1/*
2 * Copyright 2006 The Android Open Source Project
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 SkColorFilter_DEFINED
9#define SkColorFilter_DEFINED
10
11#include "include/core/SkBlendMode.h"
12#include "include/core/SkColor.h"
13#include "include/core/SkFlattenable.h"
14#include "include/core/SkRefCnt.h"
15
16class GrColorInfo;
17class GrFragmentProcessor;
18class GrRecordingContext;
19class SkArenaAlloc;
20class SkBitmap;
21class SkColorMatrix;
22class SkColorSpace;
23struct SkStageRec;
24
25namespace skvm {
26 class Builder;
27 struct F32;
28 struct Uniforms;
29 struct Color;
30}
31
32/**
33 * ColorFilters are optional objects in the drawing pipeline. When present in
34 * a paint, they are called with the "src" colors, and return new colors, which
35 * are then passed onto the next stage (either ImageFilter or Xfermode).
36 *
37 * All subclasses are required to be reentrant-safe : it must be legal to share
38 * the same instance between several threads.
39 */
40class SK_API SkColorFilter : public SkFlattenable {
41public:
42 // DEPRECATED. skbug.com/8941
43
44 bool asColorMode(SkColor* color, SkBlendMode* mode) const {
45 return this->onAsAColorMode(color, mode);
46 }
47
48 /** If the filter can be represented by a source color plus Mode, this
49 * returns true, and sets (if not NULL) the color and mode appropriately.
50 * If not, this returns false and ignores the parameters.
51 */
52 bool asAColorMode(SkColor* color, SkBlendMode* mode) const {
53 return this->onAsAColorMode(color, mode);
54 }
55
56 /** If the filter can be represented by a 5x4 matrix, this
57 * returns true, and sets the matrix appropriately.
58 * If not, this returns false and ignores the parameter.
59 */
60 bool asAColorMatrix(float matrix[20]) const {
61 return this->onAsAColorMatrix(matrix);
62 }
63
64 bool appendStages(const SkStageRec& rec, bool shaderIsOpaque) const;
65
66 skvm::Color program(skvm::Builder*, skvm::Color,
67 SkColorSpace* dstCS, skvm::Uniforms*, SkArenaAlloc*) const;
68
69 enum Flags {
70 /** If set the filter methods will not change the alpha channel of the colors.
71 */
72 kAlphaUnchanged_Flag = 1 << 0,
73 };
74
75 /** Returns the flags for this filter. Override in subclasses to return custom flags.
76 */
77 virtual uint32_t getFlags() const { return 0; }
78
79 SkColor filterColor(SkColor) const;
80
81 /**
82 * Converts the src color (in src colorspace), into the dst colorspace,
83 * then applies this filter to it, returning the filtered color in the dst colorspace.
84 */
85 SkColor4f filterColor4f(const SkColor4f& srcColor, SkColorSpace* srcCS,
86 SkColorSpace* dstCS) const;
87
88 /** Construct a colorfilter whose effect is to first apply the inner filter and then apply
89 * this filter, applied to the output of the inner filter.
90 *
91 * result = this(inner(...))
92 */
93 sk_sp<SkColorFilter> makeComposed(sk_sp<SkColorFilter> inner) const;
94
95#if SK_SUPPORT_GPU
96 /**
97 * A subclass may implement this factory function to work with the GPU backend. It returns
98 * a GrFragmentProcessor that implemets the color filter in GPU shader code.
99 *
100 * The fragment processor receives a premultiplied input color and produces a premultiplied
101 * output color.
102 *
103 * A null return indicates that the color filter isn't implemented for the GPU backend.
104 */
105 virtual std::unique_ptr<GrFragmentProcessor> asFragmentProcessor(
106 GrRecordingContext*, const GrColorInfo& dstColorInfo) const;
107#endif
108
109 bool affectsTransparentBlack() const {
110 return this->filterColor(SK_ColorTRANSPARENT) != SK_ColorTRANSPARENT;
111 }
112
113 static void RegisterFlattenables();
114
115 static SkFlattenable::Type GetFlattenableType() {
116 return kSkColorFilter_Type;
117 }
118
119 SkFlattenable::Type getFlattenableType() const override {
120 return kSkColorFilter_Type;
121 }
122
123 static sk_sp<SkColorFilter> Deserialize(const void* data, size_t size,
124 const SkDeserialProcs* procs = nullptr) {
125 return sk_sp<SkColorFilter>(static_cast<SkColorFilter*>(
126 SkFlattenable::Deserialize(
127 kSkColorFilter_Type, data, size, procs).release()));
128 }
129
130protected:
131 SkColorFilter() {}
132
133 virtual bool onAsAColorMatrix(float[20]) const;
134 virtual bool onAsAColorMode(SkColor* color, SkBlendMode* bmode) const;
135
136private:
137 virtual bool onAppendStages(const SkStageRec& rec, bool shaderIsOpaque) const = 0;
138
139 virtual skvm::Color onProgram(skvm::Builder*, skvm::Color,
140 SkColorSpace* dstCS, skvm::Uniforms*, SkArenaAlloc*) const = 0;
141
142 typedef SkFlattenable INHERITED;
143};
144
145class SK_API SkColorFilters {
146public:
147 static sk_sp<SkColorFilter> Compose(sk_sp<SkColorFilter> outer, sk_sp<SkColorFilter> inner) {
148 return outer ? outer->makeComposed(inner) : inner;
149 }
150 static sk_sp<SkColorFilter> Blend(SkColor c, SkBlendMode mode);
151 static sk_sp<SkColorFilter> Matrix(const SkColorMatrix&);
152 static sk_sp<SkColorFilter> Matrix(const float rowMajor[20]);
153
154 // A version of Matrix which operates in HSLA space instead of RGBA.
155 // I.e. HSLA-to-RGBA(Matrix(RGBA-to-HSLA(input))).
156 static sk_sp<SkColorFilter> HSLAMatrix(const float rowMajor[20]);
157
158 static sk_sp<SkColorFilter> LinearToSRGBGamma();
159 static sk_sp<SkColorFilter> SRGBToLinearGamma();
160 static sk_sp<SkColorFilter> Lerp(float t, sk_sp<SkColorFilter> dst, sk_sp<SkColorFilter> src);
161
162private:
163 SkColorFilters() = delete;
164};
165
166#endif
167