ChainedGlossPainter.cs

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

namespace ProgressODoom {
	/// <summary>Extending this class allows you to chain multiple IGlossPainters together.</summary>
	public abstract class ChainedGlossPainter : Component, IGlossPainter, IDisposable {
		private IGlossPainter successor = null;

		/// <summary></summary>
		[Category("Painters"), Description("Gets or sets the next gloss in the chain"), Browsable(true)]
		public IGlossPainter Successor {
			get { return successor; }
			set {
				IGlossPainter nextPainter = value;
				while (nextPainter != null && nextPainter is ChainedGlossPainter) {
					if (object.ReferenceEquals(this, nextPainter)) {
						throw new ArgumentException("Gloss cannot eventually be it's own successor, an infinite loop will result");
					}
					nextPainter = ((ChainedGlossPainter)nextPainter).Successor;
				}

				successor = value;
				if (successor != null) {
					successor.PropertiesChanged += new EventHandler(successor_PropertiesChanged);
				}
				FireChange();
			}
		}
		private void successor_PropertiesChanged(object sender, EventArgs e) {
			FireChange();
		}

		private EventHandler onPropertiesChanged;
		/// <summary></summary>
		public event EventHandler PropertiesChanged {
			add {
				if (onPropertiesChanged != null) {
					foreach (Delegate d in onPropertiesChanged.GetInvocationList()) {
						if (object.ReferenceEquals(d, value)) { return; }
					}
				}
				onPropertiesChanged = (EventHandler)Delegate.Combine(onPropertiesChanged, value);
			}
			remove { onPropertiesChanged = (EventHandler)Delegate.Remove(onPropertiesChanged, value); }
		}

		/// <summary></summary>
		protected void FireChange() {
			if (onPropertiesChanged != null) { onPropertiesChanged(this, EventArgs.Empty); }
		}

		/// <summary></summary>
		/// <param name="box"></param>
		/// <param name="g"></param>
		public void PaintGloss(Rectangle box, Graphics g) {
			if (box.Width < 1) { return; }
			PaintThisGloss(box, g);
			if (successor != null) { successor.PaintGloss(box, g); }
		}

		/// <summary></summary>
		/// <param name="box"></param>
		/// <param name="g"></param>
		protected abstract void PaintThisGloss(Rectangle box, Graphics g);

		/// <summary></summary>
		/// <param name="box"></param>
		public void Resize(Rectangle box) {
			ResizeThis(box);
			if (successor != null) { successor.Resize(box); }
		}

		protected abstract void ResizeThis(Rectangle box);

		protected override void Dispose(bool disposing) {
			base.Dispose(disposing);
			if (successor != null) { successor.Dispose(); }
		}
	}
}