I have seen this question: Can't a Wayland compositor do the window decorations like on X?, but I'm wondering this:
Say I write an application using pure wayland, how do I know if the server will decorate the window? I want to support compositors who don't decorate, and compositors who do decorate (on the ones who don't, the application will decorate it manually).
Is this possible? If not, is this theoretically possible with the current wayland API (i.e. some kind of weird message passing that would require standardization)? And if not, why not?
There is currently no standardised way to identify whether the compositor decorates the windows. That being said I am not aware of any Wayland compositors that do server side decoration and all major toolkits (GTK, QT, Elementary) use client side decoration when running against Wayland.