[cairo] turn off antialiasing

[Owen Taylor]

On Mon, 2005-03-07 at 18:46 -0500, mental at rydia.net wrote:

> > Could you give me some references to that?
> > fringing in computer generated images?
> 
> Draw two dark shapes with complex edges that fit together (e.g.
> "puzzle pieces") against a light background.  There will most
> likely be a faint fringe between them (this phenomenon was the
> subject of a very recent thread on this same mailing list, in
> fact).
> 
> The fringe is unavoidable with antialiasing unless you can compute
> exact coverage (Cairo isn't set up to do that)

Actually, Cairo *is* set up exactly so that polygon edges
add up perfectly.

Exact coverage isn't really meaningful, considering that you 
only have 8 bits of channel in your rendered polygon. But there
are other algorithms that give matching edges ... in particular,
sampling at a fixed set of points in the interior of every
pixel.

Regards,
					Owen