Generate Image with Microsoft .NET Chart Controls Library without Control

Question

Is it possible to generate images (jpeg, png, etc) using the Microsoft Chart Controls library without instantiating a WinForm or ASP.NET Control class? All the examples I have seen utilize a control component. I need to create a library which contains simple methods that take data to be plotted and returns a new chart image. Examples:

public byte[] GeneratePlot(IList<SeriesData> series)
{
    // generate and return JPEG
}
public void GeneratePlot(IList<SeriesData> series, Stream outputStream)
{
    // generate JPEG and write to stream
}

If it is not possible:

1. would you recommend creating/disposing a new chart control each time the user calls the GeneratePlot() method?
2. is there another .NET library (preferably free) that you would recommend?

Thanks

Answer 1

If all you want is chart images. Then you can use the chart controls to save to disk.

myChart.SaveImage("C:\mypic.png", System.Drawing.Imaging.ImageFormat.Png)

Then load that image from the disk. If the charts are only generated once then you can also just check the filesystem for the image first and then only re-render it if it doesnt exist.

Hope this helps.

Answer 2

Yes, that's possible:

using System.Windows.Forms.DataVisualization.Charting;
using System.IO;
...
    public void GeneratePlot(IList<DataPoint> series, Stream outputStream) {
      using (var ch = new Chart()) {
        ch.ChartAreas.Add(new ChartArea());
        var s = new Series();
        foreach (var pnt in series) s.Points.Add(pnt);
        ch.Series.Add(s);
        ch.SaveImage(outputStream, ChartImageFormat.Jpeg);
      }
    }