Zoomer.cs

// User control class for the image display control
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace ImageViewerLite
{
    public partial class Zoomer : UserControl
    {
        public Zoomer()
        {
            InitializeComponent();

            this.SetStyle(
                ControlStyles.AllPaintingInWmPaint |
                ControlStyles.UserPaint |
                ControlStyles.SupportsTransparentBackColor |
                ControlStyles.DoubleBuffer, true);
        }


        private Image image;
        [ Category("Appearance"), Description("The image to display.") ]
        public Image Image
        {
            get { return image; }
            set
            {
                image = value;
                this.Invalidate();
            }
        }

        private double zoom = 1;
        [Category("Appearance"), Description("How much the image is zoomed.")]
        public double Zoom
        {
            get { return zoom; }
            set
            {
                if (value < 0)
                {
                    value = 0;
                }
                else if (value > 10)
                {
                    value = 10;
                }
                else
                {
                    zoom = value;
                }
            }
        }

        protected override void OnPaintBackground(PaintEventArgs e)
        {
            // Don't paint a background
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            double factor = (zoom);
            this.Size = new Size(
                (int)(image.Size.Width * factor),
                (int)(image.Size.Height * factor));
            e.Graphics.DrawImage(this.image, this.ClientRectangle,
                new Rectangle(0, 0, image.Width, image.Height), GraphicsUnit.Pixel);

            base.OnPaint(e);
        }

    }
}