Bug 191546 - Can we avoid compositing overlap testing after page scroll?
Summary: Can we avoid compositing overlap testing after page scroll?
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: Layout and Rendering (show other bugs)
Version: WebKit Nightly Build
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Nobody
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2018-11-12 08:36 PST by Simon Fraser (smfr)
Modified: 2018-11-12 08:36 PST (History)
3 users (show)

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Description Simon Fraser (smfr) 2018-11-12 08:36:29 PST
RenderLayerCpmpositor has:

    if (updateType == CompositingUpdateType::OnScroll || updateType == CompositingUpdateType::OnCompositedScroll) {
        // Scrolling can affect overlap. FIXME: avoid for page scrolling.
        updateRoot->setDescendantsNeedCompositingRequirementsTraversal();
    }

We already extend overlap rects for fixed and sticky layers, so we should be able to avoid any new overlap testing on page scroll.