[iOS] position:fixed inside touch-scrollable overflow is mispositioned

[WebKit-https.git] / Source / WebCore / rendering / RenderLayerBacking.cpp

diff --git a/Source/WebCore/rendering/RenderLayerBacking.cpp b/Source/WebCore/rendering/RenderLayerBacking.cpp
index cd20d44..afcfdd7 100644 (file)
--- a/Source/WebCore/rendering/RenderLayerBacking.cpp
+++ b/Source/WebCore/rendering/RenderLayerBacking.cpp
@@ -813,12 +813,11 @@ LayoutRect RenderLayerBacking::computeParentGraphicsLayerRect(RenderLayer* compo
 
 #if PLATFORM(IOS)
     if (compositedAncestor->hasTouchScrollableOverflow()) {
+        LayoutRect ancestorCompositedBounds = ancestorBackingLayer->compositedBounds();
         auto& renderBox = downcast<RenderBox>(compositedAncestor->renderer());
-        LayoutRect paddingBox(renderBox.borderLeft(), renderBox.borderTop(),
-            renderBox.width() - renderBox.borderLeft() - renderBox.borderRight(),
-            renderBox.height() - renderBox.borderTop() - renderBox.borderBottom());
+        LayoutRect paddingBox(renderBox.borderLeft(), renderBox.borderTop(), renderBox.width() - renderBox.borderLeft() - renderBox.borderRight(), renderBox.height() - renderBox.borderTop() - renderBox.borderBottom());
         ScrollOffset scrollOffset = compositedAncestor->scrollOffset();
-        parentGraphicsLayerRect = LayoutRect((paddingBox.location() - toLayoutSize(scrollOffset)), paddingBox.size());
+        parentGraphicsLayerRect = LayoutRect((paddingBox.location() - toLayoutSize(ancestorCompositedBounds.location()) - toLayoutSize(scrollOffset)), paddingBox.size());
     }
 #else
     if (compositedAncestor->needsCompositedScrolling()) {