Re: [matplotlib-devel] matplotlib.use()

[Ryan M. <rm...@gm...>]

On Fri, Jul 20, 2012 at 3:20 PM, Eric Firing <ef...@ha...> wrote:
> This would be defeating the basic idea: use() is *only* designed to take
> effect *once*.  If you need to switch backends, it takes more than what
> use() does, hence the need for switch_backend().  (But see below.)
>
> The warn=False invocation of use, with the return statement were it is
> now, is for the case where you may have a script or module that
> specifies a backend (in case it is the first or only import of
> matplotlib), but that may itself be imported or called by something else
> that has already imported matplotlib and set the backend.  In this case
> we want the warning to be suppressed, which is all the warn=False flag
> is supposed to do.  I use this myself.
>
> So it looks like the problem is that switch_backends is broken because
> what it needs matplotlib.use to do is go ahead and make the switch. This
> could be done by adding a force=True kwarg (default would be False) to
> matplotlib.use, or by deleting the reference to the backends module from
> sys.modules in switch_backends before calling matplotlib.use.  A
> variation would be to use the force kwarg and to include the
> switch_backends logic, or at least the reload line, in matplotlib.use.
> That probably makes sense: add the force kwarg, and when the module is
> replaced, reload it immediately within matplotlib.use.  Then
> pyplot.switch_backends only needs to do the pyplot-specific operations.
>   I think that is the cleanest solution.

I agree, this is a better way to go. (And occurred to me as well after
the initial PR.)

Glad I asked rather than doing my 2-line fix. The updated PR is at
https://github.com/matplotlib/matplotlib/pull/1028

Ryan

--
Ryan May
Graduate Research Assistant
School of Meteorology
University of Oklahoma