1 //--------------------------------------------------------------------------------- 2 // 3 // Little Color Management System 4 // Copyright (c) 1998-2016 Marti Maria Saguer 5 // 6 // Permission is hereby granted, free of charge, to any person obtaining 7 // a copy of this software and associated documentation files (the "Software"), 8 // to deal in the Software without restriction, including without limitation 9 // the rights to use, copy, modify, merge, publish, distribute, sublicense, 10 // and/or sell copies of the Software, and to permit persons to whom the Software 11 // is furnished to do so, subject to the following conditions: 12 // 13 // The above copyright notice and this permission notice shall be included in 14 // all copies or substantial portions of the Software. 15 // 16 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 17 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO 18 // THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 19 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 20 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 21 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 22 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 23 // 24 //--------------------------------------------------------------------------------- 25 // 26 27 #include "lcms2_internal.h" 28 29 30 // D50 - Widely used 31 const cmsCIEXYZ* CMSEXPORT cmsD50_XYZ(void) 32 { 33 static cmsCIEXYZ D50XYZ = {cmsD50X, cmsD50Y, cmsD50Z}; 34 35 return &D50XYZ; 36 } 37 38 const cmsCIExyY* CMSEXPORT cmsD50_xyY(void) 39 { 40 static cmsCIExyY D50xyY; 41 42 cmsXYZ2xyY(&D50xyY, cmsD50_XYZ()); 43 44 return &D50xyY; 45 } 46 47 // Obtains WhitePoint from Temperature 48 cmsBool CMSEXPORT cmsWhitePointFromTemp(cmsCIExyY* WhitePoint, cmsFloat64Number TempK) 49 { 50 cmsFloat64Number x, y; 51 cmsFloat64Number T, T2, T3; 52 // cmsFloat64Number M1, M2; 53 54 _cmsAssert(WhitePoint != NULL); 55 56 T = TempK; 57 T2 = T*T; // Square 58 T3 = T2*T; // Cube 59 60 // For correlated color temperature (T) between 4000K and 7000K: 61 62 if (T >= 4000. && T <= 7000.) 63 { 64 x = -4.6070*(1E9/T3) + 2.9678*(1E6/T2) + 0.09911*(1E3/T) + 0.244063; 65 } 66 else 67 // or for correlated color temperature (T) between 7000K and 25000K: 68 69 if (T > 7000.0 && T <= 25000.0) 70 { 71 x = -2.0064*(1E9/T3) + 1.9018*(1E6/T2) + 0.24748*(1E3/T) + 0.237040; 72 } 73 else { 74 cmsSignalError(0, cmsERROR_RANGE, "cmsWhitePointFromTemp: invalid temp"); 75 return FALSE; 76 } 77 78 // Obtain y(x) 79 80 y = -3.000*(x*x) + 2.870*x - 0.275; 81 82 // wave factors (not used, but here for futures extensions) 83 84 // M1 = (-1.3515 - 1.7703*x + 5.9114 *y)/(0.0241 + 0.2562*x - 0.7341*y); 85 // M2 = (0.0300 - 31.4424*x + 30.0717*y)/(0.0241 + 0.2562*x - 0.7341*y); 86 87 WhitePoint -> x = x; 88 WhitePoint -> y = y; 89 WhitePoint -> Y = 1.0; 90 91 return TRUE; 92 } 93 94 95 96 typedef struct { 97 98 cmsFloat64Number mirek; // temp (in microreciprocal kelvin) 99 cmsFloat64Number ut; // u coord of intersection w/ blackbody locus 100 cmsFloat64Number vt; // v coord of intersection w/ blackbody locus 101 cmsFloat64Number tt; // slope of ISOTEMPERATURE. line 102 103 } ISOTEMPERATURE; 104 105 static ISOTEMPERATURE isotempdata[] = { 106 // {Mirek, Ut, Vt, Tt } 107 {0, 0.18006, 0.26352, -0.24341}, 108 {10, 0.18066, 0.26589, -0.25479}, 109 {20, 0.18133, 0.26846, -0.26876}, 110 {30, 0.18208, 0.27119, -0.28539}, 111 {40, 0.18293, 0.27407, -0.30470}, 112 {50, 0.18388, 0.27709, -0.32675}, 113 {60, 0.18494, 0.28021, -0.35156}, 114 {70, 0.18611, 0.28342, -0.37915}, 115 {80, 0.18740, 0.28668, -0.40955}, 116 {90, 0.18880, 0.28997, -0.44278}, 117 {100, 0.19032, 0.29326, -0.47888}, 118 {125, 0.19462, 0.30141, -0.58204}, 119 {150, 0.19962, 0.30921, -0.70471}, 120 {175, 0.20525, 0.31647, -0.84901}, 121 {200, 0.21142, 0.32312, -1.0182 }, 122 {225, 0.21807, 0.32909, -1.2168 }, 123 {250, 0.22511, 0.33439, -1.4512 }, 124 {275, 0.23247, 0.33904, -1.7298 }, 125 {300, 0.24010, 0.34308, -2.0637 }, 126 {325, 0.24702, 0.34655, -2.4681 }, 127 {350, 0.25591, 0.34951, -2.9641 }, 128 {375, 0.26400, 0.35200, -3.5814 }, 129 {400, 0.27218, 0.35407, -4.3633 }, 130 {425, 0.28039, 0.35577, -5.3762 }, 131 {450, 0.28863, 0.35714, -6.7262 }, 132 {475, 0.29685, 0.35823, -8.5955 }, 133 {500, 0.30505, 0.35907, -11.324 }, 134 {525, 0.31320, 0.35968, -15.628 }, 135 {550, 0.32129, 0.36011, -23.325 }, 136 {575, 0.32931, 0.36038, -40.770 }, 137 {600, 0.33724, 0.36051, -116.45 } 138 }; 139 140 #define NISO sizeof(isotempdata)/sizeof(ISOTEMPERATURE) 141 142 143 // Robertson's method 144 cmsBool CMSEXPORT cmsTempFromWhitePoint(cmsFloat64Number* TempK, const cmsCIExyY* WhitePoint) 145 { 146 cmsUInt32Number j; 147 cmsFloat64Number us,vs; 148 cmsFloat64Number uj,vj,tj,di,dj,mi,mj; 149 cmsFloat64Number xs, ys; 150 151 _cmsAssert(WhitePoint != NULL); 152 _cmsAssert(TempK != NULL); 153 154 di = mi = 0; 155 xs = WhitePoint -> x; 156 ys = WhitePoint -> y; 157 158 // convert (x,y) to CIE 1960 (u,WhitePoint) 159 160 us = (2*xs) / (-xs + 6*ys + 1.5); 161 vs = (3*ys) / (-xs + 6*ys + 1.5); 162 163 164 for (j=0; j < NISO; j++) { 165 166 uj = isotempdata[j].ut; 167 vj = isotempdata[j].vt; 168 tj = isotempdata[j].tt; 169 mj = isotempdata[j].mirek; 170 171 dj = ((vs - vj) - tj * (us - uj)) / sqrt(1.0 + tj * tj); 172 173 if ((j != 0) && (di/dj < 0.0)) { 174 175 // Found a match 176 *TempK = 1000000.0 / (mi + (di / (di - dj)) * (mj - mi)); 177 return TRUE; 178 } 179 180 di = dj; 181 mi = mj; 182 } 183 184 // Not found 185 return FALSE; 186 } 187 188 189 // Compute chromatic adaptation matrix using Chad as cone matrix 190 191 static 192 cmsBool ComputeChromaticAdaptation(cmsMAT3* Conversion, 193 const cmsCIEXYZ* SourceWhitePoint, 194 const cmsCIEXYZ* DestWhitePoint, 195 const cmsMAT3* Chad) 196 197 { 198 199 cmsMAT3 Chad_Inv; 200 cmsVEC3 ConeSourceXYZ, ConeSourceRGB; 201 cmsVEC3 ConeDestXYZ, ConeDestRGB; 202 cmsMAT3 Cone, Tmp; 203 204 205 Tmp = *Chad; 206 if (!_cmsMAT3inverse(&Tmp, &Chad_Inv)) return FALSE; 207 208 _cmsVEC3init(&ConeSourceXYZ, SourceWhitePoint -> X, 209 SourceWhitePoint -> Y, 210 SourceWhitePoint -> Z); 211 212 _cmsVEC3init(&ConeDestXYZ, DestWhitePoint -> X, 213 DestWhitePoint -> Y, 214 DestWhitePoint -> Z); 215 216 _cmsMAT3eval(&ConeSourceRGB, Chad, &ConeSourceXYZ); 217 _cmsMAT3eval(&ConeDestRGB, Chad, &ConeDestXYZ); 218 219 // Build matrix 220 _cmsVEC3init(&Cone.v[0], ConeDestRGB.n[0]/ConeSourceRGB.n[0], 0.0, 0.0); 221 _cmsVEC3init(&Cone.v[1], 0.0, ConeDestRGB.n[1]/ConeSourceRGB.n[1], 0.0); 222 _cmsVEC3init(&Cone.v[2], 0.0, 0.0, ConeDestRGB.n[2]/ConeSourceRGB.n[2]); 223 224 225 // Normalize 226 _cmsMAT3per(&Tmp, &Cone, Chad); 227 _cmsMAT3per(Conversion, &Chad_Inv, &Tmp); 228 229 return TRUE; 230 } 231 232 // Returns the final chrmatic adaptation from illuminant FromIll to Illuminant ToIll 233 // The cone matrix can be specified in ConeMatrix. If NULL, Bradford is assumed 234 cmsBool _cmsAdaptationMatrix(cmsMAT3* r, const cmsMAT3* ConeMatrix, const cmsCIEXYZ* FromIll, const cmsCIEXYZ* ToIll) 235 { 236 cmsMAT3 LamRigg = {{ // Bradford matrix 237 {{ 0.8951, 0.2664, -0.1614 }}, 238 {{ -0.7502, 1.7135, 0.0367 }}, 239 {{ 0.0389, -0.0685, 1.0296 }} 240 }}; 241 242 if (ConeMatrix == NULL) 243 ConeMatrix = &LamRigg; 244 245 return ComputeChromaticAdaptation(r, FromIll, ToIll, ConeMatrix); 246 } 247 248 // Same as anterior, but assuming D50 destination. White point is given in xyY 249 static 250 cmsBool _cmsAdaptMatrixToD50(cmsMAT3* r, const cmsCIExyY* SourceWhitePt) 251 { 252 cmsCIEXYZ Dn; 253 cmsMAT3 Bradford; 254 cmsMAT3 Tmp; 255 256 cmsxyY2XYZ(&Dn, SourceWhitePt); 257 258 if (!_cmsAdaptationMatrix(&Bradford, NULL, &Dn, cmsD50_XYZ())) return FALSE; 259 260 Tmp = *r; 261 _cmsMAT3per(r, &Bradford, &Tmp); 262 263 return TRUE; 264 } 265 266 // Build a White point, primary chromas transfer matrix from RGB to CIE XYZ 267 // This is just an approximation, I am not handling all the non-linear 268 // aspects of the RGB to XYZ process, and assumming that the gamma correction 269 // has transitive property in the tranformation chain. 270 // 271 // the alghoritm: 272 // 273 // - First I build the absolute conversion matrix using 274 // primaries in XYZ. This matrix is next inverted 275 // - Then I eval the source white point across this matrix 276 // obtaining the coeficients of the transformation 277 // - Then, I apply these coeficients to the original matrix 278 // 279 cmsBool _cmsBuildRGB2XYZtransferMatrix(cmsMAT3* r, const cmsCIExyY* WhitePt, const cmsCIExyYTRIPLE* Primrs) 280 { 281 cmsVEC3 WhitePoint, Coef; 282 cmsMAT3 Result, Primaries; 283 cmsFloat64Number xn, yn; 284 cmsFloat64Number xr, yr; 285 cmsFloat64Number xg, yg; 286 cmsFloat64Number xb, yb; 287 288 xn = WhitePt -> x; 289 yn = WhitePt -> y; 290 xr = Primrs -> Red.x; 291 yr = Primrs -> Red.y; 292 xg = Primrs -> Green.x; 293 yg = Primrs -> Green.y; 294 xb = Primrs -> Blue.x; 295 yb = Primrs -> Blue.y; 296 297 // Build Primaries matrix 298 _cmsVEC3init(&Primaries.v[0], xr, xg, xb); 299 _cmsVEC3init(&Primaries.v[1], yr, yg, yb); 300 _cmsVEC3init(&Primaries.v[2], (1-xr-yr), (1-xg-yg), (1-xb-yb)); 301 302 303 // Result = Primaries ^ (-1) inverse matrix 304 if (!_cmsMAT3inverse(&Primaries, &Result)) 305 return FALSE; 306 307 308 _cmsVEC3init(&WhitePoint, xn/yn, 1.0, (1.0-xn-yn)/yn); 309 310 // Across inverse primaries ... 311 _cmsMAT3eval(&Coef, &Result, &WhitePoint); 312 313 // Give us the Coefs, then I build transformation matrix 314 _cmsVEC3init(&r -> v[0], Coef.n[VX]*xr, Coef.n[VY]*xg, Coef.n[VZ]*xb); 315 _cmsVEC3init(&r -> v[1], Coef.n[VX]*yr, Coef.n[VY]*yg, Coef.n[VZ]*yb); 316 _cmsVEC3init(&r -> v[2], Coef.n[VX]*(1.0-xr-yr), Coef.n[VY]*(1.0-xg-yg), Coef.n[VZ]*(1.0-xb-yb)); 317 318 319 return _cmsAdaptMatrixToD50(r, WhitePt); 320 321 } 322 323 324 // Adapts a color to a given illuminant. Original color is expected to have 325 // a SourceWhitePt white point. 326 cmsBool CMSEXPORT cmsAdaptToIlluminant(cmsCIEXYZ* Result, 327 const cmsCIEXYZ* SourceWhitePt, 328 const cmsCIEXYZ* Illuminant, 329 const cmsCIEXYZ* Value) 330 { 331 cmsMAT3 Bradford; 332 cmsVEC3 In, Out; 333 334 _cmsAssert(Result != NULL); 335 _cmsAssert(SourceWhitePt != NULL); 336 _cmsAssert(Illuminant != NULL); 337 _cmsAssert(Value != NULL); 338 339 if (!_cmsAdaptationMatrix(&Bradford, NULL, SourceWhitePt, Illuminant)) return FALSE; 340 341 _cmsVEC3init(&In, Value -> X, Value -> Y, Value -> Z); 342 _cmsMAT3eval(&Out, &Bradford, &In); 343 344 Result -> X = Out.n[0]; 345 Result -> Y = Out.n[1]; 346 Result -> Z = Out.n[2]; 347 348 return TRUE; 349 } 350 351 352
