198086 2019-05-21 15:01:54 -0700 Layer with negative z-index in a scroller doesn't scroll with the scroller 2019-06-26 18:04:56 -0700 1 1 1 Unclassified WebKit Compositing WebKit Nightly Build Unspecified Unspecified ASSIGNED https://bugs.webkit.org/show_bug.cgi?id=199253 InRadar P2 Normal --- 1 simon.fraser simon.fraser koivisto simon.fraser webkit-bug-importer oldest_to_newest 1537999 0 370345 simon.fraser 2019-05-21 15:01:54 -0700 Created attachment 370345 Testcase Scroller with a negative z-index child fails to composite, and scroll the scroller. 1538003 1 webkit-bug-importer 2019-05-21 15:05:17 -0700 <rdar://problem/51002331> 1538004 2 webkit-bug-importer 2019-05-21 15:05:22 -0700 <rdar://problem/51002332> 1541107 3 simon.fraser 2019-06-02 09:58:31 -0700 We don't composite the negative z child, and it doesn't use backing sharing. 1541108 4 simon.fraser 2019-06-02 10:01:07 -0700 isNonScrolledLayerInsideScrolledCompositedAncestor() needs to take care of this, but not in a way that prevents backing sharing. 1548142 5 simon.fraser 2019-06-26 15:13:55 -0700 Another problem here is that in the first compositing update, we hit the 'traverseUnchangedSubtree' code path for the negative z-order child, because we haven't composited the scroller yet, so we don't composite the child. 1548288 6 simon.fraser 2019-06-26 18:04:56 -0700 The patch in bug 199253 mostly fixes this, other than bad state on the first layer traversal which I'll keep this bug open for. 370345 2019-05-21 15:01:54 -0700 2019-05-21 15:01:54 -0700 Testcase scroller-with-negative-z-children.html text/html 1341 simon.fraser PCFET0NUWVBFIGh0bWw+IDwhLS0gd2Via2l0LXRlc3QtcnVubmVyIFsgaW50ZXJuYWw6QXN5bmNP dmVyZmxvd1Njcm9sbGluZ0VuYWJsZWQ9dHJ1ZSBdIC0tPgo8aHRtbD4KPGhlYWQ+CiAgICA8c3R5 bGU+CgkJLnNjcm9sbGVyIHsKCQkJcG9zaXRpb246IHJlbGF0aXZlOwoJCQlvdmVyZmxvdy15OiBz Y3JvbGw7CgkJCXdpZHRoOiAzMDBweDsKCQkJaGVpZ2h0OiAzMDBweDsKCQkJYm9yZGVyOiAxcHgg c29saWQgYmxhY2s7CgkJfQoJCQoJCS5ib3ggewoJCQlwb3NpdGlvbjogcmVsYXRpdmU7CgkJCW1h cmdpbjogMjBweDsKCQkgICAgd2lkdGg6IDEwMHB4OwoJCSAgICBoZWlnaHQ6IDEwMHB4OwoJCSAg ICBiYWNrZ3JvdW5kLWNvbG9yOiBncmVlbjsKCQl9CgoJCS5pbnNpZGUgewoJCQlsZWZ0OiAyMHB4 OwoJCX0KCQkKCQkubmVnYXRpdmUgewoJCQl6LWluZGV4OiAtMTsKCQl9CgoJCS5vdXRzaWRlIHsK CQkJcG9zaXRpb246IHJlbGF0aXZlOwoJCQltYXJnaW46IDIwcHg7CgkJICAgIHdpZHRoOiAxMDBw eDsKCQkgICAgaGVpZ2h0OiAxMDBweDsKCQkgICAgYmFja2dyb3VuZC1jb2xvcjogc2lsdmVyOwoJ CX0KCgkJLnRyaWdnZXIgewoJCQlwb3NpdGlvbjogYWJzb2x1dGU7CiAgICAgICAgICAgIHRvcDog MTBweDsKCQkJbGVmdDogMTBweDsKCQkJd2lkdGg6IDUwcHg7CgkJCWhlaWdodDogMjAwcHg7CgkJ CWJhY2tncm91bmQtY29sb3I6IHNpbHZlcjsKCQkgICAgdHJhbnNmb3JtOiB0cmFuc2xhdGVaKDAp OwoJCX0KICAgIDwvc3R5bGU+Cgk8c2NyaXB0PgoJCWlmICh3aW5kb3cudGVzdFJ1bm5lcikKCQkJ dGVzdFJ1bm5lci5kdW1wQXNUZXh0KCk7CgoJCXdpbmRvdy5hZGRFdmVudExpc3RlbmVyKCdsb2Fk JywgKCkgPT4gewoJCQlpZiAod2luZG93LnRlc3RSdW5uZXIpCgkJCQlkb2N1bWVudC5nZXRFbGVt ZW50QnlJZCgnbGF5ZXJzJykuaW5uZXJUZXh0ID0gd2luZG93LmludGVybmFscy5sYXllclRyZWVB c1RleHQoZG9jdW1lbnQpOwoJCX0sIGZhbHNlKTsKCTwvc2NyaXB0Pgo8L2hlYWQ+Cjxib2R5PgoJ PGRpdiBjbGFzcz0ic2Nyb2xsZXIiPgoJCTxkaXYgY2xhc3M9InRyaWdnZXIiPjwvZGl2PgogICAg ICAgIDxkaXYgY2xhc3M9Imluc2lkZSBib3giPjwvZGl2PgogICAgICAgIDxkaXYgY2xhc3M9Imlu c2lkZSBuZWdhdGl2ZSBib3giPjwvZGl2PgogICAgICAgIDxkaXYgY2xhc3M9Imluc2lkZSBib3gi PjwvZGl2PgogICAgICAgIDxkaXYgY2xhc3M9Imluc2lkZSBib3giPjwvZGl2PgoJPC9kaXY+Cgk8 ZGl2IGNsYXNzPSJvdXRzaWRlIj48L2Rpdj4KPHByZSBpZD0ibGF5ZXJzIj5MYXllciB0cmVlIGdv ZXMgaGVyZTwvcHJlPgo8L2JvZHk+CjwvaHRtbD4K