legend not properly set in Graphics().matplotlib()

[ppurka]

Bug :) Should be easy to fix.

sage: q = plot(x, legend_label='aha')
sage: q.legend(True)                 
sage: qm = q.matplotlib()
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)

/home/punarbasu/Installations/sage-5.0.rc0.11080/devel/sage-main/<ipython console> in <module>()

/home/punarbasu/Installations/sage-5.0.rc0.11080/local/lib/python2.7/site-packages/sage/plot/graphics.pyc in matplotlib(self, filename, xmin, xmax, ymin, ymax, figsize, figure, sub, axes, axes_labels, fontsize, frame, verify, aspect_ratio, gridlines, gridlinesstyle, vgridlinesstyle, hgridlinesstyle, show_legend, legend_options, axes_pad, ticks_integer, tick_formatter, ticks)
   1714             lopts.update(legend_options)
   1715             lopts.update(self._legend_opts)
-> 1716             prop = FontProperties(family=lopts.pop('font_family'), weight=lopts.pop('font_weight'), \
   1717                     size=lopts.pop('font_size'), style=lopts.pop('font_style'), variant=lopts.pop('font_variant'))
   1718             color = lopts.pop('back_color')

KeyError: 'font_family'
sage: 

---

Apply trac_12960-fix_legend.2.patch to devel/sage

[ppurka]

Hmm.. the matplotlib arguments are also changed it seems. I will revert that.

[ppurka]

apply to devel/sage

[kcrisman]

Does this really work? I'm unclear as to how this would work in the case show is None. Or maybe it's not supposed to then, since it's not being shown... in which case why not just put this in the matplotlib definition, which currently has legend_options={}? Or maybe with a @suboptions decorator like in show? This seems more "Sage-ic".

[ppurka]

Whoever wrote the legend code probably didn't want unnecessary initializations. I kept it the same, that is the legend_opts don't get populated unless it is absolutely required. Otherwise we could just initialize it in __init__ instead of passing @options or @suboptions all over the place.

If show_legend is None, then of course, nothing happens. If it is set to True, then something weird can happen. I will check this case.

[ppurka]

Ok. This is a much better fix since it takes care of all cases, for example if you pass an incomplete set of options in the legend={} argument, set show_legend=True, etc.

[kcrisman]

Yes, this makes a lot more sense. Needs doctests!

[ppurka]

apply to devel/sage

[ppurka]

Updated the patch with a test.

[kcrisman]

Looks great, thanks for the good work!