222132 2021-02-18 14:20:32 -0800 Sticky/fixed layers that are resized on the main thread can appear stretched when scrolling 2022-12-30 08:22:39 -0800 1 1 1 Unclassified WebKit Compositing Safari Technology Preview Unspecified Unspecified RESOLVED FIXED https://bugs.webkit.org/show_bug.cgi?id=222124 https://bugs.webkit.org/show_bug.cgi?id=222092 https://bugs.webkit.org/show_bug.cgi?id=244767 InRadar P2 Normal --- 1 simon.fraser simon.fraser morungos simon.fraser webkit-bug-importer oldest_to_newest 1731021 0 simon.fraser 2021-02-18 14:20:32 -0800 Scroll-coordinated layers, for fixed and sticky, get their CALayer's position changed on the scrolling thread. However, if the main thread also commits a size change, but the layer contents are slow to paint, then CA can do the size change on the scrolling thread before the contents are painted, resulting in stretched content. This happens on https://www.apple.com/ipad-air/ in low memory configurations. The fix is to use another layer as the "anchor" for fixed and sticky. 1731022 1 simon.fraser 2021-02-18 14:21:35 -0800 Relates to rdar://71881767 1731028 2 420873 simon.fraser 2021-02-18 14:27:37 -0800 Created attachment 420873 Testcase (BYOI) 1733516 3 webkit-bug-importer 2021-02-25 14:21:14 -0800 <rdar://problem/74760592> 1892266 4 461716 simon.fraser 2022-08-18 11:14:53 -0700 Created attachment 461716 Testcase 1892317 5 simon.fraser 2022-08-18 16:01:30 -0700 This also affects GitHub pages like https://github.com/WebKit/WebKit/pull/2941/files 1892549 6 simon.fraser 2022-08-19 16:24:00 -0700 Pull request: https://github.com/WebKit/WebKit/pull/3492 1894218 7 ews-feeder 2022-08-27 09:32:03 -0700 Committed 253865@main (69483ca1904a): <https://commits.webkit.org/253865@main> Reviewed commits have been landed. Closing PR #3492 and removing active labels. 1922281 8 zalan 2022-12-30 08:22:39 -0800 *** Bug 249848 has been marked as a duplicate of this bug. *** 420873 2021-02-18 14:27:37 -0800 2022-08-18 11:14:53 -0700 Testcase (BYOI) sticky-script-affected-bounds.html text/html 1570 simon.fraser PCFET0NUWVBFIGh0bWw+CjxodG1sPgo8aGVhZD4KICAgIDxtZXRhIG5hbWU9InZpZXdwb3J0IiBj b250ZW50PSJ3aWR0aD1kZXZpY2Utd2lkdGgsIGluaXRpYWwtc2NhbGU9MSwgc2hyaW5rLXRvLWZp dD1ubyI+CiAgICA8c3R5bGU+CiAgICAgICAgYm9keSB7CiAgICAgICAgICAgIGhlaWdodDogMzAw MHB4OwogICAgICAgIH0KICAgICAgICAKICAgICAgICAuY29udGFpbmVyIHsKICAgICAgICAgICAg bWFyZ2luLXRvcDogMjAwcHg7CiAgICAgICAgICAgIGhlaWdodDogMTIwMHB4OwogICAgICAgICAg ICBib3JkZXI6IDFweCBzb2xpZCBibGFjazsKICAgICAgICB9CiAgICAgICAgLmJveCB7CiAgICAg ICAgICAgIHdpZHRoOiA2MDBweDsKICAgICAgICAgICAgaGVpZ2h0OiA2MDBweDsKICAgICAgICAg ICAgYmFja2dyb3VuZC1jb2xvcjogc2lsdmVyOwogICAgICAgICAgICBwb3NpdGlvbjogc3RpY2t5 OwogICAgICAgICAgICB0b3A6IDIwMHB4OwogICAgICAgICAgICBsZWZ0OiAxMDBweDsKICAgICAg 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