C#

        private void drawOnPic()<br />
        {<br />
            // Attach grapich to picturebox<br />
            Graphics g = Graphics.FromImage(pictureBox1.Image);<br />
<br />
            // Create a new pen that we shall use for drawing the line<br />
            Pen PenStyle = new Pen(Color.Red, 1);<br />
<br />
            // Draw a 50x50 pixels rectangle (x, y, width, hight)<br />
            g.DrawRectangle(PenStyle, 20, 20, 50, 50);<br />
        }<br />
<br />
        private void button1_Click(object sender, EventArgs e)<br />
        {<br />
            pictureBox1.Invalidate();<br />
        }<br />
<br />
        private void Form1_Load(object sender, EventArgs e)<br />
        {<br />
            drawOnPic();<br />
        }

<br />
private Bitmap GetBitmap()<br />
        {<br />
            Bitmap bmp = new Bitmap(plotterForm.expressionPlotter.Width, plotterForm.expressionPlotter.Height);<br />
            Graphics g = Graphics.FromImage(bmp);<br />
            Screen screen = Screen.FromControl(plotterForm.expressionPlotter);<br />
            g.CopyFromScreen(new Point(screen.Bounds.Location.X, screen.Bounds.Location.Y), Point.Empty, plotterForm.expressionPlotter.Size);<br />
            return bmp;<br />
        }