// --------------------------------------------------------------------------------------------------------------------

 // <copyright file="TrackerManipulator.cs" company="OxyPlot">

 //   The MIT License (MIT)

 //

 //   Copyright (c) 2012 Oystein Bjorke

 //

 //   Permission is hereby granted, free of charge, to any person obtaining a

 //   copy of this software and associated documentation files (the

 //   "Software"), to deal in the Software without restriction, including

 //   without limitation the rights to use, copy, modify, merge, publish,

 //   distribute, sublicense, and/or sell copies of the Software, and to

 //   permit persons to whom the Software is furnished to do so, subject to

 //   the following conditions:

 //

 //   The above copyright notice and this permission notice shall be included

 //   in all copies or substantial portions of the Software.

 //

 //   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

 //   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

 //   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.

 //   IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY

 //   CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,

 //   TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE

 //   SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 // </copyright>

 // <summary>

 //   The tracker manipulator.

 // </summary>

 // --------------------------------------------------------------------------------------------------------------------

 namespace OxyPlot

 {

     using OxyPlot.Series;

     /// <summary>

     /// Provides a plot control manipulator for tracker functionality.

     /// </summary>

     public class TrackerManipulator : ManipulatorBase

     {

         /// <summary>

         /// The current series.

         /// </summary>

         private ITrackableSeries currentSeries;

         /// <summary>

         /// Initializes a new instance of the <see cref="TrackerManipulator"/> class.

         /// </summary>

         /// <param name="plotControl">

         /// The plot control.

         /// </param>

         public TrackerManipulator(IPlotControl plotControl)

             : base(plotControl)

         {

             this.Snap = true;

             this.PointsOnly = false;

         }

         /// <summary>

         /// Gets or sets a value indicating whether to show tracker on points only (not interpolating).

         /// </summary>

         public bool PointsOnly { get; set; }

         /// <summary>

         /// Gets or sets a value indicating whether to snap to the nearest point.

         /// </summary>

         public bool Snap { get; set; }

         /// <summary>

         /// Occurs when a manipulation is complete.

         /// </summary>

         /// <param name="e">

         /// The <see cref="OxyPlot.ManipulationEventArgs"/> instance containing the event data.

         /// </param>

         public override void Completed(ManipulationEventArgs e)

         {

             base.Completed(e);

             if (this.currentSeries == null)

             {

                 return;

             }

             this.currentSeries = null;

             this.PlotControl.HideTracker();

         }

         /// <summary>

         /// Occurs when the input device changes position during a manipulation.

         /// </summary>

         /// <param name="e">

         /// The <see cref="OxyPlot.ManipulationEventArgs"/> instance containing the event data.

         /// </param>

         public override void Delta(ManipulationEventArgs e)

         {

             base.Delta(e);

             if (this.currentSeries == null)

             {

                 return;

             }

             if (!this.PlotControl.ActualModel.PlotArea.Contains(e.CurrentPosition.X, e.CurrentPosition.Y))

             {

                 return;

             }

             TrackerHitResult result = GetNearestHit(this.currentSeries, e.CurrentPosition, this.Snap, this.PointsOnly);

             if (result != null)

             {

                 result.PlotModel = this.PlotControl.ActualModel;

                 this.PlotControl.ShowTracker(result);

             }

         }

         /// <summary>

         /// Gets the cursor for the manipulation.

         /// </summary>

         /// <returns>

         /// The cursor.

         /// </returns>

         public override CursorType GetCursorType()

         {

             return CursorType.Default;

         }

         /// <summary>

         /// Occurs when an input device begins a manipulation on the plot.

         /// </summary>

         /// <param name="e">

         /// The <see cref="OxyPlot.ManipulationEventArgs"/> instance containing the event data.

         /// </param>

         public override void Started(ManipulationEventArgs e)

         {

             base.Started(e);

             this.currentSeries = this.PlotControl.GetSeriesFromPoint(e.CurrentPosition);

             this.Delta(e);

         }

         /// <summary>

         /// Gets the nearest tracker hit.

         /// </summary>

         /// <param name="s">

         /// The series.

         /// </param>

         /// <param name="point">

         /// The point.

         /// </param>

         /// <param name="snap">

         /// Snap to points.

         /// </param>

         /// <param name="pointsOnly">

         /// Check points only (no interpolation).

         /// </param>

         /// <returns>

         /// A tracker hit result.

         /// </returns>

         private static TrackerHitResult GetNearestHit(ITrackableSeries s, ScreenPoint point, bool snap, bool pointsOnly)

         {

             if (s == null)

             {

                 return null;

             }

             // Check data points only

             if (snap || pointsOnly)

             {

                 TrackerHitResult result = s.GetNearestPoint(point, false);

                 if (result != null)

                 {

                     if (result.Position.DistanceTo(point) < 20)

                     {

                         return result;

                     }

                 }

             }

             // Check between data points (if possible)

             if (!pointsOnly)

             {

                 TrackerHitResult result = s.GetNearestPoint(point, true);

                 return result;

             }

             return null;

         }

     }

 }