scene

When plotting curves with ZedGraph, the content flickers when the mouse is hovering, and the frequency is high.

 

 

Find its source code and find that it refreshes the Tooltip once, regardless of the extent of the mouse movement or even whether the mouse moves or not.

Note:

Blog Home Page:
https://blog.csdn.net/badao_liumang_qizhi
Focus on Public Number
Domineering program ape
Get programming-related e-books, tutorial pushes, and free downloads.

Realization

First come to ZedGraph's official website

https://sourceforge.net/projects/zedgraph/

Then click on the zedgraph source under File

 

 

Select the corresponding version, here is 5.1.5

 

 

After successful download, unpack zip

Find the project file under source, double-click to open with VS

 

 

Then find ZedGraphControl.Events.cs

 

 

Find its ZedGraphControl_MouseMove method This method is event handling when the mouse moves

You can see how it handles two methods, HandlePointValues, when displaying the coordinates of points on a line, and HandleCursorValues, when getting the coordinates of points on the nearest curve.

 

 

See how your ZedGraph is turned on.

If it is set to go through line points

zgc.IsShowPointValues = true;

 

Modify then

HandlePointValues( mousePt );

This method

First declare a class variable

private object lastObj;

 

Used to store the last used object, then find its criteria, add whether the current is the same object as the last one

 

 

Then assign the current object to the last object when the last method returns.

lastObj = nearestObj;

 

Full reference code

private Point HandlePointValues( Point mousePt )
  {
   int iPt;
   GraphPane pane;
   object nearestObj;

   using ( Graphics g = this.CreateGraphics() )
   {

    if ( _masterPane.FindNearestPaneObject( mousePt,
     g, out pane, out nearestObj, out iPt ) )
    {
                    if (nearestObj is CurveItem && iPt >= 0 && !object.Equals(nearestObj, lastObj))
     {
      CurveItem curve = (CurveItem)nearestObj;
      // Provide Callback for User to customize the tooltips
      if ( this.PointValueEvent != null )
      {
       string label = this.PointValueEvent( this, pane, curve, iPt );
       if ( label != null && label.Length > 0 )
       {
        this.pointToolTip.SetToolTip( this, label );
        this.pointToolTip.Active = true;
       }
       else
        this.pointToolTip.Active = false;
      }
      else
      {

       if ( curve is PieItem )
       {
        this.pointToolTip.SetToolTip( this,
         ( (PieItem)curve ).Value.ToString( _pointValueFormat ) );
       }
       //       else if ( curve is OHLCBarItem || curve is JapaneseCandleStickItem )
       //       {
       //        StockPt spt = (StockPt)curve.Points[iPt];
       //        this.pointToolTip.SetToolTip( this, ( (XDate) spt.Date ).ToString( "MM/dd/yyyy" ) + "\nOpen: $" +
       //        spt.Open.ToString( "N2" ) +
       //        "\nHigh: $" +
       //        spt.High.ToString( "N2" ) + "\nLow: $" +
       //        spt.Low.ToString( "N2" ) + "\nClose: $" +
       //        spt.Close.ToString
       //        ( "N2" ) );
       //       }
       else
       {
        PointPair pt = curve.Points[iPt];

        if ( pt.Tag is string )
         this.pointToolTip.SetToolTip( this, (string)pt.Tag );
        else
        {
         double xVal, yVal, lowVal;
         ValueHandler valueHandler = new ValueHandler( pane, false );
         if ( ( curve is BarItem || curve is ErrorBarItem || curve is HiLowBarItem )
           && pane.BarSettings.Base != BarBase.X )
          valueHandler.GetValues( curve, iPt, out yVal, out lowVal, out xVal );
         else
          valueHandler.GetValues( curve, iPt, out xVal, out lowVal, out yVal );

         string xStr = MakeValueLabel( curve.GetXAxis( pane ), xVal, iPt,
          curve.IsOverrideOrdinal );
         string yStr = MakeValueLabel( curve.GetYAxis( pane ), yVal, iPt,
          curve.IsOverrideOrdinal );

         this.pointToolTip.SetToolTip( this, "( " + xStr + ", " + yStr + " )" );

         //this.pointToolTip.SetToolTip( this,
         // curve.Points[iPt].ToString( this.pointValueFormat ) );
        }
       }

       this.pointToolTip.Active = true;
      }
     }
     else
      this.pointToolTip.Active = false;
    }
    else
     this.pointToolTip.Active = false;

    //g.Dispose();
   }
            lastObj = nearestObj; 
   return mousePt;
  }

 

Other optimizations and functional modifications can be explored on their own.

If you set the coordinates in ZedGraph to show the points on the nearest curve, that is

zgc.IsShowCursorValues = true;

 

Modify the source HandleCursorValues method

Also declare a class variable to store the last obtained point

private Point lastMovedPoint;

 

Then add judgment to the method and pass

this.pointToolTip.AutomaticDelay = 1000;

 

Set the prompt delay by one second.Finally, the current point is assigned to the class variable.

lastMovedPoint = mousePt;

Complete sample code

private Point HandleCursorValues( Point mousePt )
  {
            GraphPane pane = _masterPane.FindPane(mousePt);
            if (pane != null && pane.Chart._rect.Contains(mousePt) && !mousePt.Equals(lastMovedPoint))
            {
                // Provide Callback for User to customize the tooltips
                if (this.CursorValueEvent != null)
                {
                    string label = this.CursorValueEvent(this, pane, mousePt);
                    if (label != null && label.Length > 0)
                    {
                        this.pointToolTip.AutomaticDelay = 1000;
                        this.pointToolTip.SetToolTip(this, label);
                        this.pointToolTip.Active = true;
                    }
                    else
                    {
                        this.pointToolTip.Active = false;
                    }
                    lastMovedPoint = mousePt;
                }
                else
                {
                    double x, x2, y, y2;
                    pane.ReverseTransform(mousePt, out x, out x2, out y, out y2);
                    string xStr = MakeValueLabel(pane.XAxis, x, -1, true);
                    string yStr = MakeValueLabel(pane.YAxis, y, -1, true);
                    string y2Str = MakeValueLabel(pane.Y2Axis, y2, -1, true);
                    this.pointToolTip.AutomaticDelay = 1000;
                    this.pointToolTip.SetToolTip(this, "( " + xStr + ", " + yStr + ", " + y2Str + " )");
                    this.pointToolTip.Active = true;
                }
               
            }
            else
                this.pointToolTip.Active = false;

            return mousePt;
           
  }

 

Note:

This only focuses on modifying this.CursorValueEvent when the user overrides this event!= When null, you can modify it to suit your needs.

ZedGraph5.1.5 Source and Modified Source Download

Focus on Public Number:

Domineering program ape

Reply:

ZedGraph Source Modification