Changeset 287031 in webkit

Timestamp:

Dec 14, 2021, 10:30:27 AM (5 years ago)

Author:

Alan Coon

Message:

Cherry-pick r286999. rdar://problem/86425321

Momentum Event Dispatcher: Excessive "kick" at the beginning of scrolling (especially on 60fps displays)
​https://bugs.webkit.org/show_bug.cgi?id=234279
<rdar://problem/86425321>

Reviewed by Simon Fraser.

• WebProcess/WebPage/MomentumEventDispatcher.cpp: (WebKit::MomentumEventDispatcher::handleWheelEvent): (WebKit::MomentumEventDispatcher::didStartMomentumPhase): Instead of back-dating the animation to try to acquire a momentum-start delta, pass the one we got from the event through, and start the animation curve at momentum-start time. Also, critically, inset ourselves along the curve by the amount of that initial delta (since the time starts now).

Tested at both 60fps and 120fps, this significantly smooths out the
transition from fingers-down phase to the generated momentum phase,
avoiding the overly large initial delta.

• WebProcess/WebPage/MomentumEventDispatcher.h:

git-svn-id: ​https://svn.webkit.org/repository/webkit/trunk@286999 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Location:

branches/safari-612-branch/Source/WebKit

Files:

• ChangeLog (modified) (1 diff)
• WebProcess/WebPage/MomentumEventDispatcher.cpp (modified) (3 diffs)
• WebProcess/WebPage/MomentumEventDispatcher.h (modified) (1 diff)

branches/safari-612-branch/Source/WebKit/ChangeLog

@@ +1 @@
+2021-12-14  Alan Coon  <alancoon@apple.com>
+
+        Cherry-pick r286999. rdar://problem/86425321
+
+    Momentum Event Dispatcher: Excessive "kick" at the beginning of scrolling (especially on 60fps displays)
+    https://bugs.webkit.org/show_bug.cgi?id=234279
+    <rdar://problem/86425321>
+    
+    Reviewed by Simon Fraser.
+    
+    * WebProcess/WebPage/MomentumEventDispatcher.cpp:
+    (WebKit::MomentumEventDispatcher::handleWheelEvent):
+    (WebKit::MomentumEventDispatcher::didStartMomentumPhase):
+    Instead of back-dating the animation to try to acquire a momentum-start
+    delta, pass the one we got from the event through, and start the animation
+    curve at momentum-start time. Also, critically, inset ourselves along
+    the curve by the amount of that initial delta (since the time starts now).
+    
+    Tested at both 60fps and 120fps, this significantly smooths out the
+    transition from fingers-down phase to the generated momentum phase,
+    avoiding the overly large initial delta.
+    
+    * WebProcess/WebPage/MomentumEventDispatcher.h:
+    
+    
+    git-svn-id: https://svn.webkit.org/repository/webkit/trunk@286999 268f45cc-cd09-0410-ab3c-d52691b4dbfc
+
+    2021-12-13  Tim Horton  <timothy_horton@apple.com>
+
+            Momentum Event Dispatcher: Excessive "kick" at the beginning of scrolling (especially on 60fps displays)
+            https://bugs.webkit.org/show_bug.cgi?id=234279
+            <rdar://problem/86425321>
+
+            Reviewed by Simon Fraser.
+
+            * WebProcess/WebPage/MomentumEventDispatcher.cpp:
+            (WebKit::MomentumEventDispatcher::handleWheelEvent):
+            (WebKit::MomentumEventDispatcher::didStartMomentumPhase):
+            Instead of back-dating the animation to try to acquire a momentum-start
+            delta, pass the one we got from the event through, and start the animation
+            curve at momentum-start time. Also, critically, inset ourselves along
+            the curve by the amount of that initial delta (since the time starts now).
+
+            Tested at both 60fps and 120fps, this significantly smooths out the
+            transition from fingers-down phase to the generated momentum phase,
+            avoiding the overly large initial delta.
+
+            * WebProcess/WebPage/MomentumEventDispatcher.h:
+
 2021-12-13  Alan Coon  <alancoon@apple.com>
 

branches/safari-612-branch/Source/WebKit/WebProcess/WebPage/MomentumEventDispatcher.cpp

@@ -101 +101 @@
     }
 
-    if (event.phase() == WebWheelEvent::PhaseEnded)
-        m_lastEndedEventTimestamp = event.ioHIDEventTimestamp();
-
     if (eventShouldStartSyntheticMomentumPhase(pageIdentifier, event))
         didStartMomentumPhase(pageIdentifier, event);
@@ -191 +188 @@
     tracePoint(SyntheticMomentumStart);
 
-    auto momentumStartInterval = event.ioHIDEventTimestamp() - m_lastEndedEventTimestamp;
-
     m_currentGesture.active = true;
     m_currentGesture.pageIdentifier = pageIdentifier;
     m_currentGesture.initiatingEvent = event;
     m_currentGesture.currentOffset = { };
-    m_currentGesture.startTime = MonotonicTime::now() - momentumStartInterval;
+    m_currentGesture.startTime = MonotonicTime::now();
     m_currentGesture.displayNominalFrameRate = displayProperties->nominalFrameRate;
     m_currentGesture.accelerationCurve = [&] () -> std::optional<ScrollingAccelerationCurve> {
@@ -214 +209 @@
     buildOffsetTableWithInitialDelta(*event.rawPlatformDelta() * idealCurveMultiplier);
 
-    dispatchSyntheticMomentumEvent(WebWheelEvent::PhaseBegan, consumeDeltaForCurrentTime());
+    WebCore::FloatSize consumedDelta = event.delta();
+    if (m_currentGesture.initiatingEvent->directionInvertedFromDevice())
+        consumedDelta.scale(-1);
+    m_currentGesture.currentOffset += consumedDelta;
+    
+    dispatchSyntheticMomentumEvent(WebWheelEvent::PhaseBegan, event.delta());
 }
 

branches/safari-612-branch/Source/WebKit/WebProcess/WebPage/MomentumEventDispatcher.h

@@ -124 +124 @@
 
     std::optional<WallTime> m_lastScrollTimestamp;
-    WallTime m_lastEndedEventTimestamp;
     std::optional<WebWheelEvent> m_lastIncomingEvent;
     WebCore::RectEdges<bool> m_lastRubberBandableEdges;