ENH: add vertical layout

jklymak · jklymak · commit 81209e6ae971 · 2019-07-28T14:56:03.000-07:00
diff --git a/lib/matplotlib/figure.py b/lib/matplotlib/figure.py
@@ -1780,11 +1780,14 @@ def legend(self, *args, outside=False, axs=None, **kwargs):
         Parameters
         ----------
 
-        outside: bool
+        outside: bool or string
             If ``constrained_layout=True``, then try and place legend outside
             axes listed in *axs*, or highest-level gridspec if axs is empty.
             Note, "center" and "best" options to *loc* do not work with
-            ``outside=True``
+            ``outside=True``.  The corner values of *loc* (i.e. "upper right")
+            will default to a horizontal layout of the legend, but this can
+            be changed by specifying a string
+            ``outside="vertical", loc="upper right"``.
 
         axs :  sequence of `~.axes.Axes`
             axes to gather handles from (if *handles* is empty).
@@ -1844,8 +1847,8 @@ def legend(self, *args, outside=False, axs=None, **kwargs):
                     gs = axs
                 else:
                     gs = axs[0].get_gridspec()
-            l = gs.legend_outside(loc=loc, handles=handles, labels=labels,
-                                     **kwargs)
+            l = gs.legend_outside(loc=loc, align=outside, handles=handles,
+                                  labels=labels, **kwargs)
         l._remove_method = self.legends.remove
         self.stale = True
         return l
diff --git a/lib/matplotlib/gridspec.py b/lib/matplotlib/gridspec.py
@@ -176,7 +176,8 @@ def _normalize(key, size, axis):  # Includes last index.
 
         return SubplotSpec(self, num1, num2)
 
-    def legend_outside(self, handles=None, labels=None, axs=None, **kwargs):
+    def legend_outside(self, handles=None, labels=None, axs=None,
+                       align='horizontal', **kwargs):
         """
         legend for this gridspec, offset from all the subplots.
 
@@ -205,18 +206,32 @@ def legend_outside(self, handles=None, labels=None, axs=None, **kwargs):
 
         leg._update_width_height()
 
+        if leg._loc in [5, 7, 4, 1]:
+            stack = 'right'
+        elif leg._loc in [6, 2, 3]:
+            stack = 'left'
+        elif leg._loc in [8]:
+            stack = 'bottom'
+        else:
+            stack = 'top'
+
+        if align == 'vertical':
+            if leg._loc in [1, 2]:
+                stack = 'top'
+            elif leg._loc in [3, 4]:
+                stack = 'bottom'
+
         for child in self._layoutbox.children:
             if child._is_subplotspec_layoutbox():
-                if leg._loc in [1, 4, 5, 7]:
-                    # stack to the right...
+                if stack == 'right':
                     layoutbox.hstack([child, leg._layoutbox], padding=paddingw)
-                elif leg._loc in [2, 3, 6]:
+                elif stack == 'left':
                     # stack to the left...
                     layoutbox.hstack([leg._layoutbox, child], padding=paddingw)
-                elif leg._loc in [8]:
+                elif stack == 'bottom':
                     # stack to the bottom...
                     layoutbox.vstack([child, leg._layoutbox], padding=paddingh)
-                elif leg._loc in [9]:
+                elif stack == 'top':
                     # stack to the top...
                     layoutbox.vstack([leg._layoutbox, child], padding=paddingh)
         self.figure.legends.append(leg)
