1 | /////////////////////////////////////////////////////////////////////////// |
2 | // |
3 | // Copyright (c) 2003, Industrial Light & Magic, a division of Lucas |
4 | // Digital Ltd. LLC |
5 | // |
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32 | // |
33 | /////////////////////////////////////////////////////////////////////////// |
34 | |
35 | |
36 | #ifndef INCLUDED_IMF_CHROMATICITIES_H |
37 | #define INCLUDED_IMF_CHROMATICITIES_H |
38 | |
39 | //----------------------------------------------------------------------------- |
40 | // |
41 | // CIE (x,y) chromaticities, and conversions between |
42 | // RGB tiples and CIE XYZ tristimulus values. |
43 | // |
44 | //----------------------------------------------------------------------------- |
45 | |
46 | #include "ImathVec.h" |
47 | #include "ImathMatrix.h" |
48 | #include "ImfNamespace.h" |
49 | #include "ImfExport.h" |
50 | |
51 | |
52 | OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_ENTER |
53 | |
54 | |
55 | struct IMF_EXPORT Chromaticities |
56 | { |
57 | //----------------------------------------------- |
58 | // The CIE x and y coordinates of the RGB triples |
59 | // (1,0,0), (0,1,0), (0,0,1) and (1,1,1). |
60 | //----------------------------------------------- |
61 | |
62 | IMATH_NAMESPACE::V2f red; |
63 | IMATH_NAMESPACE::V2f green; |
64 | IMATH_NAMESPACE::V2f blue; |
65 | IMATH_NAMESPACE::V2f white; |
66 | |
67 | //-------------------------------------------- |
68 | // Default constructor produces chromaticities |
69 | // according to Rec. ITU-R BT.709-3 |
70 | //-------------------------------------------- |
71 | |
72 | Chromaticities (const IMATH_NAMESPACE::V2f &red = IMATH_NAMESPACE::V2f (0.6400f, 0.3300f), |
73 | const IMATH_NAMESPACE::V2f &green = IMATH_NAMESPACE::V2f (0.3000f, 0.6000f), |
74 | const IMATH_NAMESPACE::V2f &blue = IMATH_NAMESPACE::V2f (0.1500f, 0.0600f), |
75 | const IMATH_NAMESPACE::V2f &white = IMATH_NAMESPACE::V2f (0.3127f, 0.3290f)); |
76 | |
77 | |
78 | //--------- |
79 | // Equality |
80 | //--------- |
81 | |
82 | bool operator == (const Chromaticities &v) const; |
83 | bool operator != (const Chromaticities &v) const; |
84 | }; |
85 | |
86 | |
87 | // |
88 | // Conversions between RGB and CIE XYZ |
89 | // |
90 | // RGB to XYZ: |
91 | // |
92 | // Given a set of chromaticities, c, and the luminance, Y, of the RGB |
93 | // triple (1,1,1), or "white", RGBtoXYZ(c,Y) computes a matrix, M, so |
94 | // that multiplying an RGB value, v, with M produces an equivalent |
95 | // XYZ value, w. (w == v * M) |
96 | // |
97 | // If we define that |
98 | // |
99 | // (Xr, Yr, Zr) == (1, 0, 0) * M |
100 | // (Xg, Yg, Zg) == (0, 1, 0) * M |
101 | // (Xb, Yb, Zb) == (0, 0, 1) * M |
102 | // (Xw, Yw, Zw) == (1, 1, 1) * M, |
103 | // |
104 | // then the following statements are true: |
105 | // |
106 | // Xr / (Xr + Yr + Zr) == c.red.x |
107 | // Yr / (Xr + Yr + Zr) == c.red.y |
108 | // |
109 | // Xg / (Xg + Yg + Zg) == c.red.x |
110 | // Yg / (Xg + Yg + Zg) == c.red.y |
111 | // |
112 | // Xb / (Xb + Yb + Zb) == c.red.x |
113 | // Yb / (Xb + Yb + Zb) == c.red.y |
114 | // |
115 | // Xw / (Xw + Yw + Zw) == c.red.x |
116 | // Yw / (Xw + Yw + Zw) == c.red.y |
117 | // |
118 | // Yw == Y. |
119 | // |
120 | // XYZ to RGB: |
121 | // |
122 | // YYZtoRGB(c,Y) returns RGBtoXYZ(c,Y).inverse(). |
123 | // |
124 | |
125 | IMF_EXPORT IMATH_NAMESPACE::M44f RGBtoXYZ (const Chromaticities chroma, float Y); |
126 | IMF_EXPORT IMATH_NAMESPACE::M44f XYZtoRGB (const Chromaticities chroma, float Y); |
127 | |
128 | |
129 | OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_EXIT |
130 | |
131 | #endif |
132 | |