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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