I have just finished reviewing the app/ folder. I think that I get a rough idea of how things work in code, reproducing the basic steps from initializing the controller, opening a file, setting a style, computing the view map and rendering the strokes. From what I understand, I need to see how the Canvas class works in more detail, so I will do that tomorrow. I am keeping in mind that the first phase will make Freestyle independent from Qt, so all dependencies have to be looked at in detail.
Stéphane, I have surely overlooked but I haven’t been able to see the interactive shader window or the “Compute Steerable Viewmap” in Freestyle. Are they used in the Mac OS X version ? What are steerable view-maps ?