pub fn mark(
profile: &Profile,
point: &Vector2,
joint: &str,
) -> GeopResult<(Profile, String)>Expand description
The closed profile with a joint at point, and that joint’s name:
the joint already there, or — where point lies along a curve — a new
one named joint, the curve split there, its second half X#joint.
Where exactly along the curve is a free choice within where point
could be: the halves are exact pieces of it either way. An error if
point is on no curve of the profile.