Custom legends in GWpy¶

GWpy overrides the default Axes class with one that uses a different default legend handler for line plots. This means that, by default, lines in a legend will be thicker than on a standard matplotlib figure:

>>> import gwpy  # <- import anything from gwpy
>>> from matplotlib import pyplot
>>> fig = pyplot.figure()
>>> ax = fig.gca()
>>> ax.plot(range(10), label='My data')
>>> ax.legend()
>>> fig.show()

(png)

This can be disabled by passing an empty handler_map to the legend() method:

>>> fig = pyplot.figure()
>>> ax = fig.gca()
>>> ax.plot(range(10), label='My data')
>>> ax.legend(handler_map=None)
>>> fig.show()

(png)

Similarly, you can implement your own custom legend handler and overwrite things yourself. Below is a simple example, but for more details see matplotlib:sphx_glr_tutorials_intermediate_legend_guide.py:

>>> from matplotlib.legend_handler import HandlerLine2D
>>> from matplotlib.lines import Line2D
>>> class MyHandler(HandlerLine2D):
...     def create_artists(self, *args, **kwargs):
...         line, marker = super(MyHandler, self).create_artists(
...             *args,
...             **kwargs,
...         )
...         line.set_linewidth(4.)
...         line.set_linestyle('--')
...         return line, marker
>>> fig = pyplot.figure()
>>> ax = fig.gca()
>>> ax.plot(range(10), label='My data')
>>> ax.legend(handler_map={Line2D: MyHandler()}, handlelength=10)
>>> fig.show()