[cairo] Drawing diagonal lines with antialiasing off

[mental at rydia.net]

Quoting Behdad Esfahbod <behdad at cs.toronto.edu>:

> On Wed, 28 Sep 2005, Bill Spitzak wrote:
>
> > Using linewidth of 0 for hairlines is well established by
> PostScript,
> > OpenGL, PDF, and many other graphics API's.
>
> I like having hairlines in cairo too.

I also think hairlines would be good to have.

Really, all these other issues aside, people will expect them
because of the other APIs.

I had kind of expected that Cairo would support them myself, having
never gotten around to trying them or reading the documentation
that thoroughly.  So there is a POLS issue too.

-mental