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 "SkShader.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 NULL. 18 */ 19class SK_API SkEmptyShader : public SkShader { 20public: 21 SkEmptyShader() {} 22 23 virtual size_t contextSize() const SK_OVERRIDE { 24 // Even though createContext returns NULL we have to return a value of at least 25 // sizeof(SkShader::Context) to satisfy SkSmallAllocator. 26 return sizeof(SkShader::Context); 27 } 28 29 SK_TO_STRING_OVERRIDE() 30 SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkEmptyShader) 31 32protected: 33#ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING 34 SkEmptyShader(SkReadBuffer& buffer) : INHERITED(buffer) {} 35#endif 36 37 virtual SkShader::Context* onCreateContext(const ContextRec&, void*) const SK_OVERRIDE { 38 return NULL; 39 } 40 41private: 42 typedef SkShader INHERITED; 43}; 44 45#endif 46