Hello, can freefem + + use spline interpolation？

Thank you for your reply. Is there an example of freefem + + for spline interpolation?

Hello, do you have to build your own finite element space when this spline interpolation is used in FreeFem++? Take Lagrange interpolation as an example to define the finite element space, feaspace Wh (Th, P2). How to define this spline?