[matplotlib-devel] matplotlib.use()

Hi,

I'm here at the SciPy sprints trying to fix switching inline/gui for
the ipython notebook. I've noticed something weird about
matplotlib.use() :

    if 'matplotlib.backends' in sys.modules:
        if warn: warnings.warn(_use_error_msg)
        return
    if arg.startswith('module://'):
        name = arg
    else:
        # Lowercase only non-module backend names (modules are case-sensitive)
        arg = arg.lower()
        name = validate_backend(arg)
    rcParams['backend'] = name

Notice the return if it finds the module loaded. This return basically
makes it impossible to make use() have any effect one backends has
been loaded. However, matplotlib.pyplot.switch_backend(). Eric added
this in 2008 as a bug fix, but no more detail than that. Does anyone
have a problem putting the return with the warning? Therefore if you
pass warn=False, you can actually make the setting take effect, but
the average user won't accidentally shoot their foot off. Something
like:

    if 'matplotlib.backends' in sys.modules:
        if warn:
            warnings.warn(_use_error_msg)
            return


Ryan

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