Changeset 246926 in webkit

Timestamp:

Jun 28, 2019 10:12:27 AM (5 years ago)

Author:

Antti Koivisto

Message:

[iOS Scrolling] Propagate scrolls to non-nested UIScrollViews
​https://bugs.webkit.org/show_bug.cgi?id=199222

Reviewed by Simon Fraser.

We may generate scrolling hierarchies where the scrolling ancestor of a layer is not
an ancestor in the layer tree. We handle this in most situations but there is still
a problem where a scroller fails to propage scroll to the ancestor when it reaches
the edge.

This patch hooks up a new SPI that allows us to tell UIKit about non-ancestor scrolling
relations and solve this problem.

• UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.h:
• UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.mm:

(WebKit::findActingScrollParent):

• UIProcess/RemoteLayerTree/ios/ScrollingTreeScrollingNodeDelegateIOS.h:
• UIProcess/RemoteLayerTree/ios/ScrollingTreeScrollingNodeDelegateIOS.mm:

(-[WKScrollingNodeScrollViewDelegate _actingParentScrollViewForScrollView:]):

Hook into UIKit SPI.

(WebKit::ScrollingTreeScrollingNodeDelegateIOS::findActingScrollParent):

Location:

trunk/Source/WebKit

Files:

• ChangeLog (modified) (1 diff)
• UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.h (modified) (2 diffs)
• UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.mm (modified) (1 diff)
• UIProcess/RemoteLayerTree/ios/ScrollingTreeScrollingNodeDelegateIOS.h (modified) (1 diff)
• UIProcess/RemoteLayerTree/ios/ScrollingTreeScrollingNodeDelegateIOS.mm (modified) (3 diffs)

trunk/Source/WebKit/ChangeLog

@@ +1 @@
+2019-06-28  Antti Koivisto  <antti@apple.com>
+
+        [iOS Scrolling] Propagate scrolls to non-nested UIScrollViews
+        https://bugs.webkit.org/show_bug.cgi?id=199222
+
+        Reviewed by Simon Fraser.
+
+        We may generate scrolling hierarchies where the scrolling ancestor of a layer is not
+        an ancestor in the layer tree. We  handle this in most situations but there is still
+        a problem where a scroller fails to propage scroll to the ancestor when it reaches
+        the edge.
+
+        This patch hooks up a new SPI that allows us to tell UIKit about non-ancestor scrolling
+        relations and solve this problem.
+
+        * UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.h:
+        * UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.mm:
+        (WebKit::findActingScrollParent):
+        * UIProcess/RemoteLayerTree/ios/ScrollingTreeScrollingNodeDelegateIOS.h:
+        * UIProcess/RemoteLayerTree/ios/ScrollingTreeScrollingNodeDelegateIOS.mm:
+        (-[WKScrollingNodeScrollViewDelegate _actingParentScrollViewForScrollView:]):
+
+        Hook into UIKit SPI.
+
+        (WebKit::ScrollingTreeScrollingNodeDelegateIOS::findActingScrollParent):
+
 2019-06-28  Konstantin Tokarev  <annulen@yandex.ru>
 

trunk/Source/WebKit/UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.h

@@ -32 +32 @@
 
 namespace WebKit {
+class RemoteLayerTreeHost;
 class WebPageProxy;
 }
@@ -78 +79 @@
 OptionSet<WebCore::TouchAction> touchActionsForPoint(UIView *rootView, const WebCore::IntPoint&);
 #endif
+UIScrollView *findActingScrollParent(UIScrollView *, const RemoteLayerTreeHost&);
 
 }

trunk/Source/WebKit/UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.mm

@@ -125 +125 @@
 #endif
 
+UIScrollView *findActingScrollParent(UIScrollView *scrollView, const RemoteLayerTreeHost& host)
+{
+    HashSet<WebCore::GraphicsLayer::PlatformLayerID> scrollersToSkip;
+
+    for (UIView *view = [scrollView superview]; view; view = [view superview]) {
+        if ([view isKindOfClass:[WKChildScrollView class]] && !scrollersToSkip.contains(RemoteLayerTreeNode::layerID(view.layer))) {
+            // FIXME: Ideally we would return the scroller we want in all cases but the current UIKit SPI only allows returning a non-ancestor.
+            return nil;
+        }
+
+        if (auto* node = RemoteLayerTreeNode::forCALayer(view.layer)) {
+            switch (node->relatedScrollContainerPositioningBehavior()) {
+            case WebCore::ScrollPositioningBehavior::Moves:
+                if (!node->relatedScrollContainerIDs().isEmpty()) {
+                    if (auto* nonAncestorScrollingNode = host.nodeForID(node->relatedScrollContainerIDs()[0]))
+                        return (WKChildScrollView *)nonAncestorScrollingNode->uiView();
+                }
+                break;
+            case WebCore::ScrollPositioningBehavior::Stationary:
+                scrollersToSkip.add(node->relatedScrollContainerIDs().begin(), node->relatedScrollContainerIDs().end());
+                break;
+            case WebCore::ScrollPositioningBehavior::None:
+                break;
+            }
+        }
+    }
+    return nil;
+}
+
 }
 

trunk/Source/WebKit/UIProcess/RemoteLayerTree/ios/ScrollingTreeScrollingNodeDelegateIOS.h

@@ -74 +74 @@
 #endif
 
+    UIScrollView *findActingScrollParent(UIScrollView *);
+
 private:
     UIScrollView *scrollView() const;

trunk/Source/WebKit/UIProcess/RemoteLayerTree/ios/ScrollingTreeScrollingNodeDelegateIOS.mm

@@ -29 +29 @@
 #if PLATFORM(IOS_FAMILY) && ENABLE(ASYNC_SCROLLING)
 
+#import "RemoteLayerTreeViews.h"
 #import "RemoteScrollingCoordinatorProxy.h"
 #import "RemoteScrollingTree.h"
@@ -60 +61 @@
 
     return self;
+}
+
+- (UIScrollView *)_actingParentScrollViewForScrollView:(UIScrollView *)scrollView
+{
+    // An "acting parent" is a non-ancestor scrolling parent. We tell this to UIKit so it can propagate scrolls correctly.
+    return _scrollingTreeNodeDelegate->findActingScrollParent(scrollView);
 }
 
@@ -339 +346 @@
 }
 
+UIScrollView *ScrollingTreeScrollingNodeDelegateIOS::findActingScrollParent(UIScrollView *scrollView)
+{
+    ASSERT(scrollView == this->scrollView());
+
+    auto& scrollingCoordinatorProxy = downcast<RemoteScrollingTree>(scrollingTree()).scrollingCoordinatorProxy();
+    return WebKit::findActingScrollParent(scrollView, *scrollingCoordinatorProxy.layerTreeHost());
+}
+
 #if ENABLE(POINTER_EVENTS)
 void ScrollingTreeScrollingNodeDelegateIOS::computeActiveTouchActionsForGestureRecognizer(UIGestureRecognizer* gestureRecognizer)