Re: [Matplotlib-users] Using the lasso tool when file is not main

[Mark B. <mar...@gm...>]

Thanks Ben, that solved my issue. I guess I got thrown off because the
plot stayed open, as you described. It's hard to troubleshoot when you
don't get any errors. In the future I will attach all of my objects.
-Mark

On Fri, Sep 7, 2012 at 12:03 PM, Benjamin Root <ben...@ou...> wrote:
> I think I see your problem... see below:
>
>
> class start_lasso():
>     def __init__(self):
>         data = [Datum(*xy) for xy in rand(100, 2)]
>
>         fig = figure()
>         ax = fig.add_subplot(111, xlim=(0,1), ylim=(0,1),
> autoscale_on=False)
>         lman = LassoManager(ax, data)
>         show()
>
> You aren't saving any of the objects created in the "start_lasso" class to
> your start_lasso object.  Luckily, with the way pyplot works, the figure
> object your create gets implicitly saved to the "pyplot state manager" (a
> sort of smart global location for the figure objects), and the axes object
> gets implicitly attached to the figure object.  Therefore, when the python
> execution goes out of this scope, the figure object and the axes do not get
> garbage-collected.  However, the lasso widget that gets created and all the
> callbacks that were attached are all done with weak references to the figure
> and axes.  So when you leave this scope, the LassoManager no longer exists
> and the callback fails to execute (as designed).
>
> So, make sure that at least lman (and possibly fig and ax) gets saved to the
> start_lasso object to solve that part of the problem.  Next, you don't save
> the start_lasso object your create anywhere, so even if you saved lman to
> start_lasso, the start_lasso object gets garbage-collected anyway as a
> temporary.
>
> I hope this is clear.  Let me know if you still have more issues.
>
> Cheers!
> Ben Root
>