This page contains a simple Treemap library for use with Processing It is a minor adaptation of Martin Wattenberg and Ben Bederson's Treemap Java Algorithms collection, released under the Mozilla Public License. Only a small percentage of the original code has been altered from their original library. The reference covers the details.
The Processing library can be found here: library.zip. Unzip the file, and place the treemap folder into your Processing → Libraries folder. Restart Processing if it's already running so that it picks up the new library.
Reference and source code is included with the download. This code was packaged for the book Visualizing Data by Ben Fry for the examples in Chapter 7.