* doubles, in the form x0, y0,
* x1, y1, .... NULL means don't
* fill in anything in this form.
* Caller must make sure that this
* array has enough space. */
* doubles, in the form x0, y0,
* x1, y1, .... NULL means don't
* fill in anything in this form.
* Caller must make sure that this
* array has enough space. */