[Telepathy] Vino-telepathy for a single window?

[Dafydd Harries]

Ar 05/08/2009 am 13:38, ysgrifennodd Benjamin M. Schwartz:
> Simon McVittie wrote:
> > On Wed, 05 Aug 2009 at 12:20:02 -0400, Benjamin M. Schwartz wrote:
> >> So my question is: Do you think it would be possible, with the
> >> Vino+telepathy codebase, to stop and start screen updates based on an
> >> external signal, while allowing client-server interaction to continue?
> > 
> > I think this is entirely Vino and not at all Telepathy, to be honest :-)
> 
> Yeah, I just thought there might be someone here familiar with the code.
> 
> > I don't know anything about the internals of Vino, but I suspect it might not
> > be significantly harder to "say what you mean" and have Vino spy on a
> > particular window rather than the whole desktop (which would also make it
> > much more useful outside Sugar).
> 
> I don't know much about Vino.  x11vnc can do this, but if another window
> moves above the selected one, the server will happily transmit whatever's
> on top.

Presumably it's using XGetImage, which doesn't handle occluded regions
properly. It's possible to do this properly using XComposite + XDamage.
XComposite lets you redirect the drawing offscreen so you can copy the
contents regardless of occlusion, and XDamage will tell you when it changes so
you can update.

I agree with Simon's analysis that this seems like a Vino problem than a
Telepathy problem.