graphs and charts on the iPhone

My client has requested data to be presented in a graphical forma开发者_如何学Pythont on the iPhone (a pie chart or something similar). I am wondering how others have handled this - A.) deliver the raw data to the phone and somehow build the chart on the phone, or B.) have the back-end services build the chart and deliver it (png format) to the phone?

Thanks for any advice.

Check out Core Plot.

http://code.google.com/p/core-plot/

Another alternative is to use the Google ChartAPI:

http://code.google.com/apis/chart/docs/gallery/pie_charts.html