C# Windows Forms ImageMap Control

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

namespace DotNetOpenSource.Controls
{
    /// <summary>
    /// Summary description for ImageMap.
    /// </summary>
    [ToolboxBitmap(typeof (ImageMap))]
    public class ImageMap : PictureBox
    {
        private GraphicsPath _pathData;
        private int _activeIndex = -1;
        private ArrayList _pathsArray;
        private ToolTip _toolTip;

        /// <summary>
        /// Required designer variable.
        /// </summary>
        private Container components;

        public delegate void RegionClickDelegate(int index, string key);

        [Category("Action")]
        public event RegionClickDelegate RegionClick;

        public ImageMap()
        {
            _pathsArray = new ArrayList();
            _pathData = new GraphicsPath();
            _pathData.FillMode = FillMode.Winding;

            components = new Container();
            _toolTip = new ToolTip(components);
            _toolTip.AutoPopDelay = 5000;
            _toolTip.InitialDelay = 1000;
            _toolTip.ReshowDelay = 500;
        }


        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                if (components != null)
                    components.Dispose();
            }
            base.Dispose(disposing);
        }


        public int AddElipse(string key, Point center, int radius)
        {
            return AddElipse(key, center.X, center.Y, radius);
        }

        public int AddElipse(string key, int x, int y, int radius)
        {
            if (_pathsArray.Count > 0)
                _pathData.SetMarkers();
            _pathData.AddEllipse(x - radius, y - radius, radius*2, radius*2);
            return _pathsArray.Add(key);
        }

        public int AddRectangle(string key, int x1, int y1, int x2, int y2)
        {
            return AddRectangle(key, new Rectangle(x1, y1, (x2 - x1), (y2 - y1)));
        }

        public int AddRectangle(string key, Rectangle rectangle)
        {
            if (_pathsArray.Count > 0)
                _pathData.SetMarkers();
            _pathData.AddRectangle(rectangle);
            return _pathsArray.Add(key);
        }

        public int AddPolygon(string key, Point[] points)
        {
            if (_pathsArray.Count > 0)
                _pathData.SetMarkers();
            _pathData.AddPolygon(points);
            return _pathsArray.Add(key);
        }

        protected override void OnMouseMove(MouseEventArgs e)
        {
            base.OnMouseMove(e);

            int newIndex = GetActiveIndexAtPoint(new Point(e.X, e.Y));
            if (newIndex > -1)
            {
                Cursor = Cursors.Hand;
                if (_activeIndex != newIndex)
                    _toolTip.SetToolTip(this, _pathsArray[newIndex].ToString());
            }
            else
            {
                Cursor = Cursors.Default;
                _toolTip.RemoveAll();
            }
            _activeIndex = newIndex;
        }

        protected override void OnMouseLeave(EventArgs e)
        {
            base.OnMouseLeave(e);

            _activeIndex = -1;
            Cursor = Cursors.Default;
        }

        protected override void OnClick(EventArgs e)
        {
            base.OnClick(e);

            Point p = PointToClient(Cursor.Position);
            if (_activeIndex == -1)
                GetActiveIndexAtPoint(p);
            if (_activeIndex > -1 && RegionClick != null)
                RegionClick(_activeIndex, _pathsArray[_activeIndex].ToString());
        }


        public GraphicsPath GetPath(int index)
        {
            var path = new GraphicsPath();
            var iterator = new GraphicsPathIterator(_pathData);
            iterator.Rewind();
            for (int current = 0; current < iterator.SubpathCount; current++)
            {
                iterator.NextMarker(path);
                if (current == index)
                    return path;
            }
            return null;
        }

        [Browsable(false)]
        public override Image BackgroundImage
        {
            get { return base.BackgroundImage; }
            set { base.BackgroundImage = value; }
        }


        private int GetActiveIndexAtPoint(Point point)
        {
            var path = new GraphicsPath();
            var iterator = new GraphicsPathIterator(_pathData);
            iterator.Rewind();
            for (int current = 0; current < iterator.SubpathCount; current++)
            {
                iterator.NextMarker(path);
                if (path.IsVisible(point, CreateGraphics()))
                    return current;
            }
            return -1;
        }
    }
}