[Matplotlib-users] callbacks / custom nav toolbar

[Daniel H. <dh...@gm...>]

I was trying to implement my own nav toolbar, and everything works great
except an exception that gets thrown intermittently when in zoom
rubberbanding operation, from this bit of code in CallbackRegistry
(cbook.py):


    def process(self, s, *args, **kwargs):
        """
        process signal *s*.  All of the functions registered to receive
        callbacks on *s* will be called with *\*args* and *\*\*kwargs*
        """
        self._check_signal(s)
        for cid, proxy in self.callbacks[s].items():
            # Clean out dead references
            if proxy.inst is not None and proxy.inst() is None:
                del self.callbacks[s][cid]  #<----------- the cid key
doesn't exist.
            else:
                proxy(*args, **kwargs)


is it OK to eat and ignore this exception?  Everything seems to work just
fine.

I know that this is probably one of those weak-reference callbacks getting
dropped, but I don't make any connections to 'button_release_event'
 anywhere in my code, and that's what 's' is in the above code when the
dictionary key is missing. In other areas of my code where I am making
connections, I did make sure that I'm saving a reference to them myself.




-- 
Daniel Hyams
dh...@gm...