Changeset 285917 in webkit

Timestamp:

Nov 16, 2021, 10:25:17 PM (5 years ago)

Author:

Simon Fraser

Message:

Stop a momentum scroll animation when receiving a momentum end event
​https://bugs.webkit.org/show_bug.cgi?id=233236

Reviewed by Tim Horton.

Source/WebCore:

The stream of momentum events is terminated by an "end" event under two circumstances:

1. The gesture finished naturally without interruption.
2. The user tapped the trackpad with two fingers.

Unfortunately we can't tell these apart, so we always have to stop the animation.

Sadly this reveals a hole in the testing infrastructure. All the "changed" momentum
events in the sequence handed to UIHelper.mouseWheelSequence() are ignored while the
animation is running, but the "ended" event stops the animation. So any test without
a reasonable number of "changed" events will terminate its animation prematurely.
We can't fix this without new testing infrastructure (webkit.org/b/233234).

Test: fast/scrolling/mac/momentum-animator-end-event-stops.html

• platform/ScrollingEffectsController.h:
• platform/mac/ScrollingEffectsController.mm:

(WebCore::ScrollingEffectsController::handleWheelEvent):

LayoutTests:

New test, and skip one that breaks now because we need a fix for webkit.org/b/233234.

• fast/scrolling/mac/momentum-animator-end-event-stops-expected.txt: Added.
• fast/scrolling/mac/momentum-animator-end-event-stops.html: Added.
• platform/mac-wk2/TestExpectations:

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/scrolling/mac/momentum-animator-end-event-stops-expected.txt (added)
• LayoutTests/fast/scrolling/mac/momentum-animator-end-event-stops.html (added)
• LayoutTests/platform/mac-wk2/TestExpectations (modified) (1 diff)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/platform/ScrollingEffectsController.h (modified) (1 diff)
• Source/WebCore/platform/mac/ScrollingEffectsController.mm (modified) (2 diffs)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2021-11-16  Simon Fraser  <simon.fraser@apple.com>
+
+        Stop a momentum scroll animation when receiving a momentum end event
+        https://bugs.webkit.org/show_bug.cgi?id=233236
+
+        Reviewed by Tim Horton.
+
+        New test, and skip one that breaks now because we need a fix for webkit.org/b/233234.
+
+        * fast/scrolling/mac/momentum-animator-end-event-stops-expected.txt: Added.
+        * fast/scrolling/mac/momentum-animator-end-event-stops.html: Added.
+        * platform/mac-wk2/TestExpectations:
+
 2021-11-16  Sihui Liu  <sihui_liu@apple.com>
 

trunk/LayoutTests/platform/mac-wk2/TestExpectations

@@ -1563 +1563 @@
 
 webkit.org/b/228591 fast/scrolling/mac/programmatic-scroll-overrides-rubberband.html [ Pass Failure ]
+webkit.org/b/233234 fast/scrolling/mac/momentum-animator-in-overflow.html [ Failure ]
 
 webkit.org/b/229156 [ BigSur+ ] webrtc/video-addTrack.html [ Pass Failure ]

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2021-11-16  Simon Fraser  <simon.fraser@apple.com>
+
+        Stop a momentum scroll animation when receiving a momentum end event
+        https://bugs.webkit.org/show_bug.cgi?id=233236
+
+        Reviewed by Tim Horton.
+
+        The stream of momentum events is terminated by an "end" event under two circumstances:
+        1. The gesture finished naturally without interruption.
+        2. The user tapped the trackpad with two fingers.
+
+        Unfortunately we can't tell these apart, so we always have to stop the animation.
+        
+        Sadly this reveals a hole in the testing infrastructure. All the "changed" momentum
+        events in the sequence handed to UIHelper.mouseWheelSequence() are ignored while the
+        animation is running, but the "ended" event stops the animation. So any test without
+        a reasonable number of "changed" events will terminate its animation prematurely.
+        We can't fix this without new testing infrastructure (webkit.org/b/233234).
+
+        Test: fast/scrolling/mac/momentum-animator-end-event-stops.html
+
+        * platform/ScrollingEffectsController.h:
+        * platform/mac/ScrollingEffectsController.mm:
+        (WebCore::ScrollingEffectsController::handleWheelEvent):
+
 2021-11-16  Said Abou-Hallawa  <said@apple.com>
 

trunk/Source/WebCore/platform/ScrollingEffectsController.h

@@ -264 +264 @@
     FloatSize m_scrollingVelocityForScrollSnap;
 #if !LOG_DISABLED
+    FloatPoint m_eventDrivenScrollMomentumStartOffset;
     FloatPoint m_eventDrivenScrollOffset;
+    WallTime m_momentumBeganEventTime;
 #endif
 

trunk/Source/WebCore/platform/mac/ScrollingEffectsController.mm

@@ -181 +181 @@
     }
 
+#if !LOG_DISABLED
+    if (wheelEvent.momentumPhase() == PlatformWheelEventPhase::Began)
+        m_momentumBeganEventTime = wheelEvent.timestamp();
+#endif
+
+    if (wheelEvent.momentumPhase() == PlatformWheelEventPhase::Ended && momentumScrollingAnimatorEnabled()) {
+#if !LOG_DISABLED
+        auto timeSinceStart = wheelEvent.timestamp() - m_momentumBeganEventTime;
+        auto distance = m_eventDrivenScrollOffset - m_eventDrivenScrollMomentumStartOffset;
+#endif
+        // FIXME: We can't distinguish between the natural end of a momentum sequence, and a two-finger tap on the trackpad (rdar://85414238),
+        // so we always have to end the animation here.
+        LOG(ScrollAnimations, "Event (%s, %s): stopping event scroll duration %.2fms distance %.2f %.2f",
+            phaseToString(wheelEvent.phase()), phaseToString(wheelEvent.momentumPhase()), timeSinceStart.milliseconds(),
+            fabs(distance.width()), fabs(distance.height()));
+        stopAnimatedNonRubberbandingScroll();
+    }
+
     bool isMomentumScrollEvent = (wheelEvent.momentumPhase() != PlatformWheelEventPhase::None);
     if (m_ignoreMomentumScrolls && (isMomentumScrollEvent || m_isAnimatingRubberBand)) {
@@ -214 +232 @@
 #if !LOG_DISABLED
             m_eventDrivenScrollOffset = m_client.scrollOffset();
+            m_eventDrivenScrollMomentumStartOffset = m_eventDrivenScrollOffset;
 #endif
         }