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

using System.Collections.Generic;
using System.Windows;
using System.Windows.Media;
using Microsoft.Research.DynamicDataDisplay.DataSources;
using Microsoft.Research.DynamicDataDisplay.PointMarkers;
using Microsoft.Research.DynamicDataDisplay.Common;
using System.Windows.Controls;

namespace Microsoft.Research.DynamicDataDisplay
{
  public class ElementMarkerPointsGraph : PointsGraphBase
  {
    /// <summary>List with created but unused markers</summary>
    private readonly List<UIElement> unused = new List<UIElement>();

    /// <summary>Initializes a new instance of the <see cref="MarkerPointsGraph"/> class.</summary>
    public ElementMarkerPointsGraph()
    {
      ManualTranslate = true; // We'll handle translation by ourselves
    }

    /// <summary>Initializes a new instance of the <see cref="MarkerPointsGraph"/> class.</summary>
    /// <param name="dataSource">The data source.</param>
    public ElementMarkerPointsGraph(IPointDataSource dataSource)
      : this()
    {
      DataSource = dataSource;
    }

    Grid grid;
    Canvas canvas;

    protected override void OnPlotterAttached(Plotter plotter)
    {
      base.OnPlotterAttached(plotter);

      grid = new Grid();
      canvas = new Canvas { ClipToBounds = true };
      grid.Children.Add(canvas);

      Plotter2D.CentralGrid.Children.Add(grid);
    }

    protected override void OnPlotterDetaching(Plotter plotter)
    {
      Plotter2D.CentralGrid.Children.Remove(grid);
      grid = null;
      canvas = null;

      base.OnPlotterDetaching(plotter);
    }

    protected override void OnDataChanged()
    {
      //      if (canvas != null)
      //      {
      //                foreach(UIElement child in canvas.Children)
      //                    unused.Add(child);
      //        canvas.Children.Clear();
      //      }
      // todo почему так?
      base.OnDataChanged();
    }

    public ElementPointMarker Marker
    {
      get { return (ElementPointMarker)GetValue(MarkerProperty); }
      set { SetValue(MarkerProperty, value); }
    }

    public static readonly DependencyProperty MarkerProperty =
      DependencyProperty.Register(
        "Marker",
        typeof(ElementPointMarker),
        typeof(ElementMarkerPointsGraph),
        new FrameworkPropertyMetadata { DefaultValue = null, AffectsRender = true }
          );

    protected override void OnRenderCore(DrawingContext dc, RenderState state)
    {
      if (Marker == null)
        return;

      if (DataSource == null) // No data is specified
      {
        if (canvas != null)
        {
          foreach (UIElement child in canvas.Children)
            unused.Add(child);
          canvas.Children.Clear();
        }
      }
      else // There is some data
      {
      
        int index = 0;
        var transform = GetTransform();
        using (IPointEnumerator enumerator = DataSource.GetEnumerator(GetContext()))
        {
          Point point = new Point();

          DataRect bounds = DataRect.Empty;

          while (enumerator.MoveNext())
          {
            enumerator.GetCurrent(ref point);
            enumerator.ApplyMappings(Marker);

            if (index >= canvas.Children.Count)
            {
              UIElement newMarker;
              if (unused.Count > 0)
              {
                newMarker = unused[unused.Count - 1];
                unused.RemoveAt(unused.Count - 1);
              }
              else
                newMarker = Marker.CreateMarker();
              canvas.Children.Add(newMarker);
            }

            Marker.SetMarkerProperties(canvas.Children[index]);
            bounds.Union(point);
            Point screenPoint = point.DataToScreen(transform);
            Marker.SetPosition(canvas.Children[index], screenPoint);
            index++;
          }

          Viewport2D.SetContentBounds(this, bounds);

          while (index < canvas.Children.Count)
          {
            unused.Add(canvas.Children[index]);
            canvas.Children.RemoveAt(index);
          }
        }
      }
    }
  }
}