GetContourGradient function
Implementation
List<VM.Vector2> GetContourGradient(List<VM.Vector2> contour) {
List<VM.Vector2> out = <VM.Vector2>[];
final cl = contour.length;
for (int i = 0; i < contour.length; i++) {
int im1 = i - 1;
if (im1 < 0) im1 += cl;
int ip1 = i + 1;
if (ip1 >= cl) ip1 -= cl;
VM.Vector2 v = _getMovement(contour[im1], contour[i], contour[ip1]);
out.add(v);
}
return out;
}