Bug 227487

Summary:	Pictures outside a zoomed area reload themselves when zooming out
Product:	WebKit	Reporter:	tym46383
Component:	Compositing	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	bfulgham, sabouhallawa, simon.fraser, thorton, webkit-bug-importer, zalan
Priority:	P2	Keywords:	InRadar
Version:	Safari Technology Preview
Hardware:	Mac (Apple Silicon)
OS:	Other

Description tym46383 2021-06-29 08:58:47 PDT

When I'm on a page with a lot of pictures and zoom in, zooming back out causes the pictures that weren't in the zoomed view to be invisible until I finish the zooming gesture. The best example of this I have currently is https://www.tripadvisor.com/RoadTrip-g191-United_States.html.

To reproduce: Zoom in with a gesture. Zoom back out. Notice that the images that were outside the zoomed area are momentarily white before reappearing. It's particularly noticeable if you hold the gesture for a bit before moving your fingers.

Comment 1 Radar WebKit Bug Importer 2021-07-06 08:59:17 PDT

<rdar://problem/80213268>

Comment 2 Simon Fraser (smfr) 2021-07-06 12:17:07 PDT

We drop compositing layer backing coverage for the layers outside the viewport, then only bring it back in as the zoom ends (the zoom is not live, like it is on iOS).