cross-client surface references

[Alexander Larsson]

On Fri, 2015-07-03 at 18:10 +0800, Jonas Ådahl wrote:

> 
> With "see" I suppose you mean "be aware and map", because it wouldn't
> see the content.

Sure, there is no need for the other client to ever see (or change) the
contents of the window (or get events or whatever). This is purely
about being able to refer to the other clients window when specifying
relationships between surfaces.

> For the record, the original foreign surface idea was about putting 
> less
> privileged clients's surfaces inside a more privileged client's 
> parent
> surface, which indeed is quite the opposite of whats the intention 
> here.
> 

I think this is better handled by a sub-compositor. In fact, i took
Jaspers initial wakefield proof of concept and extended it to be a
generic such sub-compositor for Gtk:

https://github.com/alexlarsson/wakefield

This is interesting because its even cross-backend. I.e. you can run
the wakefield compositor on the gdk X11 backend, spawn a child process
that uses the wayland gdk backend and embedd it. (I know you know about
this but others on the list may not.)