I have two parametric planar curves.
The curves are not self-intersecting.
Curve $C_0$ is inside $C_1$.
With $t \in [0..1]$
$ C_0:x = f_0(t); y = g_0(t) $
$ C_1:x = f_1(t); y = g_1(t) $
Now I'm interested by the surface between theses two curves.
$Surf(d,t) = \{(d*f_0(t)+(1-d)*f_1(t); d*g_0(t)+(1-d)*g_1(t)) (t,d) \in [0..1]^2\} $.
I would like to compute the couple $(d(a,b),t(a,b))$ for every point $P(a,b)$ inside $C_1$ (the outer curve), and outside $C_0$,
My goal is to generate a gradient along each segment joining the two curves.