smoothPath function

Path smoothPath(List<Offset> points)

Builds a smooth cubic-bezier Path that passes through every vertex in points using a Catmull-Rom spline (tension 0.5). Falls back to straight segments below three points, where a curve is undefined.

Implementation

Path smoothPath(List<Offset> points) {
  final path = Path();
  if (points.isEmpty) return path;
  path.moveTo(points[0].dx, points[0].dy);
  if (points.length < 3) {
    for (var i = 1; i < points.length; i++) {
      path.lineTo(points[i].dx, points[i].dy);
    }
    return path;
  }
  for (var i = 0; i < points.length - 1; i++) {
    final p0 = points[i - 1 < 0 ? i : i - 1];
    final p1 = points[i];
    final p2 = points[i + 1];
    final p3 = points[i + 2 > points.length - 1 ? i + 1 : i + 2];
    final c1 = Offset(p1.dx + (p2.dx - p0.dx) / 6, p1.dy + (p2.dy - p0.dy) / 6);
    final c2 = Offset(p2.dx - (p3.dx - p1.dx) / 6, p2.dy - (p3.dy - p1.dy) / 6);
    path.cubicTo(c1.dx, c1.dy, c2.dx, c2.dy, p2.dx, p2.dy);
  }
  return path;
}