COMPAT: mpl 3.0 (#22870)

* COMPAT: mpl 3.0

* faster test

doc/source/whatsnew/v0.24.0.txt

@@ -193,6 +193,8 @@ Other Enhancements
 - :meth:`Series.resample` and :meth:`DataFrame.resample` have gained the :meth:`Resampler.quantile` (:issue:`15023`).
 - :meth:`Index.to_frame` now supports overriding column name(s) (:issue:`22580`).
 - New attribute :attr:`__git_version__` will return git commit sha of current build (:issue:`21295`).
+- Compatibility with Matplotlib 3.0 (:issue:`22790`).
+
 .. _whatsnew_0240.api_breaking:
 
 Backwards incompatible API changes

pandas/plotting/_compat.py

@@ -29,3 +29,4 @@ def inner():
 _mpl_ge_2_0_1 = _mpl_version('2.0.1', operator.ge)
 _mpl_ge_2_1_0 = _mpl_version('2.1.0', operator.ge)
 _mpl_ge_2_2_0 = _mpl_version('2.2.0', operator.ge)
+_mpl_ge_3_0_0 = _mpl_version('3.0.0', operator.ge)

pandas/plotting/_core.py

@@ -32,7 +32,8 @@
 
 from pandas.plotting._compat import (_mpl_ge_1_3_1,
                                      _mpl_ge_1_5_0,
-                                     _mpl_ge_2_0_0)
+                                     _mpl_ge_2_0_0,
+                                     _mpl_ge_3_0_0)
 from pandas.plotting._style import (plot_params,
                                     _get_standard_colors)
 from pandas.plotting._tools import (_subplots, _flatten, table,
@@ -843,11 +844,16 @@ def _plot_colorbar(self, ax, **kwds):
         # For a more detailed description of the issue
         # see the following link:
         # https://github.com/ipython/ipython/issues/11215
-
         img = ax.collections[0]
         cbar = self.fig.colorbar(img, ax=ax, **kwds)
+
+        if _mpl_ge_3_0_0():
+            # The workaround below is no longer necessary.
+            return
+
         points = ax.get_position().get_points()
         cbar_points = cbar.ax.get_position().get_points()
+
         cbar.ax.set_position([cbar_points[0, 0],
                               points[0, 1],
                               cbar_points[1, 0] - cbar_points[0, 0],

pandas/tests/plotting/common.py

@@ -57,6 +57,7 @@ def setup_method(self, method):
         self.mpl_ge_2_0_0 = plotting._compat._mpl_ge_2_0_0()
         self.mpl_ge_2_0_1 = plotting._compat._mpl_ge_2_0_1()
         self.mpl_ge_2_2_0 = plotting._compat._mpl_ge_2_2_0()
+        self.mpl_ge_3_0_0 = plotting._compat._mpl_ge_3_0_0()
 
         if self.mpl_ge_1_4_0:
             self.bp_n_objects = 7

pandas/tests/plotting/test_datetimelike.py

@@ -151,7 +151,7 @@ def test_high_freq(self):
         freaks = ['ms', 'us']
         for freq in freaks:
             _, ax = self.plt.subplots()
-            rng = date_range('1/1/2012', periods=100000, freq=freq)
+            rng = date_range('1/1/2012', periods=100, freq=freq)
             ser = Series(np.random.randn(len(rng)), rng)
             _check_plot_works(ser.plot, ax=ax)
 
@@ -1492,7 +1492,11 @@ def test_matplotlib_scatter_datetime64(self):
         ax.scatter(x="time", y="y", data=df)
         fig.canvas.draw()
         label = ax.get_xticklabels()[0]
-        assert label.get_text() == '2017-12-12'
+        if self.mpl_ge_3_0_0:
+            expected = "2017-12-08"
+        else:
+            expected = "2017-12-12"
+        assert label.get_text() == expected
 
 
 def _check_plot_works(f, freq=None, series=None, *args, **kwargs):