Composite overlay window

[Kristian Høgsberg]

Hi,

I was discussing the new overlay window additions in composite with 
Søren, and he pointed out that there is no way to specify the visual for 
the overlay window:

	Window
	XCompositeGetOverlayWindow (Display *dpy, Window window);
   	
	void
	XCompositeReleaseOverlayWindow (Display *dpy, Window window);

and reading the code, it turns out that it's just using the root visual. 
  I was of the impression that one of the compelling arguments for going 
with the overlay window approach was that you'd get to specify the 
visual when creating the overlay window.

Should we add a visual argument to XCompositeGetOverlayWindow?  Also, it 
looks like the only reason for passing in a window is to get at the 
screen that window belongs to.  In that case, I think it would be 
clearer to just pass in the screen number.

cheers,
Kristian