Bug 197387

Summary: [macOS] scroll event doesn't fire on Visual Viewport API
Product: WebKit Reporter: Ryosuke Niwa <rniwa>
Component: ScrollingAssignee: Nobody <webkit-unassigned>
Status: RESOLVED INVALID    
Severity: Normal CC: simon.fraser, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
Bug Depends on:    
Bug Blocks: 170982    

Description Ryosuke Niwa 2019-04-29 14:22:09 PDT
Apparently we don't fire scroll event on visual viewport API on macOS :(
Comment 1 Radar WebKit Bug Importer 2019-04-29 14:23:43 PDT
<rdar://problem/50311222>
Comment 2 Ryosuke Niwa 2019-05-02 22:36:15 PDT
Actually, the current behavior of WebKit matches that of Chrome so this is probably not really a bug. In fact, offsetTop/offsetLeft are always 0 on macOS when it's not zoomed. When we're zoomed, we'd fire scroll events as expected. This is somewhat counterintuitive but it's probably safe to match Chrome's behavior here.
Comment 3 Simon Fraser (smfr) 2019-05-03 09:09:11 PDT
Right, that's related to whether you fire scroll events on visual or layout viewport changes.