1/*
2 * Copyright 2011 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 SkEmptyShader_DEFINED
9#define SkEmptyShader_DEFINED
10
11#include "src/shaders/SkShaderBase.h"
12
13// TODO: move this to private, as there is a public factory on SkShader
14
15/**
16 * \class SkEmptyShader
17 * A Shader that always draws nothing. Its createContext always returns nullptr.
18 */
19class SkEmptyShader : public SkShaderBase {
20public:
21 SkEmptyShader() {}
22
23protected:
24#ifdef SK_ENABLE_LEGACY_SHADERCONTEXT
25 Context* onMakeContext(const ContextRec&, SkArenaAlloc*) const override {
26 return nullptr;
27 }
28#endif
29
30 void flatten(SkWriteBuffer& buffer) const override {
31 // Do nothing.
32 // We just don't want to fall through to SkShader::flatten(),
33 // which will write data we don't care to serialize or decode.
34 }
35
36 bool onAppendStages(const SkStageRec&) const override {
37 return false;
38 }
39
40 skvm::Color onProgram(skvm::Builder*, skvm::Coord, skvm::Coord, skvm::Color,
41 const SkMatrixProvider&, const SkMatrix*,
42 SkFilterQuality, const SkColorInfo&,
43 skvm::Uniforms*, SkArenaAlloc*) const override;
44
45private:
46 SK_FLATTENABLE_HOOKS(SkEmptyShader)
47
48 typedef SkShaderBase INHERITED;
49};
50
51#endif
52