Handle line and box on the same plot

Author: MartinBraquet

pandas/plotting/_matplotlib/core.py

@@ -59,7 +59,10 @@
 
 from pandas.io.formats.printing import pprint_thing
 from pandas.plotting._matplotlib import tools
-from pandas.plotting._matplotlib.converter import register_pandas_matplotlib_converters
+from pandas.plotting._matplotlib.converter import (
+    PeriodConverter,
+    register_pandas_matplotlib_converters,
+)
 from pandas.plotting._matplotlib.groupby import reconstruct_data_with_by
 from pandas.plotting._matplotlib.misc import unpack_single_str_list
 from pandas.plotting._matplotlib.style import get_standard_colors
@@ -1867,11 +1870,13 @@ def __init__(
 
         MPLPlot.__init__(self, data, **kwargs)
 
-        self.tick_pos = (
-            np.array(self.ax.xaxis.convert_units(self._get_xticks()))
-            if isinstance(data.index, ABCPeriodIndex)
-            else np.arange(len(data))
-        )
+        if isinstance(data.index, ABCPeriodIndex):
+            self.ax.freq = data.index.freq
+            self.tick_pos = np.array(
+                PeriodConverter.convert(data.index._mpl_repr(), None, self.ax)
+            )
+        else:
+            self.tick_pos = np.arange(len(data))
 
     @cache_readonly
     def ax_pos(self) -> np.ndarray: