Changeset 294902 in webkit

Timestamp:

May 26, 2022, 3:22:08 PM (4 years ago)

Author:

Alan Bujtas

Message:

Do not issue repaint when the ancestor layer has already been scheduled for one
​https://bugs.webkit.org/show_bug.cgi?id=240728

Reviewed by Simon Fraser.

When a renderer needs repaint, we walk the layer tree to search for the repaint container (root for all the paints).
If we find a layer between the renderer and the repaint container that has already been scheduled for a full repaint
we know that this repaint is redundant and will be covered by the ancestor layer.
Since layers paint their overflow content, this works even when the renderer "sticks out" of the ancestor layer's renderer's border box (i.e. produces ink/scrollable overflow).

• Source/WebCore/rendering/RenderLayer.cpp:

(WebCore::RenderLayer::enclosingCompositingLayerForRepaint const):
(WebCore::RenderLayer::clipCrossesPaintingBoundary const):
(WebCore::RenderLayer::calculateClipRects const):

• Source/WebCore/rendering/RenderLayer.h:

(WebCore::RenderLayer::needsFullRepaint const):

• Source/WebCore/rendering/RenderLayerCompositor.cpp:

(WebCore::RenderLayerCompositor::repaintInCompositedAncestor):

• Source/WebCore/rendering/RenderObject.cpp:

(WebCore::RenderObject::containerForRepaint const):
(WebCore::fullRepaintIsScheduled): This covers the cases when the content is embedded inside an iframe and the iframe's view is not composited.
(WebCore::RenderObject::repaint const):
(WebCore::RenderObject::repaintRectangle const):

• Source/WebCore/rendering/RenderView.cpp:

(WebCore::RenderView::paintBoxDecorations):

Canonical link: ​https://commits.webkit.org/251025@main

Location:

trunk/Source/WebCore/rendering

Files:

• RenderLayer.cpp (modified) (4 diffs)
• RenderLayer.h (modified) (2 diffs)
• RenderLayerCompositor.cpp (modified) (1 diff)
• RenderObject.cpp (modified) (5 diffs)
• RenderView.cpp (modified) (1 diff)

trunk/Source/WebCore/rendering/RenderLayer.cpp

@@ -2025 +2025 @@
 }
 
-RenderLayer* RenderLayer::enclosingCompositingLayerForRepaint(IncludeSelfOrNot includeSelf) const
+RenderLayer::EnclosingCompositingLayerStatus RenderLayer::enclosingCompositingLayerForRepaint(IncludeSelfOrNot includeSelf) const
 {
     auto repaintTargetForLayer = [](const RenderLayer& layer) -> RenderLayer* {
@@ -2036 +2036 @@
         return nullptr;
     };
-
+    auto isEligibleForFullRepaintCheck = [&](const auto& layer) {
+        return layer.isSelfPaintingLayer() && !layer.renderer().hasPotentiallyScrollableOverflow() && !is<RenderView>(layer.renderer());
+    };
+
+    auto fullRepaintAlreadyScheduled = isEligibleForFullRepaintCheck(*this) && needsFullRepaint();
     RenderLayer* repaintTarget = nullptr;
     if (includeSelf == IncludeSelf && (repaintTarget = repaintTargetForLayer(*this)))
-        return repaintTarget;
+        return { fullRepaintAlreadyScheduled, repaintTarget };
 
     for (const RenderLayer* curr = paintOrderParent(); curr; curr = curr->paintOrderParent()) {
+        fullRepaintAlreadyScheduled = fullRepaintAlreadyScheduled || (isEligibleForFullRepaintCheck(*curr) && curr->needsFullRepaint());
         if ((repaintTarget = repaintTargetForLayer(*curr)))
-            return repaintTarget;
+            return { fullRepaintAlreadyScheduled, repaintTarget };
     }
          
-    return nullptr;
+    return { };
 }
 
@@ -4613 +4618 @@
 {
     return parent()->enclosingPaginationLayer(IncludeCompositedPaginatedLayers) != enclosingPaginationLayer(IncludeCompositedPaginatedLayers)
-        || parent()->enclosingCompositingLayerForRepaint() != enclosingCompositingLayerForRepaint();
+        || parent()->enclosingCompositingLayerForRepaint().layer != enclosingCompositingLayerForRepaint().layer;
 }
 
@@ -5812 +5817 @@
 {
 #if ENABLE(ASYNC_SCROLLING)
-    auto* compositingLayer = enclosingCompositingLayerForRepaint();
+    auto* compositingLayer = enclosingCompositingLayerForRepaint().layer;
 
     auto shouldInvalidate = [&] {

trunk/Source/WebCore/rendering/RenderLayer.h

@@ -591 +591 @@
     // Enclosing compositing layer; if includeSelf is true, may return this.
     RenderLayer* enclosingCompositingLayer(IncludeSelfOrNot = IncludeSelf) const;
-    RenderLayer* enclosingCompositingLayerForRepaint(IncludeSelfOrNot = IncludeSelf) const;
+    struct EnclosingCompositingLayerStatus {
+        bool fullRepaintAlreadyScheduled { false };
+        RenderLayer* layer { nullptr };
+    };
+    EnclosingCompositingLayerStatus enclosingCompositingLayerForRepaint(IncludeSelfOrNot = IncludeSelf) const;
     // Ancestor compositing layer, excluding this.
     RenderLayer* ancestorCompositingLayer() const { return enclosingCompositingLayer(ExcludeSelf); }
@@ -722 +726 @@
     void setRepaintStatus(RepaintStatus status) { m_repaintStatus = status; }
     RepaintStatus repaintStatus() const { return static_cast<RepaintStatus>(m_repaintStatus); }
+    bool needsFullRepaint() const { return m_repaintStatus == NeedsFullRepaint || m_repaintStatus == NeedsFullRepaintForPositionedMovementLayout; }
 
     LayoutUnit staticInlinePosition() const { return m_offsetForPosition.width(); }

trunk/Source/WebCore/rendering/RenderLayerCompositor.cpp

@@ -1957 +1957 @@
 void RenderLayerCompositor::repaintInCompositedAncestor(RenderLayer& layer, const LayoutRect& rect)
 {
-    auto* compositedAncestor = layer.enclosingCompositingLayerForRepaint(ExcludeSelf);
+    auto* compositedAncestor = layer.enclosingCompositingLayerForRepaint(ExcludeSelf).layer;
     if (!compositedAncestor)
         return;

trunk/Source/WebCore/rendering/RenderObject.cpp

@@ -861 +861 @@
 {
     RenderLayerModelObject* repaintContainer = nullptr;
+    auto fullRepaintAlreadyScheduled = false;
 
     if (view().usesCompositing()) {
-        if (RenderLayer* parentLayer = enclosingLayer()) {
-            RenderLayer* compLayer = parentLayer->enclosingCompositingLayerForRepaint();
-            if (compLayer)
-                repaintContainer = &compLayer->renderer();
+        if (auto* parentLayer = enclosingLayer()) {
+            auto compLayerStatus = parentLayer->enclosingCompositingLayerForRepaint();
+            if (compLayerStatus.layer) {
+                repaintContainer = &compLayerStatus.layer->renderer();
+                fullRepaintAlreadyScheduled = compLayerStatus.fullRepaintAlreadyScheduled;
+            }
         }
     }
     if (view().hasSoftwareFilters()) {
-        if (RenderLayer* parentLayer = enclosingLayer()) {
-            RenderLayer* enclosingFilterLayer = parentLayer->enclosingFilterLayer();
-            if (enclosingFilterLayer)
-                return { false, &enclosingFilterLayer->renderer() };
+        if (auto* parentLayer = enclosingLayer()) {
+            auto* enclosingFilterLayer = parentLayer->enclosingFilterLayer();
+            if (enclosingFilterLayer) {
+                fullRepaintAlreadyScheduled = parentLayer->needsFullRepaint();
+                return { fullRepaintAlreadyScheduled, &enclosingFilterLayer->renderer() };
+            }
         }
     }
@@ -888 +893 @@
             repaintContainer = parentRenderFragmentedFlow;
     }
-    return { false, repaintContainer };
+    return { fullRepaintAlreadyScheduled, repaintContainer };
 }
 
@@ -962 +967 @@
 }
 
+static inline bool fullRepaintIsScheduled(const RenderObject& renderer)
+{
+    if (!renderer.view().usesCompositing() && !renderer.document().ownerElement())
+        return false;
+    for (auto* ancestorLayer = renderer.enclosingLayer(); ancestorLayer; ancestorLayer = ancestorLayer->paintOrderParent()) {
+        if (ancestorLayer->needsFullRepaint())
+            return true;
+    }
+    return false;
+}
+
 void RenderObject::repaint() const
 {
@@ -973 +989 @@
 
     auto repaintContainer = containerForRepaint();
+    if (!repaintContainer.renderer)
+        repaintContainer = { fullRepaintIsScheduled(*this), &view };
+
     if (!repaintContainer.fullRepaintIsScheduled)
         repaintUsingContainer(repaintContainer.renderer, clippedOverflowRectForRepaint(repaintContainer.renderer));
@@ -993 +1012 @@
 
     auto repaintContainer = containerForRepaint();
+    if (!repaintContainer.renderer)
+        repaintContainer = { fullRepaintIsScheduled(*this), &view };
+
     if (!repaintContainer.fullRepaintIsScheduled)
         repaintUsingContainer(repaintContainer.renderer, computeRectForRepaint(dirtyRect, repaintContainer.renderer), shouldClipToLayer);

trunk/Source/WebCore/rendering/RenderView.cpp

@@ -381 +381 @@
         }
 
-        if (RenderLayer* compositingLayer = layer->enclosingCompositingLayerForRepaint()) {
+        if (auto* compositingLayer = layer->enclosingCompositingLayerForRepaint().layer) {
             if (!compositingLayer->backing()->paintsIntoWindow()) {
                 frameView().setCannotBlitToWindow();