Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 8ff9ee25d0ec06f7173aa827b6bf4307ffe400b8
https://github.com/WebKit/WebKit/commit/8ff9ee25d0ec06f7173aa827b6bf4307ffe400b8
Author: Simon Fraser <[email protected]>
Date: 2026-04-22 (Wed, 22 Apr 2026)
Changed paths:
M Source/WebCore/page/scrolling/ScrollingTree.cpp
M Source/WebCore/page/scrolling/ScrollingTree.h
Log Message:
-----------
Avoid updating UI-side layer positions for no-op transactions
https://bugs.webkit.org/show_bug.cgi?id=312959
rdar://175308880
Reviewed by Brent Fulgham.
Currently, after every RemoteLayerTree commit that is received by the UI
process,
we call `applyScrollingTreeLayerPositionsAfterCommit()`, which traverses the
scrolling
tree and updates CALayer positions.
If the transaction contains no scrolling tree changes, then this is not
necessary;
`applyLayerPositions()` only needs to be called after a scrolling tree state
change,
or after a user scroll.
Track this state via `ScrollingTree::m_needsApplyLayerPositions()`, and set the
flag
under `commitTreeState()` and `scrollingTreeNodeDidScroll()`. It's the
`commitTreeState(()`
call that's skipped when `stateTree->hasChangedProperties()` is false.
This should be a minor power saving.
* Source/WebCore/page/scrolling/ScrollingTree.cpp:
(WebCore::ScrollingTree::scrollingTreeNodeDidScroll):
(WebCore::ScrollingTree::commitTreeStateInternal):
(WebCore::ScrollingTree::applyLayerPositions):
* Source/WebCore/page/scrolling/ScrollingTree.h:
(WebCore::ScrollingTree::setNeedsApplyLayerPositions):
Canonical link: https://commits.webkit.org/311816@main
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