[cairo] bug in cairo_in_stroke() ?

[control H]

On Wed, May 25, 2011 at 9:02 PM, control H <control.h at gmail.com> wrote:
> Hi,
>
> I see unexpected behavior in the cairo_in_stroke() function. Attached
> is a simple program showing the problem. It seems the slope makes a
> difference. Resizing the window gives different results.
>
> Is this a bug?
>

Oh I forgot to tell:

cairo version: 1.10.2
Gtk version: 2.22.0
Glib version: 2.28.0

Can people confirm this is a bug in cairo_in_stroke() ?