"""
legend - Plot a legend.
"""
from pygmt.clib import Session
from pygmt.exceptions import GMTInvalidInput
from pygmt.helpers import (
build_arg_string,
data_kind,
fmt_docstring,
kwargs_to_strings,
use_alias,
)
@fmt_docstring
@use_alias(
R="region",
J="projection",
D="position",
F="box",
V="verbose",
X="xshift",
Y="yshift",
p="perspective",
t="transparency",
)
@kwargs_to_strings(R="sequence", p="sequence")
def legend(self, spec=None, position="JTR+jTR+o0.2c", box="+gwhite+p1p", **kwargs):
"""
Plot legends on maps.
Makes legends that can be overlaid on maps. Reads specific
legend-related information from an input file, or automatically creates
legend entries from plotted symbols that have labels. Unless otherwise
noted, annotations will be made using the primary annotation font and
size in effect (i.e., FONT_ANNOT_PRIMARY).
Full option list at :gmt-docs:`legend.html`
{aliases}
Parameters
----------
spec : None or str
Either None (default) for using the automatically generated legend
specification file, or a filename pointing to the legend
specification file.
{J}
{R}
position : str
``'[g|j|J|n|x]refpoint+wwidth[/height][+jjustify][+lspacing]
[+odx[/dy]]'`` Defines the reference point on the map for the
legend. By default, uses 'JTR+jTR+o0.2c' which places the legend at
the top-right corner inside the map frame, with a 0.2 cm offset.
box : bool or str
``'[+cclearances][+gfill][+i[[gap/]pen]][+p[pen]][+r[radius]]
[+s[[dx/dy/][shade]]]'`` Without further options, draws a
rectangular border around the legend using **MAP_FRAME_PEN**. By
default, uses '+gwhite+p1p' which draws a box around the legend
using a 1 point black pen and adds a white background.
{V}
{XY}
{p}
{t}
"""
kwargs = self._preprocess(**kwargs) # pylint: disable=protected-access
if "D" not in kwargs:
kwargs["D"] = position
if "F" not in kwargs:
kwargs["F"] = box
with Session() as lib:
if spec is None:
specfile = ""
elif data_kind(spec) == "file":
specfile = spec
else:
raise GMTInvalidInput("Unrecognized data type: {}".format(type(spec)))
arg_str = " ".join([specfile, build_arg_string(kwargs)])
lib.call_module("legend", arg_str)