tangentAt method

Point tangentAt(
  1. double t
)

Get the tangent direction at parameter t.

Implementation

Point tangentAt(double t) {
  const dt = 0.0001;
  final p1 = pointAt(t);
  final p2 = pointAt(t + dt);
  final dx = p2.x - p1.x;
  final dy = p2.y - p1.y;
  final len = sqrt(dx * dx + dy * dy);
  if (len == 0) return Point(1, 0);
  return Point(dx / len, dy / len);
}