source: branches/HeuristicLab.Problems.GrammaticalOptimization/DynamicDataDisplay/Charts/Shapes/ViewportRay.cs @ 13398

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

namespace Microsoft.Research.DynamicDataDisplay.Charts.Shapes
{
  /// <summary>
  /// Represents a ray in viewport space.
  /// </summary>
  public class ViewportRay : ViewportLine
  {
    private readonly LineGeometry geometry = new LineGeometry();
    private double direction = -1;

    /// <summary>
    /// Initializes a new instance of the <see cref="ViewportRay"/> class.
    /// </summary>
    public ViewportRay() { }

    /// <summary>
    /// Gets or sets the direction of ViewportRay.
    /// Positive value means that line will be drawn up to positive infinity,
    /// and negative - up to negative infinity. Default value is negative.
    /// </summary>
    /// <value>The direction.</value>
    public double Direction
    {
      get { return direction; }
      set { direction = value; }
    }

    protected override void UpdateUIRepresentationCore()
    {
      base.UpdateUIRepresentationCore();

      Viewport2D viewport = Plotter.Viewport;
      double deltaX = Point1.X - Point2.X;
      double deltaY = Point1.Y - Point2.Y;
      double m = deltaY / deltaX;
      double b = Point1.Y - Point1.X * deltaY / deltaX;

      Func<double, double> func = x => m * x + b;

      double xMin = viewport.Visible.XMin;
      double xMax = viewport.Visible.XMax;
      Point p1 = new Point(xMin, func(xMin)).DataToScreen(viewport.Transform);
      Point p2 = new Point(xMax, func(xMax)).DataToScreen(viewport.Transform);

      if (direction > 0)
        p1 = Point2.DataToScreen(viewport.Transform);
      else
        p2 = Point1.DataToScreen(viewport.Transform);

      geometry.StartPoint = p1;
      geometry.EndPoint = p2;
    }

    protected override Geometry DefiningGeometry
    {
      get { return geometry; }
    }
  }
}