SkSGMaskEffect.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 SkSGMaskEffect_DEFINED
#define SkSGMaskEffect_DEFINED
 
#include "include/core/SkRect.h"
#include "include/core/SkRefCnt.h"
#include "modules/sksg/include/SkSGEffectNode.h"
#include "modules/sksg/include/SkSGRenderNode.h"
 
#include <cstdint>
#include <utility>
 
class SkCanvas;
class SkMatrix;
struct SkPoint;
 
namespace sksg {
class InvalidationController;
 
/**
 * Concrete Effect node, applying a mask to its descendants.
 *
 */
class MaskEffect final : public EffectNode {
public:
    enum class Mode : uint32_t {
        kAlphaNormal,
        kAlphaInvert,
        kLumaNormal,
        kLumaInvert,
    };
 
    static sk_sp<MaskEffect> Make(sk_sp<RenderNode> child, sk_sp<RenderNode> mask,
                                  Mode mode = Mode::kAlphaNormal) {
        return (child && mask)
            ? sk_sp<MaskEffect>(new MaskEffect(std::move(child), std::move(mask), mode))
            : nullptr;
    }
 
    ~MaskEffect() override;
 
protected:
    MaskEffect(sk_sp<RenderNode>, sk_sp<RenderNode> mask, Mode);
 
    void onRender(SkCanvas*, const RenderContext*) const override;
    const RenderNode* onNodeAt(const SkPoint&)     const override;
 
    SkRect onRevalidate(InvalidationController*, const SkMatrix&) override;
 
private:
    const sk_sp<RenderNode> fMaskNode;
    const Mode              fMaskMode;
 
    using INHERITED = EffectNode;
};
 
} // namespace sksg
 
#endif // SkSGMaskEffect_DEFINED