Find the point of closest approach between a curve and a shape.

Input parameters:

1. Cr → Curve for proximity test.
2. Sh → Shapes to approximate.

Output parameters:

1. Pc → Point on curve at closest approach.
2. Ps → Point on shape at closest approach.
3. Lc → Curve locus at closest approach.
4. Ix → Index of closest shape.
5. Dx → Distance between the two points at closest approach.