compiz - Dec 2006 - Question regarding window output extents

Hi,

in a plugin I am developing with some other people (namely: tabbed
window grouper), we want to paint a glow like effect around the windows.
This is done by adding the glow as "second decoration" around the
window
decoration.
The question now is: How can we communicate the fact that there is a
second set of decoration properly to other plugins so that window
damaging and transformation are aware of the glow? 
>From my understanding, the member "output" of the CompWindow
structure
is supposed to do exactly that. But its contents get overwritten by the
decoration plugin on every window state change and window
activation/deactivation, so our plugin can't use it (and the function
setWindowFrameExtents) directly because the changes aren't persistent.

Is there a function or struct member I can use to propagate this
properly? Any suggestions are highly appreciated.

Thanks!

Regards,

Danny

Hi,
> The question now is: How can we communicate the fact that there is a
> second set of decoration properly to other plugins so that window
> damaging and transformation are aware of the glow? 
> >From my understanding, the member "output" of the CompWindow
structure
> is supposed to do exactly that. But its contents get overwritten by the
> decoration plugin on every window state change and window
> activation/deactivation, so our plugin can't use it (and the function
> setWindowFrameExtents) directly because the changes aren't persistent.
After some more research, I'd like to add a comment:
As w->output really seems to be the struct responsible for what I'd like
to do, I have a proposal for solving that problem:

- Add a wrappable notify function, called from inside
setWindowFrameExtents - the prototype could look that way:

void windowFrameUpdateNotify (CompWindow *w, Bool inputChanged, Bool
outputChanged);

- Plugins which want to manipulate w->input or w->output then can hook
(AKA wrap) into this notify function and can adjust the structs to their
needs.

- If the plugins only are allowed to enlarge w->output and not to shrink
it, this approach is even plugin load order independant.

Questions/Remarks/Comments?

Regards,

Danny