New version of xfixes with client side cursor support

[David Reveman]

On Fri, 2007-02-16 at 17:00 -0800, Keith Packard wrote:
> On Fri, 2007-02-16 at 17:08 +0100, David Reveman wrote:
> > attached are patches that adds functionality to the xfixes that
> > compositing managers can use to render cursors on the client side.
> > 
> > Sprite position, cursor dimensions and hot spot location which could
> > only be received using GetCursorImage request before have been added to
> > the CursorNotify event so that a round trip isn't necessary for getting
> > these properties. This means that CursorNotify events are now generated
> > every time the sprite position changes. We can have the server not send
> > more events than before to clients that don't support version 5 of
> > xfixes if people are concerned about existing clients getting more
> > events than before. I left this out of the patch for now as I don't
> > think it's a major problem.
> 
> If you're changing functionality of existing extension requests, I'd
> suggest just offering a way to ask for the new functionality, leaving
> the existing bits in place.

OK, I can easily add another event type for this if that's better.

> 
> > NameCursorPixmap request has been added and it can be used to get a
> > pixmap which contains the current cursor bits.
> 
> Hmm. I see all kinds of ordering issues here, as cursors come and go
> rapidly and clients respond asynchronously to those changes. Your
> suggested request doesn't name a specific cursor, it just names the
> *current* cursor, which may have nothing to do with the image you were
> expecting to manipulate. What you want is to be able to talk about the
> cursor which was displayed when you received notification.
> 
> No, I don't have a good plan here, I'm just suggesting that creating a
> pixmap for a random cursor may not generate useful results.

It's no worse than NameWindowPixmap, which will give you a pixmap for
some random state of the window and not necessarily the pixmap that
matches the size indicated by the last ConfigureNotify.

Sure, it might be nice with something better but I don't think that
makes sense unless we're interested in improving NameWindowPixmap too.

- David