Hello,

I've implemented a custom tooltip for the Polar Series, since I want to be able to visualize each continous point for a polar series and not just the marker tooltips.

This is the XAML for my Polar Chart (almost the same as the sample Polar chart):

<ig:XamDataChart x:Name="PolarLineChart" Grid.Column="0" Grid.Row="1" SeriesMouseMove="PolarLineChart_OnSeriesMouseMove" HorizontalZoomable="True"                                            HorizontalZoombarVisibility="Visible" VerticalZoomable="True" VerticalZoombarVisibility="Visible"

                          Legend="{StaticResource Legend}" CrosshairVisibility="Visible" PlotAreaBorderBrush="{x:Null}" >
        <ig:SyncManager.SyncSettings>
              <ig:SyncSettings SyncChannel="SyncPolarSeries" SynchronizeHorizontally="True" SynchronizeVertically="True" />
        </ig:SyncManager.SyncSettings>
         <ig:XamDataChart.Axes>
                 <ig:NumericAngleAxis x:Name="NumericAngleAxis1" Canvas.ZIndex="10" CrossingAxis="{Binding ElementName=NumericRadiusAxis1}" Interval=".5"                  

                                                MaximumValue="10" MinimumValue="0" StartAngleOffset="0">
                           <ig:NumericAngleAxis.LabelSettings>
                                <ig:AxisLabelSettings Location="InsideTop" Extent="20" />
                           </ig:NumericAngleAxis.LabelSettings>
                 </ig:NumericAngleAxis>
                  <ig:NumericRadiusAxis x:Name="NumericRadiusAxis1" Canvas.ZIndex="10" StrokeThickness="2" CrossingAxis="{Binding ElementName=NumericAngleAxis1}"

                                                CrossingValue="0" MinimumValue="0" MaximumValue="10" Interval="1">
                          <ig:NumericRadiusAxis.LabelSettings>
                                   <ig:AxisLabelSettings Location="InsideBottom" />
                           </ig:NumericRadiusAxis.LabelSettings>
                   </ig:NumericRadiusAxis>
              </ig:XamDataChart.Axes>
      <ig:XamDataChart.Series>
               <ig:PolarLineSeries Title="2010"
                                         AngleAxis="{Binding ElementName=NumericAngleAxis1}"
                                         RadiusAxis="{Binding ElementName=NumericRadiusAxis1}"
                                         AngleMemberPath="X" MarkerType="None"
                                         RadiusMemberPath="Y" ItemsSource="{Binding Path=Points, Source={StaticResource EnergyProductionCollection}}"
                                          Thickness="5" >
                 </ig:PolarLineSeries>
      </ig:XamDataChart.Series>
</ig:XamDataChart>

The underlying data is a List<Point>()

For other numeric series, what I've been doing is attaching to the SeriesMouseMove event and working with positions and unscaled values as follows:

private void chart_SeriesMouseMove(object sender, ChartMouseEventArgs e)
{        

         var position = e.GetPosition(e.Series);

         var viewport = new Rect(0, 0, e.Series.ActualWidth, e.Series.ActualHeight);

         var scalerParams = new ScalerParams(e.Series.SeriesViewer.WindowRect, viewport, false);

         var scatterSeries = e.Series as ScatterSeries;

         double x = scatterSeries.XAxis.GetUnscaledValue(position.X, scalerParams);

         double y = scatterSeries.YAxis.GetUnscaledValue(position.Y, scalerParams);         

         var selectedPoint = new Point
         {
             X = x,
             Y = y
         };

         // Show the point in the UI...

}

The above method works great on regular numeric X axis and Y axis.

But for Polar Axes, the UnscaledValue doesn't comply correctly due to the angle and radius. I've tried other methods like UnscaledAngleValue but the angle I get must be based on the Axis values, not the actual position in the plot area.

Is there a way I can get underlying values (interpolated or exact points) by using the current mouse position?

(This means: If I set a Point of 1,2, whenever I move through that point I want 1,2 returned to me).

Hope it's clear.

Thank you very much.

Kind regards,

Sebastian