source: branches/HeuristicLab.Problems.GrammaticalOptimization/DynamicDataDisplay/ViewportConstraints/ViewportConstraint.cs @ 13788

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using Microsoft.Research.DynamicDataDisplay.Common;

namespace Microsoft.Research.DynamicDataDisplay.ViewportConstraints
{
  /// <summary>
  /// Represents a base class for all constraints that are being applied to viewport's visible rect.
  /// </summary>
  public abstract class ViewportConstraint
  {
    /// <summary>
    /// Applies the constraint.
    /// </summary>
    /// <param name="previousDataRect">Previous data rectangle.</param>
    /// <param name="proposedDataRect">Proposed data rectangle.</param>
    /// <param name="viewport">The viewport, to which current restriction is being applied.</param>
    /// <returns>New changed visible rectangle.</returns>
    public abstract DataRect Apply(DataRect previousDataRect, DataRect proposedDataRect, Viewport2D viewport);

    /// <summary>
    /// Raises the changed event.
    /// </summary>
    protected void RaiseChanged()
    {
      Changed.Raise(this);
    }
    /// <summary>
    /// Occurs when constraint changes.
    /// Causes update of <see cref="Viewport"/>'s Visible property.
    /// </summary>
    public event EventHandler Changed;
  }
}