public static void Rotate(this IDrawingTransform _, double radians, Point?center = null)
 {
     _.Rotate(radians, center != null ? center.Value.X : (double?)null, center != null ? center.Value.Y : (double?)null);
 }
 public void Rotate(double radians, double?centerX = null, double?centerY = null)
 {
     _transform.Rotate(radians, centerX, centerY);
 }