[scroll-anchoring] Implement scroll anchoring for subscrollers

https://bugs.webkit.org/show_bug.cgi?id=261775 rdar://115746157 Reviewed by Simon Fraser. Implement scroll anchoring for subscrollers. * Source/WebCore/dom/Document.cpp: (WebCore::Document::runScrollSteps): * Source/WebCore/page/LocalFrameView.cpp: (WebCore::LocalFrameView::LocalFrameView): (WebCore::LocalFrameView::scrollPositionChanged): (WebCore::LocalFrameView::updateScrollAnchoringElementsForScrollableAreas): (WebCore::LocalFrameView::invalidateScrollAnchoringElement): Deleted. (WebCore::LocalFrameView::updateScrollAnchoringElement): Deleted. (WebCore::LocalFrameView::updateScrollPositionForScrollAnchoringController): Deleted. * Source/WebCore/page/LocalFrameView.h: * Source/WebCore/page/scrolling/ScrollAnchoringController.cpp: (WebCore::ScrollAnchoringController::ScrollAnchoringController): (WebCore::ScrollAnchoringController::invalidateAnchorElement): (WebCore::ScrollAnchoringController::updateAnchorElement): (WebCore::ScrollAnchoringController::adjustScrollPositionForAnchoring): * Source/WebCore/page/scrolling/ScrollAnchoringController.h: * Source/WebCore/platform/ScrollableArea.cpp: (WebCore::ScrollableArea::setScrollAnchoringController): (WebCore::ScrollableArea::scrollAnchoringController): (WebCore::ScrollableArea::scrollPositionChanged): (WebCore::ScrollableArea::updateScrollAnchoringElement): (WebCore::ScrollableArea::updateScrollPositionForScrollAnchoringController): (WebCore::ScrollableArea::invalidateScrollAnchoringElement): * Source/WebCore/platform/ScrollableArea.h: (WebCore::ScrollableArea::updateScrollAnchoringElement): Deleted. (WebCore::ScrollableArea::updateScrollPositionForScrollAnchoringController): Deleted. * Source/WebCore/rendering/RenderLayerScrollableArea.cpp: (WebCore::RenderLayerScrollableArea::RenderLayerScrollableArea): Canonical link: https://commits.webkit.org/268848@main
WebKit · Oct 4, 2023 · a886605 · a886605
1 parent d3044ed
commit a886605
Show file tree

Hide file tree

Showing 29 changed files with 181 additions and 90 deletions.
diff --git a/LayoutTests/TestExpectations b/LayoutTests/TestExpectations
@@ -5432,6 +5432,8 @@ security/contentSecurityPolicy/plugins-types-blocks-youtube-plugin-replacement.h
 userscripts/user-script-plugin-document.html [ Skip ]
 
 webkit.org/b/242983 imported/w3c/web-platform-tests/css/css-scroll-anchoring/fullscreen-crash.html [ Skip ]
+webkit.org/b/261849 imported/w3c/web-platform-tests/css/css-scroll-anchoring/heuristic-with-offset-update-from-scroll-event-listener.html [ Skip ]
+webkit.org/b/261849  imported/w3c/web-platform-tests/css/css-scroll-anchoring/zero-scroll-offset.html [ Skip ]
 
 # These tests are image failures
 imported/w3c/web-platform-tests/css/css-scroll-anchoring/vertical-rl-viewport-size-change-000.html [ Skip ]

diff --git a/LayoutTests/accessibility/scroll-to-global-point-iframe-nested.html b/LayoutTests/accessibility/scroll-to-global-point-iframe-nested.html
@@ -1,4 +1,4 @@
-<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
+<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN"><!-- webkit-test-runner [ CSSScrollAnchoringEnabled=false ] -->
 <html>
 <head>
 <script src="../resources/accessibility-helper.js"></script>

diff --git a/LayoutTests/accessibility/scroll-to-global-point-nested.html b/LayoutTests/accessibility/scroll-to-global-point-nested.html
@@ -1,4 +1,4 @@
-<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
+<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN"><!-- webkit-test-runner [ CSSScrollAnchoringEnabled=false ] -->
 <html>
 <head>
 <script src="../resources/accessibility-helper.js"></script>

diff --git a/LayoutTests/fast/scrolling/ios/adjust-scroll-snap-during-gesture.html b/LayoutTests/fast/scrolling/ios/adjust-scroll-snap-during-gesture.html
@@ -1,4 +1,4 @@
-<!DOCTYPE html> <!-- webkit-test-runner [ AsyncOverflowScrollingEnabled=true ] -->
+<!DOCTYPE html> <!-- webkit-test-runner [ AsyncOverflowScrollingEnabled=true CSSScrollAnchoringEnabled=false ] -->
 <html>
 <head>
     <style>

diff --git a/LayoutTests/fast/scrolling/ios/mixing-user-and-programmatic-scroll-002.html b/LayoutTests/fast/scrolling/ios/mixing-user-and-programmatic-scroll-002.html
@@ -1,4 +1,4 @@
-<!DOCTYPE html>
+<!DOCTYPE html><!-- webkit-test-runner [ CSSScrollAnchoringEnabled=false ] -->
 <html>
   <head>
     <title>Mixing user and programmatic scroll of iframe</title>

diff --git a/LayoutTests/fast/scrolling/ios/mixing-user-and-programmatic-scroll-003.html b/LayoutTests/fast/scrolling/ios/mixing-user-and-programmatic-scroll-003.html
@@ -1,4 +1,4 @@
-<!DOCTYPE html>
+<!DOCTYPE html><!-- webkit-test-runner [ CSSScrollAnchoringEnabled=false ] -->
 <html>
   <head>
     <title>Mixing user and programmatic scroll of iframe</title>

diff --git a/LayoutTests/fast/scrolling/ios/mixing-user-and-programmatic-scroll-006.html b/LayoutTests/fast/scrolling/ios/mixing-user-and-programmatic-scroll-006.html
@@ -1,4 +1,4 @@
-<!DOCTYPE html>
+<!DOCTYPE html><!-- webkit-test-runner [ CSSScrollAnchoringEnabled=false ] -->
 <html>
   <head>
     <title>Mixing user and programmatic scroll of iframe</title>

diff --git a/LayoutTests/fast/scrolling/ios/scroll-iframe-001.html b/LayoutTests/fast/scrolling/ios/scroll-iframe-001.html
@@ -1,4 +1,4 @@
-<!DOCTYPE html>
+<!DOCTYPE html><!-- webkit-test-runner [ CSSScrollAnchoringEnabled=false ] -->
 <html>
   <head>
     <title>Scrolling of iframe</title>

diff --git a/LayoutTests/fast/scrolling/ios/scroll-iframe-002.html b/LayoutTests/fast/scrolling/ios/scroll-iframe-002.html
@@ -1,4 +1,4 @@
-<!DOCTYPE html>
+<!DOCTYPE html><!-- webkit-test-runner [ CSSScrollAnchoringEnabled=false ] -->
 <html>
   <head>
     <title>Scrolling of iframe</title>

diff --git a/LayoutTests/fast/scrolling/ios/scroll-iframe-003.html b/LayoutTests/fast/scrolling/ios/scroll-iframe-003.html
@@ -1,4 +1,4 @@
-<!DOCTYPE html>
+<!DOCTYPE html><!-- webkit-test-runner [ CSSScrollAnchoringEnabled=false ] -->
 <html>
   <head>
     <title>Scrolling of iframe</title>

diff --git a/LayoutTests/fast/scrolling/mac/adjust-scroll-snap-during-gesture.html b/LayoutTests/fast/scrolling/mac/adjust-scroll-snap-during-gesture.html
@@ -1,4 +1,4 @@
-<!DOCTYPE html> <!-- webkit-test-runner [ AsyncOverflowScrollingEnabled=true ] -->
+<!DOCTYPE html> <!-- webkit-test-runner [ AsyncOverflowScrollingEnabled=true CSSScrollAnchoringEnabled=false ] -->
 <html>
 <head>
     <style>

diff --git a/...ed/w3c/web-platform-tests/css/css-scroll-anchoring/ancestor-change-heuristic-expected.txt b/...ed/w3c/web-platform-tests/css/css-scroll-anchoring/ancestor-change-heuristic-expected.txt
@@ -1,4 +1,4 @@
 
 FAIL Ancestor changes in document scroller. assert_equals: expected 150 but got 220
-FAIL Ancestor changes in scrollable <div>. assert_equals: expected 200 but got 150
+FAIL Ancestor changes in scrollable <div>. assert_equals: expected 150 but got 220
 
diff --git a/...platform-tests/css/css-scroll-anchoring/anchor-updates-after-explicit-scroll-expected.txt b/...platform-tests/css/css-scroll-anchoring/anchor-updates-after-explicit-scroll-expected.txt
@@ -1,3 +1,3 @@
 
-FAIL Anchor node recomputed after an explicit scroll occurs. assert_equals: expected 600 but got 500
+FAIL Anchor node recomputed after an explicit scroll occurs. assert_equals: expected 200 but got 100
 
diff --git a/...w3c/web-platform-tests/css/css-scroll-anchoring/heuristic-with-offset-update-expected.txt b/...w3c/web-platform-tests/css/css-scroll-anchoring/heuristic-with-offset-update-expected.txt
@@ -1,3 +1,3 @@
 
-PASS Positioned ancestors with dynamic changes to offsets trigger scroll suppressions.
+FAIL Positioned ancestors with dynamic changes to offsets trigger scroll suppressions. assert_equals: expected 200 but got 310
 
diff --git a/...d/w3c/web-platform-tests/css/css-scroll-anchoring/multicol-fragmented-anchor-expected.txt b/...d/w3c/web-platform-tests/css/css-scroll-anchoring/multicol-fragmented-anchor-expected.txt
@@ -1,4 +1,4 @@
 content
 
-FAIL An element in a fragmented div should be able to be selected as an anchor node. assert_equals: expected 20 but got 10
+PASS An element in a fragmented div should be able to be selected as an anchor node.
 
diff --git a/...sts/imported/w3c/web-platform-tests/css/css-scroll-anchoring/opt-out-dynamic-expected.txt b/...sts/imported/w3c/web-platform-tests/css/css-scroll-anchoring/opt-out-dynamic-expected.txt
@@ -1,4 +1,4 @@
 content
 
-FAIL Dynamically styling 'overflow-anchor: none' on the anchor node should prevent scroll anchoring assert_equals: expected 150 but got 100
+FAIL Dynamically styling 'overflow-anchor: none' on the anchor node should prevent scroll anchoring assert_equals: expected 150 but got 200
 
diff --git a/...ted/w3c/web-platform-tests/css/css-scroll-anchoring/opt-out-dynamic-scroller-expected.txt b/...ted/w3c/web-platform-tests/css/css-scroll-anchoring/opt-out-dynamic-scroller-expected.txt
@@ -1,4 +1,4 @@
 content
 
-FAIL Dynamically styling 'overflow-anchor: none' on the scroller element should prevent scroll anchoring assert_equals: expected 150 but got 100
+FAIL Dynamically styling 'overflow-anchor: none' on the scroller element should prevent scroll anchoring assert_equals: expected 150 but got 200
 
diff --git a/...ed/w3c/web-platform-tests/css/css-scroll-anchoring/position-change-heuristic-expected.txt b/...ed/w3c/web-platform-tests/css/css-scroll-anchoring/position-change-heuristic-expected.txt
@@ -1,4 +1,4 @@
 
 FAIL Position changes in document scroller. assert_equals: expected 200 but got 175
-FAIL Position changes in scrollable <div>. assert_equals: expected 225 but got 200
+FAIL Position changes in scrollable <div>. assert_equals: expected 200 but got 175
 
diff --git a/...ests/css/css-scroll-anchoring/position-change-heuristic-in-nested-scroll-box-expected.txt b/...ests/css/css-scroll-anchoring/position-change-heuristic-in-nested-scroll-box-expected.txt
@@ -1,4 +1,4 @@
 
-FAIL Position changes in document scroller. assert_equals: expected 200 but got 175
+FAIL Position changes in document scroller. assert_equals: expected 225 but got 200
 FAIL Position changes in scrollable <div>. assert_equals: expected 225 but got 200
 
diff --git a/...tTests/scrollingcoordinator/mac/latching/scrolling-select-should-not-latch-mainframe.html b/...tTests/scrollingcoordinator/mac/latching/scrolling-select-should-not-latch-mainframe.html
@@ -1,4 +1,4 @@
-<!DOCTYPE html> <!-- webkit-test-runner [ AsyncOverflowScrollingEnabled=true ] -->
+<!DOCTYPE html> <!-- webkit-test-runner [ AsyncOverflowScrollingEnabled=true CSSScrollAnchoringEnabled=false ] -->
 <html>
 <head>
     <style>

diff --git a/Source/WebCore/dom/Document.cpp b/Source/WebCore/dom/Document.cpp
@@ -4661,7 +4661,7 @@ void Document::runScrollSteps()
         if (scrollAnimationsInProgress)
             page()->scheduleRenderingUpdate({ RenderingUpdateStep::Scroll });
 
-        frameView->updateScrollAnchoringElement();
+        frameView->updateScrollAnchoringElementsForScrollableAreas();
         frameView->updateScrollAnchoringPositionForScrollableAreas();
     }
 

diff --git a/Source/WebCore/page/LocalFrameView.cpp b/Source/WebCore/page/LocalFrameView.cpp
@@ -218,7 +218,7 @@ LocalFrameView::LocalFrameView(LocalFrame& frame)
     ScrollableArea::setVerticalScrollElasticity(verticalElasticity);
     ScrollableArea::setHorizontalScrollElasticity(horizontalElasticity);
 #endif
-    if (frame.document() && frame.document()->settings().cssScrollAnchoringEnabled())
+    if (m_frame->settings().cssScrollAnchoringEnabled())
         m_scrollAnchoringController = WTF::makeUnique<ScrollAnchoringController>(*this);
 }
 
@@ -2859,7 +2859,9 @@ void LocalFrameView::scrollOffsetChangedViaPlatformWidgetImpl(const ScrollOffset
     updateCompositingLayersAfterScrolling();
     repaintSlowRepaintObjects();
     scrollPositionChanged(scrollPositionFromOffset(oldOffset), scrollPositionFromOffset(newOffset));
-
+    invalidateScrollAnchoringElement();
+    updateScrollAnchoringElement();
+
     if (auto* renderView = this->renderView()) {
         if (renderView->usesCompositing())
             renderView->compositor().didChangeVisibleRect();
@@ -2895,9 +2897,6 @@ void LocalFrameView::scrollPositionChanged(const ScrollPosition& oldPosition, co
         if (auto* layer = renderView->layer())
             m_frame->editor().renderLayerDidScroll(*layer);
     }
-
-    invalidateScrollAnchoringElement();
-    updateScrollAnchoringElement();
 }
 
 void LocalFrameView::applyRecursivelyWithVisibleRect(const Function<void(LocalFrameView& frameView, const IntRect& visibleRect)>& apply)
@@ -3867,24 +3866,6 @@ void LocalFrameView::performPostLayoutTasks()
     m_frame->document()->scheduleDeferredAXObjectCacheUpdate();
 }
 
-void LocalFrameView::invalidateScrollAnchoringElement()
-{
-    if (m_scrollAnchoringController)
-        m_scrollAnchoringController->invalidateAnchorElement();
-}
-
-void LocalFrameView::updateScrollAnchoringElement()
-{
-    if (m_scrollAnchoringController)
-        m_scrollAnchoringController->updateAnchorElement();
-}
-
-void LocalFrameView::updateScrollPositionForScrollAnchoringController()
-{
-    if (m_scrollAnchoringController)
-        m_scrollAnchoringController->adjustScrollPositionForAnchoring();
-}
-
 void LocalFrameView::dequeueScrollableAreaForScrollAnchoringUpdate(ScrollableArea& scrollableArea)
 {
     m_scrollableAreasWithScrollAnchoringControllersNeedingUpdate.remove(scrollableArea);
@@ -3895,6 +3876,15 @@ void LocalFrameView::queueScrollableAreaForScrollAnchoringUpdate(ScrollableArea&
     m_scrollableAreasWithScrollAnchoringControllersNeedingUpdate.add(scrollableArea);
 }
 
+void LocalFrameView::updateScrollAnchoringElementsForScrollableAreas()
+{
+    updateScrollAnchoringElement();
+    if (!m_scrollableAreas)
+        return;
+    for (auto& scrollableArea : *m_scrollableAreas)
+        scrollableArea.updateScrollAnchoringElement();
+}
+
 void LocalFrameView::updateScrollAnchoringPositionForScrollableAreas()
 {
     auto scrollableAreasNeedingUpdate = std::exchange(m_scrollableAreasWithScrollAnchoringControllersNeedingUpdate, { });
@@ -6452,6 +6442,24 @@ void LocalFrameView::writeRenderTreeAsText(TextStream& ts, OptionSet<RenderAsTex
     externalRepresentationForLocalFrame(ts, frame(), behavior);
 }
 
+void LocalFrameView::updateScrollAnchoringElement()
+{
+    if (m_scrollAnchoringController)
+        m_scrollAnchoringController->updateAnchorElement();
+}
+
+void LocalFrameView::updateScrollPositionForScrollAnchoringController()
+{
+    if (m_scrollAnchoringController)
+        m_scrollAnchoringController->adjustScrollPositionForAnchoring();
+}
+
+void LocalFrameView::invalidateScrollAnchoringElement()
+{
+    if (m_scrollAnchoringController)
+        m_scrollAnchoringController->invalidateAnchorElement();
+}
+
 } // namespace WebCore
 
 #undef PAGE_ID

diff --git a/Source/WebCore/page/LocalFrameView.h b/Source/WebCore/page/LocalFrameView.h
@@ -736,14 +736,15 @@ class LocalFrameView final : public FrameView {
     ScrollbarGutter scrollbarGutterStyle() const final;
     ScrollbarWidth scrollbarWidthStyle() const final;
 
-    void updateScrollAnchoringElement() final;
-    void updateScrollPositionForScrollAnchoringController() final;
-    void invalidateScrollAnchoringElement();
-
     void dequeueScrollableAreaForScrollAnchoringUpdate(ScrollableArea&);
     void queueScrollableAreaForScrollAnchoringUpdate(ScrollableArea&);
+    void updateScrollAnchoringElementsForScrollableAreas();
     void updateScrollAnchoringPositionForScrollableAreas();
 
+    void updateScrollAnchoringElement() final;
+    void updateScrollPositionForScrollAnchoringController() final;
+    void invalidateScrollAnchoringElement() final;
+
 private:
     explicit LocalFrameView(LocalFrame&);
 
@@ -1026,9 +1027,10 @@ class LocalFrameView final : public FrameView {
     ViewportRendererType m_viewportRendererType { ViewportRendererType::None };
     ScrollPinningBehavior m_scrollPinningBehavior { ScrollPinningBehavior::DoNotPin };
     SelectionRevealMode m_selectionRevealModeForFocusedElement { SelectionRevealMode::DoNotReveal };
-    std::unique_ptr<ScrollAnchoringController> m_scrollAnchoringController;
     ScrollableAreaSet m_scrollableAreasWithScrollAnchoringControllersNeedingUpdate;
 
+    std::unique_ptr<ScrollAnchoringController> m_scrollAnchoringController;
+
     bool m_shouldUpdateWhileOffscreen { true };
     bool m_overflowStatusDirty { true };
     bool m_horizontalOverflow { false };