include/effects/SkTransparentShader.h

/*
 * Copyright 2006 The Android Open Source Project
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */


#ifndef SkTransparentShader_DEFINED
#define SkTransparentShader_DEFINED

#include "SkShader.h"

class SkTransparentShader : public SkShader {
public:
    SkTransparentShader() {}

    virtual uint32_t getFlags() SK_OVERRIDE;
    virtual bool    setContext( const SkBitmap& device,
                                const SkPaint& paint,
                                const SkMatrix& matrix) SK_OVERRIDE;
    virtual void    shadeSpan(int x, int y, SkPMColor[], int count) SK_OVERRIDE;
    virtual void    shadeSpan16(int x, int y, uint16_t span[], int count) SK_OVERRIDE;

    // overrides for SkFlattenable
    virtual Factory getFactory() SK_OVERRIDE;
    virtual void flatten(SkFlattenableWriteBuffer&) SK_OVERRIDE;

private:
    // these are a cache from the call to setContext()
    const SkBitmap* fDevice;
    uint8_t         fAlpha;

    SkTransparentShader(SkFlattenableReadBuffer& buffer) : INHERITED(buffer) {}
    
    static SkFlattenable* Create(SkFlattenableReadBuffer& buffer) {
        return SkNEW_ARGS(SkTransparentShader, (buffer));
    }

    typedef SkShader INHERITED;
};

#endif