clampRadius function
Implementation
@pragma('vm:prefer-inline')
Offset clampRadius(Offset o, double maxR) {
final d2 = o.distanceSquared;
if (d2 <= 1e-12) return o;
final d = math.sqrt(d2);
if (d <= maxR) return o;
final s = maxR / d;
return Offset(o.dx * s, o.dy * s);
}