Sub-surface protocol

[Pekka Paalanen]

On Thu, 13 Dec 2012 12:33:33 -0500
Kristian Høgsberg <hoegsberg at gmail.com> wrote:

> On Thu, Dec 13, 2012 at 04:07:44PM +0100, John Kåre Alsaker wrote:
> > 
> > On Thu, Dec 13, 2012 at 3:30 PM, Pekka Paalanen <ppaalanen at gmail.com> wrote:
> > >
> > > On Thu, 13 Dec 2012 14:51:17 +0100
> > > John Kåre Alsaker <john.kare.alsaker at gmail.com> wrote:
> > >
> > >> I see that in weston the shell is very glad in inspecting geometry. We
> > >> also have to alpha property per-surface instead of per
> > >> wl_shell_surface. For fading windows we may want to compose the
> > >> wl_surface_group into a single image.
> > >
> > > I don't think we want to do intermediate composites, unless we can put
> > > it into a plane. Otherwise it's just extra data movement. It seems to
> > > be very easy to hook a compound window into the input and repaint
> > > procedures by just adding all the wl_surfaces into the big surface
> > > list created during weston_output_repaint(). I don't have to revamp
> > > either input nor repaint code. I actually got that part working right
> > > now.
> > >
> > > For alpha, we can easily enough change the surface alpha for all...
> > > wait, that would not really work right. We'd have to manipulate the
> > > repaint regions, too. Maybe that's not even enough, oh well.
> > We have to compose it or we'll see through parts that's supposed to be
> > opaque (I think Cinnamon does that for it's menu, it looks odd).
> 
> Yeah, that's a good point.

Blending of full-surface alpha may become a source of great pain, but
we'll tackle it when we have a test case.


Thanks,
pq