Bug with setting axis limits

While not common, it does happen. I'm reminded of a

    > handbook that was produced here that generated an incorrect
    > plot because of a clipping error. We didn't write that
    > clipping software, but it was embarrasing nonetheless. It's
    > worth some effort to get it right I think. Before wasting
    > more discussion over it I guess I'd like to know which
    > backends don't support generalized clipping for lines and
    > polygons.

I'll delve deeper into agg and find out what exactly is going.

BTW, Maxim has revamped the antigrain site, added documentation, and
released some new code. I'm obviously waiting until the dust settles
on the next matlotlib release before upgrading (and upgrading
matplotlib agg cvs will be a bit of a pain since many file names hanve