"""
Plotting helpers.

 * We set the default tick_formatter to 'latex'.

 * We replace the plot() function with our own version that sets some
   default legend options.

"""

from sage.all import *

# Graphics.SHOW_OPTIONS contains the default options that will be
# passed to show(). It already handles merging the user-specified
# options, so we just tap into that power.
show_opts = sage.plot.graphics.Graphics.SHOW_OPTIONS
show_opts['tick_formatter'] = 'latex'

# Save the default plot() function so that we can call it within
# mjo_plot and not die of recursion.
sage_plot = plot

def mjo_plot(*args, **kwargs):
    """
    Replacement for the default plot function.

     - If there's a legend, set the background color to 'white' and
       give it a drop shadow.

    """
    default_legend_opts = { 'back_color': 'white',
                            'shadow': True }

    # Create an empty plot using the default options.
    p = Graphics()
    p.set_legend_options(**default_legend_opts)

    # After trac #12936, this should propagate those options.
    p += sage_plot(*args, **kwargs)

    return p


# Replace both the global `plot` and the ones in the modules. I am
# unclear about why this is necessary, and don't care too much.
plot = mjo_plot
sage.plot.plot.plot = mjo_plot
sage.plot.all.plot = mjo_plot