The solver source code is derived from the 0.6 release of Cassowary. It has been modified by Svilen Dobrev to remove memory leaks. His work can be found separately as SWIG bindings:
The original Cassowary sources are available from its website:
http://www.cs.washington.edu/research/constraints/cassowary/
His modifications are available under the BSD license, while Casuarius as a whole follows the license of Cassowary itself, LGPL v2.1 or (at your option) a later version of the LGPL. See the files LICENSE and COPYING.LGPL for details.
Please be sure to have Cython 0.15.1 or above in order to compile this extension module. It has been tested on OS X (using llvm-gcc 4.2) and Windows (using mingw). Other Windows C++ compilers may or may not work.
Please contact the Enthought mailing list <enthought-dev@enthought.com> for support.