1/*
2 * Copyright 2016 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef SkColorSpace_DEFINED
9#define SkColorSpace_DEFINED
10
11#include "include/core/SkRefCnt.h"
12#include "include/private/SkFixed.h"
13#include "include/private/SkOnce.h"
14#include "include/third_party/skcms/skcms.h"
15#include <memory>
16
17class SkData;
18
19/**
20 * Describes a color gamut with primaries and a white point.
21 */
22struct SK_API SkColorSpacePrimaries {
23 float fRX;
24 float fRY;
25 float fGX;
26 float fGY;
27 float fBX;
28 float fBY;
29 float fWX;
30 float fWY;
31
32 /**
33 * Convert primaries and a white point to a toXYZD50 matrix, the preferred color gamut
34 * representation of SkColorSpace.
35 */
36 bool toXYZD50(skcms_Matrix3x3* toXYZD50) const;
37};
38
39namespace SkNamedTransferFn {
40
41// Like SkNamedGamut::kSRGB, keeping this bitwise exactly the same as skcms makes things fastest.
42static constexpr skcms_TransferFunction kSRGB =
43 { 2.4f, (float)(1/1.055), (float)(0.055/1.055), (float)(1/12.92), 0.04045f, 0.0f, 0.0f };
44
45static constexpr skcms_TransferFunction k2Dot2 =
46 { 2.2f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };
47
48static constexpr skcms_TransferFunction kLinear =
49 { 1.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };
50
51static constexpr skcms_TransferFunction kRec2020 =
52 {2.22222f, 0.909672f, 0.0903276f, 0.222222f, 0.0812429f, 0, 0};
53
54static constexpr skcms_TransferFunction kPQ =
55 {-2.0f, -107/128.0f, 1.0f, 32/2523.0f, 2413/128.0f, -2392/128.0f, 8192/1305.0f };
56
57static constexpr skcms_TransferFunction kHLG =
58 {-3.0f, 2.0f, 2.0f, 1/0.17883277f, 0.28466892f, 0.55991073f, 0.0f };
59
60} // namespace SkNamedTransferFn
61
62namespace SkNamedGamut {
63
64static constexpr skcms_Matrix3x3 kSRGB = {{
65 // ICC fixed-point (16.16) representation, taken from skcms. Please keep them exactly in sync.
66 // 0.436065674f, 0.385147095f, 0.143066406f,
67 // 0.222488403f, 0.716873169f, 0.060607910f,
68 // 0.013916016f, 0.097076416f, 0.714096069f,
69 { SkFixedToFloat(0x6FA2), SkFixedToFloat(0x6299), SkFixedToFloat(0x24A0) },
70 { SkFixedToFloat(0x38F5), SkFixedToFloat(0xB785), SkFixedToFloat(0x0F84) },
71 { SkFixedToFloat(0x0390), SkFixedToFloat(0x18DA), SkFixedToFloat(0xB6CF) },
72}};
73
74static constexpr skcms_Matrix3x3 kAdobeRGB = {{
75 // ICC fixed-point (16.16) repesentation of:
76 // 0.60974, 0.20528, 0.14919,
77 // 0.31111, 0.62567, 0.06322,
78 // 0.01947, 0.06087, 0.74457,
79 { SkFixedToFloat(0x9c18), SkFixedToFloat(0x348d), SkFixedToFloat(0x2631) },
80 { SkFixedToFloat(0x4fa5), SkFixedToFloat(0xa02c), SkFixedToFloat(0x102f) },
81 { SkFixedToFloat(0x04fc), SkFixedToFloat(0x0f95), SkFixedToFloat(0xbe9c) },
82}};
83
84static constexpr skcms_Matrix3x3 kDisplayP3 = {{
85 { 0.515102f, 0.291965f, 0.157153f },
86 { 0.241182f, 0.692236f, 0.0665819f },
87 { -0.00104941f, 0.0418818f, 0.784378f },
88}};
89
90static constexpr skcms_Matrix3x3 kRec2020 = {{
91 { 0.673459f, 0.165661f, 0.125100f },
92 { 0.279033f, 0.675338f, 0.0456288f },
93 { -0.00193139f, 0.0299794f, 0.797162f },
94}};
95
96static constexpr skcms_Matrix3x3 kXYZ = {{
97 { 1.0f, 0.0f, 0.0f },
98 { 0.0f, 1.0f, 0.0f },
99 { 0.0f, 0.0f, 1.0f },
100}};
101
102} // namespace SkNamedGamut
103
104class SK_API SkColorSpace : public SkNVRefCnt<SkColorSpace> {
105public:
106 /**
107 * Create the sRGB color space.
108 */
109 static sk_sp<SkColorSpace> MakeSRGB();
110
111 /**
112 * Colorspace with the sRGB primaries, but a linear (1.0) gamma.
113 */
114 static sk_sp<SkColorSpace> MakeSRGBLinear();
115
116 /**
117 * Create an SkColorSpace from a transfer function and a row-major 3x3 transformation to XYZ.
118 */
119 static sk_sp<SkColorSpace> MakeRGB(const skcms_TransferFunction& transferFn,
120 const skcms_Matrix3x3& toXYZ);
121
122 /**
123 * Create an SkColorSpace from a parsed (skcms) ICC profile.
124 */
125 static sk_sp<SkColorSpace> Make(const skcms_ICCProfile&);
126
127 /**
128 * Convert this color space to an skcms ICC profile struct.
129 */
130 void toProfile(skcms_ICCProfile*) const;
131
132 /**
133 * Returns true if the color space gamma is near enough to be approximated as sRGB.
134 */
135 bool gammaCloseToSRGB() const;
136
137 /**
138 * Returns true if the color space gamma is linear.
139 */
140 bool gammaIsLinear() const;
141
142 /**
143 * Sets |fn| to the transfer function from this color space. Returns true if the transfer
144 * function can be represented as coefficients to the standard ICC 7-parameter equation.
145 * Returns false otherwise (eg, PQ, HLG).
146 */
147 bool isNumericalTransferFn(skcms_TransferFunction* fn) const;
148
149 /**
150 * Returns true and sets |toXYZD50| if the color gamut can be described as a matrix.
151 * Returns false otherwise.
152 */
153 bool toXYZD50(skcms_Matrix3x3* toXYZD50) const;
154
155 /**
156 * Returns a hash of the gamut transformation to XYZ D50. Allows for fast equality checking
157 * of gamuts, at the (very small) risk of collision.
158 */
159 uint32_t toXYZD50Hash() const { return fToXYZD50Hash; }
160
161 /**
162 * Returns a color space with the same gamut as this one, but with a linear gamma.
163 * For color spaces whose gamut can not be described in terms of XYZ D50, returns
164 * linear sRGB.
165 */
166 sk_sp<SkColorSpace> makeLinearGamma() const;
167
168 /**
169 * Returns a color space with the same gamut as this one, with with the sRGB transfer
170 * function. For color spaces whose gamut can not be described in terms of XYZ D50, returns
171 * sRGB.
172 */
173 sk_sp<SkColorSpace> makeSRGBGamma() const;
174
175 /**
176 * Returns a color space with the same transfer function as this one, but with the primary
177 * colors rotated. For any XYZ space, this produces a new color space that maps RGB to GBR
178 * (when applied to a source), and maps RGB to BRG (when applied to a destination). For other
179 * types of color spaces, returns nullptr.
180 *
181 * This is used for testing, to construct color spaces that have severe and testable behavior.
182 */
183 sk_sp<SkColorSpace> makeColorSpin() const;
184
185 /**
186 * Returns true if the color space is sRGB.
187 * Returns false otherwise.
188 *
189 * This allows a little bit of tolerance, given that we might see small numerical error
190 * in some cases: converting ICC fixed point to float, converting white point to D50,
191 * rounding decisions on transfer function and matrix.
192 *
193 * This does not consider a 2.2f exponential transfer function to be sRGB. While these
194 * functions are similar (and it is sometimes useful to consider them together), this
195 * function checks for logical equality.
196 */
197 bool isSRGB() const;
198
199 /**
200 * Returns nullptr on failure. Fails when we fallback to serializing ICC data and
201 * the data is too large to serialize.
202 */
203 sk_sp<SkData> serialize() const;
204
205 /**
206 * If |memory| is nullptr, returns the size required to serialize.
207 * Otherwise, serializes into |memory| and returns the size.
208 */
209 size_t writeToMemory(void* memory) const;
210
211 static sk_sp<SkColorSpace> Deserialize(const void* data, size_t length);
212
213 /**
214 * If both are null, we return true. If one is null and the other is not, we return false.
215 * If both are non-null, we do a deeper compare.
216 */
217 static bool Equals(const SkColorSpace*, const SkColorSpace*);
218
219 void transferFn(float gabcdef[7]) const; // DEPRECATED: Remove when webview usage is gone
220 void transferFn(skcms_TransferFunction* fn) const;
221 void invTransferFn(skcms_TransferFunction* fn) const;
222 void gamutTransformTo(const SkColorSpace* dst, skcms_Matrix3x3* src_to_dst) const;
223
224 uint32_t transferFnHash() const { return fTransferFnHash; }
225 uint64_t hash() const { return (uint64_t)fTransferFnHash << 32 | fToXYZD50Hash; }
226
227private:
228 friend class SkColorSpaceSingletonFactory;
229
230 SkColorSpace(const skcms_TransferFunction& transferFn, const skcms_Matrix3x3& toXYZ);
231
232 void computeLazyDstFields() const;
233
234 uint32_t fTransferFnHash;
235 uint32_t fToXYZD50Hash;
236
237 skcms_TransferFunction fTransferFn;
238 skcms_Matrix3x3 fToXYZD50;
239
240 mutable skcms_TransferFunction fInvTransferFn;
241 mutable skcms_Matrix3x3 fFromXYZD50;
242 mutable SkOnce fLazyDstFieldsOnce;
243};
244
245#endif
246