I'm working this one out at the moment...
The "issue" is that the render function is somewhat "inbuilt" into the program, so I cant feed it in an extra value to do anything with. I was going to feed in the "current level" & if the node is at the current level of +1 level, then draw.
The shortnodepide.render function is called for EVERY node, so if you have heaps of tree children - they ALL get passed to render EVERY node.
The workaround I though of is this...
There's 2 vars - json & jsonPIE
The JSON is used to generate the tree structure, JSONPIE used to create the pie graphs.
So think of the JSONPIE data as the colouring data, and generate/manipulate that on the fly. i.e.:
node.onClick = <var JSONPIE = [node.children.data]>
You'll also need to reduce the tree depth to 1, as the colouring wouldnt make sense otherwise.
Will post up how I go.