Move emission of axes_enter/leave_event to a separate handler.

Author: anntzer

lib/matplotlib/backend_bases.py

@@ -1344,22 +1344,6 @@ def __init__(self, name, canvas, x, y, guiEvent=None):
                 self.xdata = xdata
                 self.ydata = ydata
 
-    def _process(self):
-        last = LocationEvent.lastevent
-        last_axes = last.inaxes if last is not None else None
-        if last_axes != self.inaxes:
-            if last_axes is not None:
-                try:
-                    last.canvas.callbacks.process("axes_leave_event", last)
-                except Exception:
-                    # The last canvas may already have been torn down.
-                    pass
-            if self.inaxes is not None:
-                self.canvas.callbacks.process("axes_enter_event", self)
-        LocationEvent.lastevent = (
-            None if self.name == "figure_leave_event" else self)
-        super()._process()
-
 
 class MouseButton(IntEnum):
     LEFT = 1
@@ -1549,6 +1533,22 @@ def _process(self):
         super()._process()
 
 
+def _axes_enter_leave_emitter(event):
+    last = LocationEvent.lastevent
+    last_axes = last.inaxes if last is not None else None
+    if last_axes != event.inaxes:
+        if last_axes is not None:
+            try:
+                last.canvas.callbacks.process("axes_leave_event", last)
+            except Exception:
+                # The last canvas may already have been torn down.
+                pass
+        if event.inaxes is not None:
+            event.canvas.callbacks.process("axes_enter_event", event)
+    LocationEvent.lastevent = (
+        None if event.name == "figure_leave_event" else event)
+
+
 def _get_renderer(figure, print_method=None):
     """
     Get the renderer that would be used to save a `.Figure`, and cache it on

lib/matplotlib/figure.py

@@ -23,7 +23,7 @@
 import numpy as np
 
 import matplotlib as mpl
-from matplotlib import _blocking_input, _docstring, projections
+from matplotlib import _blocking_input, backend_bases, _docstring, projections
 from matplotlib.artist import (
     Artist, allow_rasterization, _finalize_rasterization)
 from matplotlib.backend_bases import (
@@ -2376,6 +2376,8 @@ def __init__(self,
             'button_press_event', self.pick)
         self._scroll_pick_id = self._canvas_callbacks._connect_picklable(
             'scroll_event', self.pick)
+        self._axes_enter_leave_id = self._canvas_callbacks.connect(
+            'motion_notify_event', backend_bases._axes_enter_leave_emitter)
 
         if figsize is None:
             figsize = mpl.rcParams['figure.figsize']