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);
}