191218 2018-11-02 16:45:20 -0700 Touch event not firing while scrolling is in motion 2026-03-30 11:01:15 -0700 1 1 1 Unclassified WebKit UI Events Safari 12 iPhone / iPad iOS 12 NEW https://bugs.webkit.org/show_bug.cgi?id=251513 https://bugs.webkit.org/show_bug.cgi?id=310540 InRadar P2 Normal --- 1 starshiping webkit-unassigned alexander a_protyasha fred.wang simon.fraser thorton webkit-bug-importer wenson_hsieh oldest_to_newest 1474676 0 starshiping 2018-11-02 16:45:20 -0700 When user scrolls and in the deceleration phase of the inertial scrolling, user touch the screen will make the scrolling stop but no "touch" event is fired. I'd like to detect where the user touch to stop the scrolling but I can't because there's no event firing. Safari and Chrome on iphone have this issue while Android doesn't. I've created a CodePen for testing. https://codepen.io/anon/pen/MzWKrM Please help to fix this. 1593466 1 384303 fred.wang 2019-11-25 09:35:49 -0800 Created attachment 384303 testcase Reproducible in iOS 13.3 17C5046a 1593688 2 fred.wang 2019-11-26 08:51:09 -0800 Preliminary debugging on the simulator (public SDK): - When you scroll and tap the blue rectangle during scrolling, WKScrollingNodeScrollViewDelegate::scrollViewDidEndDragging is called and just informs ScrollingTreeScrollingNodeDelegateIOS about the scroll & scroll end. - When you tap directly the blue rectangle, WKContentView::_singleTapGestureRecognizer will invoke WebPageProxy::commitPotentialTap in order to tell the Web process to dispatch an event. - WKContentViewInteraction::gestureRecognizerShouldBegin has some logic when tap interrupts a scroll deceleration, but the code does not seem to be called for me. I wonder if there is something wrong in the fact that touch gesture are not handled by WKContentView during scrolling or if the scrolling delegate should do similar work as WKContentView to recognize touch gestures. 1597630 3 fred.wang 2019-12-11 08:32:13 -0800 (In reply to Frédéric Wang (:fredw) from comment #2) > - When you scroll and tap the blue rectangle during scrolling, > WKScrollingNodeScrollViewDelegate::scrollViewDidEndDragging is called and > just informs ScrollingTreeScrollingNodeDelegateIOS about the scroll & scroll > end. I tried sending the commitPotentialTap message from there but it does not work. The target node & position must be set first with a potentialTapAtPosition, so it seems the solution will be a bit more complex. > - When you tap directly the blue rectangle, > WKContentView::_singleTapGestureRecognizer will invoke > WebPageProxy::commitPotentialTap in order to tell the Web process to > dispatch an event. WKContentView::_singleTapGestureRecognizer is a WKSyntheticTapGestureRecognizer. However, this listener is not triggered when the UIScrollView is scrolling... > I wonder if there is something wrong in the fact that touch gesture are not > handled by WKContentView during scrolling or if the scrolling delegate > should do similar work as WKContentView to recognize touch gestures. If the former, I guess that's something Apple should fix. For the latter, a proper solution will probably be to use some UITapGestureRecognizer on UIScrollView, if that's ever possible. I'll investigate more on this but found https://stackoverflow.com/questions/27715448/uitapgesturerecognizer-on-uiscrollview 2192766 4 alexander 2026-03-23 07:59:41 -0700 Any plans to fix this 8 years old absolutely abysmal disregard for specification? 2195218 5 a_protyasha 2026-03-30 10:57:27 -0700 *** Bug 310540 has been marked as a duplicate of this bug. *** 2195219 6 webkit-bug-importer 2026-03-30 11:01:15 -0700 <rdar://problem/173706901> 384303 2019-11-25 09:35:49 -0800 2019-11-25 09:35:49 -0800 testcase bug-191218.html text/html 1339 fred.wang PCFET0NUWVBFIGh0bWw+CjxodG1sPgogIDxoZWFkPgogICAgPHRpdGxlPmJ1ZyAxOTEyMjE4PC90 aXRsZT4KICAgIDxtZXRhIGNoYXJzZXQ9InV0Zi04Ii8+CiAgICA8bWV0YSBuYW1lPSJ2aWV3cG9y dCIgY29udGVudD0id2lkdGg9ZGV2aWNlLXdpZHRoIj4KICAgIDxzdHlsZT4KICAgICAgI3Njcm9s bENvbnRhaW5lciB7CiAgICAgICAgICB3aWR0aDogNDAwcHg7CiAgICAgICAgICBoZWlnaHQ6IDQw MHB4OwogICAgICAgICAgb3ZlcmZsb3cteTogc2Nyb2xsOwogICAgICAgICAgcG9zaXRpb246IHJl bGF0aXZlOwogICAgICAgICAgLXdlYmtpdC1vdmVyZmxvdy1zY3JvbGxpbmc6IHRvdWNoOwogICAg ICB9CiAgICAgICNjb250ZW50IHsKICAgICAgICAgIHdpZHRoOiAxMDAlOwogICAgICAgICAgaGVp Z2h0OiAxMDAwcHg7CiAgICAgICAgICBiYWNrZ3JvdW5kOiBsaW5lYXItZ3JhZGllbnQoMTM1ZGVn LCByZWQsIGdyZWVuKTsKICAgICAgfQogICAgICAjaWNvbiB7CiAgICAgICAgICBwb3NpdGlvbjog YWJzb2x1dGU7CiAgICAgICAgICB3aWR0aDogMTAwcHg7CiAgICAgICAgICBoZWlnaHQ6IDEwMHB4 OwogICAgICAgICAgYm90dG9tOiAwcHg7CiAgICAgICAgICByaWdodDogMHB4OwogICAgICAgICAg YmFja2dyb3VuZDogYmx1ZTsKICAgICAgfQogICAgPC9zdHlsZT4KICA8L2hlYWQ+CiAgPGJvZHk+ CiAgICA8ZGl2PgogICAgICA8ZGl2IGlkPSJzY3JvbGxDb250YWluZXIiPgogICAgICAgIDxkaXYg aWQ9ImNvbnRlbnQiPjwvZGl2PgogICAgICAgIDxkaXYgaWQ9Imljb24iPjwvZGl2PgogICAgICA8 L2Rpdj4KICAgIDwvZGl2PgogICAgPHVsPgogICAgICA8bGk+VG91Y2hpbmcgdGhlIGJsdWUgc3F1 YXJlIHdpbGwgZGlzcGF0Y2ggZXZlbnRzLjwvbGk+CiAgICAgIDxsaT5UaGlzIHNob3VsZCB3b3Jr IHRvbyB3aGVuIHRoZSBsYXJnZSBzcXVhcmUgaXMgc2Nyb2xsaW5nLjwvbGk+CiAgICA8L3VsPgog ICAgPHByZSBpZD0ibG9nIj48L3ByZT4KICAgIDxzY3JpcHQ+CiAgICAgIHZhciBpY29uID0gZG9j dW1lbnQuZ2V0RWxlbWVudEJ5SWQoImljb24iKTsKICAgICAgWyJjbGljayIsICJ0b3VjaHN0YXJ0 IiwgInRvdWNoZW5kIiwgInRvdWNobW92ZSIsICJ0b3VjaGNhbmNlbCJdLmZvckVhY2gobmFtZSA9 PiB7CiAgICAgICAgaWNvbi5hZGRFdmVudExpc3RlbmVyKG5hbWUsIGZ1bmN0aW9uIChlKSB7CiAg ICAgICAgICBkb2N1bWVudC5nZXRFbGVtZW50QnlJZCgibG9nIikuaW5uZXJUZXh0ICs9IGBEaXNw YXRjaGVkICR7bmFtZX0gZXZlbnQ6ICR7ZX1cbmA7CiAgICAgICAgfSk7CiAgICAgIH0pOwogICAg PC9zY3JpcHQ+CiAgPC9ib2R5Pgo8L2h0bWw+Cg==