[PATCH v2 5/6] composite: Support updating an arbitrary subtree
ville.syrjala at Nokia.com
Mon Jan 3 04:33:32 PST 2011
On Fri, Dec 31, 2010 at 02:00:43PM -0800, ext Keith Packard wrote:
> On Fri, 31 Dec 2010 16:49:38 +0200, ville.syrjala at nokia.com wrote:
> > WindowRec has a new member 'damagedDescendants' that is used to keep
> > track of which subtrees need updating. When a window is damaged,
> > 'damagedDescendants' will be set for all the ancestors, and when a
> > subtree is updated, the tree walk can be stopped early if no damaged
> > descendants are present.
> I think this raises an interesting general topic - how much of the
> current extension private stuff should get folded into the various DIX
> structures?? We've got a bunch of non-optional extensions these days and
> it might be a nice cleanup job to take their privates and move them.
> > CompScreenRec no longer needs the 'damaged' member since the root
> > window's 'damagedDescendants' provides the same information.
> > Signed-off-by: Ville Syrjälä <ville.syrjala at nokia.com>
> This seems like a reasonable optimization to me, reducing the cost of
> having any CompositeRedirectAutomatic windows on the screen.
> I'm not entirely happy with the name compChildrenUpdate, but given that
> compWindowUpdate paints a window into its parent, I don't have a great
> suggestion for an alternative name. One option might be to move the
> painting code inside the loop:
> if (pWin->damaged)
> pWin->damaged = FALSE;
> if (!pWin->damagedDescendents)
> for (pChild = pWin->lastChild ...)
> pWin->damagedDescendents = FALSE;
> Or some such. Having two functions looping over the child list seems
OK. I'll see about making it better.
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