Line data Source code
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_A2B_DEFINED
9 : #define SkColorSpace_A2B_DEFINED
10 :
11 : #include "SkColorSpace_Base.h"
12 :
13 : #include <vector>
14 :
15 : // An alternative SkColorSpace that represents all the color space data that
16 : // is stored in an A2B0 ICC tag. This allows us to use alternative profile
17 : // connection spaces (CIELAB instead of just CIEXYZ), use color-lookup-tables
18 : // to do color space transformations not representable as TRC functions or
19 : // matrix operations, as well as have multiple TRC functions. The CLUT also
20 : // allows conversion between non-3-channel input color spaces ie CMYK(4) to
21 : // a workable PCS (ie XYZ).
22 : //
23 : // AtoBType, lut8Type and lut16Type A2B0 tag types are supported. There are
24 : // also MPET (multi-processing-elements) A2B0 tags in the standard which allow
25 : // you to combine these 3 primitives (TRC, CLUT, matrix) in any order/quantity.
26 : // MPET tags are currently unsupported by the MakeICC parser, could be supported
27 : // here by the nature of the design.
28 0 : class SkColorSpace_A2B : public SkColorSpace_Base {
29 : public:
30 0 : const SkMatrix44* toXYZD50() const override {
31 : // the matrix specified in A2B0 profiles is not necessarily
32 : // a to-XYZ matrix, as to-Lab is supported as well so returning
33 : // that could be misleading. Additionally, B-curves are applied
34 : // after the matrix is, but a toXYZD50 matrix is the last thing
35 : // applied in order to get into the (XYZ) profile connection space.
36 0 : return nullptr;
37 : }
38 :
39 0 : uint32_t toXYZD50Hash() const override {
40 : // See toXYZD50()'s comment.
41 0 : return 0;
42 : }
43 :
44 0 : const SkMatrix44* fromXYZD50() const override {
45 : // See toXYZD50()'s comment. Also, A2B0 profiles are not supported
46 : // as destination color spaces, so an inverse matrix is never wanted.
47 0 : return nullptr;
48 : }
49 :
50 : // There is no single gamma curve in an A2B0 profile
51 0 : bool onGammaCloseToSRGB() const override { return false; }
52 0 : bool onGammaIsLinear() const override { return false; }
53 0 : bool onIsNumericalTransferFn(SkColorSpaceTransferFn* coeffs) const override { return false; }
54 :
55 0 : bool onIsCMYK() const override { return kCMYK_ICCTypeFlag == fICCType; }
56 :
57 0 : sk_sp<SkColorSpace> makeLinearGamma() override {
58 : // TODO: Analyze the extrema of our projection into XYZ and use suitable primaries?
59 : // For now, just fall back to a default, because we don't have a good answer.
60 0 : return SkColorSpace::MakeSRGBLinear();
61 : }
62 :
63 0 : sk_sp<SkColorSpace> makeSRGBGamma() override {
64 : // See comment in makeLinearGamma
65 0 : return SkColorSpace::MakeSRGB();
66 : }
67 :
68 0 : Type type() const override { return Type::kA2B; }
69 :
70 0 : class Element {
71 : public:
72 0 : Element(SkGammaNamed gammaNamed, int channelCount)
73 0 : : fType(Type::kGammaNamed)
74 : , fGammaNamed(gammaNamed)
75 : , fMatrix(SkMatrix44::kUninitialized_Constructor)
76 : , fInputChannels(channelCount)
77 0 : , fOutputChannels(channelCount) {
78 0 : SkASSERT(gammaNamed != kNonStandard_SkGammaNamed);
79 0 : }
80 :
81 0 : explicit Element(sk_sp<SkGammas> gammas)
82 0 : : fType(Type::kGammas)
83 0 : , fGammas(std::move(gammas))
84 : , fMatrix(SkMatrix44::kUninitialized_Constructor)
85 0 : , fInputChannels(fGammas->channels())
86 0 : , fOutputChannels(fGammas->channels()) {
87 0 : for (int i = 0; i < fGammas->channels(); ++i) {
88 0 : if (SkGammas::Type::kTable_Type == fGammas->type(i)) {
89 0 : SkASSERT(fGammas->data(i).fTable.fSize >= 2);
90 : }
91 : }
92 0 : }
93 :
94 0 : explicit Element(sk_sp<SkColorLookUpTable> colorLUT)
95 0 : : fType(Type::kCLUT)
96 0 : , fCLUT(std::move(colorLUT))
97 : , fMatrix(SkMatrix44::kUninitialized_Constructor)
98 0 : , fInputChannels(fCLUT->inputChannels())
99 0 : , fOutputChannels(fCLUT->outputChannels())
100 0 : {}
101 :
102 0 : explicit Element(const SkMatrix44& matrix)
103 0 : : fType(Type::kMatrix)
104 : , fMatrix(matrix)
105 : , fInputChannels(3)
106 0 : , fOutputChannels(3)
107 0 : {}
108 :
109 : enum class Type {
110 : kGammaNamed,
111 : kGammas,
112 : kCLUT,
113 : kMatrix
114 : };
115 :
116 0 : Type type() const { return fType; }
117 :
118 0 : SkGammaNamed gammaNamed() const {
119 0 : SkASSERT(Type::kGammaNamed == fType);
120 0 : return fGammaNamed;
121 : }
122 :
123 0 : const SkGammas& gammas() const {
124 0 : SkASSERT(Type::kGammas == fType);
125 0 : return *fGammas;
126 : }
127 :
128 0 : const SkColorLookUpTable& colorLUT() const {
129 0 : SkASSERT(Type::kCLUT == fType);
130 0 : return *fCLUT;
131 : }
132 :
133 0 : const SkMatrix44& matrix() const {
134 0 : SkASSERT(Type::kMatrix == fType);
135 0 : return fMatrix;
136 : }
137 :
138 0 : int inputChannels() const { return fInputChannels; }
139 :
140 0 : int outputChannels() const { return fOutputChannels; }
141 :
142 : private:
143 : Type fType;
144 : SkGammaNamed fGammaNamed;
145 : sk_sp<SkGammas> fGammas;
146 : sk_sp<SkColorLookUpTable> fCLUT;
147 : SkMatrix44 fMatrix;
148 : int fInputChannels;
149 : int fOutputChannels;
150 : };
151 0 : const Element& element(int i) const { return fElements[i]; }
152 :
153 0 : int count() const { return (int)fElements.size(); }
154 :
155 : // the intermediate profile connection space that this color space
156 : // represents the transformation to
157 : enum class PCS : uint8_t {
158 : kLAB, // CIELAB
159 : kXYZ // CIEXYZ
160 : };
161 :
162 0 : PCS pcs() const { return fPCS; }
163 :
164 0 : ICCTypeFlag iccType() const { return fICCType; }
165 :
166 : SkColorSpace_A2B(ICCTypeFlag iccType, std::vector<Element> elements, PCS pcs,
167 : sk_sp<SkData> profileData);
168 :
169 : private:
170 : ICCTypeFlag fICCType;
171 : std::vector<Element> fElements;
172 : PCS fPCS;
173 :
174 : friend class SkColorSpace_Base;
175 : friend class ColorSpaceXformTest;
176 : typedef SkColorSpace_Base INHERITED;
177 : };
178 :
179 : #endif
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