Question

Im developing one GUI in C#.Net under WPF.Actually its an application for serial communication with the embedded device,I want to show a line chart with the frequently recieved data.And also I should provide an option to save those charts and to give an option to print it.How can I draw this dynamically with the support of free libraries or softwares?

Answer 1

I use Dynamic Data Display for all my WPF charting needs. It supports saving the charts, is very quick, provides seamless zooming and panning.
Namespace: xmlns:d3=”http://research.microsoft.com/DynamicDataDisplay/1.0″

XAML:

 <d3:ChartPlotter Name="plotter" Background="White">
    <d3:ChartPlotter.Resources>
        <conv:Date2AxisConverter x:Key="Date2AxisConverter"/>
    </d3:ChartPlotter.Resources>
    <d3:ChartPlotter.HorizontalAxis>
        <d3:HorizontalDateTimeAxis Name="dateAxis"/>
    </d3:ChartPlotter.HorizontalAxis>
    <d3:Header Content="{Binding PlotHeader}"/>
    <d3:VerticalAxisTitle Content="Value"/>
    <d3:HorizontalAxisTitle Content="Date"/>
</d3:ChartPlotter>

C# Code: Converter used

public class Date2AxisConverter : IValueConverter
{
    #region IValueConverter Members
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (value is DateTime && targetType == typeof(double))
        {
            return ((DateTime)value).Ticks / 10000000000.0;
            // See constructor of class Microsoft.Research.DynamicDataDisplay.Charts.DateTimeAxis
            // File: DynamicDataDisplay.Charts.Axes.DateTime.DateTimeAxis.cs

            // alternatively, see the internal class Microsoft.Research.DynamicDataDisplay.Charts.DateTimeToDoubleConversion

        }
        return null;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        // try Microsoft.Research.DynamicDataDisplay.Charts.DateTimeAxis.DoubleToDate
        throw new NotSupportedException();
    }

    #endregion
}

C# Code: Clearing Graph and Creating line graph, Here my StockasticProcessPoint is a structure with a field “DateTime t” and a field “Double value”.

using Microsoft.Research.DynamicDataDisplay;
using System.Collections.ObjectModel;
using Microsoft.Research.DynamicDataDisplay.DataSources;

public void ClearLines()
{
    var lgc = new Collection<IPlotterElement>();
    foreach (var x in plotter.Children)
    {
        if (x is LineGraph || x is ElementMarkerPointsGraph)
            lgc.Add(x);
    }

    foreach (var x in lgc)
    {
        plotter.Children.Remove(x);
    }
}

internal void SendToGraph() {

    IPointDataSource _eds = null;
    LineGraph line;

    ClearLines();

    EnumerableDataSource<StochasticProcessPoint> _edsSPP;
    _edsSPP = new EnumerableDataSource<StochasticProcessPoint>(myListOfStochasticProcessPoints);
    _edsSPP.SetXMapping(p => dateAxis.ConvertToDouble(p.t));
    _edsSPP.SetYMapping(p => p.value);
    _eds = _edsSPP;

    line = new LineGraph(_eds);
    line.LinePen = new Pen(Brushes.Black, 2);
    line.Description = new PenDescription(Description);
    plotter.Children.Add(line);
    plotter.FitToView();
}

With this, you should be able to plot a chart in WPF. Adding data live when it comes back from the serial port should be no problem. You can also look at the binding examples from DynamicDataDisplay.