// ********************************* WinRing_create_background_graphic

        void WinRing_create_background_graphic()
        {
            if (WinRing_background != null)
            {
                WinRing_background = WinRing_background.DeleteGraphicsBuffer();
            }
            WinRing_background = new ZeroitWin8ProgressRingGraphicsBuffer();
            WinRing_background.CreateGraphicsBuffer(WinRing_control_width,
                                                    Control_Height);
            WinRing_background.Graphic.SmoothingMode = SmoothingMode.
                                                       HighQuality;
        }
        // ********************************** WinRing_create_indicator_graphic

        void WinRing_create_indicator_graphic()
        {
            if (WinRing_indicator != null)
            {
                WinRing_indicator = WinRing_indicator.DeleteGraphicsBuffer();
            }
            WinRing_indicator = new ZeroitWin8ProgressRingGraphicsBuffer();
            WinRing_indicator.CreateGraphicsBuffer(WinRing_control_width,
                                                   Control_Height);
            WinRing_indicator.Graphic.SmoothingMode = SmoothingMode.
                                                      HighQuality;
        }
        // ******************************************** WinRing_memory_cleanup

        void WinRing_memory_cleanup()
        {
            // DeleteGraphicsBuffer
            // returns null
            if (WinRing_background != null)
            {
                WinRing_background = WinRing_background.DeleteGraphicsBuffer();
            }

            if (WinRing_indicator != null)
            {
                WinRing_indicator = WinRing_indicator.DeleteGraphicsBuffer();
            }
        }