[Filters] GraphicsContext filters have to apply clipping to the targe…

…t context before drawing https://bugs.webkit.org/show_bug.cgi?id=266383 rdar://118522654 Reviewed by Simon Fraser. Before applying the filter style and calling `beginTransparencyLayer()`, the clipping rectangle of the target element has to be applied to the destination GraphicsContext. Otherwise the hidden overflow drawing will appear once the `endTransparencyLayer()` is called. RenderLayer::paintLayerContents() needs to calculate the clipping rectangle before calling setupFilters() so it can be passed to FilterStyleTargetSwitcher. beginClipAndDrawSourceImage() and endClipAndDrawSourceImage() will be called when applying CSSFilter. beginDrawSourceImage() and endDrawSourceImage() will be called when applying the top-level SVGFilter since we clip to the bounding rectangle of the root element. * LayoutTests/css3/filters/drop-shadow-filter-overflow-expected.html: Added. * LayoutTests/css3/filters/drop-shadow-filter-overflow.html: Added. * Source/WebCore/platform/graphics/filters/FilterImageTargetSwitcher.cpp: (WebCore::FilterImageTargetSwitcher::beginClipAndDrawSourceImage): * Source/WebCore/platform/graphics/filters/FilterImageTargetSwitcher.h: * Source/WebCore/platform/graphics/filters/FilterStyleTargetSwitcher.cpp: (WebCore::FilterStyleTargetSwitcher::beginClipAndDrawSourceImage): * Source/WebCore/platform/graphics/filters/FilterStyleTargetSwitcher.h: * Source/WebCore/platform/graphics/filters/FilterTargetSwitcher.h: (WebCore::FilterTargetSwitcher::beginClipAndDrawSourceImage): Deleted. (WebCore::FilterTargetSwitcher::endClipAndDrawSourceImage): Deleted. (WebCore::FilterTargetSwitcher::beginDrawSourceImage): Deleted. (WebCore::FilterTargetSwitcher::endDrawSourceImage): Deleted. * Source/WebCore/rendering/RenderLayer.cpp: (WebCore::RenderLayer::setupFilters): (WebCore::RenderLayer::applyFilters): (WebCore::RenderLayer::paintLayerContents): * Source/WebCore/rendering/RenderLayer.h: * Source/WebCore/rendering/RenderLayerFilters.cpp: (WebCore::RenderLayerFilters::beginFilterEffect): * Source/WebCore/rendering/RenderLayerFilters.h: Canonical link: https://commits.webkit.org/272078@main
WebKit · Dec 14, 2023 · ddf4bec · ddf4bec
1 parent c553c8e
commit ddf4bec
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Showing 11 changed files with 97 additions and 30 deletions.
diff --git a/LayoutTests/css3/filters/drop-shadow-filter-overflow-expected.html b/LayoutTests/css3/filters/drop-shadow-filter-overflow-expected.html
@@ -0,0 +1,24 @@
+<style>
+    .container {
+        position: absolute;
+        left: 10px;
+        top: 10px;
+        height: 200px;
+        width: 200px;
+        overflow: hidden;
+        border: 1px green solid;
+    }
+    .box {
+        position: absolute;
+        left: 100px;
+        top: 150px;
+        width: 100px;
+        height: 100px;
+        background: green;
+    }
+</style>
+<body>
+    <div class="container">
+        <div class="box"></div>
+    </div>
+</body>
diff --git a/LayoutTests/css3/filters/drop-shadow-filter-overflow.html b/LayoutTests/css3/filters/drop-shadow-filter-overflow.html
@@ -0,0 +1,25 @@
+<style>
+    .container {
+        position: absolute;
+        left: 10px;
+        top: 10px;
+        height: 200px;
+        width: 200px;
+        overflow: hidden;
+        border: 1px green solid;
+    }
+    .box {
+        position: absolute;
+        left: 100px;
+        top: 150px;
+        width: 100px;
+        height: 100px;
+        background: green;
+        filter: drop-shadow(black 10px 10px 0px);
+    }
+</style>
+<body>
+    <div class="container">
+        <div class="box"></div>
+    </div>
+</body>
diff --git a/Source/WebCore/platform/graphics/filters/FilterImageTargetSwitcher.cpp b/Source/WebCore/platform/graphics/filters/FilterImageTargetSwitcher.cpp
@@ -56,7 +56,7 @@ GraphicsContext* FilterImageTargetSwitcher::drawingContext(GraphicsContext& cont
     return m_sourceImage ? &m_sourceImage->context() : &context;
 }
 
-void FilterImageTargetSwitcher::beginClipAndDrawSourceImage(GraphicsContext& destinationContext, const FloatRect& repaintRect)
+void FilterImageTargetSwitcher::beginClipAndDrawSourceImage(GraphicsContext& destinationContext, const FloatRect& repaintRect, const FloatRect&)
 {
     if (auto* context = drawingContext(destinationContext)) {
         context->save();

diff --git a/Source/WebCore/platform/graphics/filters/FilterImageTargetSwitcher.h b/Source/WebCore/platform/graphics/filters/FilterImageTargetSwitcher.h
@@ -41,8 +41,10 @@ class FilterImageTargetSwitcher final : public FilterTargetSwitcher {
 
     bool hasSourceImage() const override { return m_sourceImage; }
 
-    void beginClipAndDrawSourceImage(GraphicsContext& destinationContext, const FloatRect& repaintRect) override;
+    void beginClipAndDrawSourceImage(GraphicsContext& destinationContext, const FloatRect& repaintRect, const FloatRect& clipRect) override;
     void endClipAndDrawSourceImage(GraphicsContext& destinationContext) override;
+
+    void beginDrawSourceImage(GraphicsContext&) override { }
     void endDrawSourceImage(GraphicsContext& destinationContext) override;
 
     RefPtr<ImageBuffer> m_sourceImage;

diff --git a/Source/WebCore/platform/graphics/filters/FilterStyleTargetSwitcher.cpp b/Source/WebCore/platform/graphics/filters/FilterStyleTargetSwitcher.cpp
@@ -37,6 +37,16 @@ FilterStyleTargetSwitcher::FilterStyleTargetSwitcher(Filter& filter, const Float
 {
 }
 
+void FilterStyleTargetSwitcher::beginClipAndDrawSourceImage(GraphicsContext& destinationContext, const FloatRect&, const FloatRect& clipRect)
+{
+    for (auto& filterStyle : m_filterStyles) {
+        destinationContext.save();
+        destinationContext.clip(intersection(filterStyle.imageRect, clipRect));
+        destinationContext.setStyle(filterStyle.style);
+        destinationContext.beginTransparencyLayer(1);
+    }
+}
+
 void FilterStyleTargetSwitcher::beginDrawSourceImage(GraphicsContext& destinationContext)
 {
     for (auto& filterStyle : m_filterStyles) {

diff --git a/Source/WebCore/platform/graphics/filters/FilterStyleTargetSwitcher.h b/Source/WebCore/platform/graphics/filters/FilterStyleTargetSwitcher.h
@@ -36,6 +36,9 @@ class FilterStyleTargetSwitcher : public FilterTargetSwitcher {
     FilterStyleTargetSwitcher(Filter&, const FloatRect &sourceImageRect);
 
 private:
+    void beginClipAndDrawSourceImage(GraphicsContext& destinationContext, const FloatRect& repaintRect, const FloatRect& clipRect) override;
+    void endClipAndDrawSourceImage(GraphicsContext& destinationContext) override { endDrawSourceImage(destinationContext); }
+
     void beginDrawSourceImage(GraphicsContext& destinationContext) override;
     void endDrawSourceImage(GraphicsContext& destinationContext) override;
 

diff --git a/Source/WebCore/platform/graphics/filters/FilterTargetSwitcher.h b/Source/WebCore/platform/graphics/filters/FilterTargetSwitcher.h
@@ -46,11 +46,11 @@ class FilterTargetSwitcher {
 
     virtual bool hasSourceImage() const { return false; }
 
-    virtual void beginClipAndDrawSourceImage(GraphicsContext& destinationContext, const FloatRect&) { beginDrawSourceImage(destinationContext); }
-    virtual void endClipAndDrawSourceImage(GraphicsContext& destinationContext) { endDrawSourceImage(destinationContext); }
+    virtual void beginClipAndDrawSourceImage(GraphicsContext& destinationContext, const FloatRect& repaintRect, const FloatRect& clipRect) = 0;
+    virtual void endClipAndDrawSourceImage(GraphicsContext& destinationContext) = 0;
 
-    virtual void beginDrawSourceImage(GraphicsContext&) { }
-    virtual void endDrawSourceImage(GraphicsContext&) { }
+    virtual void beginDrawSourceImage(GraphicsContext& destinationContext) = 0;
+    virtual void endDrawSourceImage(GraphicsContext& destinationContext) = 0;
 
 protected:
     FilterTargetSwitcher(Filter&);

diff --git a/Source/WebCore/rendering/RenderLayer.cpp b/Source/WebCore/rendering/RenderLayer.cpp
@@ -3209,7 +3209,7 @@ RenderLayerFilters* RenderLayer::filtersForPainting(GraphicsContext& context, Op
     return nullptr;
 }
 
-GraphicsContext* RenderLayer::setupFilters(GraphicsContext& destinationContext, LayerPaintingInfo& paintingInfo, OptionSet<PaintLayerFlag> paintFlags, const LayoutSize& offsetFromRoot)
+GraphicsContext* RenderLayer::setupFilters(GraphicsContext& destinationContext, LayerPaintingInfo& paintingInfo, OptionSet<PaintLayerFlag> paintFlags, const LayoutSize& offsetFromRoot, const ClipRect& backgroundRect)
 {
     auto* paintingFilters = filtersForPainting(destinationContext, paintFlags);
     if (!paintingFilters)
@@ -3220,7 +3220,7 @@ GraphicsContext* RenderLayer::setupFilters(GraphicsContext& destinationContext,
 
     auto rootRelativeBounds = calculateLayerBounds(paintingInfo.rootLayer, offsetFromRoot, { });
 
-    GraphicsContext* filterContext = paintingFilters->beginFilterEffect(renderer(), destinationContext, enclosingIntRect(rootRelativeBounds), enclosingIntRect(paintingInfo.paintDirtyRect), enclosingIntRect(filterRepaintRect));
+    GraphicsContext* filterContext = paintingFilters->beginFilterEffect(renderer(), destinationContext, enclosingIntRect(rootRelativeBounds), enclosingIntRect(paintingInfo.paintDirtyRect), enclosingIntRect(filterRepaintRect), backgroundRect.rect());
     if (!filterContext)
         return nullptr;
 
@@ -3236,15 +3236,12 @@ GraphicsContext* RenderLayer::setupFilters(GraphicsContext& destinationContext,
     return filterContext;
 }
 
-void RenderLayer::applyFilters(GraphicsContext& originalContext, const LayerPaintingInfo& paintingInfo, OptionSet<PaintBehavior> behavior, const LayerFragments& layerFragments)
+void RenderLayer::applyFilters(GraphicsContext& originalContext, const LayerPaintingInfo& paintingInfo, OptionSet<PaintBehavior> behavior, const ClipRect& backgroundRect)
 {
     GraphicsContextStateSaver stateSaver(originalContext, false);
     bool needsClipping = m_filters->hasSourceImage();
 
     if (needsClipping) {
-        // FIXME: Handle more than one fragment.
-        ClipRect backgroundRect = layerFragments.isEmpty() ? ClipRect() : layerFragments[0].backgroundRect;
-
         RegionContextStateSaver regionContextStateSaver(paintingInfo.regionContext);
 
         clipToRect(originalContext, stateSaver, regionContextStateSaver, paintingInfo, behavior, backgroundRect);
@@ -3382,8 +3379,24 @@ void RenderLayer::paintLayerContents(GraphicsContext& context, const LayerPainti
     }();
 
     { // Scope for filter-related state changes.
+        ClipRect backgroundRect;
+
+        if (filtersForPainting(context, paintFlags)) {
+            // When we called collectFragments() last time, paintDirtyRect was reset to represent the filter bounds.
+            // Now we need to compute the backgroundRect uncontaminated by filters, in order to clip the filtered result.
+            // Note that we also use paintingInfo here, not localPaintingInfo which filters also contaminated.
+            LayerFragments layerFragments;
+            auto clipRectOptions = isPaintingOverflowContents ? clipRectOptionsForPaintingOverflowControls : clipRectDefaultOptions;
+            collectFragments(layerFragments, paintingInfo.rootLayer, paintingInfo.paintDirtyRect, ExcludeCompositedPaginatedLayers,
+                (localPaintFlags & PaintLayerFlag::TemporaryClipRects) ? TemporaryClipRects : PaintingClipRects, clipRectOptions, offsetFromRoot);
+            updatePaintingInfoForFragments(layerFragments, paintingInfo, localPaintFlags, shouldPaintContent, offsetFromRoot);
+
+            // FIXME: Handle more than one fragment.
+            backgroundRect = layerFragments.isEmpty() ? ClipRect() : layerFragments[0].backgroundRect;
+        }
+
         LayerPaintingInfo localPaintingInfo(paintingInfo);
-        GraphicsContext* filterContext = setupFilters(context, localPaintingInfo, paintFlags, columnAwareOffsetFromRoot);
+        GraphicsContext* filterContext = setupFilters(context, localPaintingInfo, paintFlags, columnAwareOffsetFromRoot, backgroundRect);
         if (filterContext && haveTransparency) {
             // If we have a filter and transparency, we have to eagerly start a transparency layer here, rather than risk a child layer lazily starts one with the wrong context.
             beginTransparencyLayers(context, localPaintingInfo, paintingInfo.paintDirtyRect);
@@ -3461,18 +3474,8 @@ void RenderLayer::paintLayerContents(GraphicsContext& context, const LayerPainti
                 paintOverflowControlsForFragments(layerFragments, currentContext, localPaintingInfo);
         }
 
-        if (filterContext) {
-            // When we called collectFragments() last time, paintDirtyRect was reset to represent the filter bounds.
-            // Now we need to compute the backgroundRect uncontaminated by filters, in order to clip the filtered result.
-            // Note that we also use paintingInfo here, not localPaintingInfo which filters also contaminated.
-            LayerFragments layerFragments;
-            auto clipRectOptions = isPaintingOverflowContents ? clipRectOptionsForPaintingOverflowControls : clipRectDefaultOptions;
-            collectFragments(layerFragments, paintingInfo.rootLayer, paintingInfo.paintDirtyRect, ExcludeCompositedPaginatedLayers,
-                (localPaintFlags & PaintLayerFlag::TemporaryClipRects) ? TemporaryClipRects : PaintingClipRects, clipRectOptions, offsetFromRoot);
-            updatePaintingInfoForFragments(layerFragments, paintingInfo, localPaintFlags, shouldPaintContent, offsetFromRoot);
-
-            applyFilters(context, paintingInfo, paintBehavior, layerFragments);
-        }
+        if (filterContext)
+            applyFilters(context, paintingInfo, paintBehavior, backgroundRect);
     }
 
     if (shouldPaintContent && !(selectionOnly || selectionAndBackgroundsOnly)) {

diff --git a/Source/WebCore/rendering/RenderLayer.h b/Source/WebCore/rendering/RenderLayer.h
@@ -1106,8 +1106,8 @@ class RenderLayer : public CanMakeSingleThreadWeakPtr<RenderLayer>, public CanMa
     void clearLayerScrollableArea();
 
     RenderLayerFilters* filtersForPainting(GraphicsContext&, OptionSet<PaintLayerFlag>) const;
-    GraphicsContext* setupFilters(GraphicsContext& destinationContext, LayerPaintingInfo&, OptionSet<PaintLayerFlag>, const LayoutSize& offsetFromRoot);
-    void applyFilters(GraphicsContext& originalContext, const LayerPaintingInfo&, OptionSet<PaintBehavior>, const LayerFragments&);
+    GraphicsContext* setupFilters(GraphicsContext& destinationContext, LayerPaintingInfo&, OptionSet<PaintLayerFlag>, const LayoutSize& offsetFromRoot, const ClipRect& backgroundRect);
+    void applyFilters(GraphicsContext& originalContext, const LayerPaintingInfo&, OptionSet<PaintBehavior>, const ClipRect& backgroundRect);
 
     void paintLayer(GraphicsContext&, const LayerPaintingInfo&, OptionSet<PaintLayerFlag>);
     void paintLayerWithEffects(GraphicsContext&, const LayerPaintingInfo&, OptionSet<PaintLayerFlag>);

diff --git a/Source/WebCore/rendering/RenderLayerFilters.cpp b/Source/WebCore/rendering/RenderLayerFilters.cpp
@@ -134,7 +134,7 @@ IntOutsets RenderLayerFilters::calculateOutsets(RenderElement& renderer, const F
     return CSSFilter::calculateOutsets(renderer, operations, targetBoundingBox);
 }
 
-GraphicsContext* RenderLayerFilters::beginFilterEffect(RenderElement& renderer, GraphicsContext& context, const LayoutRect& filterBoxRect, const LayoutRect& dirtyRect, const LayoutRect& layerRepaintRect)
+GraphicsContext* RenderLayerFilters::beginFilterEffect(RenderElement& renderer, GraphicsContext& context, const LayoutRect& filterBoxRect, const LayoutRect& dirtyRect, const LayoutRect& layerRepaintRect, const LayoutRect& clipRect)
 {
     auto expandedDirtyRect = dirtyRect;
     auto targetBoundingBox = intersection(filterBoxRect, dirtyRect);
@@ -195,7 +195,7 @@ GraphicsContext* RenderLayerFilters::beginFilterEffect(RenderElement& renderer,
     if (!m_targetSwitcher)
         return nullptr;
 
-    m_targetSwitcher->beginClipAndDrawSourceImage(context, m_repaintRect);
+    m_targetSwitcher->beginClipAndDrawSourceImage(context, m_repaintRect, clipRect);
 
     return m_targetSwitcher->drawingContext(context);
 }

diff --git a/Source/WebCore/rendering/RenderLayerFilters.h b/Source/WebCore/rendering/RenderLayerFilters.h
@@ -70,7 +70,7 @@ class RenderLayerFilters final : private CachedSVGDocumentClient {
     // Per render
     LayoutRect repaintRect() const { return m_repaintRect; }
 
-    GraphicsContext* beginFilterEffect(RenderElement&, GraphicsContext&, const LayoutRect& filterBoxRect, const LayoutRect& dirtyRect, const LayoutRect& layerRepaintRect);
+    GraphicsContext* beginFilterEffect(RenderElement&, GraphicsContext&, const LayoutRect& filterBoxRect, const LayoutRect& dirtyRect, const LayoutRect& layerRepaintRect, const LayoutRect& clipRect);
     void applyFilterEffect(GraphicsContext& destinationContext);
 
 private: