AppStartupGuide.MainPage.UpdateBackgroundBounds C# (CSharp) Method

        void UpdateBackgroundBounds()
        {
            if (ScrollingHost.IsItemVisible(Section3))
            {
                UpdateCurrentAndNext(Section3, Geometry3, Geometry4);
            }
            else if (ScrollingHost.IsItemVisible(Section2))
            {
                UpdateCurrentAndNext(Section2, Geometry2, Geometry3);
            }
            else if (ScrollingHost.IsItemVisible(Section1))
            {
                UpdateCurrentAndNext(Section1, Geometry1, Geometry2);
            }
        }