blob: 94040338a882fdd7018a73e845205f1f8e5542ca [file] [log] [blame]
/*
* Copyright 2022 Google LLC
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "src/shaders/SkShaderBase.h"
#include "include/core/SkFlattenable.h"
#include "src/core/SkVM.h"
/**
* \class SkEmptyShader
* A Shader that always draws nothing. Its createContext always returns nullptr.
*/
class SkEmptyShader : public SkShaderBase {
public:
SkEmptyShader() {}
protected:
void flatten(SkWriteBuffer& buffer) const override {
// Do nothing.
// We just don't want to fall through to SkShader::flatten(),
// which will write data we don't care to serialize or decode.
}
bool appendStages(const SkStageRec&, const MatrixRec&) const override { return false; }
skvm::Color program(skvm::Builder*,
skvm::Coord,
skvm::Coord,
skvm::Color,
const MatrixRec&,
const SkColorInfo&,
skvm::Uniforms*,
SkArenaAlloc*) const override;
private:
friend void ::SkRegisterEmptyShaderFlattenable();
SK_FLATTENABLE_HOOKS(SkEmptyShader)
using INHERITED = SkShaderBase;
};
skvm::Color SkEmptyShader::program(skvm::Builder*,
skvm::Coord,
skvm::Coord,
skvm::Color,
const MatrixRec&,
const SkColorInfo&,
skvm::Uniforms*,
SkArenaAlloc*) const {
return {}; // signal failure
}
sk_sp<SkFlattenable> SkEmptyShader::CreateProc(SkReadBuffer&) {
return SkShaders::Empty();
}
sk_sp<SkShader> SkShaders::Empty() { return sk_make_sp<SkEmptyShader>(); }
void SkRegisterEmptyShaderFlattenable() {
SK_REGISTER_FLATTENABLE(SkEmptyShader);
}