Server side Charting Library that is design focused

Question

I have been looking for a good server side graphing / charting library that has a lot of design options. Most seem to be very difficult to customize the specific way we are looking to.

I don't mind if it is python, php, java, etc... I just need it to generate server side and output an image to be embedded on a pdf.

Specifically I need the following.

• Gradients in bars fill color
• Ability to have rounded edges on bars of chart

From a design perspective those are the important ones that I can not find in a specific library.

Answer 1

Ended up using MatPlotLib and used the example below. Essentially you can use an image and set the repeating area of the image. Instead of the gift boxes, I used a rounded corners horizontal gradient image.

http://matplotlib.sourceforge.net/examples/pylab_examples/demo_ribbon_box.html