toContour
fun BSpline<Vector2>.toContour(tolerance: Double = 0.01, polarity: YPolarity = YPolarity.CW_NEGATIVE_Y): ShapeContour(source)
This spline as a ShapeContour: exactly, one Bézier segment per knot span, for degree 1 to 3, and approximated by cubic Béziers within tolerance for higher degrees.
Converts chain to a ShapeContour.