using System;

 using System.Collections.Generic;

 using System.Text;

 using System.Drawing;

 using System.Threading;

 using System.Windows.Forms;

 namespace Aga.Controls.Tree.NodeControls

 {

 	/// <summary>

 	/// Displays an animated icon for those nodes, who are in expanding state. 

 	/// Parent TreeView must have AsyncExpanding property set to true.

 	/// </summary>

 	public class ExpandingIcon: NodeControl

 	{

 		private static GifDecoder _gif = ResourceHelper.LoadingIcon;

 		private static int _index = 0;

 		private static volatile Thread _animatingThread;

         private static object _lock = new object();

 		public override Size MeasureSize(TreeNodeAdv node, DrawContext context)

 		{

 			return ResourceHelper.LoadingIcon.FrameSize;

 		}

 		protected override void OnIsVisibleValueNeeded(NodeControlValueEventArgs args)

 		{

 			args.Value = args.Node.IsExpandingNow;

 			base.OnIsVisibleValueNeeded(args);

 		}

 		public override void Draw(TreeNodeAdv node, DrawContext context)

 		{

 			Rectangle rect = GetBounds(node, context);

 			Image img = _gif.GetFrame(_index).Image;

 			context.Graphics.DrawImage(img, rect.Location);

 		}

 		public static void Start()

 		{

             lock (_lock)

             {

                 if (_animatingThread == null)

                 {

                     _index = 0;

                     _animatingThread = new Thread(new ThreadStart(IterateIcons));

                     _animatingThread.IsBackground = true;

                     _animatingThread.Priority = ThreadPriority.Lowest;

                     _animatingThread.Start();

                 }

             }

 		}

         public static void Stop()

         {

             lock (_lock)

             {

                 _index = 0;

                 _animatingThread = null;

             }

         }

 		private static void IterateIcons()

 		{

             while (_animatingThread != null)

 			{

 				if (_index < _gif.FrameCount - 1)

 					_index++;

 				else

 					_index = 0;

 				if (IconChanged != null)

 					IconChanged(null, EventArgs.Empty);

 				int delay = _gif.GetFrame(_index).Delay;

 				Thread.Sleep(delay);

 			}

             System.Diagnostics.Debug.WriteLine("IterateIcons Stopped");

 		}

 		public static event EventHandler IconChanged;

 	}

 }