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

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

namespace Microsoft.Research.DynamicDataDisplay.Charts.Shapes
{
  /// <summary>
  /// Paints an arrow with start and end points in viewport coordinates.
  /// </summary>
  public class Arrow : Segment
  {
    /// <summary>
    /// Initializes a new instance of the <see cref="Arrow"/> class.
    /// </summary>
    public Arrow()
    {
      Init();
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="Arrow"/> class.
    /// </summary>
    /// <param name="startPoint">The start point of arrow.</param>
    /// <param name="endPoint">The end pointof arrow .</param>
    public Arrow(Point startPoint, Point endPoint)
      : base(startPoint, endPoint)
    {
      Init();
    }

    private void Init()
    {
      geometryGroup.Children.Add(LineGeometry);
      geometryGroup.Children.Add(leftLineGeometry);
      geometryGroup.Children.Add(rightLineGeometry);
    }

    #region ArrowLength property

    /// <summary>
    /// Gets or sets the length of the arrow.
    /// </summary>
    /// <value>The length of the arrow.</value>
    public double ArrowLength
    {
      get { return (double)GetValue(ArrowLengthProperty); }
      set { SetValue(ArrowLengthProperty, value); }
    }

    /// <summary>
    /// Identifies ArrowLength dependency property.
    /// </summary>
    public static readonly DependencyProperty ArrowLengthProperty = DependencyProperty.Register(
      "ArrowLength",
      typeof(double),
      typeof(Arrow),
      new FrameworkPropertyMetadata(0.1, OnPointChanged));

    #endregion

    #region ArrowAngle property

    /// <summary>
    /// Gets or sets the arrow angle in degrees.
    /// </summary>
    /// <value>The arrow angle.</value>
    public double ArrowAngle
    {
      get { return (double)GetValue(ArrowAngleProperty); }
      set { SetValue(ArrowAngleProperty, value); }
    }

    /// <summary>
    /// Identifies ArrowAngle dependency property.
    /// </summary>
    public static readonly DependencyProperty ArrowAngleProperty = DependencyProperty.Register(
      "ArrowAngle",
      typeof(double),
      typeof(Arrow),
      new FrameworkPropertyMetadata(15.0, OnPointChanged));

    #endregion

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

      var transform = Plotter.Viewport.Transform;

      Point p1 = StartPoint.DataToScreen(transform);
      Point p2 = EndPoint.DataToScreen(transform);

      Vector arrowVector = p1 - p2;
      Vector arrowCapVector = ArrowLength * arrowVector;

      Matrix leftMatrix = Matrix.Identity;
      leftMatrix.Rotate(ArrowAngle);

      Matrix rightMatrix = Matrix.Identity;
      rightMatrix.Rotate(-ArrowAngle);

      Vector leftArrowLine = leftMatrix.Transform(arrowCapVector);
      Vector rightArrowLine = rightMatrix.Transform(arrowCapVector);

      leftLineGeometry.StartPoint = p2;
      rightLineGeometry.StartPoint = p2;

      leftLineGeometry.EndPoint = p2 + leftArrowLine;
      rightLineGeometry.EndPoint = p2 + rightArrowLine;
    }

    private LineGeometry leftLineGeometry = new LineGeometry();
    private LineGeometry rightLineGeometry = new LineGeometry();
    private GeometryGroup geometryGroup = new GeometryGroup();
    protected override Geometry DefiningGeometry
    {
      get { return geometryGroup; }
    }
  }
}