C#

public partial class ImageMap : UserControl<br />
    {        <br />
        Bitmap bitmap;        <br />
        BufferedGraphicsContext currentContext;<br />
        BufferedGraphics myBuffer;  <br />
        PointF viewPortCenter;<br />
        float Zoom = 1.0f;<br />
<br />
        bool draging = false;<br />
        Point lastMouse;<br />
        public static Rectangle rec;<br />
<br />
<br />
        public ImageMap()<br />
        {<br />
            InitializeComponent();<br />
            currentContext = BufferedGraphicsManager.Current;<br />
            setup(false);<br />
            rec = this.panel1.DisplayRectangle;<br />
        }        <br />
<br />
        private void setup(bool resetViewport)<br />
        {            <br />
            if (myBuffer != null)<br />
                myBuffer.Dispose();<br />
            myBuffer = currentContext.Allocate(this.panel1.CreateGraphics(), this.panel1.DisplayRectangle);<br />
            if (bitmap != null)<br />
            {<br />
                if (resetViewport)<br />
                    SetViewPort(new RectangleF(0, 0, bitmap.Width, bitmap.Height));                <br />
            }            <br />
            this.panel1.Focus();<br />
            this.panel1.Invalidate();<br />
        }   <br />
     <br />
        private void SetViewPort(RectangleF worldCords)<br />
        {           <br />
           //Find smallest screen extent and zoom to that<br />
            if (worldCords.Height > worldCords.Width)<br />
            {<br />
                //Use With as limiting factor<br />
                this.Zoom = worldCords.Width / bitmap.Width;<br />
            }<br />
            else<br />
                this.Zoom = worldCords.Height / bitmap.Height;<br />
<br />
            viewPortCenter = new PointF(worldCords.X +(worldCords.Width / 2.0f), worldCords.Y + (worldCords.Height / 2.0f));<br />
            <br />
        }        <br />
<br />
        private void PaintImage()<br />
        {<br />
            if (bitmap != null)<br />
            {<br />
                float widthZoomed = panel1.Width / Zoom;<br />
                float heigthZoomed = panel1.Height / Zoom;<br />
<br />
                //Do checks the reason 30,000 is used is because much over this will cause DrawImage to crash<br />
                if (widthZoomed > 30000.0f)<br />
                {<br />
                    Zoom = panel1.Width / 30000.0f;<br />
                    widthZoomed = 30000.0f;<br />
                }<br />
                if (heigthZoomed > 30000.0f)<br />
                {<br />
                    Zoom = panel1.Height / 30000.0f;<br />
                    heigthZoomed = 30000.0f;<br />
                }<br />
<br />
                //we stop at 2 because at this point you have almost zoomed into a single pixel<br />
                if (widthZoomed < 2.0f)<br />
                {<br />
                    Zoom = panel1.Width / 2.0f;<br />
                    widthZoomed = 2.0f;<br />
                }<br />
                if (heigthZoomed < 2.0f)<br />
                {<br />
                    Zoom = panel1.Height / 2.0f;<br />
                    heigthZoomed = 2.0f;<br />
                }<br />
<br />
                float wz2 = widthZoomed / 2.0f;<br />
                float hz2 = heigthZoomed / 2.0f;<br />
                Rectangle drawRect = new Rectangle(<br />
                    (int)(viewPortCenter.X - wz2),<br />
                    (int)(viewPortCenter.Y - hz2),<br />
                    (int)(widthZoomed),<br />
                    (int)(heigthZoomed));<br />
<br />
                //this.toolStripStatusLabel1.Text = "DrawRect = " + drawRect.ToString();<br />
<br />
                myBuffer.Graphics.Clear(Color.White); //Clear the Back buffer<br />
<br />
                //Draw the image, Write image to back buffer, and render back buffer<br />
                myBuffer.Graphics.DrawImage(bitmap, this.panel1.DisplayRectangle, drawRect, GraphicsUnit.Pixel);<br />
                myBuffer.Render(this.panel1.CreateGraphics());<br />
            }            <br />
        }<br />
<br />
        protected override void OnBackgroundImageChanged(EventArgs e)<br />
        {<br />
            bitmap = (Bitmap)this.BackgroundImage;<br />
            setup(true);<br />
            base.OnBackgroundImageChanged(e);<br />
        }<br />
<br />
        protected override void OnResize(EventArgs e)<br />
        {<br />
            setup(false);<br />
            base.OnResize(e);<br />
        }<br />
<br />
        private void panel1_Paint(object sender, PaintEventArgs e)<br />
        {            <br />
            PaintImage();<br />
        }<br />
<br />
        private void panel1_MouseWheel(object sender, System.Windows.Forms.MouseEventArgs e)<br />
        {<br />
            Zoom += Zoom * (e.Delta / 1200.0f); //the 1200.0f is any-number it just seem to work well so i use it.<br />
            if (e.Delta > 0) //I prefer to use the targe zoom when zooming in only, remove "if" to have it apply to zoom in and out<br />
                viewPortCenter = new PointF(viewPortCenter.X + ((e.X - (panel1.Width / 2)) /(2* Zoom)), viewPortCenter.Y + ((e.Y - (panel1.Height/2)) / (2*Zoom)));                            <br />
            this.panel1.Invalidate();            <br />
        }<br />
<br />
        private void panel1_MouseDown(object sender, MouseEventArgs e)<br />
        {<br />
            if (e.Button == MouseButtons.Left)<br />
                draging = true;<br />
        }<br />
<br />
        private void panel1_MouseMove(object sender, MouseEventArgs e)<br />
        {<br />
            if (draging)<br />
            {<br />
                viewPortCenter = new PointF(viewPortCenter.X + ((lastMouse.X - e.X)/Zoom), viewPortCenter.Y + ((lastMouse.Y- e.Y)/Zoom));                <br />
                panel1.Invalidate();                <br />
            }<br />
            lastMouse = e.Location;<br />
        }<br />
        <br />
        private void panel1_MouseUp(object sender, MouseEventArgs e)<br />
        {<br />
            if (e.Button == MouseButtons.Left)<br />
                draging = false;<br />
        }        <br />
    }

public class overRidePanel : Panel<br />
        {<br />
            protected override void OnPaintBackground(PaintEventArgs pevent) <br />
            {<br />
                <br />
            }<br />
        }