Fillet all the corners of a curve based on their angle.

Input parameters:

1. Cr → Curve to fillet.
2. Rf → The function mapping corner angle to fillet radius. Note that concave corners have negative angles.
3. Dg → Measure corner angles in degrees.
   •  True → Degrees
   • False → Radians

Output parameters:

1. Cr → Filleted curve.
2. Ar → Filleting arcs.
3. An → Segment angles at each fillet.