[Webkit-unassigned] [Bug 256260] New: Canvas will intermittently come up blurry and remain so in Safari 16

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=256260

            Bug ID: 256260
           Summary: Canvas will intermittently come up blurry and remain
                    so in Safari 16
           Product: WebKit
           Version: Safari 16
          Hardware: Unspecified
                OS: Unspecified
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: Canvas
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: gmurray at gmail.com
                CC: dino at apple.com

Even provided correct CSS size vs back buffer size for the current window.devicePixelRatio, the canvas will sometimes be blurry on some page refreshes and remain so even when repainted and/or resized.

See: https://www.infragistics.com/webcomponents-demos/charts/category-chart/line-chart-multiple-sources

Repeatedly refresh the page and notice how sometimes the text will be blurry, and sometimes the text will be crisp. Reproduced against 16.4.1 on MacOS Monterey and various iOS devices running versions of Safari 16. I was unable to reproduce this on anything running Safari 15. The text would always be crisp. Inspecting the chart, we are using the appropriate back buffer size and css size regardless as to whether it looks crisp or blurry. It just randomly works correctly or incorrectly as you refresh it. I've tried to inject a time delay before the canvases in case it has something to do with the timing of the page initialization, but this does not seem to be the case.

Note, something that may be different about this scenario compared to more simple scenarios is that there are multiple canvases of a similar size being created in concert and positioned layered upon one another.

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