start plotting backend

Author: TomAugspurger

pandas/core/config_init.py

@@ -505,3 +505,28 @@ def register_converter_cb(key):
 with cf.config_prefix("plotting.matplotlib"):
     cf.register_option("register_converters", True, register_converter_doc,
                        validator=bool, cb=register_converter_cb)
+
+
+plotting_backend_doc = """
+: str
+    The plotting backend to use.
+"""
+
+
+def plotting_backend_cb(key):
+    from pandas import Series, DataFrame
+    from pandas.plotting._base import _backends
+    from pandas.core.accessor import CachedAccessor
+
+    backend_name = cf.get_option(key)
+    print('registering', backend_name)
+    backend = _backends[backend_name]
+
+    Series.plot = CachedAccessor("plot", backend.series)
+    DataFrame.plot = CachedAccessor("plot", backend.frame)
+
+
+with cf.config_prefix("plotting"):
+    cf.register_option("backend", defval="matplotlib",
+                       doc=plotting_backend_doc,
+                       cb=plotting_backend_cb)

pandas/plotting/_base.py

@@ -0,0 +1,75 @@
+from collections import namedtuple
+
+PlottingBackend = namedtuple('PlottingBackend', 'series frame')
+
+_backends = {}
+
+
+def register_backend(name, series, frame):
+    _backends[name] = PlottingBackend(series, frame)
+
+
+class BasePlotMethods:
+    def __init__(self, data):
+        self._parent = data
+
+    def __call__(self, *args, **kwargs):
+        raise NotImplementedError
+
+    def area(self, *args, **kwargs):
+        pass
+
+    def bar(self, *args, **kwargs):
+        pass
+
+    def barh(self, *args, **kwargs):
+        pass
+
+    def box(self, *args, **kwargs):
+        pass
+
+    def density(self, *args, **kwargs):
+        pass
+
+    def hist(self, *args, **kwargs):
+        pass
+
+    def kde(self, *args, **kwargs):
+        pass
+
+    def line(self, *args, **kwargs):
+        pass
+
+    def pie(self, *args, **kwargs):
+        pass
+
+
+class SeriesPlotMethods(BasePlotMethods):
+    def __call__(self, kind='line', ax=None,
+                 figsize=None, use_index=True, title=None, grid=None,
+                 legend=False, style=None, logx=False, logy=False,
+                 loglog=False, xticks=None, yticks=None,
+                 xlim=None, ylim=None,
+                 rot=None, fontsize=None, colormap=None, table=False,
+                 yerr=None, xerr=None,
+                 label=None, secondary_y=False, **kwds):
+        raise NotImplementedError
+
+
+class FramePlotMethods(BasePlotMethods):
+
+    def __call__(self, x=None, y=None, kind='line', ax=None,
+                 subplots=False, sharex=None, sharey=False, layout=None,
+                 figsize=None, use_index=True, title=None, grid=None,
+                 legend=True, style=None, logx=False, logy=False, loglog=False,
+                 xticks=None, yticks=None, xlim=None, ylim=None,
+                 rot=None, fontsize=None, colormap=None, table=False,
+                 yerr=None, xerr=None,
+                 secondary_y=False, sort_columns=False, **kwds):
+        pass
+
+    def hexbin(self, x, y, **kwargs):
+        pass
+
+    def scatter(self, x, y, **kwargs):
+        pass

pandas/plotting/_core.py

@@ -32,6 +32,8 @@
     _flatten, _get_all_lines, _get_xlim, _handle_shared_axes, _set_ticks_props,
     _subplots, format_date_labels, table)
 
+from ._base import FramePlotMethods, SeriesPlotMethods, register_backend
+
 try:
     from pandas.plotting import _converter
 except ImportError:
@@ -2697,16 +2699,11 @@ def _grouped_plot_by_column(plotf, data, columns=None, by=None,
     return result
 
 
-class BasePlotMethods(PandasObject):
-
-    def __init__(self, data):
-        self._parent = data  # can be Series or DataFrame
-
-    def __call__(self, *args, **kwargs):
-        raise NotImplementedError
+class BaseMPLMethods(PandasObject):
+    pass
 
 
-class SeriesPlotMethods(BasePlotMethods):
+class MPLSeriesMethods(BaseMPLMethods, SeriesPlotMethods):
     """
     Series plotting accessor and method.
 
@@ -2906,7 +2903,7 @@ def pie(self, **kwds):
         return self(kind='pie', **kwds)
 
 
-class FramePlotMethods(BasePlotMethods):
+class FramePlotMethods(BaseMPLMethods, FramePlotMethods):
     """DataFrame plotting accessor and method
 
     Examples
@@ -3600,3 +3597,6 @@ def hexbin(self, x, y, C=None, reduce_C_function=None, gridsize=None,
         if gridsize is not None:
             kwds['gridsize'] = gridsize
         return self(kind='hexbin', x=x, y=y, C=C, **kwds)
+
+
+register_backend('matplotlib', SeriesPlotMethods, FramePlotMethods)

pandas/tests/plotting/test_backends.py

@@ -0,0 +1,35 @@
+import pandas as pd
+
+from pandas.plotting._base import _backends, register_backend
+from pandas.plotting._core import FramePlotMethods, SeriesPlotMethods
+
+
+def test_register_backend():
+    # define
+    count = 0
+
+    class MockedSeries(SeriesPlotMethods):
+        def line(self, *args, **kwargs):
+            nonlocal count
+            count += 1
+            super().line(*args, **kwargs)
+
+    class MockedFrame(FramePlotMethods):
+        def line(self, *args, **kwargs):
+            nonlocal count
+            count += 1
+            super().line(*args, **kwargs)
+
+    # register
+    register_backend('mocked', MockedSeries, MockedFrame)
+    assert 'mocked' in _backends
+
+    # select
+    pd.set_option("plotting.backend", "mocked")
+
+    # use
+    df = pd.DataFrame({"A": [1, 2], "B": [1, 2]})
+    df.plot.line()
+    assert count == 1
+    df['A'].plot.line()
+    assert count == 2