Source/WebCore/rendering/ClipPathPaintScope.h

/*
 * Copyright (C) 2026 Igalia S.L.
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 * Redistribution and use in source and binary forms, with or without
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 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
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#pragma once

#include "GraphicsContext.h"
#include "LayoutRect.h"
#include "RegionContext.h"
#include "RenderLayerModelObject.h"
#include "RenderStyleConstants.h"
#include "StylePathOperationWrappers.h"

namespace WebCore {

class LegacyRenderSVGResourceClipper;
class RenderSVGResourceClipper;

// Applies a clip-path to a renderer and keeps it active for the scope's lifetime. Handles CSS
// basic-shape and box clip-paths and SVG clipper resources, so it works for both CSS boxes and SVG.
// Used by the layer paint path (RenderLayer::setupClipPath) and the SVG non-layer path
// (SVGNonLayerClippingAndMaskingScope).
//
// needsMaskClipping() is true when the clip can't be a path and the caller must paint the clipper as a
// destination-in mask, using the layer's transparency layer on the layer path and its own otherwise.
class ClipPathPaintScope {
    WTF_MAKE_NONCOPYABLE(ClipPathPaintScope);
public:
    // Where the CTM sits when the clip is applied, which sets how the clip origin is computed:
    //   LayerPaint    - CTM is at the renderer (the layer transform already placed it).
    //   NonLayerPaint - CTM is at the renderer's container, so the clip origin also adds the
    //                   renderer's currentSVGLayoutLocation. Used by the SVG non-layer paint path.
    enum class CoordinateMode : bool {
        LayerPaint,
        NonLayerPaint
    };

    ClipPathPaintScope(GraphicsContext&, RegionContext*, RenderLayerModelObject&, const LayoutSize& offsetFromRoot, const LayoutSize& subpixelOffset, const LayoutRect& clippedContentBounds, bool isCollectingEventRegion, CoordinateMode);

    bool needsMaskClipping() const { return m_needsMaskClipping; }

    static std::pair<Path, WindRule> computeClipPath(const RenderLayerModelObject&, const LayoutSize& offsetFromRoot, const LayoutRect& rootRelativeBoundsForNonBoxes);
    static FloatRect referenceBoxRectForClipPath(const RenderLayerModelObject&, CSSBoxType, const LayoutSize& offsetFromRoot, const LayoutRect& rootRelativeBounds);

private:
    // Applies one kind of clip-path. The constructor picks which based on the renderer's clip-path.
    void applyBasicShapeOrBoxClip(GraphicsContext&, RenderLayerModelObject&, const LayoutSize& offsetFromRoot, const LayoutSize& subpixelOffset, const LayoutRect& clippedContentBounds, bool isCollectingEventRegion, CoordinateMode);
    void applySVGResourceClip(GraphicsContext&, RenderLayerModelObject&, RenderSVGResourceClipper&, const LayoutSize& offsetFromRoot, const LayoutSize& subpixelOffset, const LayoutRect& clippedContentBounds, CoordinateMode);
    void applyLegacySVGResourceClip(GraphicsContext&, RenderLayerModelObject&, LegacyRenderSVGResourceClipper&, const LayoutSize& offsetFromRoot, const LayoutRect& clippedContentBounds);

    GraphicsContextStateSaver m_clipSaver;
    RegionContextStateSaver m_regionSaver;
    bool m_needsMaskClipping : 1 { false };
};

} // namespace WebCore