Cairo.Matrix.TransformPoint C# (CSharp) Метод

        public void TransformPoint(ref double x, ref double y)
        {
            NativeMethods.cairo_matrix_transform_point (this, ref x, ref y);
        }

 public void DeviceToUser(ref double x, ref double y)
 {
     Cairo.Matrix inv = (Cairo.Matrix) this.transformMatrix.Clone();
     Cairo.Status cs  = inv.Invert();
     if (cs == Cairo.Status.Success)
     {
         inv.TransformPoint(ref x, ref y);
     }
     else
     {
         throw new Exception("Unable to transform device coordinates to user coordinates because the matrix was uninvertible (" + cs.ToString() + ").");
     }
 }