fractional scaling: window animations glitch for unscaled windows
When using fractional scaling (e.g. 125%) and maximizing a unscaled window (that is, a window not having the same ceiled buffer scale as the actor, e.g. xwayland windows, which always have buffer scale of 1), there's a glitch in window animations, showing the window e.g. half the size during the animation.
The problem seems to lie in
shell_util_get_content_for_window_actor (https://gitlab.gnome.org/GNOME/gnome-shell/blob/03c493088394589b2ef0b432e536c752fcd3f151/src/shell-util.c#L430), which calls
meta_shaped_texture_get_image, which again returns a
cairo_surface_t in buffer size. In case of scale mismatch between actor and buffer, we would need to scale the cairo surface up before showing.
Because the function will hopefully get updated before 3.34 (after mutter!409 (merged) and following landed, so we can fix mutter#146 (closed)), I'd suggest to not fix it right now, but keep it in mind.