@thi.ng/geom-splines/quadratic-tangent.js

nD cubic & quadratic curve analysis, conversion, interpolation, splitting

import { addW2 } from "@thi.ng/vectors/addw";
import { normalize } from "@thi.ng/vectors/normalize";
import { sub } from "@thi.ng/vectors/sub";
const quadraticTangentAt = (out, a, b, c, t, len = 1) => normalize(
  out,
  addW2(out, sub(out, b, a), sub([], c, b), 2 * (1 - t), 2 * t),
  len
);
export {
  quadraticTangentAt
};