230751 2021-09-24 08:19:43 -0700 REGRESSION (Safari 15): Protomaps is very slow/hangy in Safari (large paths?) 2021-10-28 21:22:08 -0700 1 1 1 Unclassified WebKit Canvas Safari Technology Preview Unspecified Unspecified RESOLVED DUPLICATE 231157 InRadar P2 Normal --- 1 simon.fraser webkit-unassigned bdon dino heycam simon.fraser webkit-bug-importer oldest_to_newest 1796887 0 simon.fraser 2021-09-24 08:19:43 -0700 https://protomaps.github.io/protomaps.js/examples/leaflet.html#11/35.6079/139.7458 is very slow, to the point of hanging. Seems like a canvas/GPU process thing. 1796888 1 webkit-bug-importer 2021-09-24 08:20:28 -0700 <rdar://problem/83497019> 1797734 2 bdon 2021-09-27 18:46:31 -0700 Hi, library author here. To describe what I'm seeing: On Safari 15 on macOS Big Sur, Technology Preview, and iOS 15 Safari, the tab will either crash or the UI thread will hang randomly after panning/zooming for a while, sometimes immediately on page load. I can confirm that turning off “GPU Process: Canvas Rendering” fixes the problem, but that isn't a viable workaround for users. From experimenting with the Canvas calls in the library it seems to be related to rasterizing a path (context.fill(), context.stroke()) with hundreds to thousands of vertices. Similar bug reports: 1. https://developer.apple.com/forums/thread/685866 2. https://github.com/ant-design/ant-design-charts/issues/855 3. https://github.com/flutter/flutter/issues/89655 1797740 3 simon.fraser 2021-09-27 19:01:20 -0700 Thanks for the update, we're tracking this regression. 1803669 4 bdon 2021-10-13 01:01:24 -0700 As an update, I'm pretty sure the root cause here is the same at https://bugs.webkit.org/show_bug.cgi?id=231157 . I've implemented a workaround for the library to limit the # of vertices in a single call to stroke() or fill(). It's been successful so far on the devices I've tested, will report back after more testing. 1809921 5 heycam 2021-10-28 17:33:52 -0700 Brandon, is the workaround already present in the URL Simon linked in comment 0? Testing with that URL I couldn't reproduce the hanging. If so, then we should probably just dupe this bug to the long path issue in bug 231157. 1809934 6 bdon 2021-10-28 18:58:46 -0700 Cameron, There is a partial workaround implemented on that page which makes it more difficult to reproduce, but the crash/hang is still present; I do believe the root cause is the same, so you can mark this as a dupe. Brandon 1809955 7 heycam 2021-10-28 21:22:08 -0700 Thanks for confirming. *** This bug has been marked as a duplicate of bug 231157 ***