Interpolate a point along a cubic bezier curve.

interpolateCubicBezier.ts

export function interpolateCubicBezier(
  p0: { x: number; y: number },
  c0: { x: number; y: number },
  c1: { x: number; y: number },
  p1: { x: number; y: number }
) {
  // 0 <= t <= 1
  return function interpolator(t: number) {
    return [
      pow(1 - t, 3) * p0.x +
        3 * pow(1 - t, 2) * t * c0.x +
        3 * (1 - t) * pow(t, 2) * c1.x +
        pow(t, 3) * p1.x,
      pow(1 - t, 3) * p0.y +
        3 * pow(1 - t, 2) * t * c0.y +
        3 * (1 - t) * pow(t, 2) * c1.y +
        pow(t, 3) * p1.y,
    ]
  }
}