[cairo] turn off antialiasing

[David Reveman]

On Tue, 2005-03-08 at 09:08 +0100, Johannes Berg wrote: 
> On Mo, 2005-03-07 at 18:46 -0500, mental at rydia.net wrote:
> > > Why would you like to turn antialiasing off on some objects?
> > 
> > Faster rendering, depending on how those objects would be used.
> > 
> >  shape-rendering="optimizeSpeed"
> 
> This seems to imply that Cairo needs hints not just to avoid AA but also
> use the speediest setting, or am I totally off by imagining that on
> certain backends doing AA would be faster than not doing it (for some
> objects)?

cairo_set_tolerance can be used for this, we can make so that having
tolerance set to greater than half a device unit would speed things up a
lot. I know that this is at least possible for the glitz backend.  

-David