/// <summary>
/// Initializes a new instance of the <see cref="GazeSelectionService" /> class.
/// </summary>
/// <param name="eventAggregator">Provides pub/sub events (obtained through DI).</param>
public GazeSelectionService(IEventAggregator eventAggregator)
{
this.timedPoints = new TimedPoints(Configuration.PointKeepAliveTimeSpan);
this.averagingFilter = new AveragingLastNpointsWithinTimeSpanFilter(3, TimeSpan.FromMilliseconds(75));
this.dataPerControl = new ConcurrentDictionary <SelectableControl, ISelectableControlViewModel>();
this.KnownWindows.Add(Application.Current.MainWindow);
eventAggregator.GetEvent <Events.NewCoordinateEvent>().Subscribe(this.ProcessPoint);
Application.Current.MainWindow.Closing +=
(sender, args) => eventAggregator.GetEvent <Events.NewCoordinateEvent>().Unsubscribe(this.ProcessPoint);
}
/// <summary>
/// Filters the specified timed points.
/// </summary>
/// <param name="timedPoints">The timed points.</param>
/// <returns>
/// An average of the last N points (as long as they fall within a given timespan from <see cref="DateTime.Now" />).
/// </returns>
public override Point?Filter(TimedPoints timedPoints)
{
if (timedPoints == null)
{
return(null);
}
var withinTimeSpan = timedPoints.Where(pair => DateTime.Now - pair.Key <= this.timeSpan).ToList();
if (withinTimeSpan.Count < this.numberOfPoints)
{
return(null);
}
var pointsToAverage = withinTimeSpan.OrderByDescending(pair => pair.Key).Take(this.numberOfPoints).ToList();
var averageX = pointsToAverage.Select(pair => pair.Value.X).Average();
var averageY = pointsToAverage.Select(pair => pair.Value.Y).Average();
return(new Point(averageX, averageY));
}
/// <summary> /// Filters the specified timed points. /// </summary> /// <param name="timedPoints">The timed points.</param> /// <returns> /// An average of the points. The actual average depends on implementation (e.g. it could be an average of the /// last 5 points, or of the 10 points nearest to the last in a given timespan) /// </returns> public abstract Point?Filter(TimedPoints timedPoints);
