source: branches/HeuristicLab.Problems.GrammaticalOptimization/DynamicDataDisplay/ViewportConstraints/FollowWidthConstraint.cs @ 13847

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.ComponentModel;

namespace Microsoft.Research.DynamicDataDisplay.ViewportConstraints
{
  /// <summary>
  /// Represents a viewport constraint which modifies x coordinates of result visible rect to be adjacent to the right border of initial rect and have a fixed given width.
  /// Probably is better to add to FitToViewConstraints collection of <see cref="Viewport"/>.
  /// </summary>
  public class FollowWidthConstraint : ViewportConstraint
  {
    /// <summary>
    /// Initializes a new instance of the <see cref="FollowWidthConstraint"/> class.
    /// </summary>
    public FollowWidthConstraint() { }

    /// <summary>
    /// Initializes a new instance of the <see cref="FollowWidthConstraint"/> class with the given width.
    /// </summary>
    /// <param name="width">The width.</param>
    public FollowWidthConstraint(double width)
    {
      Width = width;
    }

    private double width = 1;
    /// <summary>
    /// Gets or sets the width of result visible rectangle.
    /// Default value is 1.0.
    /// </summary>
    /// <value>The width.</value>
    [DefaultValue(1.0)]
    public double Width
    {
      get { return width; }
      set
      {
        if (width != value)
        {
          width = value;
          RaiseChanged();
        }
      }
    }

    /// <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 constraint is being applied.</param>
    /// <returns>New changed visible rectangle.</returns>
    public override DataRect Apply(DataRect previousDataRect, DataRect proposedDataRect, Viewport2D viewport)
    {
      if (proposedDataRect.IsEmpty)
        return proposedDataRect;

      double followWidth = proposedDataRect.Width;
      if (!viewport.UnitedContentBounds.IsEmpty)
      {
        followWidth = Math.Min(width, viewport.UnitedContentBounds.Width);
      }
      if (followWidth.IsInfinite())
        followWidth = width;

      Rect visible = new Rect(proposedDataRect.XMin + proposedDataRect.Width - followWidth, proposedDataRect.YMin, followWidth, proposedDataRect.Height);

      return visible;
    }
  }
}