public static unsafe void AddLineAtX(IntPtr pointer, double x, double thick, byte r, byte g, byte b)
        {
            GCHandle handle = GCHandle.FromIntPtr(pointer);

            if (handle.IsAllocated)
            {
                PlotModel model = handle.Target as PlotModel;
                if (model != null)
                {
                    model.AddLineAtX(x, OxyColor.FromRgb(r, g, b), thick);
                }
            }
        }