ENH: Fix support for matplotlib's constrained_layout (#25261)

doc/source/whatsnew/v1.3.0.rst

@@ -384,7 +384,7 @@ Plotting
 ^^^^^^^^
 
 - Bug in :func:`scatter_matrix` raising when 2d ``ax`` argument passed (:issue:`16253`)
--
+- Prevent warnings when matplotlib's ``constrained_layout`` is enabled (:issue:`25261`)
 -
 
 Groupby/resample/rolling

pandas/plotting/_matplotlib/boxplot.py

@@ -16,7 +16,11 @@
 from pandas.io.formats.printing import pprint_thing
 from pandas.plotting._matplotlib.core import LinePlot, MPLPlot
 from pandas.plotting._matplotlib.style import get_standard_colors
-from pandas.plotting._matplotlib.tools import create_subplots, flatten_axes
+from pandas.plotting._matplotlib.tools import (
+    create_subplots,
+    flatten_axes,
+    maybe_adjust_figure,
+)
 
 if TYPE_CHECKING:
     from matplotlib.axes import Axes
@@ -229,7 +233,7 @@ def _grouped_plot_by_column(
 
     byline = by[0] if len(by) == 1 else by
     fig.suptitle(f"Boxplot grouped by {byline}")
-    fig.subplots_adjust(bottom=0.15, top=0.9, left=0.1, right=0.9, wspace=0.2)
+    maybe_adjust_figure(fig, bottom=0.15, top=0.9, left=0.1, right=0.9, wspace=0.2)
 
     return result
 
@@ -436,7 +440,7 @@ def boxplot_frame_groupby(
             )
             ax.set_title(pprint_thing(key))
             ret.loc[key] = d
-        fig.subplots_adjust(bottom=0.15, top=0.9, left=0.1, right=0.9, wspace=0.2)
+        maybe_adjust_figure(fig, bottom=0.15, top=0.9, left=0.1, right=0.9, wspace=0.2)
     else:
         keys, frames = zip(*grouped)
         if grouped.axis == 0:

pandas/plotting/_matplotlib/hist.py

@@ -13,6 +13,7 @@
 from pandas.plotting._matplotlib.tools import (
     create_subplots,
     flatten_axes,
+    maybe_adjust_figure,
     set_ticks_props,
 )
 
@@ -296,8 +297,8 @@ def plot_group(group, ax):
         axes, xlabelsize=xlabelsize, xrot=xrot, ylabelsize=ylabelsize, yrot=yrot
     )
 
-    fig.subplots_adjust(
-        bottom=0.15, top=0.9, left=0.1, right=0.9, hspace=0.5, wspace=0.3
+    maybe_adjust_figure(
+        fig, bottom=0.15, top=0.9, left=0.1, right=0.9, hspace=0.5, wspace=0.3
     )
     return axes
 
@@ -456,6 +457,6 @@ def hist_frame(
     set_ticks_props(
         axes, xlabelsize=xlabelsize, xrot=xrot, ylabelsize=ylabelsize, yrot=yrot
     )
-    fig.subplots_adjust(wspace=0.3, hspace=0.3)
+    maybe_adjust_figure(fig, wspace=0.3, hspace=0.3)
 
     return axes

pandas/plotting/_matplotlib/misc.py

@@ -11,7 +11,12 @@
 
 from pandas.io.formats.printing import pprint_thing
 from pandas.plotting._matplotlib.style import get_standard_colors
-from pandas.plotting._matplotlib.tools import create_subplots, set_ticks_props
+from pandas.plotting._matplotlib.tools import (
+    create_subplots,
+    do_adjust_figure,
+    maybe_adjust_figure,
+    set_ticks_props,
+)
 
 if TYPE_CHECKING:
     from matplotlib.axes import Axes
@@ -39,7 +44,7 @@ def scatter_matrix(
     fig, axes = create_subplots(naxes=naxes, figsize=figsize, ax=ax, squeeze=False)
 
     # no gaps between subplots
-    fig.subplots_adjust(wspace=0, hspace=0)
+    maybe_adjust_figure(fig, wspace=0, hspace=0)
 
     mask = notna(df)
 
@@ -329,7 +334,8 @@ def bootstrap_plot(
     for axis in axes:
         plt.setp(axis.get_xticklabels(), fontsize=8)
         plt.setp(axis.get_yticklabels(), fontsize=8)
-    plt.tight_layout()
+    if do_adjust_figure(fig):
+        plt.tight_layout()
     return fig
 
 

pandas/plotting/_matplotlib/tools.py

@@ -19,17 +19,31 @@
 if TYPE_CHECKING:
     from matplotlib.axes import Axes
     from matplotlib.axis import Axis
+    from matplotlib.figure import Figure
     from matplotlib.lines import Line2D
     from matplotlib.table import Table
 
 
+def do_adjust_figure(fig: Figure):
+    """Whether fig has constrained_layout enabled."""
+    if not hasattr(fig, "get_constrained_layout"):
+        return False
+    return not fig.get_constrained_layout()
+
+
+def maybe_adjust_figure(fig: Figure, *args, **kwargs):
+    """Call fig.subplots_adjust unless fig has constrained_layout enabled."""
+    if do_adjust_figure(fig):
+        fig.subplots_adjust(*args, **kwargs)
+
+
 def format_date_labels(ax: Axes, rot):
     # mini version of autofmt_xdate
     for label in ax.get_xticklabels():
         label.set_ha("right")
         label.set_rotation(rot)
     fig = ax.get_figure()
-    fig.subplots_adjust(bottom=0.2)
+    maybe_adjust_figure(fig, bottom=0.2)
 
 
 def table(

pandas/tests/plotting/frame/test_frame_subplots.py

@@ -482,6 +482,19 @@ def test_subplots_sharex_false(self):
         tm.assert_numpy_array_equal(axs[0].get_xticks(), expected_ax1)
         tm.assert_numpy_array_equal(axs[1].get_xticks(), expected_ax2)
 
+    def test_subplots_constrained_layout(self):
+        # GH 25261
+        idx = date_range(start="now", periods=10)
+        df = DataFrame(np.random.rand(10, 3), index=idx)
+        kwargs = {}
+        if hasattr(self.plt.Figure, "get_constrained_layout"):
+            kwargs["constrained_layout"] = True
+        fig, axes = self.plt.subplots(2, **kwargs)
+        with tm.assert_produces_warning(None):
+            df.plot(ax=axes[0])
+            with tm.ensure_clean(return_filelike=True) as path:
+                self.plt.savefig(path)
+
     @pytest.mark.parametrize(
         "index_name, old_label, new_label",
         [