A sideways rubber band can break a vertical scroll snap animation

• Component: Scrolling
• Status: RESOLVED WORKSFORME

[Simon Fraser (smfr)]

In a vertically document with snap points, if your vertical scroll gesture has some horizontal component, we can start a rubberband animation in X which kills the scroll snap momentum animation:

ThreadedScrollingTree::willStartRenderingUpdate - scrollingThreadIsActive 1
ScrollingEffectsController::applyScrollDeltaWithStretching() - stretchScrollForce width=4 height=0 move delta width=0 height=0 dampedDelta width=1 height=0
ThreadedScrollingTree::willStartRenderingUpdate - scrollingThreadIsActive 1
ScrollingEffectsController::applyScrollDeltaWithStretching() - stretchScrollForce width=4 height=0 move delta width=0 height=0 dampedDelta width=1 height=0
ThreadedScrollingTree::willStartRenderingUpdate - scrollingThreadIsActive 1
ScrollingEffectsController::applyScrollDeltaWithStretching() - stretchScrollForce width=5 height=0 move delta width=1 height=0 dampedDelta width=1 height=0
ScrollingEffectsController::applyScrollDeltaWithStretching() - stretchScrollForce width=6 height=0 move delta width=1 height=0 dampedDelta width=1 height=0
ScrollingEffectsController 0x31062c180 updateRubberBandingState - isRubberBanding 0
ScrollingEffectsController 0x31062c180 startMomentumScrollWithInitialVelocity width=0 height=0 from (1,319)
ScrollingEffectsController 0x31062c180 scrollAnimationWillStart ScrollAnimation 0x3106124b0 momentum active 1 current offset (0,0)
ScrollingEffectsController::startRubberBandAnimationIfNecessary() - rubberBandAnimationRunning 0 stretchAmount width=1 height=0 targetOffset (1,319)
ScrollingEffectsController 0x31062c180 scrollAnimationDidEnd ScrollAnimation 0x3106124b0 momentum active 0 current offset (0,0)
ScrollingEffectsController 0x31062c180 stopAnimatedScroll
ScrollingEffectsController::startRubberBandAnimation() - starting rubbberband with targetOffset (0,319) initialVelocity width=0 height=0 initialOverscroll width=1 height=0
ScrollingEffectsController 0x31062c180 scrollAnimationWillStart ScrollAnimation 0x31f8bf240 rubber-band active 1 current offset (0,0)
ScrollingEffectsController 0x31062c180 updateRubberBandingState - isRubberBanding 1
ScrollingEffectsController 0x31062c180 scrollAnimationDidUpdate ScrollAnimation 0x31f8bf240 rubber-band active 1 current offset (1,319) (main thread 0) scrolling to (1,319)
ThreadedScrollingTree::willStartRenderingUpdate - scrollingThreadIsActive 1
ScrollingEffectsController 0x31062c180 scrollAnimationDidUpdate ScrollAnimation 0x31f8bf240 rubber-band active 1 current offset (1,319) (main thread 0) scrolling to (1,319)
ThreadedScrollingTree::willStartRenderingUpdate - scrollingThreadIsActive 1
ScrollingEffectsController 0x31062c180 scrollAnimationDidUpdate ScrollAnimation 0x31f8bf240 rubber-band active 1 current offset (1,319) (main thread 0) scrolling to (1,319)
ThreadedScrollingTree::willStartRenderingUpdate - scrollingThreadIsActive 1
ScrollingEffectsController 0x31062c180 scrollAnimationDidUpdate ScrollAnimation 0x31f8bf240 rubber-band active 1 current offset (0,319) (main thread 0) scrolling to (0,319)
ScrollingEffectsController 0x31062c180 updateRubberBandingState - isRubberBanding 0
ScrollingEffectsController 0x31062c180 scrollAnimationDidEnd ScrollAnimation 0x31f8bf240 rubber-band active 0 current offset (0,319)
ThreadedScrollingTree::willStartRenderingUpdate - scrollingThreadIsActive 1
ThreadedScrollingTree::willStartRenderingUpdate - scrollingThreadIsActive 0

[Radar WebKit Bug Importer]

<rdar://problem/85041566>

[Simon Fraser (smfr)]

This will be a regression from the scroll animation refactoring.

[Simon Fraser (smfr)]

Created attachment 443694 [details]
Test case

[Brent Fulgham]

QA is unable to reproduce this.