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comparison mupdf-source/thirdparty/lcms2/src/cmswtpnt.c @ 2:b50eed0cc0ef upstream

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ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. The directory name has changed: no version number in the expanded directory now.
author Franz Glasner <fzglas.hg@dom66.de>
date Mon, 15 Sep 2025 11:43:07 +0200
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1:1d09e1dec1d9 2:b50eed0cc0ef
1 //---------------------------------------------------------------------------------
2 //
3 // Little Color Management System
4 // Copyright (c) 1998-2023 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(cmsContext ContextID)
32 {
33 static cmsCIEXYZ D50XYZ = {cmsD50X, cmsD50Y, cmsD50Z};
34 cmsUNUSED_PARAMETER(ContextID);
35
36 return &D50XYZ;
37 }
38
39 const cmsCIExyY* CMSEXPORT cmsD50_xyY(cmsContext ContextID)
40 {
41 static cmsCIExyY D50xyY;
42
43 cmsXYZ2xyY(ContextID, &D50xyY, cmsD50_XYZ(ContextID));
44
45 return &D50xyY;
46 }
47
48 // Obtains WhitePoint from Temperature
49 cmsBool CMSEXPORT cmsWhitePointFromTemp(cmsContext ContextID, cmsCIExyY* WhitePoint, cmsFloat64Number TempK)
50 {
51 cmsFloat64Number x, y;
52 cmsFloat64Number T, T2, T3;
53 // cmsFloat64Number M1, M2;
54 cmsUNUSED_PARAMETER(ContextID);
55
56 _cmsAssert(WhitePoint != NULL);
57
58 T = TempK;
59 T2 = T*T; // Square
60 T3 = T2*T; // Cube
61
62 // For correlated color temperature (T) between 4000K and 7000K:
63
64 if (T >= 4000. && T <= 7000.)
65 {
66 x = -4.6070*(1E9/T3) + 2.9678*(1E6/T2) + 0.09911*(1E3/T) + 0.244063;
67 }
68 else
69 // or for correlated color temperature (T) between 7000K and 25000K:
70
71 if (T > 7000.0 && T <= 25000.0)
72 {
73 x = -2.0064*(1E9/T3) + 1.9018*(1E6/T2) + 0.24748*(1E3/T) + 0.237040;
74 }
75 else {
76 cmsSignalError(0, cmsERROR_RANGE, "cmsWhitePointFromTemp: invalid temp");
77 return FALSE;
78 }
79
80 // Obtain y(x)
81 y = -3.000*(x*x) + 2.870*x - 0.275;
82
83 // wave factors (not used, but here for futures extensions)
84
85 // M1 = (-1.3515 - 1.7703*x + 5.9114 *y)/(0.0241 + 0.2562*x - 0.7341*y);
86 // M2 = (0.0300 - 31.4424*x + 30.0717*y)/(0.0241 + 0.2562*x - 0.7341*y);
87
88 WhitePoint -> x = x;
89 WhitePoint -> y = y;
90 WhitePoint -> Y = 1.0;
91
92 return TRUE;
93 }
94
95
96
97 typedef struct {
98
99 cmsFloat64Number mirek; // temp (in microreciprocal kelvin)
100 cmsFloat64Number ut; // u coord of intersection w/ blackbody locus
101 cmsFloat64Number vt; // v coord of intersection w/ blackbody locus
102 cmsFloat64Number tt; // slope of ISOTEMPERATURE. line
103
104 } ISOTEMPERATURE;
105
106 static const ISOTEMPERATURE isotempdata[] = {
107 // {Mirek, Ut, Vt, Tt }
108 {0, 0.18006, 0.26352, -0.24341},
109 {10, 0.18066, 0.26589, -0.25479},
110 {20, 0.18133, 0.26846, -0.26876},
111 {30, 0.18208, 0.27119, -0.28539},
112 {40, 0.18293, 0.27407, -0.30470},
113 {50, 0.18388, 0.27709, -0.32675},
114 {60, 0.18494, 0.28021, -0.35156},
115 {70, 0.18611, 0.28342, -0.37915},
116 {80, 0.18740, 0.28668, -0.40955},
117 {90, 0.18880, 0.28997, -0.44278},
118 {100, 0.19032, 0.29326, -0.47888},
119 {125, 0.19462, 0.30141, -0.58204},
120 {150, 0.19962, 0.30921, -0.70471},
121 {175, 0.20525, 0.31647, -0.84901},
122 {200, 0.21142, 0.32312, -1.0182 },
123 {225, 0.21807, 0.32909, -1.2168 },
124 {250, 0.22511, 0.33439, -1.4512 },
125 {275, 0.23247, 0.33904, -1.7298 },
126 {300, 0.24010, 0.34308, -2.0637 },
127 {325, 0.24702, 0.34655, -2.4681 },
128 {350, 0.25591, 0.34951, -2.9641 },
129 {375, 0.26400, 0.35200, -3.5814 },
130 {400, 0.27218, 0.35407, -4.3633 },
131 {425, 0.28039, 0.35577, -5.3762 },
132 {450, 0.28863, 0.35714, -6.7262 },
133 {475, 0.29685, 0.35823, -8.5955 },
134 {500, 0.30505, 0.35907, -11.324 },
135 {525, 0.31320, 0.35968, -15.628 },
136 {550, 0.32129, 0.36011, -23.325 },
137 {575, 0.32931, 0.36038, -40.770 },
138 {600, 0.33724, 0.36051, -116.45 }
139 };
140
141 #define NISO sizeof(isotempdata)/sizeof(ISOTEMPERATURE)
142
143
144 // Robertson's method
145 cmsBool CMSEXPORT cmsTempFromWhitePoint(cmsContext ContextID, cmsFloat64Number* TempK, const cmsCIExyY* WhitePoint)
146 {
147 cmsUInt32Number j;
148 cmsFloat64Number us,vs;
149 cmsFloat64Number uj,vj,tj,di,dj,mi,mj;
150 cmsFloat64Number xs, ys;
151 cmsUNUSED_PARAMETER(ContextID);
152
153 _cmsAssert(WhitePoint != NULL);
154 _cmsAssert(TempK != NULL);
155
156 di = mi = 0;
157 xs = WhitePoint -> x;
158 ys = WhitePoint -> y;
159
160 // convert (x,y) to CIE 1960 (u,WhitePoint)
161
162 us = (2*xs) / (-xs + 6*ys + 1.5);
163 vs = (3*ys) / (-xs + 6*ys + 1.5);
164
165
166 for (j=0; j < NISO; j++) {
167
168 uj = isotempdata[j].ut;
169 vj = isotempdata[j].vt;
170 tj = isotempdata[j].tt;
171 mj = isotempdata[j].mirek;
172
173 dj = ((vs - vj) - tj * (us - uj)) / sqrt(1.0 + tj * tj);
174
175 if ((j != 0) && (di/dj < 0.0)) {
176
177 // Found a match
178 *TempK = 1000000.0 / (mi + (di / (di - dj)) * (mj - mi));
179 return TRUE;
180 }
181
182 di = dj;
183 mi = mj;
184 }
185
186 // Not found
187 return FALSE;
188 }
189
190
191 // Compute chromatic adaptation matrix using Chad as cone matrix
192
193 static
194 cmsBool ComputeChromaticAdaptation(cmsContext ContextID, cmsMAT3* Conversion,
195 const cmsCIEXYZ* SourceWhitePoint,
196 const cmsCIEXYZ* DestWhitePoint,
197 const cmsMAT3* Chad)
198
199 {
200
201 cmsMAT3 Chad_Inv;
202 cmsVEC3 ConeSourceXYZ, ConeSourceRGB;
203 cmsVEC3 ConeDestXYZ, ConeDestRGB;
204 cmsMAT3 Cone, Tmp;
205
206
207 Tmp = *Chad;
208 if (!_cmsMAT3inverse(ContextID, &Tmp, &Chad_Inv)) return FALSE;
209
210 _cmsVEC3init(ContextID, &ConeSourceXYZ, SourceWhitePoint -> X,
211 SourceWhitePoint -> Y,
212 SourceWhitePoint -> Z);
213
214 _cmsVEC3init(ContextID, &ConeDestXYZ, DestWhitePoint -> X,
215 DestWhitePoint -> Y,
216 DestWhitePoint -> Z);
217
218 _cmsMAT3eval(ContextID, &ConeSourceRGB, Chad, &ConeSourceXYZ);
219 _cmsMAT3eval(ContextID, &ConeDestRGB, Chad, &ConeDestXYZ);
220
221 if ((fabs(ConeSourceRGB.n[0]) < MATRIX_DET_TOLERANCE) ||
222 (fabs(ConeSourceRGB.n[1]) < MATRIX_DET_TOLERANCE) ||
223 (fabs(ConeSourceRGB.n[2]) < MATRIX_DET_TOLERANCE)) return FALSE;
224
225 // Build matrix
226 _cmsVEC3init(ContextID, &Cone.v[0], ConeDestRGB.n[0]/ConeSourceRGB.n[0], 0.0, 0.0);
227 _cmsVEC3init(ContextID, &Cone.v[1], 0.0, ConeDestRGB.n[1]/ConeSourceRGB.n[1], 0.0);
228 _cmsVEC3init(ContextID, &Cone.v[2], 0.0, 0.0, ConeDestRGB.n[2]/ConeSourceRGB.n[2]);
229
230 // Normalize
231 _cmsMAT3per(ContextID, &Tmp, &Cone, Chad);
232 _cmsMAT3per(ContextID, Conversion, &Chad_Inv, &Tmp);
233
234 return TRUE;
235 }
236
237 // Returns the final chrmatic adaptation from illuminant FromIll to Illuminant ToIll
238 // The cone matrix can be specified in ConeMatrix. If NULL, Bradford is assumed
239 cmsBool _cmsAdaptationMatrix(cmsContext ContextID, cmsMAT3* r, const cmsMAT3* ConeMatrix, const cmsCIEXYZ* FromIll, const cmsCIEXYZ* ToIll)
240 {
241 cmsMAT3 LamRigg = {{ // Bradford matrix
242 {{ 0.8951, 0.2664, -0.1614 }},
243 {{ -0.7502, 1.7135, 0.0367 }},
244 {{ 0.0389, -0.0685, 1.0296 }}
245 }};
246
247 if (ConeMatrix == NULL)
248 ConeMatrix = &LamRigg;
249
250 return ComputeChromaticAdaptation(ContextID, r, FromIll, ToIll, ConeMatrix);
251 }
252
253 // Same as anterior, but assuming D50 destination. White point is given in xyY
254 static
255 cmsBool _cmsAdaptMatrixToD50(cmsContext ContextID, cmsMAT3* r, const cmsCIExyY* SourceWhitePt)
256 {
257 cmsCIEXYZ Dn;
258 cmsMAT3 Bradford;
259 cmsMAT3 Tmp;
260
261 cmsxyY2XYZ(ContextID, &Dn, SourceWhitePt);
262
263 if (!_cmsAdaptationMatrix(ContextID, &Bradford, NULL, &Dn, cmsD50_XYZ(ContextID))) return FALSE;
264
265 Tmp = *r;
266 _cmsMAT3per(ContextID, r, &Bradford, &Tmp);
267
268 return TRUE;
269 }
270
271 // Build a White point, primary chromas transfer matrix from RGB to CIE XYZ
272 // This is just an approximation, I am not handling all the non-linear
273 // aspects of the RGB to XYZ process, and assuming that the gamma correction
274 // has transitive property in the transformation chain.
275 //
276 // the algorithm:
277 //
278 // - First I build the absolute conversion matrix using
279 // primaries in XYZ. This matrix is next inverted
280 // - Then I eval the source white point across this matrix
281 // obtaining the coefficients of the transformation
282 // - Then, I apply these coefficients to the original matrix
283 //
284 cmsBool _cmsBuildRGB2XYZtransferMatrix(cmsContext ContextID, cmsMAT3* r, const cmsCIExyY* WhitePt, const cmsCIExyYTRIPLE* Primrs)
285 {
286 cmsVEC3 WhitePoint, Coef;
287 cmsMAT3 Result, Primaries;
288 cmsFloat64Number xn, yn;
289 cmsFloat64Number xr, yr;
290 cmsFloat64Number xg, yg;
291 cmsFloat64Number xb, yb;
292
293 xn = WhitePt -> x;
294 yn = WhitePt -> y;
295 xr = Primrs -> Red.x;
296 yr = Primrs -> Red.y;
297 xg = Primrs -> Green.x;
298 yg = Primrs -> Green.y;
299 xb = Primrs -> Blue.x;
300 yb = Primrs -> Blue.y;
301
302 // Build Primaries matrix
303 _cmsVEC3init(ContextID, &Primaries.v[0], xr, xg, xb);
304 _cmsVEC3init(ContextID, &Primaries.v[1], yr, yg, yb);
305 _cmsVEC3init(ContextID, &Primaries.v[2], (1-xr-yr), (1-xg-yg), (1-xb-yb));
306
307
308 // Result = Primaries ^ (-1) inverse matrix
309 if (!_cmsMAT3inverse(ContextID, &Primaries, &Result))
310 return FALSE;
311
312
313 _cmsVEC3init(ContextID, &WhitePoint, xn/yn, 1.0, (1.0-xn-yn)/yn);
314
315 // Across inverse primaries ...
316 _cmsMAT3eval(ContextID, &Coef, &Result, &WhitePoint);
317
318 // Give us the Coefs, then I build transformation matrix
319 _cmsVEC3init(ContextID, &r -> v[0], Coef.n[VX]*xr, Coef.n[VY]*xg, Coef.n[VZ]*xb);
320 _cmsVEC3init(ContextID, &r -> v[1], Coef.n[VX]*yr, Coef.n[VY]*yg, Coef.n[VZ]*yb);
321 _cmsVEC3init(ContextID, &r -> v[2], Coef.n[VX]*(1.0-xr-yr), Coef.n[VY]*(1.0-xg-yg), Coef.n[VZ]*(1.0-xb-yb));
322
323
324 return _cmsAdaptMatrixToD50(ContextID, r, WhitePt);
325
326 }
327
328
329 // Adapts a color to a given illuminant. Original color is expected to have
330 // a SourceWhitePt white point.
331 cmsBool CMSEXPORT cmsAdaptToIlluminant(cmsContext ContextID, cmsCIEXYZ* Result,
332 const cmsCIEXYZ* SourceWhitePt,
333 const cmsCIEXYZ* Illuminant,
334 const cmsCIEXYZ* Value)
335 {
336 cmsMAT3 Bradford;
337 cmsVEC3 In, Out;
338
339 _cmsAssert(Result != NULL);
340 _cmsAssert(SourceWhitePt != NULL);
341 _cmsAssert(Illuminant != NULL);
342 _cmsAssert(Value != NULL);
343
344 if (!_cmsAdaptationMatrix(ContextID, &Bradford, NULL, SourceWhitePt, Illuminant)) return FALSE;
345
346 _cmsVEC3init(ContextID, &In, Value -> X, Value -> Y, Value -> Z);
347 _cmsMAT3eval(ContextID, &Out, &Bradford, &In);
348
349 Result -> X = Out.n[0];
350 Result -> Y = Out.n[1];
351 Result -> Z = Out.n[2];
352
353 return TRUE;
354 }
355
356