NEW 207089
Fixed elements should stay fixed with pinch-to-zoom 
https://bugs.webkit.org/show_bug.cgi?id=207089
Summary Fixed elements should stay fixed with pinch-to-zoom
cc.glows
Reported 2020-02-01 01:38:12 PST
When pinch-to-zooming, `fixed` elements don't stay fixed for a period and can be scrolled, but elements positioned relative to it with `fixed` get positioned incorrectly when using `getBoundingClientRect()`. This doesn't occur when zoomed out normally (0:00 - 0:05). When pinch to zooming as well, fixed elements can suddenly disappear after zooming in with pinch-to-zoom. Scroll down to the bottom right of the page in the repro and zoom in. Minimal reproduction: <!DOCTYPE html> <title>Basic Visual Test</title> <style> body { height: 3000px; width: 3000px; } #reference { position: fixed; top: 150px; left: 150px; width: 200px; height: 200px; background-color: red; box-shadow: inset 0 0 0 1px black; } #popper { width: 100px; height: 100px; background-color: rebeccapurple; box-shadow: inset 0 0 0 1px black; } </style> <div id="reference">Reference Box</div> <div id="popper">Popper Box</div> <script> popper.style.position = 'fixed'; function update() { const refRect = reference.getBoundingClientRect(); const popRect = popper.getBoundingClientRect(); popper.style.left = `${refRect.right}px`; popper.style.top = `${refRect.top + popRect.height / 2}px`; } window.addEventListener('scroll', update); update(); </script>
Attachments
Video demonstration of the reproduction (2.14 MB, video/quicktime)
2020-02-01 01:48 PST, cc.glows 		no flags
Details
Test HTML (858 bytes, text/html)
2020-02-03 10:39 PST, Simon Fraser (smfr) 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
cc.glows
Comment 1 2020-02-01 01:48:10 PST
Created attachment 389456 [details] Video demonstration of the reproduction Attached a video that was missing in the original post. Apologies for the redundant wording in it — I can't edit it.
Radar WebKit Bug Importer
Comment 2 2020-02-02 13:13:49 PST
<rdar://problem/59097233>
Simon Fraser (smfr)
Comment 3 2020-02-03 10:39:03 PST
Created attachment 389537 [details] Test HTML
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