concerns over wayland and need for wayland app display to X Server

[Bill Spitzak]

On 02/19/2012 03:08 PM, Daniel Stone wrote:
> Hi,
> There's already a Wayland session that runs on X, and as you asked
> for, an X server that runs rootless on Wayland, with full and proper
> integration with a Wayland session.  Hope this satisfies you.

The "Wayland session that runs on X" is, I believe, more like "a Wayland 
desktop inside an X window" and is *not* what he is asking for.

I think he wants to see each window created by the Wayland program 
making a different X window that is completely filled by the contents of 
the Wayland window.

So far it appears that toolkits like Qt are being written to internally 
switch between Wayland and Xlib, to provide this for him. This is 
probably the best solution.

There could be a Wayland compositor that actually "composites" the 
windows into X windows, which I think matches most closely what is being 
asked for. There are serious problems however. In particular the window 
borders are drawn by the client. Stripping them off and providing enough 
information for the X server to draw new ones would require all the crap 
that is in X now for clients to communicate information to the server, 
and would break any new and clever uses of the window borders. 
Displaying them as borderless windows would also work but may make some 
X desktops act strange. Double window borders may be somewhat 
acceptable, or an api from the compositor saying "no window border is 
needed" similar to what is needed for fullscreen. Stacking issues due to 
X window managers raising on click and the inability to outwit this 
without sending a limited set of rules through "transient for" hints is 
also going to be a big pain, but it might not break clients that consist 
of only one window and popup menus.

In general I think it would be really ugly if all the mistakes of X have 
to be replicated in the Wayland api just to communicate this 
information. So I think the proper answer is "no, it is not going to 
support this perfectly, but there will be compositors that will try." 
Please do not add crap to the Wayland API just to match X!