Extract the coordinates of the boundary points and the value of a function on them

dolfinx
3 
v_cg1 = VectorElement("CG", domain.ufl_cell(), 1)
V = dolfinx.fem.FunctionSpace(domain, v_cg1)
f = Function(V)

f is a function null in the domain but with values on the boundary. My goal is to deform the boundary of the mesh according to this function.