1//---------------------------------------------------------------------------------
2//
3//  Little Color Management System
4//  Copyright (c) 1998-2014 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
31const cmsCIEXYZ* CMSEXPORT cmsD50_XYZ(void)
32{
33    static cmsCIEXYZ D50XYZ = {cmsD50X, cmsD50Y, cmsD50Z};
34
35    return &D50XYZ;
36}
37
38const 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
48cmsBool  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
96typedef 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
105static 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
144cmsBool  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
191static
192cmsBool 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
234cmsBool  _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
249static
250cmsBool _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//
279cmsBool _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.
326cmsBool 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