src/core/SkPaintPriv.h

/*
 * Copyright 2013 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SkPaintPriv_DEFINED
#define SkPaintPriv_DEFINED

#include "SkTypes.h"

class SkBitmap;
class SkImage;
class SkPaint;

class SkPaintPriv {
public:
    enum ShaderOverrideOpacity {
        kNone_ShaderOverrideOpacity,        //!< there is no overriding shader (bitmap or image)
        kOpaque_ShaderOverrideOpacity,      //!< the overriding shader is opaque
        kNotOpaque_ShaderOverrideOpacity,   //!< the overriding shader may not be opaque
    };

    /**
     *  Returns true if drawing with this paint (or nullptr) will ovewrite all affected pixels.
     *
     *  Note: returns conservative true, meaning it may return false even though the paint might
     *        in fact overwrite its pixels.
     */
    static bool Overwrites(const SkPaint* paint, ShaderOverrideOpacity);

    static bool Overwrites(const SkPaint& paint) {
        return Overwrites(&paint, kNone_ShaderOverrideOpacity);
    }

    /**
     *  Returns true if drawing this bitmap with this paint (or nullptr) will ovewrite all affected
     *  pixels.
     */
    static bool Overwrites(const SkBitmap&, const SkPaint* paint);

    /**
     *  Returns true if drawing this image with this paint (or nullptr) will ovewrite all affected
     *  pixels.
     */
    static bool Overwrites(const SkImage*, const SkPaint* paint);
};

#endif