source: branches/HeuristicLab.Problems.GrammaticalOptimization/DynamicDataDisplay/Charts/MagnifyingGlass.xaml.cs @ 13401

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace Microsoft.Research.DynamicDataDisplay
{
  public partial class MagnifyingGlass : Grid, IPlotterElement
  {
    public MagnifyingGlass()
    {
      InitializeComponent();
      Loaded += MagnifyingGlass_Loaded;

      whiteEllipse.Visibility = Visibility.Collapsed;
      magnifierEllipse.Visibility = Visibility.Collapsed;
    }

    private void MagnifyingGlass_Loaded(object sender, RoutedEventArgs e)
    {
      UpdateViewbox();
    }

    protected override void OnPreviewMouseWheel(MouseWheelEventArgs e)
    {
      Magnification += e.Delta / Mouse.MouseWheelDeltaForOneLine * 0.2;
      e.Handled = false;
    }

    private void plotter_PreviewMouseMove(object sender, MouseEventArgs e)
    {
      VisualBrush b = (VisualBrush)magnifierEllipse.Fill;
      Point pos = e.GetPosition(plotter.ParallelCanvas);

      Point plotterPos = e.GetPosition(plotter);

      Rect viewBox = b.Viewbox;
      double xoffset = viewBox.Width / 2.0;
      double yoffset = viewBox.Height / 2.0;
      viewBox.X = plotterPos.X - xoffset;
      viewBox.Y = plotterPos.Y - yoffset;
      b.Viewbox = viewBox;
      Canvas.SetLeft(this, pos.X - Width / 2);
      Canvas.SetTop(this, pos.Y - Height / 2);
    }

    private double magnification = 2.0;
    public double Magnification
    {
      get { return magnification; }
      set
      {
        magnification = value;

        UpdateViewbox();
      }
    }

    private void UpdateViewbox()
    {
      if (!IsLoaded)
        return;

      VisualBrush b = (VisualBrush)magnifierEllipse.Fill;
      Rect viewBox = b.Viewbox;
      viewBox.Width = Width / magnification;
      viewBox.Height = Height / magnification;
      b.Viewbox = viewBox;
    }

    protected override void OnPropertyChanged(DependencyPropertyChangedEventArgs e)
    {
      base.OnPropertyChanged(e);

      if (e.Property == WidthProperty || e.Property == HeightProperty)
      {
        UpdateViewbox();
      }
    }

    #region IPlotterElement Members

    Plotter plotter;
    public void OnPlotterAttached(Plotter plotter)
    {
      this.plotter = plotter;
      plotter.ParallelCanvas.Children.Add(this);
      plotter.PreviewMouseMove += plotter_PreviewMouseMove;
      plotter.MouseEnter += new MouseEventHandler(plotter_MouseEnter);
      plotter.MouseLeave += new MouseEventHandler(plotter_MouseLeave);

      VisualBrush b = (VisualBrush)magnifierEllipse.Fill;
      b.Visual = plotter.MainGrid;
    }

    void plotter_MouseLeave(object sender, MouseEventArgs e)
    {
      whiteEllipse.Visibility = Visibility.Collapsed;
      magnifierEllipse.Visibility = Visibility.Collapsed;
    }

    void plotter_MouseEnter(object sender, MouseEventArgs e)
    {
      whiteEllipse.Visibility = Visibility.Visible;
      magnifierEllipse.Visibility = Visibility.Visible;
    }

    public void OnPlotterDetaching(Plotter plotter)
    {
      plotter.MouseEnter -= new MouseEventHandler(plotter_MouseEnter);
      plotter.MouseLeave -= new MouseEventHandler(plotter_MouseLeave);

      plotter.PreviewMouseMove -= plotter_PreviewMouseMove;
      plotter.ParallelCanvas.Children.Remove(this);
      this.plotter = null;

      VisualBrush b = (VisualBrush)magnifierEllipse.Fill;
      b.Visual = null;
    }

    public Plotter Plotter
    {
      get { return plotter; ; }
    }

    #endregion
  }
}