NEW232374
iPhone landscape animations lags 
https://bugs.webkit.org/show_bug.cgi?id=232374
Summary iPhone landscape animations lags
Roland Soos
Reported 2021-10-27 05:00:59 PDT
Created attachment 442579 [details] Screencapture Steps to reproduce: 1. Rotate your iPhone to landscape orientation 2. Open https://smartslider3.com/bugs/webkit/bganimlag/ 3. Swipe left and right to trigger the animation What's went wrong? Animation lags and sometime the page crashes and reloads. Also phone starts to getting hot, probably CPU is working really hard. In portrait orientation everything is fine and smooth. Able to reproduce on IOS 14.5 and IOS 15.0.2 See attached screencapture.mov
Attachments
Screencapture (4.66 MB, video/quicktime)
2021-10-27 05:00 PDT, Roland Soos 		no flags
Details
Layers screenshot (2.14 MB, image/png)
2021-10-27 23:07 PDT, Simon Fraser (smfr) 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Sam Sneddon [:gsnedders]
Comment 1 2021-10-27 22:17:45 PDT
Repros on Safari 15.1 on macOS 12.0.1 on M1; looks like all its time is spent in compositing and paint.
Simon Fraser (smfr)
Comment 2 2021-10-27 23:07:49 PDT
Created attachment 442676 [details] Layers screenshot The content is making large numbers of layers which are much bigger in landscape, triggering jetsam of the web content process.
Simon Fraser (smfr)
Comment 3 2021-10-27 23:10:38 PDT
mid-animation you have 70 "div#n2-ss-3053 .n2-ss-background-animation .n2-ss-slide-background" elements each of which has translateZ() forcing a layer. That seems a little excessive.
Roland Soos
Comment 4 2021-10-27 23:17:06 PDT
Thanks for checking! Probably it would be better if we would write this "effect" in WebGL canvas.
Alexey Proskuryakov
Comment 5 2021-10-30 17:04:37 PDT
On iPhone 13 Pro and iOS 15.1, this crashes every time (probably out of memory).
Radar WebKit Bug Importer
Comment 6 2021-11-03 05:01:22 PDT
<rdar://problem/84970233>
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