/Main/src/DynamicDataDisplay/ViewportConstraints/ConstraintCollection.cs

using System.Linq;

using System.Windows;

using Microsoft.Research.DynamicDataDisplay;

using Microsoft.Research.DynamicDataDisplay.Common;

using Microsoft.Research.DynamicDataDisplay.Common.Auxiliary;

using System;

using System.Collections.Specialized;



namespace Microsoft.Research.DynamicDataDisplay.ViewportConstraints

{

	/// <summary>

	/// Represents a collection of <see cref="ViewportConstraint"/>s.

	/// <remarks>

	/// ViewportConstraint that is being added should not be null.

	/// </remarks>

	/// </summary>

	public sealed class ConstraintCollection : D3Collection<ViewportConstraint>

	{

		private readonly Viewport2D viewport;

		internal ConstraintCollection(Viewport2D viewport)

		{

			if (viewport == null)

				throw new ArgumentNullException("viewport");



			this.viewport = viewport;

		}



		protected override void OnItemAdding(ViewportConstraint item)

		{

			if (item == null)

				throw new ArgumentNullException("item");

		}



		protected override void OnItemAdded(ViewportConstraint item)

		{

			item.Changed += OnItemChanged;

			ISupportAttachToViewport attachable = item as ISupportAttachToViewport;

			if (attachable != null)

			{

				attachable.Attach(viewport);

			}

		}



		private void OnItemChanged(object sender, EventArgs e)

		{

			OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));

		}



		protected override void OnItemRemoving(ViewportConstraint item)

		{

			ISupportAttachToViewport attachable = item as ISupportAttachToViewport;

			if (attachable != null)

			{

				attachable.Detach(viewport);

			}

			item.Changed -= OnItemChanged;

		}



		internal DataRect Apply(DataRect oldVisible, DataRect newVisible, Viewport2D viewport)

		{

			DataRect res = newVisible;

			foreach (var constraint in this)

			{

				res = constraint.Apply(oldVisible, res, viewport);

			}

			return res;

		}

	}

}