Why is X11 windowing code producing XLIB raw window handle while using XCB for talking to X11?

[kvark]

See https://github.com/rust-windowing/winit/blob/master/src/platform_impl/linux/x11/window.rs#L1860

As far as I see, all the talking to X11 is done via xcb_connection aka XCB. Is there a specific reason we aren't producing RawWindowHandle::Xcb?

The context of the question is that I have a different windowing system that does produce rwh::Xcb handle, and it stubbornly refuses to work with window transparency and Vulkan, somehow. So I'm curious about the thought process in winit.

[notgull]

The main reason is because Xlib is generally more supported among graphics subsystems due to its staying power. So even though XCB is much safer, we keep around an Xlib connection for this purpose. Among others, but we're trying to reduce the surface area, see #3198

[kchibisov]

Yeah, GLX and some other stuff can not work without xlib. We also need xim for now, etc.

There could be an option to use just xcb in the future though.