RESOLVED FIXED 188655
REGRESSION (r233268): contents of an animated element inside overflow:hidden disappear 
https://bugs.webkit.org/show_bug.cgi?id=188655
Summary REGRESSION (r233268): contents of an animated element inside overflow:hidden ...
Antoine Quint
Reported 2018-08-16 08:40:02 PDT
Created attachment 347266 [details] Test The attached test case regressed with https://trac.webkit.org/changeset/233268 which was a fix for https://bugs.webkit.org/show_bug.cgi?id=186909. The issue goes away under several scenarios: - use an <img> directly instead of a <picture> - change .grid to not have explicit left and transform values and change slide-in to animate to translateX(100%) - add an explicit 0% { transform: translateX(-100%) } keframe for the slide-in animation
Attachments
Test (702 bytes, text/html)
2018-08-16 08:40 PDT, Antoine Quint 		no flags
Details
simpler test (650 bytes, text/html)
2018-11-11 15:57 PST, Simon Fraser (smfr) 		no flags
Details
Patch (14.18 KB, patch)
2018-12-13 18:50 PST, Simon Fraser (smfr) 		graouts: review+
ews-watchlist: commit-queue-
DetailsFormatted DiffDiff
Archive of layout-test-results from ews121 for ios-simulator-wk2 (2.51 MB, application/zip)
2018-12-13 20:32 PST, EWS Watchlist 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Radar WebKit Bug Importer
Comment 1 2018-08-16 08:41:58 PDT
<rdar://problem/43382687>
Simon Fraser (smfr)
Comment 2 2018-11-11 15:57:08 PST
Created attachment 354513 [details] simpler test
Simon Fraser (smfr)
Comment 3 2018-12-13 17:21:30 PST
I think this happens when the un-animated state of the element has a transform. We are confused, in GraphicsLayerCA::computeVisibleAndCoverageRect(), about layerTransform and currentTransform, and seem to use different ones for layerBounds and coverageRect.
Simon Fraser (smfr)
Comment 4 2018-12-13 18:14:40 PST
Ah, the actual issue is that getOverlapBoundsIncludingChildrenAccountingForTransformAnimations() looks at keyframes to get the bounds, but in this example there is no 0% keyframe, so we fail to take the static translateX(-100%) into account.
Simon Fraser (smfr)
Comment 5 2018-12-13 18:50:46 PST
Created attachment 357283 [details] Patch
EWS Watchlist
Comment 6 2018-12-13 20:32:53 PST
Comment on attachment 357283 [details] Patch Attachment 357283 [details] did not pass ios-sim-ews (ios-simulator-wk2): Output: https://webkit-queues.webkit.org/results/10391430 New failing tests: legacy-animation-engine/compositing/backing/backing-store-attachment-empty-keyframe.html compositing/backing/backing-store-attachment-empty-keyframe.html
EWS Watchlist
Comment 7 2018-12-13 20:32:56 PST
Created attachment 357295 [details] Archive of layout-test-results from ews121 for ios-simulator-wk2 The attached test failures were seen while running run-webkit-tests on the ios-sim-ews. Bot: ews121 Port: ios-simulator-wk2 Platform: Mac OS X 10.13.6
Simon Fraser (smfr)
Comment 8 2018-12-14 11:06:13 PST
https://trac.webkit.org/changeset/239222/webkit
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