At Rain I have the privilege of working with some of the most talented designers in the industry. They often dream up new ways to visualize data. While it’s exciting to see what they come up with, it’s also kind of daunting from time-to-time because I have to figure out a way to build these views/components!

Recently I had the challenge of trying to implement a pie chart which changed its innerRadius whenever a wedge in the chart was rolled over. The designer wanted it to grow and animate to that new radius.  Essentially they wanted something kinda like this:

Selected index's inner radius changes when rolled over

I immediately cringed a little bit because although the charting components are extremely powerful, they can also be very difficult to extend.  So I started refreshing my mind on how the charting components work and spent a bit of time looking on Ely Greenfield’s site for tips (he’s the charting master of the Flex SDK team).  While I wound up building the component myself since it didn’t already exist on the intertubes, Ely’s examples showed me the proper way charting components should be extended.

In the end I wound up extending PieSeries and creating my own which I called VariableInnerRadiusPieSeries (creative right?).  The code actually wound up being much simpler that I initially thought!.  Check out the example (right click to see the source).