Overlay regions do not correctly handle sticky positioned scrolling n…

…odes

https://bugs.webkit.org/show_bug.cgi?id=243973
<rdar://98640826>

Reviewed by Tim Horton.

Sticky node regions should be added to the overlay regions but their rectangles
can move during scrolling. Also fixed or sticky rectangles can change
during page zoom.

To support this, instead of storing a list of rectangles, store a list of
layer IDs with event regions and then compute the rectangles.

* Source/WebKit/UIProcess/API/ios/WKWebViewIOS.mm:
(addOverlayEventRegions):
Store only the layer ID.

(-[WKWebView _updateOverlayRegions:destroyedLayers:]):
Recompute the rectangles from the current frames of the nodes whenever the layer
properties change. Scrolling and page zoom where this would be impacted both
trigger a change in layer properties.

* Source/WebKit/UIProcess/RemoteLayerTree/RemoteLayerTreeDrawingAreaProxy.h:
Renamed function.

* Source/WebKit/UIProcess/RemoteLayerTree/RemoteLayerTreeHost.h:
(WebKit::RemoteLayerTreeHost::overlayRegionIDs const):
(WebKit::RemoteLayerTreeHost::updateOverlayRegionIDs):
Renamed.

* Source/WebKit/UIProcess/RemoteLayerTree/ios/RemoteScrollingCoordinatorProxyIOS.mm:
(WebKit::RemoteScrollingCoordinatorProxy::connectStateNodeLayers):
Call renamed function.

Canonical link: https://commits.webkit.org/253603@main

Source/WebKit/UIProcess/API/ios/WKWebViewIOS.mm

@@ -1054,7 +1054,7 @@ - (void)_didCommitLayerTree:(const WebKit::RemoteLayerTreeTransaction&)layerTree
 }
 
 #if ENABLE(OVERLAY_REGIONS_IN_EVENT_REGION)
-static void addOverlayEventRegions(WebCore::GraphicsLayer::PlatformLayerID layerID, const WebKit::RemoteLayerTreeTransaction::LayerPropertiesMap& changedLayerPropertiesMap, HashMap<WebCore::GraphicsLayer::PlatformLayerID, CGRect>& overlayRegionsWithIDs, const WebKit::RemoteLayerTreeHost& layerTreeHost, UIView *rootView)
+static void addOverlayEventRegions(WebCore::GraphicsLayer::PlatformLayerID layerID, const WebKit::RemoteLayerTreeTransaction::LayerPropertiesMap& changedLayerPropertiesMap, HashSet<WebCore::GraphicsLayer::PlatformLayerID>& overlayRegionIDs, const WebKit::RemoteLayerTreeHost& layerTreeHost)
 {
     using WebKit::RemoteLayerTreeTransaction;
     const auto& it = changedLayerPropertiesMap.find(layerID);
@@ -1063,13 +1063,11 @@ static void addOverlayEventRegions(WebCore::GraphicsLayer::PlatformLayerID layer
 
     const auto& layerProperties = *it->value;
     CGRect rect = layerProperties.eventRegion.region().bounds();
-    if ((layerProperties.changedProperties & RemoteLayerTreeTransaction::EventRegionChanged) && !CGRectIsEmpty(rect)) {
-        if (const auto* node = layerTreeHost.nodeForID(layerID))
-            overlayRegionsWithIDs.set(layerID, [node->uiView() convertRect:rect toView:rootView]);
-    }
+    if ((layerProperties.changedProperties & RemoteLayerTreeTransaction::EventRegionChanged) && !CGRectIsEmpty(rect))
+        overlayRegionIDs.add(layerID);
 
     for (auto childLayerID : layerProperties.children)
-        addOverlayEventRegions(childLayerID, changedLayerPropertiesMap, overlayRegionsWithIDs, layerTreeHost, rootView);
+        addOverlayEventRegions(childLayerID, changedLayerPropertiesMap, overlayRegionIDs, layerTreeHost);
 }
 
 - (void)_updateOverlayRegions:(const WebKit::RemoteLayerTreeTransaction::LayerPropertiesMap&)changedLayerPropertiesMap destroyedLayers:(const Vector<WebCore::GraphicsLayer::PlatformLayerID>&)destroyedLayers
@@ -1086,19 +1084,21 @@ - (void)_updateOverlayRegions:(const WebKit::RemoteLayerTreeTransaction::LayerPr
     scrollingCoordinatorProxy->removeFixedScrollingNodeLayerIDs(destroyedLayers);
     const auto& fixedIDs = scrollingCoordinatorProxy->fixedScrollingNodeLayerIDs();
 
-    auto overlayRegionsWithIDs = layerTreeHost.overlayRegionsWithIDs();
+    auto overlayRegionIDs = layerTreeHost.overlayRegionIDs();
     for (auto layerID : destroyedLayers)
-        overlayRegionsWithIDs.remove(layerID);
+        overlayRegionIDs.remove(layerID);
 
     for (auto layerID : fixedIDs)
-        addOverlayEventRegions(layerID, changedLayerPropertiesMap, overlayRegionsWithIDs, layerTreeHost, self);
+        addOverlayEventRegions(layerID, changedLayerPropertiesMap, overlayRegionIDs, layerTreeHost);
 
     Vector<CGRect> overlayRegions;
-    for (const auto& [layerID, rect] : overlayRegionsWithIDs)
-        overlayRegions.append(rect);
+    for (const auto layerID : overlayRegionIDs) {
+        if (const auto* node = layerTreeHost.nodeForID(layerID))
+            overlayRegions.append([node->uiView() convertRect:node->eventRegion().region().bounds() toView:self]);
+    }
 
     if ([_scrollView _updateOverlayRegions:overlayRegions])
-        layerTreeProxy.updateOverlayRegionsWithIDs(overlayRegionsWithIDs);
+        layerTreeProxy.updateOverlayRegionIDs(overlayRegionIDs);
 }
 #endif // ENABLE(OVERLAY_REGIONS_IN_EVENT_REGION)
 

Source/WebKit/UIProcess/RemoteLayerTree/RemoteLayerTreeDrawingAreaProxy.h

@@ -61,7 +61,7 @@ class RemoteLayerTreeDrawingAreaProxy final : public DrawingAreaProxy {
     CALayer *layerWithIDForTesting(uint64_t) const;
 
 #if ENABLE(OVERLAY_REGIONS_IN_EVENT_REGION)
-    void updateOverlayRegionsWithIDs(const HashMap<WebCore::GraphicsLayer::PlatformLayerID, CGRect> &overlayRegions) { m_remoteLayerTreeHost->updateOverlayRegionsWithIDs(overlayRegions); }
+    void updateOverlayRegionIDs(const HashSet<WebCore::GraphicsLayer::PlatformLayerID> &overlayRegionIDs) { m_remoteLayerTreeHost->updateOverlayRegionIDs(overlayRegionIDs); }
 #endif
 
 private:

Source/WebKit/UIProcess/RemoteLayerTree/RemoteLayerTreeHost.h

@@ -77,8 +77,8 @@ class RemoteLayerTreeHost {
 
     bool replayCGDisplayListsIntoBackingStore() const;
 #if ENABLE(OVERLAY_REGIONS_IN_EVENT_REGION)
-    const HashMap<WebCore::GraphicsLayer::PlatformLayerID, CGRect>& overlayRegionsWithIDs() const { return m_overlayRegionsWithIDs; }
-    void updateOverlayRegionsWithIDs(const HashMap<WebCore::GraphicsLayer::PlatformLayerID, CGRect> &overlayRegions) { m_overlayRegionsWithIDs = overlayRegions; }
+    const HashSet<WebCore::GraphicsLayer::PlatformLayerID>& overlayRegionIDs() const { return m_overlayRegionIDs; }
+    void updateOverlayRegionIDs(const HashSet<WebCore::GraphicsLayer::PlatformLayerID> &overlayRegionNodes) { m_overlayRegionIDs = overlayRegionNodes; }
 #endif
 
 private:
@@ -94,7 +94,7 @@ class RemoteLayerTreeHost {
     HashMap<WebCore::GraphicsLayer::PlatformLayerID, std::unique_ptr<RemoteLayerTreeNode>> m_nodes;
     HashMap<WebCore::GraphicsLayer::PlatformLayerID, RetainPtr<WKAnimationDelegate>> m_animationDelegates;
 #if ENABLE(OVERLAY_REGIONS_IN_EVENT_REGION)
-    HashMap<WebCore::GraphicsLayer::PlatformLayerID, CGRect> m_overlayRegionsWithIDs;
+    HashSet<WebCore::GraphicsLayer::PlatformLayerID> m_overlayRegionIDs;
 #endif
     bool m_isDebugLayerTreeHost { false };
 };

Source/WebKit/UIProcess/RemoteLayerTree/ios/RemoteScrollingCoordinatorProxyIOS.mm

@@ -89,7 +89,7 @@
             auto platformLayerID = PlatformLayerID { currNode->layer() };
             currNode->setLayer(layerTreeHost.layerForID(platformLayerID));
 #if ENABLE(OVERLAY_REGIONS_IN_EVENT_REGION)
-            if (platformLayerID && currNode->isFixedNode())
+            if (platformLayerID && (currNode->isFixedNode() || currNode->isStickyNode()))
                 m_fixedScrollingNodeLayerIDs.add(platformLayerID);
 #endif
         }