Track twinned axes and keep their positions synchronized

efiring · efiring · commit 2f6147fa9690 · 2018-01-03T16:30:27.000-10:00
diff --git a/lib/matplotlib/axes/_base.py b/lib/matplotlib/axes/_base.py
@@ -414,6 +414,7 @@ class _AxesBase(martist.Artist):
 
     _shared_x_axes = cbook.Grouper()
     _shared_y_axes = cbook.Grouper()
+    _twinned_axes = cbook.Grouper()
 
     def __str__(self):
         return "{0}({1[0]:g},{1[1]:g};{1[2]:g}x{1[3]:g})".format(
@@ -874,10 +875,14 @@ def set_position(self, pos, which='both'):
         """
         if not isinstance(pos, mtransforms.BboxBase):
             pos = mtransforms.Bbox.from_bounds(*pos)
-        if which in ('both', 'active'):
-            self._position.set(pos)
-        if which in ('both', 'original'):
-            self._originalPosition.set(pos)
+        twins = self._twinned_axes.get_siblings(self)
+        if not twins:
+            twins = [self]
+        for ax in twins:
+            if which in ('both', 'active'):
+                ax._position.set(pos)
+            if which in ('both', 'original'):
+                ax._originalPosition.set(pos)
         self.stale = True
 
     def reset_position(self):
@@ -887,8 +892,12 @@ def reset_position(self):
         This resets the a possible position change due to aspect constraints.
         For an explanation of the positions see `.set_position`.
         """
-        pos = self.get_position(original=True)
-        self.set_position(pos, which='active')
+        twins = self._twinned_axes.get_siblings(self)
+        if not twins:
+            twins = [self]
+        for ax in twins:
+            pos = ax.get_position(original=True)
+            ax.set_position(pos, which='active')
 
     def set_axes_locator(self, locator):
         """
@@ -4116,10 +4125,12 @@ def _make_twin_axes(self, *kl, **kwargs):
         """
         make a twinx axes of self. This is used for twinx and twiny.
         """
+        # Typically, SubplotBase._make_twin_axes is called instead of this.
         ax2 = self.figure.add_axes(self.get_position(True), *kl, **kwargs)
         # do not touch every thing shared, just this and it's twin.
         self.set_adjustable('datalim')
         ax2.set_adjustable('datalim')
+        self._twinned_axes.join(self, ax2)
         return ax2
 
     def twinx(self):
diff --git a/lib/matplotlib/axes/_subplots.py b/lib/matplotlib/axes/_subplots.py
@@ -154,6 +154,7 @@ def _make_twin_axes(self, *kl, **kwargs):
         ax2 = subplot_class_factory(projection_class)(self.figure,
                                                       *kl, **kwargs)
         self.figure.add_subplot(ax2)
+        self._twinned_axes.join(self, ax2)
         return ax2
 
 _subplot_classes = {}
diff --git a/lib/mpl_toolkits/axes_grid1/axes_divider.py b/lib/mpl_toolkits/axes_grid1/axes_divider.py
@@ -918,6 +918,7 @@ def _make_twin_axes(self, *kl, **kwargs):
         ax2 = type(self)(self.figure, self.get_position(True), *kl, **kwargs)
         ax2.set_axes_locator(self.get_axes_locator())
         self.figure.add_axes(ax2)
+        self._twinned_axes.join(self, ax2)
         return ax2
 
 _locatableaxes_classes = {}
