composite manager and memory mgmt

[Felix Bellaby]

On Sat, 2007-03-24 at 08:52 +0000, Felix Bellaby wrote:
> On Fri, 2007-03-23 at 15:38 +0200, Tapani Plli wrote:
> > Possible usecases are usage of shadows on application menu's and dialogs
> > + moving elements (menus, infoprints). In Maemo we have these small
> > infoprints (think of notifications), they can be animated (as well as
> > have translucency) with composite.
> > 
> > Right now I'm experimenting with menus and infoprints. Usage of
> > composite also does some nice buffering for (complex) gtktreeviews, no
> > more flickering white boxes then.
> 
> That suggests that there is no need for the other main windows to be
> mapped. Could you force them to unmap? It would ensure that no memory
> was wasted maintaining pixmaps for compositing those windows.

Alternatively, it might suffice to unredirect the windows while leaving
them mapped. Providing that you use the composite overlay window for
your drawing (rather than drawing onto root) then the overlay window
should hide the unredirected windows, allowing you to forget about
them. 

This should act as an alternative means of avoiding the allocation of
pixmap memory for the obscured windows, though I have never tried it. It
should be easier to implement than unmapping the windows, though it
would probably be less efficient.

Felix