radeon EXA performance questions

[Owen Taylor]

On Mon, 2008-08-04 at 19:51 +0200, Clemens Eisserer wrote:
> Hi,
> 
> > Firefox uses GetImage when drawing "natively themed" widgets in a web
> > page, like buttons or input boxes. (It draws them with GTK+ to a pixmap,
> > then gets the image from there and composites it into a page.)
> 
> Thats because GTK's theming interface makes it really hard for non gtk
> apps/toolkits to use it efficiently, for every widget drawn you have
> to readback from vram, which is especially bad with accaleration in
> place.
>
> They switched to Cairo with 2.6, but were so afraid breaking the theme
> interface that they prefer to create/destroy cairo-contexts for every
> small line which is drawn.

"They", hmm. Oh, you mean me.

API is not broken in the GTK+ 2.x line, period. Doesn't happen. Doesn't
mean that other things could not have been done in a compatible fashion.
But creation of cairo contexts is not a bottleneck in any profile I've
ever looked at, so that wouldn't be the motivating factor.

> Even the  GtkCairoIntegration todo list mentions problems with the
> current design:
> > 5. Gtk+ themes need to support Cairo surfaces so that e.g.
> > insensitivity can be rendered without workarounds (e.g. insensitivity
> > for a TreeView cellrenderer rendering Cairo image surfaces)
> 
> Wrote a proof-of-concept patch some time ago, but no-one of the gnome
> guys found it even worth looking at this:
> http://bugzilla.gnome.org/show_bug.cgi?id=515600
> Even telling me that its crap would have made me happier than
> completly ignoring it.
> 
> Now GTK-3 is starting to become reality ... and what I have heard its
> still not the long-needed re-design, just another extension of the
> so-many-times extended/hacked code with only some minor cleanups.

Please read:

http://mail.gnome.org/archives/gtk-devel-list/2008-July/msg00088.html

For more constructive ways to move forward.

- Owen