Wayland frame requests without rendering

[mahkoh]

Description

For event-driven applications it is sometimes desirable to always render in response to frame request callbacks. Currently there is no way to ensure the delivery of a frame callback without either presenting via the WSI or manually performing wayland requests.

It is already possible to create frame requests at any point. But winit provides no API to commit such a frame request.

Relevant platforms

Wayland

[kchibisov]

From what I remember it was recommended to not do so, and if you draw from idle you should draw immediately since frame callbacks don't help here?

I generally don't mind it once we have a a direct access to wayland backend.

[mahkoh]

Frame callbacks can be used to pace animation. If each animation frame causes damage, then this works with winit. But if an animation does not cause damage, then you have no way to pace the next animation frame.

It would be possible to work around this by getting the refresh rate of the surface (from presentation feedback). But winit does not provide this information either.