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 */ 19 class SkEmptyShader : public SkShaderBase { 20 public: SkEmptyShader()21 SkEmptyShader() {} 22 23 protected: 24 #ifdef SK_ENABLE_LEGACY_SHADERCONTEXT onMakeContext(const ContextRec &,SkArenaAlloc *)25 Context* onMakeContext(const ContextRec&, SkArenaAlloc*) const override { 26 return nullptr; 27 } 28 #endif 29 flatten(SkWriteBuffer & buffer)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 onAppendStages(const SkStageRec &)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*, const SkColorInfo&, 42 skvm::Uniforms*, SkArenaAlloc*) const override; 43 44 private: 45 SK_FLATTENABLE_HOOKS(SkEmptyShader) 46 47 using INHERITED = SkShaderBase; 48 }; 49 50 #endif 51