soc-2008-mxcurioni: Tested SWIG-less environment more and understood why the former predicate methods were not working. As Stéphane had mentioned a few months ago, Freestyle uses SWIG directors to provide cross-language polymorphism. The API and the system I had provided did not support that feature and only implementations in C++ were supported. To correct the problem, after researching how directors are implemented in SWIG, I provided the same functionality. So far, I only provided the code for the UnaryPredicate1D class and it works. The implementation is in intern/python/Director.cpp and Operators.cpp. I will port the remaining directors tonight and continue to test it.

To prevent strokes from piling up after each render,  I clear the canvas at each render now (as it should have been all along)

source/blender/freestyle/intern/python/BPy_Operators.cpp

@@ -164,7 +164,11 @@ PyObject * Operators_select(BPy_Operators* self, PyObject *args)
 		Py_RETURN_NONE;
 	}
 
-	Operators::select(*( ((BPy_UnaryPredicate1D *) obj)->up1D ));
+	UnaryPredicate1D *up1D = ((BPy_UnaryPredicate1D *) obj)->up1D;
+	if( PyObject_HasAttrString( obj, "__call__") )
+		up1D->setPythonObject( obj );
+	
+	Operators::select(*up1D);
 
 	Py_RETURN_NONE;
 }