matplotlib · anntzer · Mar 25, 2018 · Mar 25, 2018
diff --git a/lib/matplotlib/artist.py b/lib/matplotlib/artist.py
@@ -112,7 +112,7 @@ def __init__(self):
         except AttributeError:
             # Handle self.axes as a read-only property, as in Figure.
             pass
-        self._remove_method = None
+        self._on_remove = []
         self._url = None
         self._gid = None
         self._snap = None
@@ -142,31 +142,33 @@ def remove(self):
         Note: there is no support for removing the artist's legend entry.
         """
 
-        # There is no method to set the callback.  Instead the parent should
-        # set the _remove_method attribute directly.  This would be a
-        # protected attribute if Python supported that sort of thing.  The
-        # callback has one parameter, which is the child to be removed.
-        if self._remove_method is not None:
-            self._remove_method(self)
-            # clear stale callback
-            self.stale_callback = None
-            _ax_flag = False
-            if hasattr(self, 'axes') and self.axes:
-                # remove from the mouse hit list
-                self.axes.mouseover_set.discard(self)
-                # mark the axes as stale
-                self.axes.stale = True
-                # decouple the artist from the axes
-                self.axes = None
-                _ax_flag = True
-
-            if self.figure:
-                self.figure = None
-                if not _ax_flag:
-                    self.figure = True
-
-        else:
+        # There is no method to set the callbacks.  Instead the parent should
+        # populate the _on_remove list directly.  This would be a protected
+        # attribute if Python supported that sort of thing.  The callbacks have
+        # one parameter, which is the child to be removed.
+        if not self._on_remove:
             raise NotImplementedError('cannot remove artist')
+
+        for cb in self._on_remove:
+            cb(self)
+        self._on_remove = []
+        # clear stale callback
+        self.stale_callback = None
+        _ax_flag = False
+        if hasattr(self, 'axes') and self.axes:
+            # remove from the mouse hit list
+            self.axes.mouseover_set.discard(self)
+            # mark the axes as stale
+            self.axes.stale = True
+            # decouple the artist from the axes
+            self.axes = None
+            _ax_flag = True
+
+        if self.figure:
+            self.figure = None
+            if not _ax_flag:
+                self.figure = True
+
         # TODO: the fix for the collections relim problem is to move the
         # limits calculation into the artist itself, including the property of
         # whether or not the artist should affect the limits.  Then there will

diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -378,7 +378,7 @@ def legend(self, *args, **kwargs):
         if len(extra_args):
             raise TypeError('legend only accepts two non-keyword arguments')
         self.legend_ = mlegend.Legend(self, handles, labels, **kwargs)
-        self.legend_._remove_method = self._remove_legend
+        self.legend_._on_remove = [self._remove_legend]
         return self.legend_
 
     def _remove_legend(self, legend):

diff --git a/lib/matplotlib/axes/_base.py b/lib/matplotlib/axes/_base.py
@@ -1860,7 +1860,7 @@ def add_artist(self, a):
         """
         a.axes = self
         self.artists.append(a)
-        a._remove_method = self.artists.remove
+        a._on_remove = [self.artists.remove]
         self._set_artist_props(a)
         a.set_clip_path(self.patch)
         self.stale = True
@@ -1877,7 +1877,7 @@ def add_collection(self, collection, autolim=True):
         if not label:
             collection.set_label('_collection%d' % len(self.collections))
         self.collections.append(collection)
-        collection._remove_method = self.collections.remove
+        collection._on_remove = [self.collections.remove]
         self._set_artist_props(collection)
 
         if collection.get_clip_path() is None:
@@ -1899,7 +1899,7 @@ def add_image(self, image):
         if not image.get_label():
             image.set_label('_image%d' % len(self.images))
         self.images.append(image)
-        image._remove_method = self.images.remove
+        image._on_remove = [self.images.remove]
         self.stale = True
         return image
 
@@ -1922,7 +1922,7 @@ def add_line(self, line):
         if not line.get_label():
             line.set_label('_line%d' % len(self.lines))
         self.lines.append(line)
-        line._remove_method = self.lines.remove
+        line._on_remove = [self.lines.remove]
         self.stale = True
         return line
 
@@ -1932,7 +1932,7 @@ def _add_text(self, txt):
         """
         self._set_artist_props(txt)
         self.texts.append(txt)
-        txt._remove_method = self.texts.remove
+        txt._on_remove = [self.texts.remove]
         self.stale = True
         return txt
 
@@ -1995,7 +1995,7 @@ def add_patch(self, p):
             p.set_clip_path(self.patch)
         self._update_patch_limits(p)
         self.patches.append(p)
-        p._remove_method = self.patches.remove
+        p._on_remove = [self.patches.remove]
         return p
 
     def _update_patch_limits(self, patch):
@@ -2041,7 +2041,7 @@ def add_table(self, tab):
         self._set_artist_props(tab)
         self.tables.append(tab)
         tab.set_clip_path(self.patch)
-        tab._remove_method = self.tables.remove
+        tab._on_remove = [self.tables.remove]
         return tab
 
     def add_container(self, container):
@@ -2055,7 +2055,7 @@ def add_container(self, container):
         if not label:
             container.set_label('_container%d' % len(self.containers))
         self.containers.append(container)
-        container._remove_method = self.containers.remove
+        container._on_remove = [self.containers.remove]
         return container
 
     def _on_units_changed(self, scalex=False, scaley=False):

diff --git a/lib/matplotlib/container.py b/lib/matplotlib/container.py
@@ -22,23 +22,21 @@ def __init__(self, kl, label=None):
         self.eventson = False  # fire events only if eventson
         self._oid = 0  # an observer id
         self._propobservers = {}  # a dict from oids to funcs
-
-        self._remove_method = None
+        self._on_remove = []
    
         self.set_label(label)
 
     @cbook.deprecated("3.0")
     def set_remove_method(self, f):
-        self._remove_method = f
+        self._on_remove = [f]
 
     def remove(self):
         for c in cbook.flatten(
                 self, scalarp=lambda x: isinstance(x, martist.Artist)):
             if c is not None:
                 c.remove()
-
-        if self._remove_method:
-            self._remove_method(self)
+        for cb in self._on_remove:
+            cb(self)
 
     def get_label(self):
         """

diff --git a/lib/matplotlib/figure.py b/lib/matplotlib/figure.py
@@ -885,7 +885,7 @@ def figimage(self, X, xo=0, yo=0, alpha=None, norm=None, cmap=None,
         if norm is None:
             im.set_clim(vmin, vmax)
         self.images.append(im)
-        im._remove_method = self.images.remove
+        im._on_remove = [self.images.remove]
         self.stale = True
         return im
 
@@ -1157,7 +1157,7 @@ def add_axes(self, *args, **kwargs):
 
         self._axstack.add(key, a)
         self.sca(a)
-        a._remove_method = self._remove_ax
+        a._on_remove = [self._remove_ax]
         self.stale = True
         a.stale_callback = _stale_figure_callback
         return a
@@ -1264,7 +1264,7 @@ def add_subplot(self, *args, **kwargs):
             a = subplot_class_factory(projection_class)(self, *args, **kwargs)
         self._axstack.add(key, a)
         self.sca(a)
-        a._remove_method = self._remove_ax
+        a._on_remove = [self._remove_ax]
         self.stale = True
         a.stale_callback = _stale_figure_callback
         return a
@@ -1598,7 +1598,7 @@ def legend(self, *args, **kwargs):
             pass
         l = mlegend.Legend(self, handles, labels, *extra_args, **kwargs)
         self.legends.append(l)
-        l._remove_method = self.legends.remove
+        l._on_remove = [self.legends.remove]
         self.stale = True
         return l
 
@@ -1626,7 +1626,7 @@ def text(self, x, y, s, *args, **kwargs):
         t.update(override)
         self._set_artist_props(t)
         self.texts.append(t)
-        t._remove_method = self.texts.remove
+        t._on_remove = [self.texts.remove]
         self.stale = True
         return t
 

diff --git a/lib/matplotlib/legend.py b/lib/matplotlib/legend.py
@@ -1107,24 +1107,26 @@ def draggable(self, state=None, use_blit=False, update="loc"):
         when dragged. If update is "loc", the *loc* parameter of the legend
         is changed. If "bbox", the *bbox_to_anchor* parameter is changed.
         """
-        is_draggable = self._draggable is not None
-
         # if state is None we'll toggle
         if state is None:
-            state = not is_draggable
+            state = self._draggable is None
 
         if state:
             if self._draggable is None:
-                self._draggable = DraggableLegend(self,
-                                                  use_blit,
-                                                  update=update)
+                self._draggable = DraggableLegend(
+                    self, use_blit, update=update)
+                self._on_remove.append(self._set_undraggable)
         else:
-            if self._draggable is not None:
-                self._draggable.disconnect()
-            self._draggable = None
+            self._set_undraggable()
 
         return self._draggable
 
+    def _set_undraggable(self, _=None):
+        if self._draggable is not None:
+            self._on_remove.remove(self._set_undraggable)
+            self._draggable.disconnect()
+            self._draggable = None
+
 
 # Helper functions to parse legend arguments for both `figure.legend` and
 # `axes.legend`:

diff --git a/lib/matplotlib/text.py b/lib/matplotlib/text.py
@@ -1837,22 +1837,26 @@ def draggable(self, state=None, use_blit=False):
         draggable is on.
         """
         from matplotlib.offsetbox import DraggableAnnotation
-        is_draggable = self._draggable is not None
 
         # if state is None we'll toggle
         if state is None:
-            state = not is_draggable
+            state = self._draggable is None
 
         if state:
             if self._draggable is None:
                 self._draggable = DraggableAnnotation(self, use_blit)
+                self._on_remove.append(self._set_undraggable)
         else:
-            if self._draggable is not None:
-                self._draggable.disconnect()
-            self._draggable = None
+            self._set_undraggable()
 
         return self._draggable
 
+    def _set_undraggable(self, _=None):
+        if self._draggable is not None:
+            self._on_remove.remove(self._set_undraggable)
+            self._draggable.disconnect()
+            self._draggable = None
+
 
 class Annotation(Text, _AnnotationBase):
     def __str__(self):

diff --git a/lib/mpl_toolkits/axes_grid1/parasite_axes.py b/lib/mpl_toolkits/axes_grid1/parasite_axes.py
@@ -242,7 +242,7 @@ def get_aux_axes(self, tr, viewlim_mode="equal", axes_class=None):
         # note that ax2.transData == tr + ax1.transData
         # Anthing you draw in ax2 will match the ticks and grids of ax1.
         self.parasites.append(ax2)
-        ax2._remove_method = self.parasites.remove
+        ax2._on_remove = [self.parasites.remove]
         return ax2
 
     def _get_legend_handles(self, legend_handler_map=None):
@@ -303,7 +303,7 @@ def twinx(self, axes_class=None):
 
         ax2 = parasite_axes_class(self, sharex=self, frameon=False)
         self.parasites.append(ax2)
-        ax2._remove_method = self._remove_twinx
+        ax2._on_remove = [self._remove_twinx]
 
         self.axis["right"].set_visible(False)
 
@@ -332,7 +332,7 @@ def twiny(self, axes_class=None):
 
         ax2 = parasite_axes_class(self, sharey=self, frameon=False)
         self.parasites.append(ax2)
-        ax2._remove_method = self._remove_twiny
+        ax2._on_remove = [self._remove_twiny]
 
         self.axis["top"].set_visible(False)
 
@@ -367,7 +367,6 @@ def twin(self, aux_trans=None, axes_class=None):
             ax2 = parasite_axes_auxtrans_class(
                 self, aux_trans, viewlim_mode="transform")
         self.parasites.append(ax2)
-        ax2._remove_method = self.parasites.remove
 
         self.axis["top", "right"].set_visible(False)
 
@@ -378,7 +377,7 @@ def _remove_method(h):
             self.parasites.remove(h)
             self.axis["top", "right"].set_visible(True)
             self.axis["top", "right"].toggle(ticklabels=False, label=False)
-        ax2._remove_method = _remove_method
+        ax2._on_remove = [_remove_method]
 
         return ax2