raphlinus

use kurbo::{CubicBez, ParamCurveDeriv};

/// Compute bounds on curvature
pub fn kbound(c: CubicBez) -> (f64, f64) {
    let q = c.deriv();
    let p1xp0 = q.p1.to_vec2().cross(q.p0.to_vec2());
    let p2xp0 = q.p2.to_vec2().cross(q.p0.to_vec2());
    let p2xp1 = q.p2.to_vec2().cross(q.p1.to_vec2());
    let c0 = 2. * p1xp0;
    let c1 = 2. * (p2xp0 - 2.0 * p1xp0);