SkSGOpacityEffect.h

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/*
 * Copyright 2018 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
#ifndef SkSGOpacityEffect_DEFINED
#define SkSGOpacityEffect_DEFINED
 
#include "include/core/SkRect.h"
#include "include/core/SkRefCnt.h"
#include "modules/sksg/include/SkSGEffectNode.h"
#include "modules/sksg/include/SkSGNode.h"
#include "modules/sksg/include/SkSGRenderNode.h"
 
#include <utility>
 
class SkCanvas;
class SkMatrix;
struct SkPoint;
 
namespace sksg {
class InvalidationController;
 
/**
 * Concrete Effect node, applying opacity to its descendants.
 *
 */
class OpacityEffect final : public EffectNode {
public:
    static sk_sp<OpacityEffect> Make(sk_sp<RenderNode> child, float opacity = 1) {
        return child ? sk_sp<OpacityEffect>(new OpacityEffect(std::move(child), opacity)) : nullptr;
    }
 
    SG_ATTRIBUTE(Opacity, float, fOpacity)
 
protected:
    OpacityEffect(sk_sp<RenderNode>, float);
 
    void onRender(SkCanvas*, const RenderContext*) const override;
    const RenderNode* onNodeAt(const SkPoint&)     const override;
 
    SkRect onRevalidate(InvalidationController*, const SkMatrix&) override;
 
private:
    float fOpacity;
 
    using INHERITED = EffectNode;
};
 
} // namespace sksg
 
#endif // SkSGOpacityEffect_DEFINED