The subclass takes care of registering and delivering callbacks.
[[comment elements.callbacks]]
elements.callbacks.add
add a new callback elements.callbacks.add(callback_type, callback_handler, bodylist=None): return int
Users can add callbacks for certain (or all) collisions
Parameters:
callback_type ......... see elements.locals and manual.html#callbacks
callback_handler ...... a function which should be executed on the specified event
shapelist (optional) .. which shapes should cause the callback -- leave empty for all
Return:
callback_id ... used to remove a callback later (int)
[[comment elements.callbacks.add]]
elements.callbacks.get
get a callback listing elements.callbacks.get(callback_type): return List