Changeset 285883 in webkit

Timestamp:

Nov 16, 2021, 2:05:01 PM (5 years ago)

Author:

Simon Fraser

Message:

Use IOHIDEvent timestamps for momentum velocity computation
​https://bugs.webkit.org/show_bug.cgi?id=233168

Reviewed by Tim Horton.

NSEvent timetamps can have some jitter on some devices (rdar://85309639) so drop
down to IOHIDEvent timestamps when computing the initial velocity for a momentum
scroll animation, for improved accuracy.

• page/mac/WheelEventDeltaFilterMac.h:
• page/mac/WheelEventDeltaFilterMac.mm:

(WebCore::WheelEventDeltaFilterMac::updateFromEvent):
(WebCore::WheelEventDeltaFilterMac::reset):

• page/scrolling/ThreadedScrollingTree.cpp:

(WebCore::ThreadedScrollingTree::willStartRenderingUpdate):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• page/mac/WheelEventDeltaFilterMac.h (modified) (1 diff)
• page/mac/WheelEventDeltaFilterMac.mm (modified) (6 diffs)
• page/scrolling/ThreadedScrollingTree.cpp (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2021-11-16  Simon Fraser  <simon.fraser@apple.com>
+
+        Use IOHIDEvent timestamps for momentum velocity computation
+        https://bugs.webkit.org/show_bug.cgi?id=233168
+
+        Reviewed by Tim Horton.
+
+        NSEvent timetamps can have some jitter on some devices (rdar://85309639) so drop
+        down to IOHIDEvent timestamps when computing the initial velocity for a momentum
+        scroll animation, for improved accuracy.
+
+        * page/mac/WheelEventDeltaFilterMac.h:
+        * page/mac/WheelEventDeltaFilterMac.mm:
+        (WebCore::WheelEventDeltaFilterMac::updateFromEvent):
+        (WebCore::WheelEventDeltaFilterMac::reset):
+        * page/scrolling/ThreadedScrollingTree.cpp:
+        (WebCore::ThreadedScrollingTree::willStartRenderingUpdate):
+
 2021-11-16  Andres Gonzalez  <andresg_22@apple.com>
 

trunk/Source/WebCore/page/mac/WheelEventDeltaFilterMac.h

@@ -48 +48 @@
     RetainPtr<_NSScrollingPredominantAxisFilter> m_predominantAxisFilter;
     WallTime m_initialWallTime;
+    WallTime m_lastIOHIDEventTimestamp;
 };
 

trunk/Source/WebCore/page/mac/WheelEventDeltaFilterMac.mm

@@ -30 +30 @@
 
 #import "FloatPoint.h"
+#import "Logging.h"
 #import "PlatformWheelEvent.h"
 #import <pal/spi/mac/NSScrollingInputFilterSPI.h>
@@ -44 +45 @@
 void WheelEventDeltaFilterMac::updateFromEvent(const PlatformWheelEvent& event)
 {
-    if (event.momentumPhase() != PlatformWheelEventPhase::None)
+    if (event.momentumPhase() != PlatformWheelEventPhase::None) {
+        m_lastIOHIDEventTimestamp = event.ioHIDEventTimestamp();
         return;
+    }
 
     // The absolute value of timestamp doesn't matter; the filter looks at deltas from the previous event.
@@ -52 +55 @@
     switch (event.phase()) {
     case PlatformWheelEventPhase::None:
+    case PlatformWheelEventPhase::Ended:
         break;
 
     case PlatformWheelEventPhase::Began:
+        reset();
+        FALLTHROUGH;
     case PlatformWheelEventPhase::Changed: {
         NSPoint filteredDeltaResult;
@@ -60 +66 @@
 
         [m_predominantAxisFilter filterInputDelta:toFloatPoint(event.delta()) timestamp:timestamp.seconds() outputDelta:&filteredDeltaResult velocity:&filteredVelocityResult];
-        m_currentFilteredVelocity = toFloatSize(filteredVelocityResult);
+        auto axisFilteredVelocity = toFloatSize(filteredVelocityResult);
         m_currentFilteredDelta = toFloatSize(filteredDeltaResult);
+
+        // Use a 1ms minimum to avoid divide by zero. The usual cadence of these events matches screen refresh rate.
+        auto deltaFromLastEvent = std::max(event.ioHIDEventTimestamp() - m_lastIOHIDEventTimestamp, 1_ms);
+        m_currentFilteredVelocity = event.delta() / deltaFromLastEvent.seconds();
+
+        // Apply the axis-locking that m_predominantAxisFilter does.
+        if (!axisFilteredVelocity.width())
+            m_currentFilteredVelocity.setWidth(0);
+        if (!axisFilteredVelocity.height())
+            m_currentFilteredVelocity.setHeight(0);
+
+        LOG(ScrollAnimations, "WheelEventDeltaFilterMac::updateFromEvent: _NSScrollingPredominantAxisFilter velocity %.2f, %2f, IOHIDEvent velocity %.2f,%.2f",
+            axisFilteredVelocity.width(), axisFilteredVelocity.height(), m_currentFilteredVelocity.width(), m_currentFilteredVelocity.height());
         break;
     }
@@ -67 +86 @@
     case PlatformWheelEventPhase::Cancelled:
     case PlatformWheelEventPhase::Stationary:
-    case PlatformWheelEventPhase::Ended:
         reset();
         break;
     }
+
+    m_lastIOHIDEventTimestamp = event.ioHIDEventTimestamp();
 }
 
@@ -78 +98 @@
     m_currentFilteredVelocity = { };
     m_currentFilteredDelta = { };
+    m_lastIOHIDEventTimestamp = { };
 }
 

trunk/Source/WebCore/page/scrolling/ThreadedScrollingTree.cpp

@@ -338 +338 @@
     ASSERT(isMainThread());
 
-    LOG_WITH_STREAM(ScrollAnimations, stream << "ThreadedScrollingTree::willStartRenderingUpdate - scrollingThreadIsActive " << scrollingThreadIsActive());
-
     if (!scrollingThreadIsActive())
         return;