Function XdgToplevel.setFullscreen

Make the surface fullscreen.

After requesting that the surface should be fullscreened, the compositor will respond by emitting a configure event. Whether the client is actually put into a fullscreen state is subject to compositor policies. The client must also acknowledge the configure when committing the new content (see ack_configure).

The output passed by the request indicates the client's preference as to which display it should be set fullscreen on. If this value is NULL, it's up to the compositor to choose which display will be used to map this surface.

If the surface doesn't cover the whole output, the compositor will position the surface in the center of the output and compensate with with border fill covering the rest of the output. The content of the border fill is undefined, but should be assumed to be in some way that attempts to blend into the surrounding area (e.g. solid black).

If the fullscreened surface is not opaque, the compositor must make sure that other screen content not part of the same surface tree (made up of subsurfaces, popups or similarly coupled surfaces) are not visible below the fullscreened surface.