/*

 * Copyright 2011 Google Inc.

 *

 * Use of this source code is governed by a BSD-style license that can be

 * found in the LICENSE file.

 */

#ifndef SkEmptyShader_DEFINED

#define SkEmptyShader_DEFINED

#include "src/shaders/SkShaderBase.h"

// TODO: move this to private, as there is a public factory on SkShader

/**

 *  \class SkEmptyShader

 *  A Shader that always draws nothing. Its createContext always returns nullptr.

 */

class SkEmptyShader : public SkShaderBase {

public:

    SkEmptyShader() {}

protected:

#ifdef SK_ENABLE_LEGACY_SHADERCONTEXT

    Context* onMakeContext(const ContextRec&, SkArenaAlloc*) const override {

        return nullptr;

    }

#endif

    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 onAppendStages(const SkStageRec&) const override {

        return false;

    }

    skvm::Color onProgram(skvm::Builder*, skvm::Coord, skvm::Coord, skvm::Color,

                          const SkMatrixProvider&, const SkMatrix*, const SkColorInfo&,

                          skvm::Uniforms*, SkArenaAlloc*) const override;

private:

    SK_FLATTENABLE_HOOKS(SkEmptyShader)

    using INHERITED = SkShaderBase;

};

#endif