Source/core/platform/graphics/skia/OpaqueRegionSkia.h

/*
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#ifndef OpaqueRegionSkia_h
#define OpaqueRegionSkia_h

#include "platform/geometry/IntRect.h"

#include "SkBitmap.h"
#include "SkCanvas.h"
#include "SkPaint.h"
#include "SkPoint.h"
#include "SkRect.h"

namespace WebCore {
class GraphicsContext;

// This class is an encapsulation of functionality for GraphicsContext, and its methods are mirrored
// there for the outside world. It tracks paints and computes what area will be opaque.
class OpaqueRegionSkia FINAL {
public:
    OpaqueRegionSkia();

    // The resulting opaque region as a single rect.
    IntRect asRect() const;

    void pushCanvasLayer(const SkPaint*);
    void popCanvasLayer(const GraphicsContext*);

    void setImageMask(const SkRect& imageOpaqueRect);

    enum DrawType {
        FillOnly,
        FillOrStroke
    };

    void didDrawRect(const GraphicsContext*, const SkRect&, const SkPaint&, const SkBitmap* sourceBitmap);
    void didDrawPath(const GraphicsContext*, const SkPath&, const SkPaint&);
    void didDrawPoints(const GraphicsContext*, SkCanvas::PointMode, int numPoints, const SkPoint[], const SkPaint&);
    void didDrawBounded(const GraphicsContext*, const SkRect&, const SkPaint&);
    void didDrawUnbounded(const GraphicsContext*, const SkPaint&, DrawType);

    struct CanvasLayerState {
        CanvasLayerState()
            : hasImageMask(false)
            , opaqueRect(SkRect::MakeEmpty())
        { }

        SkPaint paint;

        // An image mask is being applied to the layer.
        bool hasImageMask;
        // The opaque area in the image mask.
        SkRect imageOpaqueRect;

        SkRect opaqueRect;
    };

private:
    void didDraw(const GraphicsContext*, const SkRect&, const SkPaint&, const SkBitmap* sourceBitmap, bool fillsBounds, DrawType);
    void applyOpaqueRegionFromLayer(const GraphicsContext*, const SkRect& layerOpaqueRect, const SkPaint&);
    void markRectAsOpaque(const SkRect&);
    void markRectAsNonOpaque(const SkRect&);
    void markAllAsNonOpaque();

    SkRect& currentTrackingOpaqueRect();

    SkRect m_opaqueRect;

    Vector<CanvasLayerState, 3> m_canvasLayerStack;
};

}
#endif // OpaqueRegionSkia_h