Add tight_layout method on FacetGrid and PairGrid (#2073)

* Add Grid.tight_layout for legend-aware automatic layout

* Use Grid.tight_layout internally

doc/releases/v0.11.0.txt

@@ -6,6 +6,8 @@ v0.11.0 (Unreleased)
 
 - Standardized the parameter names for the oldest functions (:func:`distplot`, :func:`kdeplot`, and :func:`rugplot`) to be `x` and `y`, as in other functions. Using the old names will warn now and break in the future.
 
+- Added a ``tight_layout`` method to :class:`FacetGrid` and :class:`PairGrid`, which runs the :func:`matplotlib.pyplot.tight_layout` algorithm without interference from the external legend.
+
 - Added an explicit warning in :func:`swarmplot` when more than 2% of the points are overlap in the "gutters" of the swarm.
 
 - Added the ``axes_dict`` attribute to :class:`FacetGrid` for named access to the component axes.

doc/requirements.txt

@@ -1,4 +1,5 @@
 sphinx==2.3.1
 sphinx_bootstrap_theme==0.6.5  # Later versions mess up the css somehow
+numpydoc
 nbconvert
 ipykernel

seaborn/axisgrid.py

@@ -23,6 +23,10 @@ class Grid(object):
     _margin_titles = False
     _legend_out = True
 
+    def __init__(self):
+
+        self._tight_layout_rect = [0, 0, 1, 1]
+
     def set(self, **kwargs):
         """Set attributes on each subplot Axes."""
         for ax in self.axes.flat:
@@ -35,6 +39,12 @@ def savefig(self, *args, **kwargs):
         kwargs.setdefault("bbox_inches", "tight")
         self.fig.savefig(*args, **kwargs)
 
+    def tight_layout(self, *args, **kwargs):
+        """Call fig.tight_layout within rect that exclude the legend."""
+        kwargs = kwargs.copy()
+        kwargs.setdefault("rect", self._tight_layout_rect)
+        self.fig.tight_layout(*args, **kwargs)
+
     def add_legend(self, legend_data=None, title=None, label_order=None,
                    **kwargs):
         """Draw a legend, maybe placing it outside axes and resizing the figure.
@@ -125,6 +135,7 @@ def add_legend(self, legend_data=None, title=None, label_order=None,
 
             # Place the subplot axes to give space for the legend
             self.fig.subplots_adjust(right=right)
+            self._tight_layout_rect[2] = right
 
         else:
             # Draw a legend in the first axis
@@ -240,6 +251,8 @@ def __init__(
         gridspec_kws=None, size=None
     ):
 
+        super(FacetGrid, self).__init__()
+
         # Handle deprecations
         if size is not None:
             height = size
@@ -385,7 +398,7 @@ def __init__(
 
         # --- Make the axes look good
 
-        fig.tight_layout()
+        self.tight_layout()
         if despine:
             self.despine()
 
@@ -871,7 +884,7 @@ def _finalize_grid(self, axlabels):
         """Finalize the annotations and layout."""
         self.set_axis_labels(*axlabels)
         self.set_titles()
-        self.fig.tight_layout()
+        self.tight_layout()
 
     def facet_axis(self, row_i, col_j):
         """Make the axis identified by these indices active and return it."""
@@ -1285,6 +1298,8 @@ def __init__(
 
         """
 
+        super(PairGrid, self).__init__()
+
         # Handle deprecations
         if size is not None:
             height = size
@@ -1373,7 +1388,7 @@ def __init__(
         if despine:
             self._despine = True
             utils.despine(fig=fig)
-        fig.tight_layout(pad=layout_pad)
+        self.tight_layout(pad=layout_pad)
 
     def map(self, func, **kwargs):
         """Plot with the same function in every subplot.

seaborn/tests/test_axisgrid.py

@@ -306,6 +306,18 @@ def test_legendout_with_colwrap(self):
         g.map(plt.plot, "x", "y", linewidth=3)
         g.add_legend()
 
+    def test_legend_tight_layout(self):
+
+        g = ag.FacetGrid(self.df, hue='b')
+        g.map(plt.plot, "x", "y", linewidth=3)
+        g.add_legend()
+        g.tight_layout()
+
+        axes_right_edge = g.ax.get_window_extent().xmax
+        legend_left_edge = g._legend.get_window_extent().xmin
+
+        assert axes_right_edge < legend_left_edge
+
     def test_subplot_kws(self):
 
         g = ag.FacetGrid(self.df, despine=False,