The bug listed in #767408 is caused by the default x range to be
[-3,3], so when the parametric plot is computed, the x values are
clipped to [-3,3].
I've changed the default to be the same large value as the default y
ranges, and this fixes the parametric plots. It also doesn't cause
any problems with 2-D plots because a range must be specified.
However, with the new adaptive plotting, the default number of ticks
(samples) is 10. For normal 2D plots, this is adaptively adjusted, so
it's not a problem. However, for parametric plots, the number of
ticks is not changed, so parametric plots only have 10 samples taken.
The plots aren't so good. :-(
I'm not sure how to proceed from here. Any suggestions how to set the
number of ticks?
Ray