[Webkit-unassigned] [Bug 274262] New: REGRESSION (macOS 14.4?) Toggling visibility on canvas parent undoes the effect of clearRect()

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=274262

            Bug ID: 274262
           Summary: REGRESSION (macOS 14.4?) Toggling visibility on canvas
                    parent undoes the effect of clearRect()
           Product: WebKit
           Version: WebKit Nightly Build
          Hardware: Unspecified
                OS: Unspecified
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: Canvas
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: simon.fraser at apple.com
                CC: dino at apple.com

Created attachment 471423

  --> https://bugs.webkit.org/attachment.cgi?id=471423&action=review

Test case from the reporter

Translated from https://forums.developer.apple.com/forums/thread/751730:

After drawing on the canvas in the Safari browser, execute clearRect().
After that, if you set visibility: hidden on the parent div of the canvas, the drawing that was supposed to be erased will be restored.
However, the parent div is no longer drawn because visibility: hidden is working normally.
Also, this phenomenon seems to be affected by the browser's magnification rate.
At least on the Macbook Air listed below, this only occurs when the magnification is 100%.
This phenomenon does not seem to occur in previous versions.
Are there any plans to fix this bug?

ModelOS&Version                                     Y/N version
MacbookAir M2 2022 macOS Sonoma 14.4.1              y   17.4.1
Mac Studio 2022 Apple M1 Max macOS Monterey 12.5    n   16.0
MacBook Air M1 2020 macOS Sonoma 14.3.1             n   17.3.1
iPadPro gen6 iPadOS 17.4.1                          y   -
iPad gen10 iPadOS 17.4.1                            n   -

For a demo to check the phenomenon, save the HTML file below and open it in your browser.
To reproduce, press the buttons in the order of draw -> clear -> hide.
The yellow parent div disappears, whereas a black square appears that I should have cleared from the canvas.

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