MouseManipulator.cs

// --------------------------------------------------------------------------------------------------------------------
// <copyright file="MouseManipulator.cs" company="OxyPlot">
//   Copyright (c) 2014 OxyPlot contributors
// </copyright>
// <summary>
//   Provides an abstract base class for manipulators that handles mouse events.
// </summary>
// --------------------------------------------------------------------------------------------------------------------

namespace OxyPlot
{
    /// <summary>
    /// Provides an abstract base class for manipulators that handles mouse events.
    /// </summary>
    public abstract class MouseManipulator : PlotManipulator<OxyMouseEventArgs>
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="MouseManipulator" /> class.
        /// </summary>
        /// <param name="plotView">The plot view.</param>
        protected MouseManipulator(IPlotView plotView)
            : base(plotView)
        {
        }

        /// <summary>
        /// Gets or sets the first position of the manipulation.
        /// </summary>
        public ScreenPoint StartPosition { get; protected set; }

        /// <summary>
        /// Occurs when an input device begins a manipulation on the plot.
        /// </summary>
        /// <param name="e">The <see cref="OxyInputEventArgs" /> instance containing the event data.</param>
        public override void Started(OxyMouseEventArgs e)
        {
            if (this.XAxis == null || this.YAxis == null)
                this.AssignAxes(e.Position);
            base.Started(e);
            this.StartPosition = e.Position;
        }
    }
}