Re: 0.95-pre1 bug with Arc connectors.

["Rob McDonald" <robm asdl gatech edu>]

> > On 0.95-pre1 Windows, arc connections sometimes vanish.  This behaves
> > somewhat like a problem with a trig function.  Maybe a classic atan vs.
> > atan2 issue.  Basically, when you grab the control point and try to
adjust
> > how curved an arc is, for some ranges of arc, the line disappears.  This
can
> > be worked around by switching the starting and ending points.  Then, the
> > point of dissappearance is reversed...
>
> Are these accurate steps to reproduce what you see:
>
> Make a new diagram
> Turn on snap-to-grid
> Draw an arc between two adjacent grid points
> Move the arc midpoint back and forth -- on one side it disappears, on
> the other it's there.

I can reproduce the problem in that manner.

However, snap-to-grid doesn't matter for me.  I just tested it without snap
turned on.

The arc doesn't need to go between two adjacent grid points, I just picked
two arbitrary separated points.

If the arc is vertical, it appears to happen crisply based on which 'side'
it is on.  However, if the arc end points are at arbitrary points, the arc
vanishing seems to be a bit more complex.  However, it is very easy for me
to reproduce.  You'll know it when you see it.

It appears to be somewhat related to one or the other of the endpoints going
vertical, but not absolutely so.

              Rob