[cairo] Disabling antialiased shape drawing

[Robert O'Callahan]

On Thu, 2005-08-04 at 22:05 -0500, Billy Biggs wrote:
> Robert O'Callahan (rocallahan at novell.com):
> 
> > >  2. The API can be safely ignored by backends that do not require this
> > >     setting, such as the PS or PDF outputs.
> > 
> > Making this API non-mandatory means that an application that wants to
> > use supersampling has to know, for each surface type it uses, whether
> > or not the surface type really supports this API. But such
> > applications already need to know which surface types need
> > supersampling, so I guess this is OK, as long as a surface type's
> > support for this API is considered part of the interface and isn't
> > removed in the future.
> 
>   I think you need something else.  I want to ask a backend to disable
> antialiasing, and I think you want to ask if you should do supersampling
> for it.  I don't think that one pair of functions should try to do both.

If I create the surface, I may not need to ask whether the surface
supports supersampling. I may just know that Xlib surfaces do and PDF
surfaces don't. I have your API to turn off antialiasing for the Xlib
surface, but I need some assurance that the Xlib surface is really going
to turn it off when I ask it to. All I need is the promise that
Xlib-surface's existing support won't be taken away.

Rob