"Keep UI responsive" tab not rendering?

[cmdcolin]

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I see the tab for the left most "Avoid jank" tab shows both worker and main thread renderings, but the "Keep UI responsive" only shows the main thread rendering e.g. only a growing/shrinking rainbow circle on the left

Version 75.0.3770.100 (Official Build) snap (64-bit)

[sergeevabc]

Err… Another confused user here. Setup: FF 70.0.1 x64, a fresh profile with gfx.offscreencanvas.enabled set true. I see some animation on the left, but empty white area on the right (screenshot). Dear @devnook, could you be so kind to shed some light, why?

[cmdcolin]

@sergeevabc I think I figured it out.

Note that firefox does not in any case have offscreen 2d canvases so it will not work in the right side in firefox

See https://developer.mozilla.org/en-US/docs/Web/API/OffscreenCanvas/getContext and the linked bug https://bugzilla.mozilla.org/show_bug.cgi?id=801176

Really would like firefox to get offscreen 2d canvas sometime too :)

I also figured out my confusion. The way the demo works for "keep ui responsive" tab is that there is a toggle switch, and then only when it is in the webworker can you keep clicking the "button" which is just the text "INTERACT: COUNTER N"