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root/radiance/ray/src/common/spec_rgb.c
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Comparing ray/src/common/spec_rgb.c (file contents):
Revision 2.5 by greg, Sun Oct 15 14:08:01 1995 UTC vs.
Revision 2.29 by greg, Tue Nov 21 01:30:20 2023 UTC

# Line 1 | Line 1
1 – /* Copyright (c) 1990 Regents of the University of California */
2 –
1   #ifndef lint
2 < static char SCCSid[] = "$SunId$ LBL";
2 > static const char       RCSid[] = "$Id$";
3   #endif
6 –
4   /*
5   * Convert colors and spectral ranges.
6 + * Added von Kries white-balance calculations 10/01 (GW).
7 + *
8 + * Externals declared in color.h
9   */
10  
11 + #include "copyright.h"
12 +
13 + #include <stdio.h>
14 + #include <string.h>
15   #include "color.h"
16  
17 + #define CEPS    1e-4                    /* color epsilon */
18  
19 < RGBPRIMS  stdprims = STDPRIMS;          /* standard primary chromaticities */
19 > #define CEQ(v1,v2)      (((v1) <= (v2)+CEPS) & ((v2) <= (v1)+CEPS))
20  
21 + #define XYEQ(c1,c2)     (CEQ((c1)[CIEX],(c2)[CIEX]) & CEQ((c1)[CIEY],(c2)[CIEY]))
22 +
23 +
24 + RGBPRIMS  stdprims = STDPRIMS;  /* standard primary chromaticities */
25 + RGBPRIMS  xyzprims = {1,0, 0,1, 0,0, 1.f/3.f,1.f/3.f};
26 +
27 + COLOR  cblack = BLKCOLOR;               /* global black color */
28 + COLOR  cwhite = WHTCOLOR;               /* global white color */
29 +
30 + float  xyneu[2] = {1./3., 1./3.};       /* neutral xy chromaticities */
31 +
32   /*
33 < *      The following table contains the CIE tristimulus integrals
34 < *  for X, Y, and Z.  The table is cumulative, so that
35 < *  each color coordinate integrates to 1.
33 > *      The tables below encode the CIE 1931 2° standard observer
34 > * functions for X, Y, and Z.  These tables are cumulative, as are
35 > * ones that follow.
36   */
37  
38 < #define  STARTWL        380             /* starting wavelength (nanometers) */
39 < #define  INCWL          10              /* wavelength increment */
24 < #define  NINC           40              /* # of values */
38 > #define CIE_X_WLMIN     362
39 > #define CIE_X_WLMAX     774
40  
41 < static BYTE  chroma[3][NINC] = {
42 <        {                                                       /* X */
43 <                0,   0,   0,   2,   6,   13,  22,  30,  36,  41,
44 <                42,  43,  43,  44,  46,  52,  60,  71,  87,  106,
45 <                128, 153, 178, 200, 219, 233, 243, 249, 252, 254,
46 <                255, 255, 255, 255, 255, 255, 255, 255, 255, 255
47 <        }, {                                                    /* Y */
48 <                0,   0,   0,   0,   0,   1,   2,   4,   7,   11,
49 <                17,  24,  34,  48,  64,  84,  105, 127, 148, 169,
50 <                188, 205, 220, 232, 240, 246, 250, 253, 254, 255,
51 <                255, 255, 255, 255, 255, 255, 255, 255, 255, 255
52 <        }, {                                                    /* Z */
53 <                0,   0,   2,   10,  32,  66,  118, 153, 191, 220,
54 <                237, 246, 251, 253, 254, 255, 255, 255, 255, 255,
55 <                255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
56 <                255, 255, 255, 255, 255, 255, 255, 255, 255, 255
57 <        }
41 > static const unsigned short     cie_x_cumul[CIE_X_WLMAX-CIE_X_WLMIN+1] = {
42 > 0,1,1,1,1,1,1,2,2,2,3,3,3,4,5,5,6,7,8,9,10,11,12,14,16,18,20,23,26,29,
43 > 33,37,41,47,53,60,68,77,86,97,108,121,135,151,170,190,214,241,271,304,
44 > 342,385,432,486,545,612,686,768,860,961,1073,1195,1326,1467,1618,
45 > 1776,1943,2117,2298,2485,2677,2875,3076,3281,3489,3700,3912,4125,4340,4555,
46 > 4769,4983,5197,5409,5620,5830,6038,6244,6448,6651,6851,7049,7245,7437,
47 > 7627,7813,7995,8173,8347,8517,8682,8842,8996,9143,9284,9418,9545,9665,
48 > 9778,9884,9984,10077,10164,10245,10321,10390,10454,10513,10566,10615,
49 > 10659,10698,10734,10766,10794,10819,10842,10861,10879,10893,10906,10917,
50 > 10926,10933,10939,10944,10948,10951,10953,10955,10957,10958,10960,10961,
51 > 10964,10967,10971,10977,10984,10994,11006,11020,11038,11060,11085,11114,
52 > 11148,11187,11231,11280,11335,11396,11464,11537,11618,11705,11799,11901,
53 > 12010,12126,12249,12380,12518,12664,12818,12980,13150,13328,13515,13709,
54 > 13913,14124,14345,14574,14813,15060,15317,15582,15858,16142,16437,16741,
55 > 17055,17379,17713,18057,18412,18776,19151,19536,19931,20337,20753,21180,
56 > 21616,22063,22520,22988,23465,23953,24450,24957,25474,26000,26535,27080,
57 > 27633,28195,28765,29343,29929,30522,31122,31729,32342,32961,33585,34215,
58 > 34849,35487,36129,36775,37423,38073,38724,39375,40027,40679,41329,41978,
59 > 42625,43270,43911,44548,45181,45808,46429,47044,47652,48253,48845,49430,
60 > 50005,50571,51128,51674,52209,52733,53245,53745,54232,54706,55167,55614,
61 > 56048,56468,56876,57269,57651,58019,58376,58720,59052,59373,59681,59979,
62 > 60265,60539,60803,61056,61298,61529,61750,61962,62163,62355,62538,62712,
63 > 62877,63034,63183,63325,63459,63586,63706,63820,63927,64028,64123,64213,
64 > 64297,64376,64451,64520,64586,64647,64704,64758,64808,64855,64899,64941,
65 > 64980,65016,65051,65083,65114,65143,65169,65194,65218,65240,65260,65278,
66 > 65296,65312,65327,65341,65354,65366,65377,65387,65397,65406,65415,65423,
67 > 65430,65437,65444,65450,65455,65461,65466,65470,65475,65479,65483,65486,
68 > 65489,65493,65495,65498,65501,65503,65505,65507,65509,65511,65513,65514,
69 > 65516,65517,65518,65519,65520,65521,65522,65523,65524,65525,65526,65526,
70 > 65527,65527,65528,65528,65529,65529,65530,65530,65530,65531,65531,65531,
71 > 65532,65532,65532,65532,65532,65533,65533,65533,65533,65533,65533,65533,
72 > 65533,65534,65534,65534,65534,65534,65534,65534,65534,65534,65534,65534,
73 > 65534,65534,65534,65534,65535
74   };
75  
76 < COLORMAT  xyz2rgbmat = {                /* XYZ to RGB */
76 > #define CIE_Y_WLMIN     386
77 > #define CIE_Y_WLMAX     760
78 >
79 > static const unsigned short     cie_y_cumul[CIE_Y_WLMAX-CIE_Y_WLMIN+1] = {
80 > 0,1,1,1,1,1,1,1,1,1,2,2,2,2,2,3,3,3,4,4,5,5,6,7,8,8,10,11,12,14,
81 > 15,17,19,22,25,28,31,35,40,45,50,56,63,70,78,86,95,105,115,126,
82 > 138,150,164,178,193,208,225,242,260,280,300,321,343,367,391,
83 > 417,443,472,501,532,564,598,633,670,708,748,790,833,879,926,
84 > 975,1027,1080,1136,1194,1255,1318,1384,1453,1525,1601,1679,1761,
85 > 1846,1935,2027,2123,2223,2327,2435,2548,2665,2787,2915,3048,3187,
86 > 3332,3484,3643,3808,3981,4162,4352,4550,4757,4975,5203,5442,5691,
87 > 5952,6225,6509,6805,7114,7435,7769,8116,8476,8849,9235,9634,10045,
88 > 10469,10904,11351,11808,12275,12752,13239,13734,14239,14752,15273,
89 > 15801,16337,16880,17429,17984,18546,19112,19684,20260,20841,21426,
90 > 22015,22608,23203,23802,24403,25007,25612,26220,26828,27439,28050,
91 > 28662,29275,29888,30501,31114,31727,32340,32951,33561,34170,34777,
92 > 35382,35985,36585,37182,37777,38368,38955,39539,40119,40695,41266,
93 > 41832,42393,42950,43501,44046,44586,45119,45646,46167,46682,47189,
94 > 47690,48183,48670,49149,49621,50085,50542,50991,51432,51866,52293,
95 > 52711,53122,53524,53919,54306,54685,55057,55420,55775,56123,56463,
96 > 56795,57119,57435,57743,58044,58337,58623,58901,59172,59435,59691,
97 > 59939,60180,60414,60640,60859,61070,61274,61471,61661,61844,62019,
98 > 62188,62351,62507,62657,62802,62940,63073,63201,63323,63441,63553,
99 > 63660,63763,63861,63954,64043,64128,64208,64285,64358,64427,64493,
100 > 64555,64614,64670,64723,64773,64820,64865,64907,64947,64984,65019,
101 > 65052,65083,65113,65140,65166,65190,65212,65233,65253,65271,65288,
102 > 65304,65319,65334,65347,65360,65371,65383,65393,65403,65412,65420,
103 > 65428,65435,65442,65449,65454,65460,65465,65470,65474,65478,65482,
104 > 65485,65488,65492,65494,65497,65500,65502,65504,65506,65508,65510,
105 > 65512,65513,65515,65516,65517,65519,65520,65521,65522,65523,65523,
106 > 65524,65525,65526,65526,65527,65527,65528,65528,65529,65529,65530,
107 > 65530,65530,65531,65531,65531,65532,65532,65532,65532,65532,65533,
108 > 65533,65533,65533,65533,65533,65533,65534,65534,65534,65534,65534,
109 > 65534,65534,65534,65534,65534,65534,65534,65534,65534,65534,65534,65535
110 > };
111 >
112 > #define CIE_Z_WLMIN     359
113 > #define CIE_Z_WLMAX     624
114 >
115 > static const unsigned short     cie_z_cumul[CIE_Z_WLMAX-CIE_Z_WLMIN+1] = {
116 > 0,1,1,2,2,3,4,5,6,7,8,9,11,12,14,16,19,22,25,28,32,37,41,47,52,59,66,75,84,
117 > 95,107,121,136,154,173,196,221,250,283,321,362,408,458,512,573,640,717,804,
118 > 903,1015,1142,1285,1446,1627,1830,2058,2313,2598,2917,3272,3668,4108,4597,
119 > 5135,5723,6360,7044,7773,8544,9356,10205,11090,12006,12952,13923,14918,
120 > 15934,16967,18016,19076,20148,21227,22312,23401,24492,25585,26678,27771,
121 > 28861,29950,31037,32121,33202,34281,35355,36424,37487,38542,39588,40624,
122 > 41647,42657,43652,44631,45590,46527,47438,48321,49173,49993,50783,51542,
123 > 52270,52968,53636,54275,54885,55465,56018,56543,57042,57514,57961,58384,
124 > 58784,59162,59519,59856,60175,60477,60762,61032,61287,61529,61757,61974,
125 > 62179,62374,62559,62734,62901,63059,63211,63355,63492,63622,63745,63862,
126 > 63971,64075,64172,64263,64347,64427,64500,64569,64632,64692,64747,64798,
127 > 64846,64891,64933,64973,65010,65045,65078,65109,65139,65166,65192,65216,
128 > 65239,65260,65280,65298,65315,65331,65345,65359,65371,65383,65393,65403,
129 > 65412,65420,65428,65435,65441,65447,65452,65457,65462,65466,65470,65473,
130 > 65476,65479,65482,65485,65487,65489,65491,65493,65495,65497,65498,65500,
131 > 65501,65503,65504,65505,65506,65508,65509,65510,65511,65512,65513,65514,
132 > 65515,65516,65517,65518,65519,65520,65520,65521,65522,65523,65523,65524,
133 > 65525,65525,65526,65527,65527,65528,65528,65529,65529,65530,65530,65531,
134 > 65531,65531,65532,65532,65532,65532,65533,65533,65533,65533,65533,65533,
135 > 65534,65534,65534,65534,65534,65534,65534,65534,65534,65535
136 > };
137 >
138 > #define SCOTOPIC_WLMIN  382
139 > #define SCOTOPIC_WLMAX  684
140 >
141 > static const unsigned short     scotopic_cumul[SCOTOPIC_WLMAX-SCOTOPIC_WLMIN+1] = {
142 > 0, 1, 1, 2, 3, 4, 5, 6, 7, 9, 10, 12, 15, 17, 20, 24, 28, 33, 38, 44,
143 > 52, 60, 69, 80, 93, 107, 123, 142, 163, 186, 213, 242, 275, 312, 353,
144 > 398, 448, 502, 562, 627, 698, 775, 859, 949, 1046, 1150, 1261, 1380,
145 > 1507, 1642, 1785, 1936, 2096, 2265, 2442, 2628, 2823, 3027, 3239, 3461,
146 > 3691, 3930, 4178, 4435, 4700, 4974, 5257, 5548, 5847, 6154, 6469, 6793,
147 > 7123, 7462, 7809, 8162, 8524, 8892, 9268, 9651, 10041, 10438, 10843, 11254,
148 > 11673, 12099, 12532, 12973, 13422, 13878, 14342, 14814, 15293, 15780, 16276,
149 > 16779, 17290, 17809, 18336, 18872, 19415, 19967, 20526, 21093, 21667, 22249,
150 > 22839, 23436, 24039, 24649, 25266, 25890, 26519, 27154, 27795, 28441, 29092,
151 > 29747, 30405, 31068, 31734, 32402, 33074, 33747, 34420, 35095, 35771, 36446,
152 > 37119, 37793, 38464, 39132, 39798, 40460, 41118, 41772, 42421, 43064, 43701,
153 > 44332, 44957, 45575, 46185, 46787, 47381, 47967, 48543, 49110, 49668, 50215,
154 > 50753, 51280, 51797, 52302, 52797, 53281, 53754, 54215, 54665, 55104, 55531,
155 > 55947, 56352, 56744, 57125, 57495, 57853, 58200, 58536, 58860, 59174, 59477,
156 > 59769, 60051, 60322, 60583, 60834, 61075, 61306, 61528, 61741, 61944, 62139,
157 > 62326, 62504, 62674, 62836, 62991, 63138, 63278, 63412, 63538, 63659, 63773,
158 > 63881, 63983, 64080, 64172, 64259, 64340, 64418, 64490, 64559, 64623, 64684,
159 > 64742, 64795, 64846, 64893, 64937, 64978, 65017, 65053, 65087, 65119, 65149,
160 > 65176, 65202, 65226, 65248, 65269, 65289, 65307, 65323, 65339, 65353, 65367,
161 > 65379, 65391, 65402, 65412, 65421, 65430, 65438, 65445, 65452, 65458, 65464,
162 > 65469, 65474, 65479, 65483, 65487, 65491, 65494, 65497, 65500, 65503, 65505,
163 > 65507, 65509, 65511, 65513, 65514, 65516, 65517, 65519, 65520, 65521, 65522,
164 > 65523, 65524, 65525, 65525, 65526, 65527, 65527, 65528, 65528, 65529, 65529,
165 > 65529, 65530, 65530, 65530, 65531, 65531, 65531, 65531, 65532, 65532, 65532,
166 > 65532, 65532, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533, 65533,
167 > 65533, 65534, 65534, 65534, 65534, 65534, 65534, 65534, 65534, 65535
168 > };
169 >
170 > #define MELANOPIC_WLMIN 380
171 > #define MELANOPIC_WLMAX 651
172 >
173 > static const unsigned short     melanopic_cumul[MELANOPIC_WLMAX-MELANOPIC_WLMIN+1] = {
174 > 0, 1, 2, 3, 4, 5, 7, 8, 10, 12, 14, 17, 20, 23, 27, 32, 37, 42, 49, 56,
175 > 65, 75, 86, 99, 114, 131, 150, 173, 200, 230, 265, 303, 347, 395, 448,
176 > 508, 574, 650, 734, 828, 931, 1041, 1158, 1283, 1415, 1554, 1703, 1862,
177 > 2031, 2211, 2400, 2600, 2809, 3028, 3257, 3497, 3748, 4012, 4288, 4576,
178 > 4876, 5187, 5509, 5842, 6185, 6540, 6905, 7283, 7673, 8075, 8489, 8915,
179 > 9351, 9799, 10259, 10729, 11211, 11705, 12211, 12729, 13258, 13799,
180 > 14351, 14915, 15491, 16078, 16676, 17286, 17908, 18541, 19184, 19837,
181 > 20498, 21168, 21846, 22532, 23226, 23928, 24637, 25353, 26075, 26802,
182 > 27532, 28267, 29005, 29746, 30488, 31233, 31979, 32726, 33473, 34220,
183 > 34966, 35711, 36455, 37196, 37935, 38671, 39403, 40129, 40851, 41568,
184 > 42279, 42983, 43680, 44369, 45050, 45724, 46388, 47043, 47688, 48322,
185 > 48945, 49557, 50156, 50743, 51317, 51879, 52428, 52964, 53487, 53997,
186 > 54493, 54976, 55445, 55901, 56343, 56771, 57186, 57587, 57976, 58351,
187 > 58712, 59061, 59397, 59720, 60031, 60330, 60616, 60891, 61154, 61405,
188 > 61646, 61875, 62094, 62303, 62501, 62690, 62870, 63040, 63201, 63354,
189 > 63498, 63634, 63763, 63884, 63998, 64105, 64206, 64300, 64389, 64472,
190 > 64549, 64622, 64689, 64753, 64811, 64866, 64917, 64964, 65008, 65049,
191 > 65086, 65121, 65154, 65184, 65211, 65237, 65260, 65282, 65302, 65321,
192 > 65338, 65354, 65368, 65381, 65394, 65405, 65415, 65425, 65434, 65442,
193 > 65449, 65456, 65463, 65468, 65474, 65479, 65483, 65487, 65491, 65494,
194 > 65498, 65501, 65503, 65506, 65508, 65510, 65512, 65514, 65515, 65517,
195 > 65518, 65520, 65521, 65522, 65523, 65524, 65525, 65525, 65526, 65527,
196 > 65527, 65528, 65528, 65529, 65529, 65530, 65530, 65530, 65531, 65531,
197 > 65531, 65531, 65532, 65532, 65532, 65532, 65532, 65533, 65533, 65533,
198 > 65533, 65533, 65533, 65533, 65533, 65533, 65534, 65534, 65534, 65535
199 > };
200 >
201 > COLORMAT  xyz2rgbmat = {                /* XYZ to RGB (no white balance) */
202          {(CIE_y_g - CIE_y_b - CIE_x_b*CIE_y_g + CIE_y_b*CIE_x_g)/CIE_C_rD,
203           (CIE_x_b - CIE_x_g - CIE_x_b*CIE_y_g + CIE_x_g*CIE_y_b)/CIE_C_rD,
204           (CIE_x_g*CIE_y_b - CIE_x_b*CIE_y_g)/CIE_C_rD},
# Line 54 | Line 210 | COLORMAT  xyz2rgbmat = {               /* XYZ to RGB */
210           (CIE_x_r*CIE_y_g - CIE_x_g*CIE_y_r)/CIE_C_bD}
211   };
212  
213 < COLORMAT  rgb2xyzmat = {                /* RGB to XYZ */
213 > COLORMAT  rgb2xyzmat = {                /* RGB to XYZ (no white balance) */
214          {CIE_x_r*CIE_C_rD/CIE_D,CIE_x_g*CIE_C_gD/CIE_D,CIE_x_b*CIE_C_bD/CIE_D},
215          {CIE_y_r*CIE_C_rD/CIE_D,CIE_y_g*CIE_C_gD/CIE_D,CIE_y_b*CIE_C_bD/CIE_D},
216          {(1.-CIE_x_r-CIE_y_r)*CIE_C_rD/CIE_D,
# Line 62 | Line 218 | COLORMAT  rgb2xyzmat = {               /* RGB to XYZ */
218           (1.-CIE_x_b-CIE_y_b)*CIE_C_bD/CIE_D}
219   };
220  
221 + COLORMAT  vkmat = {             /* Sharp primary matrix */
222 +        { 1.2694, -0.0988, -0.1706},
223 +        {-0.8364,  1.8006,  0.0357},
224 +        { 0.0297, -0.0315,  1.0018}
225 + };
226  
227 + COLORMAT  ivkmat = {            /* inverse Sharp primary matrix */
228 +        { 0.8156,  0.0472,  0.1372},
229 +        { 0.3791,  0.5769,  0.0440},
230 +        {-0.0123,  0.0167,  0.9955}
231 + };
232  
233 < spec_rgb(col, s, e)             /* compute RGB color from spectral range */
234 < COLOR  col;
235 < int  s, e;
233 >
234 > void
235 > spec_cie(                       /* compute XYZ color from a spectral range */
236 > COLOR  col,             /* returned color */
237 > int  s,                 /* starting and ending wavelengths */
238 > int  e
239 > )
240   {
241 +        if (s > e) { int i = s; s = e; e = i; }
242 +
243 +        if ((s >= CIE_X_WLMAX) | (e <= CIE_X_WLMIN))
244 +                col[CIEX] = 0;
245 +        else
246 +                col[CIEX] = (cie_x_cumul[e>=CIE_X_WLMAX ? CIE_X_WLMAX-CIE_X_WLMIN : e-CIE_X_WLMIN] -
247 +                        cie_x_cumul[(s>CIE_X_WLMIN)*(s-CIE_X_WLMIN)])*(1./65535.);
248 +
249 +        if ((s >= CIE_Y_WLMAX) | (e <= CIE_Y_WLMIN))
250 +                col[CIEY] = 0;
251 +        else
252 +                col[CIEY] = (cie_y_cumul[e>=CIE_Y_WLMAX ? CIE_Y_WLMAX-CIE_Y_WLMIN : e-CIE_Y_WLMIN] -
253 +                        cie_y_cumul[(s>CIE_Y_WLMIN)*(s-CIE_Y_WLMIN)])*(1./65535.);
254 +
255 +        if ((s >= CIE_Z_WLMAX) | (e <= CIE_Z_WLMIN))
256 +                col[CIEZ] = 0;
257 +        else
258 +                col[CIEZ] = (cie_z_cumul[e>=CIE_Z_WLMAX ? CIE_Z_WLMAX-CIE_Z_WLMIN : e-CIE_Z_WLMIN] -
259 +                        cie_z_cumul[(s>CIE_Z_WLMIN)*(s-CIE_Z_WLMIN)])*(1./65535.);
260 + }
261 +
262 +
263 + void
264 + spec_rgb(                       /* compute RGB color from spectral range */
265 + COLOR  col,
266 + int  s,
267 + int  e
268 + )
269 + {
270          COLOR  ciecolor;
271  
272          spec_cie(ciecolor, s, e);
# Line 75 | Line 274 | int  s, e;
274   }
275  
276  
277 < spec_cie(col, s, e)             /* compute a color from a spectral range */
278 < COLOR  col;             /* returned color */
279 < int  s, e;              /* starting and ending wavelengths */
277 > static double
278 > spec_dot(                       /* spectrum dot-product with cumulative observer */
279 >        SCOLOR scol,
280 >        int  ncs,
281 >        const float wlpt[4],
282 >        const unsigned short cumul[],
283 >        int  wlmin,
284 >        int  wlmax
285 > )
286   {
287 <        register int  i, d, r;
288 <        
289 <        s -= STARTWL;
290 <        if (s < 0)
86 <                s = 0;
287 >        const double    wlstp = (wlpt[0] - wlpt[3])/(double)ncs;
288 >        int             wl1 = (int)wlpt[3];
289 >        int             n = 0;
290 >        double          sum = 0;
291  
292 <        e -= STARTWL;
293 <        if (e <= s) {
294 <                col[CIEX] = col[CIEY] = col[CIEZ] = 0.0;
292 >        if (wl1 < wlmin) {
293 >                n += (int)((wlmin - wl1)/wlstp);
294 >                wl1 = wlmin;
295 >        } else if (wl1 >= wlmax)
296 >                return(.0);
297 >
298 >        while (n < ncs) {
299 >                int     wl0 = wl1;
300 >                wl1 = (int)(ncs==3 ? wlpt[2-n] : wlpt[3] + (n+1)*wlstp);
301 >                if (wl1 >= wlmax) {
302 >                        sum += (65535 - cumul[wl0-wlmin]) * scol[ncs-1-n];
303 >                        break;
304 >                }
305 >                sum += (cumul[wl1-wlmin] - cumul[wl0-wlmin]) * scol[ncs-1-n++];
306 >        }
307 >        return(sum * (1./65535.));
308 > }
309 >
310 >
311 > void
312 > scolor2cie(                     /* accurate conversion from spectrum to XYZ */
313 >        COLOR col,
314 >        SCOLOR scol,
315 >        int ncs,
316 >        const float wlpt[4]
317 > )
318 > {
319 >        if (ncs == 3) {         /* not a spectrum! */
320 >                rgb_cie(col, scol);
321                  return;
322          }
323 <        if (e >= INCWL*(NINC - 1))
324 <                e = INCWL*(NINC - 1) - 1;
323 >        col[CIEX] = spec_dot(scol, ncs, wlpt, cie_x_cumul, CIE_X_WLMIN, CIE_X_WLMAX);
324 >        col[CIEY] = spec_dot(scol, ncs, wlpt, cie_y_cumul, CIE_Y_WLMIN, CIE_Y_WLMAX);
325 >        col[CIEZ] = spec_dot(scol, ncs, wlpt, cie_z_cumul, CIE_Z_WLMIN, CIE_Z_WLMAX);
326 > }
327  
96 –        d = e / INCWL;                  /* interpolate values */
97 –        r = e % INCWL;
98 –        for (i = 0; i < 3; i++)
99 –                col[i] = chroma[i][d]*(INCWL - r) + chroma[i][d + 1]*r;
328  
329 <        d = s / INCWL;
330 <        r = s % INCWL;
331 <        for (i = 0; i < 3; i++)
332 <                col[i] -= chroma[i][d]*(INCWL - r) - chroma[i][d + 1]*r;
329 > void
330 > scolor2rgb(                     /* accurate conversion from spectrum to RGB */
331 >        COLOR col,
332 >        SCOLOR scol,
333 >        int ncs,
334 >        const float wlpt[4]
335 > )
336 > {
337 >        COLOR   ciecolor;
338  
339 <        col[CIEX] = (col[CIEX] + 0.5) * (1./(256*INCWL));
340 <        col[CIEY] = (col[CIEY] + 0.5) * (1./(256*INCWL));
341 <        col[CIEZ] = (col[CIEZ] + 0.5) * (1./(256*INCWL));
339 >        if (ncs == 3) {         /* not really a spectrum, so we punt... */
340 >                copycolor(col, scol);
341 >                return;
342 >        }
343 >        scolor2cie(ciecolor, scol, ncs, wlpt);
344 >        cie_rgb(col, ciecolor);
345   }
346  
347  
348 < colortrans(c2, mat, c1)         /* convert c1 by mat and put into c2 */
349 < register COLORMAT  mat;
350 < register COLOR  c1, c2;
348 > double
349 > scolor_photopic(                /* compute scotopic integral for spectral color */
350 >        SCOLOR  scol
351 > )
352   {
353 <        static float  cout[3];
353 >        if (NCSAMP == 3)
354 >                return bright(scol);
355  
356 +        return(spec_dot(scol, NCSAMP, WLPART, cie_y_cumul, CIE_Y_WLMIN, CIE_Y_WLMAX));
357 + }
358 +
359 +
360 + double
361 + scolor_scotopic(                /* compute Y channel for spectral color */
362 +        SCOLOR  scol
363 + )
364 + {
365 +        return(spec_dot(scol, NCSAMP, WLPART, scotopic_cumul, SCOTOPIC_WLMIN, SCOTOPIC_WLMAX));
366 + }
367 +
368 +
369 + double
370 + scolor_melanopic(               /* compute melanopic integral for spectral color */
371 +        SCOLOR  scol
372 + )
373 + {
374 +        return(spec_dot(scol, NCSAMP, WLPART, melanopic_cumul, MELANOPIC_WLMIN, MELANOPIC_WLMAX));
375 + }
376 +
377 +
378 + void
379 + cie_rgb(                        /* convert CIE color to standard RGB */
380 + COLOR   rgb,
381 + COLOR  xyz
382 + )
383 + {
384 +        colortrans(rgb, xyz2rgbmat, xyz);
385 +        clipgamut(rgb, xyz[CIEY], CGAMUT_LOWER, cblack, cwhite);
386 + }
387 +
388 +
389 + int
390 + clipgamut(                      /* clip to gamut cube */
391 + COLOR  col,
392 + double  brt,
393 + int  gamut,
394 + COLOR  lower,
395 + COLOR  upper
396 + )
397 + {
398 +        int  rflags = 0;
399 +        double  brtmin, brtmax, v, vv;
400 +        COLOR  cgry;
401 +        int  i;
402 +                                        /* check for no check */
403 +        if (gamut == 0) return(0);
404 +                                        /* check brightness limits */
405 +        brtmin = 1./3.*(lower[0]+lower[1]+lower[2]);
406 +        if (gamut & CGAMUT_LOWER && brt < brtmin) {
407 +                copycolor(col, lower);
408 +                return(CGAMUT_LOWER);
409 +        }
410 +        brtmax = 1./3.*(upper[0]+upper[1]+upper[2]);
411 +        if (gamut & CGAMUT_UPPER && brt > brtmax) {
412 +                copycolor(col, upper);
413 +                return(CGAMUT_UPPER);
414 +        }
415 +                                        /* compute equivalent grey */
416 +        v = (brt - brtmin)/(brtmax - brtmin);
417 +        for (i = 0; i < 3; i++)
418 +                cgry[i] = v*upper[i] + (1.-v)*lower[i];
419 +        vv = 1.;                        /* check each limit */
420 +        for (i = 0; i < 3; i++)
421 +                if (gamut & CGAMUT_LOWER && col[i] < lower[i]) {
422 +                        v = (lower[i] - cgry[i])/(col[i] - cgry[i]);
423 +                        if (v < vv) vv = v;
424 +                        rflags |= CGAMUT_LOWER;
425 +                } else if (gamut & CGAMUT_UPPER && col[i] > upper[i]) {
426 +                        v = (upper[i] - cgry[i])/(col[i] - cgry[i]);
427 +                        if (v < vv) vv = v;
428 +                        rflags |= CGAMUT_UPPER;
429 +                }
430 +        if (rflags)                     /* desaturate to cube face */
431 +                for (i = 0; i < 3; i++)
432 +                        col[i] = vv*col[i] + (1.-vv)*cgry[i];
433 +        return(rflags);
434 + }
435 +
436 +
437 + void
438 + colortrans(                     /* convert c1 by mat and put into c2 */
439 + COLOR  c2,
440 + COLORMAT  mat,
441 + COLOR  c1
442 + )
443 + {
444 +        COLOR   cout;
445 +
446          cout[0] = mat[0][0]*c1[0] + mat[0][1]*c1[1] + mat[0][2]*c1[2];
447          cout[1] = mat[1][0]*c1[0] + mat[1][1]*c1[1] + mat[1][2]*c1[2];
448          cout[2] = mat[2][0]*c1[0] + mat[2][1]*c1[1] + mat[2][2]*c1[2];
449 <        if((c2[0] = cout[0]) < 0.) c2[0] = 0.;
450 <        if((c2[1] = cout[1]) < 0.) c2[1] = 0.;
123 <        if((c2[2] = cout[2]) < 0.) c2[2] = 0.;
449 >
450 >        copycolor(c2, cout);
451   }
452  
453  
454 < multcolormat(m3, m2, m1)        /* multiply m1 by m2 and put into m3 */
455 < COLORMAT  m1, m2, m3;           /* m3 can be either m1 or m2 w/o harm */
454 > void
455 > multcolormat(                   /* multiply m1 by m2 and put into m3 */
456 > COLORMAT  m3,                   /* m3 can be either m1 or m2 w/o harm */
457 > COLORMAT  m2,
458 > COLORMAT  m1
459 > )
460   {
461          COLORMAT  mt;
462 <        register int  i, j;
462 >        int  i, j;
463  
464          for (i = 0; i < 3; i++)
465                  for (j = 0; j < 3; j++)
# Line 139 | Line 470 | COLORMAT  m1, m2, m3;          /* m3 can be either m1 or m2 w/
470   }
471  
472  
473 < compxyz2rgbmat(mat, pr)         /* compute conversion from CIE to RGB space */
474 < COLORMAT  mat;
475 < register RGBPRIMS  pr;
473 > int
474 > colorprimsOK(                   /* are color primaries reasonable? */
475 > RGBPRIMS  pr
476 > )
477   {
478 +        int     i, j;
479 +                                /* check white point */
480 +        if ((pr[3][CIEX] <= CEPS) | (pr[3][CIEX] >= 1.-CEPS) |
481 +                        (pr[3][CIEY] <= CEPS) | (pr[3][CIEY] >= 1.-CEPS))
482 +                return(0);
483 +        for (i = 3; i--; )      /* check for XYZ color primaries */
484 +                if (!CEQ(pr[i][CIEX],(i==0)) | !CEQ(pr[i][CIEY],(i==1)))
485 +                        break;
486 +        if (i < 0)
487 +                return(-1);     /* flag as XYZ color space */
488 +                                /* check color primaries */
489 +        for (i = 0; i < 3; i++) {
490 +                if ((pr[i][CIEX] <= -2.) | (pr[i][CIEY] <= -2.))
491 +                        return(0);
492 +                if ((pr[i][CIEX] >= 3.) | (pr[i][CIEY] >= 3.))
493 +                        return(0);
494 +                if (pr[i][CIEX] + pr[i][CIEY] <= -2.)
495 +                        return(0);
496 +                if (pr[i][CIEX] + pr[i][CIEY] >= 3.)
497 +                        return(0);
498 +        }
499 +        for (i = 0; i < 4; i++) /* make sure space is 3-dimensional */
500 +                for (j = i+1; j < 4; j++)
501 +                        if (CEQ(pr[i][CIEX],pr[j][CIEX]) &
502 +                                        CEQ(pr[i][CIEY],pr[j][CIEY]))
503 +                                return(0);
504 +        return(1);
505 + }
506 +
507 +
508 +
509 + int
510 + compxyz2rgbmat(                 /* compute conversion from CIE to RGB space */
511 + COLORMAT  mat,
512 + RGBPRIMS  pr
513 + )
514 + {
515          double  C_rD, C_gD, C_bD;
516  
517 +        if (pr == stdprims) {   /* can use xyz2rgbmat */
518 +                cpcolormat(mat, xyz2rgbmat);
519 +                return(1);
520 +        }
521 +        if (pr == xyzprims) {   /* identity */
522 +                memset(mat, 0, sizeof(COLORMAT));
523 +                mat[0][0] = mat[1][1] = mat[2][2] = 1.f;
524 +                return(1);
525 +        }
526 +        if (CEQ(pr[WHT][CIEX],0.) | CEQ(pr[WHT][CIEY],0.))
527 +                return(0);
528          C_rD = (1./pr[WHT][CIEY]) *
529                          ( pr[WHT][CIEX]*(pr[GRN][CIEY] - pr[BLU][CIEY]) -
530                            pr[WHT][CIEY]*(pr[GRN][CIEX] - pr[BLU][CIEX]) +
531                    pr[GRN][CIEX]*pr[BLU][CIEY] - pr[BLU][CIEX]*pr[GRN][CIEY] ) ;
532 +        if (CEQ(C_rD,0.))
533 +                return(0);
534          C_gD = (1./pr[WHT][CIEY]) *
535                          ( pr[WHT][CIEX]*(pr[BLU][CIEY] - pr[RED][CIEY]) -
536                            pr[WHT][CIEY]*(pr[BLU][CIEX] - pr[RED][CIEX]) -
537                    pr[RED][CIEX]*pr[BLU][CIEY] + pr[BLU][CIEX]*pr[RED][CIEY] ) ;
538 +        if (CEQ(C_gD,0.))
539 +                return(0);
540          C_bD = (1./pr[WHT][CIEY]) *
541                          ( pr[WHT][CIEX]*(pr[RED][CIEY] - pr[GRN][CIEY]) -
542                            pr[WHT][CIEY]*(pr[RED][CIEX] - pr[GRN][CIEX]) +
543                    pr[RED][CIEX]*pr[GRN][CIEY] - pr[GRN][CIEX]*pr[RED][CIEY] ) ;
544 <
544 >        if (CEQ(C_bD,0.))
545 >                return(0);
546          mat[0][0] = (pr[GRN][CIEY] - pr[BLU][CIEY] -
547                          pr[BLU][CIEX]*pr[GRN][CIEY] +
548                          pr[BLU][CIEY]*pr[GRN][CIEX])/C_rD ;
# Line 182 | Line 567 | register RGBPRIMS  pr;
567                          pr[RED][CIEX]*pr[GRN][CIEY])/C_bD ;
568          mat[2][2] = (pr[RED][CIEX]*pr[GRN][CIEY] -
569                          pr[GRN][CIEX]*pr[RED][CIEY])/C_bD ;
570 +        return(1);
571   }
572  
573  
574 < comprgb2xyzmat(mat, pr)         /* compute conversion from RGB to CIE space */
575 < COLORMAT  mat;
576 < register RGBPRIMS  pr;
574 > int
575 > comprgb2xyzmat(                 /* compute conversion from RGB to CIE space */
576 > COLORMAT  mat,
577 > RGBPRIMS  pr
578 > )
579   {
580          double  C_rD, C_gD, C_bD, D;
581  
582 +        if (pr == stdprims) {   /* can use rgb2xyzmat */
583 +                cpcolormat(mat, rgb2xyzmat);
584 +                return(1);
585 +        }
586 +        if (pr == xyzprims) {   /* identity */
587 +                memset(mat, 0, sizeof(COLORMAT));
588 +                mat[0][0] = mat[1][1] = mat[2][2] = 1.f;
589 +                return(1);
590 +        }
591 +        if (CEQ(pr[WHT][CIEX],0.) | CEQ(pr[WHT][CIEY],0.))
592 +                return(0);
593          C_rD = (1./pr[WHT][CIEY]) *
594                          ( pr[WHT][CIEX]*(pr[GRN][CIEY] - pr[BLU][CIEY]) -
595                            pr[WHT][CIEY]*(pr[GRN][CIEX] - pr[BLU][CIEX]) +
# Line 206 | Line 605 | register RGBPRIMS  pr;
605          D = pr[RED][CIEX]*(pr[GRN][CIEY] - pr[BLU][CIEY]) +
606                          pr[GRN][CIEX]*(pr[BLU][CIEY] - pr[RED][CIEY]) +
607                          pr[BLU][CIEX]*(pr[RED][CIEY] - pr[GRN][CIEY]) ;
608 +        if (CEQ(D,0.))
609 +                return(0);
610          mat[0][0] = pr[RED][CIEX]*C_rD/D;
611          mat[0][1] = pr[GRN][CIEX]*C_gD/D;
612          mat[0][2] = pr[BLU][CIEX]*C_bD/D;
# Line 215 | Line 616 | register RGBPRIMS  pr;
616          mat[2][0] = (1.-pr[RED][CIEX]-pr[RED][CIEY])*C_rD/D;
617          mat[2][1] = (1.-pr[GRN][CIEX]-pr[GRN][CIEY])*C_gD/D;
618          mat[2][2] = (1.-pr[BLU][CIEX]-pr[BLU][CIEY])*C_bD/D;
619 +        return(1);
620   }
621  
622  
623 < comprgb2rgbmat(mat, pr1, pr2)   /* compute conversion from RGB1 to RGB2 */
624 < COLORMAT  mat;
625 < RGBPRIMS  pr1, pr2;
623 > int
624 > comprgb2rgbmat(                 /* compute conversion from RGB1 to RGB2 */
625 > COLORMAT  mat,
626 > RGBPRIMS  pr1,
627 > RGBPRIMS  pr2
628 > )
629   {
630          COLORMAT  pr1toxyz, xyztopr2;
631  
632 <        if (pr1 == stdprims)    /* can use rgb2xyzmat */
633 <                cpcolormat(pr1toxyz, rgb2xyzmat);
634 <        else                    /* otherwise compute it */
635 <                comprgb2xyzmat(pr1toxyz, pr1);
636 <        if (pr2 == stdprims)    /* can use xyz2rgbmat */
637 <                cpcolormat(xyztopr2, xyz2rgbmat);
638 <        else                    /* otherwise compute it */
639 <                compxyz2rgbmat(xyztopr2, pr2);
632 >        if (pr1 == pr2) {
633 >                memset(mat, 0, sizeof(COLORMAT));
634 >                mat[0][0] = mat[1][1] = mat[2][2] = 1.f;
635 >                return(1);
636 >        }
637 >        if (!comprgb2xyzmat(pr1toxyz, pr1))
638 >                return(0);
639 >        if (!compxyz2rgbmat(xyztopr2, pr2))
640 >                return(0);
641                                  /* combine transforms */
642          multcolormat(mat, pr1toxyz, xyztopr2);
643 +        return(1);
644 + }
645 +
646 +
647 + int
648 + compxyzWBmat(                   /* CIE von Kries transform from wht1 to wht2 */
649 + COLORMAT  mat,
650 + float  wht1[2],
651 + float  wht2[2]
652 + )
653 + {
654 +        COLOR   cw1, cw2;
655 +        if (XYEQ(wht1,wht2)) {
656 +                memset(mat, 0, sizeof(COLORMAT));
657 +                mat[0][0] = mat[1][1] = mat[2][2] = 1.f;
658 +                return(1);
659 +        }
660 +        if (CEQ(wht1[CIEX],0.) | CEQ(wht1[CIEY],0.))
661 +                return(0);
662 +        cw1[RED] = wht1[CIEX]/wht1[CIEY];
663 +        cw1[GRN] = 1.;
664 +        cw1[BLU] = (1. - wht1[CIEX] - wht1[CIEY])/wht1[CIEY];
665 +        colortrans(cw1, vkmat, cw1);
666 +        if (CEQ(wht2[CIEX],0.) | CEQ(wht2[CIEY],0.))
667 +                return(0);
668 +        cw2[RED] = wht2[CIEX]/wht2[CIEY];
669 +        cw2[GRN] = 1.;
670 +        cw2[BLU] = (1. - wht2[CIEX] - wht2[CIEY])/wht2[CIEY];
671 +        colortrans(cw2, vkmat, cw2);
672 +        if (CEQ(cw1[RED],0.) | CEQ(cw1[GRN],0.) | CEQ(cw1[BLU],0.))
673 +                return(0);
674 +        mat[0][0] = cw2[RED]/cw1[RED];
675 +        mat[1][1] = cw2[GRN]/cw1[GRN];
676 +        mat[2][2] = cw2[BLU]/cw1[BLU];
677 +        mat[0][1] = mat[0][2] = mat[1][0] =
678 +        mat[1][2] = mat[2][0] = mat[2][1] = 0.0;
679 +        multcolormat(mat, vkmat, mat);
680 +        multcolormat(mat, mat, ivkmat);
681 +        return(1);
682 + }
683 +
684 +
685 + int
686 + compxyz2rgbWBmat(               /* von Kries conversion from CIE to RGB space */
687 + COLORMAT  mat,
688 + RGBPRIMS  pr
689 + )
690 + {
691 +        COLORMAT        wbmat;
692 +
693 +        if (!compxyz2rgbmat(mat, pr))
694 +                return(0);
695 +        if (XYEQ(pr[WHT],xyneu))
696 +                return(1);
697 +        if (!compxyzWBmat(wbmat, xyneu, pr[WHT]))
698 +                return(0);
699 +        multcolormat(mat, wbmat, mat);
700 +        return(1);
701 + }
702 +
703 + int
704 + comprgb2xyzWBmat(               /* von Kries conversion from RGB to CIE space */
705 + COLORMAT  mat,
706 + RGBPRIMS  pr
707 + )
708 + {
709 +        COLORMAT        wbmat;
710 +        
711 +        if (!comprgb2xyzmat(mat, pr))
712 +                return(0);
713 +        if (XYEQ(pr[WHT],xyneu))
714 +                return(1);
715 +        if (!compxyzWBmat(wbmat, pr[WHT], xyneu))
716 +                return(0);
717 +        multcolormat(mat, mat, wbmat);
718 +        return(1);
719 + }
720 +
721 + int
722 + comprgb2rgbWBmat(               /* von Kries conversion from RGB1 to RGB2 */
723 + COLORMAT  mat,
724 + RGBPRIMS  pr1,
725 + RGBPRIMS  pr2
726 + )
727 + {
728 +        COLORMAT  pr1toxyz, xyztopr2, wbmat;
729 +
730 +        if (pr1 == pr2) {
731 +                memset(mat, 0, sizeof(COLORMAT));
732 +                mat[0][0] = mat[1][1] = mat[2][2] = 1.f;
733 +                return(1);
734 +        }
735 +        if (!comprgb2xyzmat(pr1toxyz, pr1))
736 +                return(0);
737 +        if (!compxyzWBmat(wbmat, pr1[WHT], pr2[WHT]))
738 +                return(0);
739 +        if (!compxyz2rgbmat(xyztopr2, pr2))
740 +                return(0);
741 +                                /* combine transforms */
742 +        multcolormat(mat, pr1toxyz, wbmat);
743 +        multcolormat(mat, mat, xyztopr2);
744 +        return(1);
745   }

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