What is the type of application that you are currently using?
Although our library has an API for drawing various objects and it is possible to draw a chart manually, there is no functionality that will allow you to draw an entire chart by using the data. I believe that your current approach is ok and you can continue using it. Another approach will be to use one of the desktop suites (WPF or WinForms) to export the chart to an image and create the PDF. For example here is how you can export the WPF chart to an image: WPF ChartView Export.
I hope this helps. Should you have any other questions do not hesitate to ask.