Function flo_curves::bezier::fit_curve_cubic

pub fn fit_curve_cubic<Curve: BezierCurveFactory + BezierCurve>(
    points: &[Curve::Point],
    start_tangent: &Curve::Point,
    end_tangent: &Curve::Point,
    max_error: f64,
) -> Vec<Curve>

Fits a bezier curve to a subset of points

Usually you should use fit_curve unless you have a specific reason for using this function (fit_curve will call this function). There are two main reasons for calling this directly: if you have a better estimation of the tangent at the start and end of the curve than the one made fit_curve (which is based on the first and last two points of the curve), or if fit_curve is breaking down the set of points in a way that produces a poor fit for your use-case (it fits points in groups of 100).

start_tangent and end_tangent should be unit vectors indicating the direction of the curve at the start and end after fitting. start_tangent should point in the direction of the curve moving forwards, and end_tangent should point in the opposite direction (ie, these represent the direction of the control points at the start and end of the curve). Choosing bad values for these tangents will still result in a curve that fits well against the points but will have many subdivisions towards the start or end.

The algorithm here is to attempt to fit a single bezier curve against the points, estimate the point which has the highest error, and if too high subdivide at that point and try again.