1 //---------------------------------------------------------------------------------
2 //
3 // Little Color Management System
4 // Copyright (c) 1998-2017 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
cmsD50_XYZ(void)31 const cmsCIEXYZ* CMSEXPORT cmsD50_XYZ(void)
32 {
33 static cmsCIEXYZ D50XYZ = {cmsD50X, cmsD50Y, cmsD50Z};
34
35 return &D50XYZ;
36 }
37
cmsD50_xyY(void)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
cmsWhitePointFromTemp(cmsCIExyY * WhitePoint,cmsFloat64Number TempK)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 y = -3.000*(x*x) + 2.870*x - 0.275;
80
81 // wave factors (not used, but here for futures extensions)
82
83 // M1 = (-1.3515 - 1.7703*x + 5.9114 *y)/(0.0241 + 0.2562*x - 0.7341*y);
84 // M2 = (0.0300 - 31.4424*x + 30.0717*y)/(0.0241 + 0.2562*x - 0.7341*y);
85
86 WhitePoint -> x = x;
87 WhitePoint -> y = y;
88 WhitePoint -> Y = 1.0;
89
90 return TRUE;
91 }
92
93
94
95 typedef struct {
96
97 cmsFloat64Number mirek; // temp (in microreciprocal kelvin)
98 cmsFloat64Number ut; // u coord of intersection w/ blackbody locus
99 cmsFloat64Number vt; // v coord of intersection w/ blackbody locus
100 cmsFloat64Number tt; // slope of ISOTEMPERATURE. line
101
102 } ISOTEMPERATURE;
103
104 static const ISOTEMPERATURE isotempdata[] = {
105 // {Mirek, Ut, Vt, Tt }
106 {0, 0.18006, 0.26352, -0.24341},
107 {10, 0.18066, 0.26589, -0.25479},
108 {20, 0.18133, 0.26846, -0.26876},
109 {30, 0.18208, 0.27119, -0.28539},
110 {40, 0.18293, 0.27407, -0.30470},
111 {50, 0.18388, 0.27709, -0.32675},
112 {60, 0.18494, 0.28021, -0.35156},
113 {70, 0.18611, 0.28342, -0.37915},
114 {80, 0.18740, 0.28668, -0.40955},
115 {90, 0.18880, 0.28997, -0.44278},
116 {100, 0.19032, 0.29326, -0.47888},
117 {125, 0.19462, 0.30141, -0.58204},
118 {150, 0.19962, 0.30921, -0.70471},
119 {175, 0.20525, 0.31647, -0.84901},
120 {200, 0.21142, 0.32312, -1.0182 },
121 {225, 0.21807, 0.32909, -1.2168 },
122 {250, 0.22511, 0.33439, -1.4512 },
123 {275, 0.23247, 0.33904, -1.7298 },
124 {300, 0.24010, 0.34308, -2.0637 },
125 {325, 0.24702, 0.34655, -2.4681 },
126 {350, 0.25591, 0.34951, -2.9641 },
127 {375, 0.26400, 0.35200, -3.5814 },
128 {400, 0.27218, 0.35407, -4.3633 },
129 {425, 0.28039, 0.35577, -5.3762 },
130 {450, 0.28863, 0.35714, -6.7262 },
131 {475, 0.29685, 0.35823, -8.5955 },
132 {500, 0.30505, 0.35907, -11.324 },
133 {525, 0.31320, 0.35968, -15.628 },
134 {550, 0.32129, 0.36011, -23.325 },
135 {575, 0.32931, 0.36038, -40.770 },
136 {600, 0.33724, 0.36051, -116.45 }
137 };
138
139 #define NISO sizeof(isotempdata)/sizeof(ISOTEMPERATURE)
140
141
142 // Robertson's method
cmsTempFromWhitePoint(cmsFloat64Number * TempK,const cmsCIExyY * WhitePoint)143 cmsBool CMSEXPORT cmsTempFromWhitePoint(cmsFloat64Number* TempK, const cmsCIExyY* WhitePoint)
144 {
145 cmsUInt32Number j;
146 cmsFloat64Number us,vs;
147 cmsFloat64Number uj,vj,tj,di,dj,mi,mj;
148 cmsFloat64Number xs, ys;
149
150 _cmsAssert(WhitePoint != NULL);
151 _cmsAssert(TempK != NULL);
152
153 di = mi = 0;
154 xs = WhitePoint -> x;
155 ys = WhitePoint -> y;
156
157 // convert (x,y) to CIE 1960 (u,WhitePoint)
158
159 us = (2*xs) / (-xs + 6*ys + 1.5);
160 vs = (3*ys) / (-xs + 6*ys + 1.5);
161
162
163 for (j=0; j < NISO; j++) {
164
165 uj = isotempdata[j].ut;
166 vj = isotempdata[j].vt;
167 tj = isotempdata[j].tt;
168 mj = isotempdata[j].mirek;
169
170 dj = ((vs - vj) - tj * (us - uj)) / sqrt(1.0 + tj * tj);
171
172 if ((j != 0) && (di/dj < 0.0)) {
173
174 // Found a match
175 *TempK = 1000000.0 / (mi + (di / (di - dj)) * (mj - mi));
176 return TRUE;
177 }
178
179 di = dj;
180 mi = mj;
181 }
182
183 // Not found
184 return FALSE;
185 }
186
187
188 // Compute chromatic adaptation matrix using Chad as cone matrix
189
190 static
ComputeChromaticAdaptation(cmsMAT3 * Conversion,const cmsCIEXYZ * SourceWhitePoint,const cmsCIEXYZ * DestWhitePoint,const cmsMAT3 * Chad)191 cmsBool ComputeChromaticAdaptation(cmsMAT3* Conversion,
192 const cmsCIEXYZ* SourceWhitePoint,
193 const cmsCIEXYZ* DestWhitePoint,
194 const cmsMAT3* Chad)
195
196 {
197
198 cmsMAT3 Chad_Inv;
199 cmsVEC3 ConeSourceXYZ, ConeSourceRGB;
200 cmsVEC3 ConeDestXYZ, ConeDestRGB;
201 cmsMAT3 Cone, Tmp;
202
203
204 Tmp = *Chad;
205 if (!_cmsMAT3inverse(&Tmp, &Chad_Inv)) return FALSE;
206
207 _cmsVEC3init(&ConeSourceXYZ, SourceWhitePoint -> X,
208 SourceWhitePoint -> Y,
209 SourceWhitePoint -> Z);
210
211 _cmsVEC3init(&ConeDestXYZ, DestWhitePoint -> X,
212 DestWhitePoint -> Y,
213 DestWhitePoint -> Z);
214
215 _cmsMAT3eval(&ConeSourceRGB, Chad, &ConeSourceXYZ);
216 _cmsMAT3eval(&ConeDestRGB, Chad, &ConeDestXYZ);
217
218 // Build matrix
219 _cmsVEC3init(&Cone.v[0], ConeDestRGB.n[0]/ConeSourceRGB.n[0], 0.0, 0.0);
220 _cmsVEC3init(&Cone.v[1], 0.0, ConeDestRGB.n[1]/ConeSourceRGB.n[1], 0.0);
221 _cmsVEC3init(&Cone.v[2], 0.0, 0.0, ConeDestRGB.n[2]/ConeSourceRGB.n[2]);
222
223
224 // Normalize
225 _cmsMAT3per(&Tmp, &Cone, Chad);
226 _cmsMAT3per(Conversion, &Chad_Inv, &Tmp);
227
228 return TRUE;
229 }
230
231 // Returns the final chrmatic adaptation from illuminant FromIll to Illuminant ToIll
232 // The cone matrix can be specified in ConeMatrix. If NULL, Bradford is assumed
_cmsAdaptationMatrix(cmsMAT3 * r,const cmsMAT3 * ConeMatrix,const cmsCIEXYZ * FromIll,const cmsCIEXYZ * ToIll)233 cmsBool _cmsAdaptationMatrix(cmsMAT3* r, const cmsMAT3* ConeMatrix, const cmsCIEXYZ* FromIll, const cmsCIEXYZ* ToIll)
234 {
235 cmsMAT3 LamRigg = {{ // Bradford matrix
236 {{ 0.8951, 0.2664, -0.1614 }},
237 {{ -0.7502, 1.7135, 0.0367 }},
238 {{ 0.0389, -0.0685, 1.0296 }}
239 }};
240
241 if (ConeMatrix == NULL)
242 ConeMatrix = &LamRigg;
243
244 return ComputeChromaticAdaptation(r, FromIll, ToIll, ConeMatrix);
245 }
246
247 // Same as anterior, but assuming D50 destination. White point is given in xyY
248 static
_cmsAdaptMatrixToD50(cmsMAT3 * r,const cmsCIExyY * SourceWhitePt)249 cmsBool _cmsAdaptMatrixToD50(cmsMAT3* r, const cmsCIExyY* SourceWhitePt)
250 {
251 cmsCIEXYZ Dn;
252 cmsMAT3 Bradford;
253 cmsMAT3 Tmp;
254
255 cmsxyY2XYZ(&Dn, SourceWhitePt);
256
257 if (!_cmsAdaptationMatrix(&Bradford, NULL, &Dn, cmsD50_XYZ())) return FALSE;
258
259 Tmp = *r;
260 _cmsMAT3per(r, &Bradford, &Tmp);
261
262 return TRUE;
263 }
264
265 // Build a White point, primary chromas transfer matrix from RGB to CIE XYZ
266 // This is just an approximation, I am not handling all the non-linear
267 // aspects of the RGB to XYZ process, and assumming that the gamma correction
268 // has transitive property in the transformation chain.
269 //
270 // the alghoritm:
271 //
272 // - First I build the absolute conversion matrix using
273 // primaries in XYZ. This matrix is next inverted
274 // - Then I eval the source white point across this matrix
275 // obtaining the coeficients of the transformation
276 // - Then, I apply these coeficients to the original matrix
277 //
_cmsBuildRGB2XYZtransferMatrix(cmsMAT3 * r,const cmsCIExyY * WhitePt,const cmsCIExyYTRIPLE * Primrs)278 cmsBool _cmsBuildRGB2XYZtransferMatrix(cmsMAT3* r, const cmsCIExyY* WhitePt, const cmsCIExyYTRIPLE* Primrs)
279 {
280 cmsVEC3 WhitePoint, Coef;
281 cmsMAT3 Result, Primaries;
282 cmsFloat64Number xn, yn;
283 cmsFloat64Number xr, yr;
284 cmsFloat64Number xg, yg;
285 cmsFloat64Number xb, yb;
286
287 xn = WhitePt -> x;
288 yn = WhitePt -> y;
289 xr = Primrs -> Red.x;
290 yr = Primrs -> Red.y;
291 xg = Primrs -> Green.x;
292 yg = Primrs -> Green.y;
293 xb = Primrs -> Blue.x;
294 yb = Primrs -> Blue.y;
295
296 // Build Primaries matrix
297 _cmsVEC3init(&Primaries.v[0], xr, xg, xb);
298 _cmsVEC3init(&Primaries.v[1], yr, yg, yb);
299 _cmsVEC3init(&Primaries.v[2], (1-xr-yr), (1-xg-yg), (1-xb-yb));
300
301
302 // Result = Primaries ^ (-1) inverse matrix
303 if (!_cmsMAT3inverse(&Primaries, &Result))
304 return FALSE;
305
306
307 _cmsVEC3init(&WhitePoint, xn/yn, 1.0, (1.0-xn-yn)/yn);
308
309 // Across inverse primaries ...
310 _cmsMAT3eval(&Coef, &Result, &WhitePoint);
311
312 // Give us the Coefs, then I build transformation matrix
313 _cmsVEC3init(&r -> v[0], Coef.n[VX]*xr, Coef.n[VY]*xg, Coef.n[VZ]*xb);
314 _cmsVEC3init(&r -> v[1], Coef.n[VX]*yr, Coef.n[VY]*yg, Coef.n[VZ]*yb);
315 _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));
316
317
318 return _cmsAdaptMatrixToD50(r, WhitePt);
319
320 }
321
322
323 // Adapts a color to a given illuminant. Original color is expected to have
324 // a SourceWhitePt white point.
cmsAdaptToIlluminant(cmsCIEXYZ * Result,const cmsCIEXYZ * SourceWhitePt,const cmsCIEXYZ * Illuminant,const cmsCIEXYZ * Value)325 cmsBool CMSEXPORT cmsAdaptToIlluminant(cmsCIEXYZ* Result,
326 const cmsCIEXYZ* SourceWhitePt,
327 const cmsCIEXYZ* Illuminant,
328 const cmsCIEXYZ* Value)
329 {
330 cmsMAT3 Bradford;
331 cmsVEC3 In, Out;
332
333 _cmsAssert(Result != NULL);
334 _cmsAssert(SourceWhitePt != NULL);
335 _cmsAssert(Illuminant != NULL);
336 _cmsAssert(Value != NULL);
337
338 if (!_cmsAdaptationMatrix(&Bradford, NULL, SourceWhitePt, Illuminant)) return FALSE;
339
340 _cmsVEC3init(&In, Value -> X, Value -> Y, Value -> Z);
341 _cmsMAT3eval(&Out, &Bradford, &In);
342
343 Result -> X = Out.n[0];
344 Result -> Y = Out.n[1];
345 Result -> Z = Out.n[2];
346
347 return TRUE;
348 }
349
350
351