plugin does play alerts incorrectly

[GloriousEggroll]

if using the plugin for something like twitch alerts via streamlabs it breaks.

what I expect:

animated gif alert to fade in while playing the gif, then fade out.

what happens:

animated gif alert plays then hangs on the image instead of exiting

note: same alert works correctly in cef based obs-browser

[fzwoch]

IS that any specific one?

Last time I tried it worked fine. But I cannot remember if it was streamlabs or some other alert provider.. But I guess it was streamlabs.. with the default alert (as I'm not really familiar with all the providers/options).

[fzwoch]

I can confirm the issue.

[fzwoch]

This may be a regression from cairo/webkitgtk? It seems like the surface buffer gets incorrectly swapped or not cleared between frames. (See ghosting like image of the zombie)

[fzwoch]

It seems to be caused by the WEBKIT_HARDWARE_ACCELERATION_POLICY_NEVER flag. When not rendering into an offscreen window but a regular window the artifacts are the same. Removing the flag so hardware acceleration is being used fixes the rendering. It is not possible to so in the context of this plugin though.

So I guess the error is in the software fallback in webkitgtk/gtk/cairo. Or maybe something completely different I haven't understood.