mono/mcs/class/System.Drawing/System.Drawing/ImageAnimator.cs

//
// System.Drawing.ImageAnimator.cs
//
// Authors:
//	Dennis Hayes ([email protected])
//	Sanjay Gupta ([email protected])
//	Sebastien Pouliot  <[email protected]>
//
// (C) 2002 Ximian, Inc
// Copyright (C) 2004,2006-2007 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System.Collections;
using System.Drawing.Imaging;
using System.Threading;

namespace System.Drawing {

	class AnimateEventArgs : EventArgs {

		private int frameCount;
		private int activeFrame;
		private Thread thread;

		public AnimateEventArgs (Image image)
		{
			frameCount = image.GetFrameCount (FrameDimension.Time);
		}
      
		public Thread RunThread {
			get { return thread; }
			set { thread = value; }
		}

		public int GetNextFrame ()
		{
			if (activeFrame < frameCount - 1)
				activeFrame++;
			else
				activeFrame = 0;

			return activeFrame;
		}
	}

	public sealed class ImageAnimator {

		static Hashtable ht = Hashtable.Synchronized (new Hashtable ());

		private ImageAnimator ()
		{
		}

		public static void Animate (Image image, EventHandler onFrameChangeHandler)
		{
			// must be non-null and contain animation time frames
			if (!CanAnimate (image))
				return;

			// is animation already in progress ?
			if (ht.ContainsKey (image))
				return;

			PropertyItem item = image.GetPropertyItem (0x5100); // FrameDelay in libgdiplus
			byte[] value = item.Value;
			int[] delay = new int [(value.Length >> 2)];
			for (int i=0, n=0; i < value.Length; i += 4, n++) {
				int d = BitConverter.ToInt32 (value, i) * 10;
				// follow worse case (Opera) see http://news.deviantart.com/article/27613/
				delay [n] = d < 100 ? 100 : d;
			}

			AnimateEventArgs aea = new AnimateEventArgs (image);
			WorkerThread wt = new WorkerThread (onFrameChangeHandler, aea, delay);
			Thread thread = new Thread (new ThreadStart (wt.LoopHandler));
			thread.IsBackground = true;
			aea.RunThread = thread;
			ht.Add (image, aea);
			thread.Start ();
		}

		public static bool CanAnimate (Image image)
		{
			if (image == null)
				return false;

			int n = image.FrameDimensionsList.Length;
			if (n < 1)
				return false;

			for (int i = 0; i < n; i++) {
				if (image.FrameDimensionsList [i].Equals (FrameDimension.Time.Guid)) {
					return (image.GetFrameCount (FrameDimension.Time) > 1);
				}
			}
			return false;
		}

		public static void StopAnimate (Image image, EventHandler onFrameChangeHandler)
		{
			if (image == null)
				return;

			if (ht.ContainsKey (image)) {
				AnimateEventArgs evtArgs = (AnimateEventArgs) ht [image];
				evtArgs.RunThread.Abort ();
				ht.Remove (image);
			}
		}

		public static void UpdateFrames ()
		{
			foreach (Image image in ht.Keys)
				UpdateImageFrame (image);
		}


		public static void UpdateFrames (Image image)
		{
			if (image == null)
				return;

			if (ht.ContainsKey (image))
				UpdateImageFrame (image);
		}

		// this method avoid checks that aren't requied for UpdateFrames()
		private static void UpdateImageFrame (Image image)
		{
			AnimateEventArgs aea = (AnimateEventArgs) ht [image];
			image.SelectActiveFrame (FrameDimension.Time, aea.GetNextFrame ());
		}
	}

	class WorkerThread {

		private EventHandler frameChangeHandler;
		private AnimateEventArgs animateEventArgs;
		private int[] delay;

		public WorkerThread (EventHandler frmChgHandler, AnimateEventArgs aniEvtArgs, int[] delay)
		{
			frameChangeHandler = frmChgHandler;
			animateEventArgs = aniEvtArgs;
			this.delay = delay;
		}

		public void LoopHandler ()
		{
			try {
				int n = 0;
				while (true) {
					Thread.Sleep (delay [n++]);
					frameChangeHandler (null, animateEventArgs);
					if (n == delay.Length)
						n = 0;
				}
			}
			catch (ThreadAbortException) {
				Thread.ResetAbort (); // we're going to finish anyway
			}
		}
	}
}