private void button1_Click(object sender, EventArgs e)
        {
            //int height = 400, width = 600;
            //Bitmap image = new Bitmap(height, width);
            Bitmap image = new Bitmap(DisplayRectangle.Width, DisplayRectangle.Height);

            using (Graphics g = Graphics.FromImage(image))
            {
                g.Clear(Color.White);
                Pen mypen = new Pen(new SolidBrush(Color.Blue), 1);
                g.DrawLine(mypen, 100, 80, 100, 340);
            }

            this.panel1.BackgroundImage = image;

        }