum*(double)cmax + |
| 345 |
C_CNSS/2.0*(cmax-1) ); |
| 346 |
} else { |
| 347 |
float rgb1[3], rgb2[3]; /* CIE xy multiply */ |
| 348 |
|
| 349 |
c_toSharpRGB(c1, y1, rgb1); |
| 350 |
c_toSharpRGB(c2, y2, rgb2); |
| 351 |
|
| 352 |
rgb2[0] *= rgb1[0]; rgb2[1] *= rgb1[1]; rgb2[2] *= rgb1[2]; |
| 353 |
|
| 354 |
yres = c_fromSharpRGB(rgb2, cres); |
| 355 |
} |
| 356 |
return(yres); |
| 357 |
} |
| 358 |
|
| 359 |
#define C1 3.741832e-16 /* W-m^2 */ |
| 360 |
#define C2 1.4388e-2 /* m-K */ |
| 361 |
|
| 362 |
#define bbsp(l,t) (C1/((l)*(l)*(l)*(l)*(l)*(exp(C2/((t)*(l)))-1.))) |
| 363 |
#define bblm(t) (C2*0.2/(t)) |
| 364 |
|
| 365 |
/* set black body spectrum */ |
| 366 |
int |
| 367 |
c_bbtemp(C_COLOR *clr, double tk) |
| 368 |
{ |
| 369 |
double sf, wl; |
| 370 |
int i; |
| 371 |
|
| 372 |
if (tk < 1000) |
| 373 |
return(0); |
| 374 |
wl = bblm(tk); /* scalefactor based on peak */ |
| 375 |
if (wl < C_CMINWL*1e-9) |
| 376 |
wl = C_CMINWL*1e-9; |
| 377 |
else if (wl > C_CMAXWL*1e-9) |
| 378 |
wl = C_CMAXWL*1e-9; |
| 379 |
sf = C_CMAXV/bbsp(wl,tk); |
| 380 |
clr->ssum = 0; |
| 381 |
for (i = 0; i < C_CNSS; i++) { |
| 382 |
wl = (C_CMINWL + i*C_CWLI)*1e-9; |
| 383 |
clr->ssum += clr->ssamp[i] = sf*bbsp(wl,tk) + .5; |
| 384 |
} |
| 385 |
clr->flags = C_CDSPEC|C_CSSPEC; |
| 386 |
return(1); |
| 387 |
} |
| 388 |
|
| 389 |
#undef C1 |
| 390 |
#undef C2 |
| 391 |
#undef bbsp |
| 392 |
#undef bblm |
| 393 |
|
| 394 |
#define UV_NORMF 410. |
| 395 |
|
| 396 |
/* encode (x,y) chromaticity */ |
| 397 |
C_CHROMA |
| 398 |
c_encodeChroma(C_COLOR *clr) |
| 399 |
{ |
| 400 |
double df; |
| 401 |
int ub, vb; |
| 402 |
|
| 403 |
c_ccvt(clr, C_CSXY); |
| 404 |
df = UV_NORMF/(-2.*clr->cx + 12.*clr->cy + 3.); |
| 405 |
ub = 4.*clr->cx * df; |
| 406 |
if (ub < 0) ub = 0; |
| 407 |
else if (ub > 0xff) ub = 0xff; |
| 408 |
vb = 9.*clr->cy * df; |
| 409 |
if (vb < 0) vb = 0; |
| 410 |
else if (vb > 0xff) vb = 0xff; |
| 411 |
|
| 412 |
return(vb<<8 | ub); |
| 413 |
} |
| 414 |
|
| 415 |
/* decode (x,y) chromaticity */ |
| 416 |
void |
| 417 |
c_decodeChroma(C_COLOR *cres, C_CHROMA ccode) |
| 418 |
{ |
| 419 |
double up = ((ccode & 0xff) + .5)*(1./UV_NORMF); |
| 420 |
double vp = ((ccode>>8 & 0xff) + .5)*(1./UV_NORMF); |
| 421 |
double df = 1./(6.*up - 16.*vp + 12.); |
| 422 |
|
| 423 |
cres->cx = 9.*up * df; |
| 424 |
cres->cy = 4.*vp * df; |
| 425 |
cres->flags = C_CDXY|C_CSXY; |
| 426 |
} |
| 427 |
|
| 428 |
#undef UV_NORMF |
