enthought/enaml — comment on commit 3a6d947d8dd305f8824972197e2dfd9392c9873b
File:  line 0
By rkern:

A couple things:

* Directly translating the Cassowary source to Python does not remove the LGPL license of the code.
* I've experimented with this before using a slightly different solver. It was a more naive approach, using a plain LP solver anew for each layout when resizing. The performance when dragging was barely acceptable. You really need the sophistication of Cassowary's iterative algorithm that lets you change the parameters slightly and reuse the solution to the previous, closely related problem as a starting point. Even with the full Cassowary algorithm, I don't expect that pure Python code will be fast enough.
* Requiring numpy/scipy would be a bummer if we want anyone else to use it. For most Enthought projects, it doesn't matter much.