Move lastevent handling to LocationEvent.process.

anntzer · anntzer · commit 684663c3f436 · 2020-10-27T12:14:10.000+01:00
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -1350,7 +1350,7 @@ class LocationEvent(Event):
         y data coordinate of the mouse.
     """
 
-    lastevent = None  # the last event that was triggered before this one
+    lastevent = None  # The last event processed so far.
 
     def __init__(self, name, canvas, x, y, guiEvent=None):
         """
@@ -1367,7 +1367,6 @@ def __init__(self, name, canvas, x, y, guiEvent=None):
 
         if x is None or y is None:
             # cannot check if event was in axes if no (x, y) info
-            self._update_enter_leave()
             return
 
         if self.canvas.mouse_grabber is None:
@@ -1385,33 +1384,21 @@ def __init__(self, name, canvas, x, y, guiEvent=None):
                 self.xdata = xdata
                 self.ydata = ydata
 
-        self._update_enter_leave()
-
-    def _update_enter_leave(self):
-        """Process the figure/axes enter leave events."""
-        if LocationEvent.lastevent is not None:
-            last = LocationEvent.lastevent
-            if last.inaxes != self.inaxes:
-                # process axes enter/leave events
+    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:
-                    if last.inaxes is not None:
-                        last.canvas.callbacks.process('axes_leave_event', last)
+                    last.canvas.callbacks.process("axes_leave_event", last)
                 except Exception:
+                    # The last canvas may already have been torn down.
                     pass
-                    # See ticket 2901582.
-                    # I think this is a valid exception to the rule
-                    # against catching all exceptions; if anything goes
-                    # wrong, we simply want to move on and process the
-                    # current event.
-                if self.inaxes is not None:
-                    self.canvas.callbacks.process('axes_enter_event', self)
-
-        else:
-            # process a figure enter event
             if self.inaxes is not None:
-                self.canvas.callbacks.process('axes_enter_event', self)
-
-        LocationEvent.lastevent = self
+                self.canvas.callbacks.process("axes_enter_event", self)
+        LocationEvent.lastevent = (
+            None if self.name == "figure_leave_event" else self)
+        super().process()
 
 
 class MouseButton(IntEnum):
diff --git a/lib/matplotlib/backends/backend_webagg_core.py b/lib/matplotlib/backends/backend_webagg_core.py
@@ -23,7 +23,8 @@
 
 from matplotlib import _api, backend_bases
 from matplotlib.backends import backend_agg
-from matplotlib.backend_bases import _Backend
+from matplotlib.backend_bases import (
+    _Backend, KeyEvent, LocationEvent, MouseEvent, ResizeEvent)
 
 _log = logging.getLogger(__name__)
 
@@ -255,40 +256,33 @@ def _handle_mouse(self, event):
         x = event['x']
         y = event['y']
         y = self.get_renderer().height - y
-
-        # Javascript button numbers and matplotlib button numbers are
-        # off by 1
+        # Javascript button numbers and Matplotlib button numbers are off by 1
         button = event['button'] + 1
 
         e_type = event['type']
-        guiEvent = event.get('guiEvent', None)
-        if e_type == 'button_press':
-            self.button_press_event(x, y, button, guiEvent=guiEvent)
+        guiEvent = event.get('guiEvent')
+        if e_type in ['button_press', 'button_release']:
+            MouseEvent(e_type + '_event', self, x, y, button,
+                       guiEvent=guiEvent).process()
         elif e_type == 'dblclick':
-            self.button_press_event(x, y, button, dblclick=True,
-                                    guiEvent=guiEvent)
-        elif e_type == 'button_release':
-            self.button_release_event(x, y, button, guiEvent=guiEvent)
-        elif e_type == 'motion_notify':
-            self.motion_notify_event(x, y, guiEvent=guiEvent)
-        elif e_type == 'figure_enter':
-            self.enter_notify_event(xy=(x, y), guiEvent=guiEvent)
-        elif e_type == 'figure_leave':
-            self.leave_notify_event()
+            MouseEvent('button_press_event', self, x, y, button, dblclick=True,
+                       guiEvent=guiEvent).process()
         elif e_type == 'scroll':
-            self.scroll_event(x, y, event['step'], guiEvent=guiEvent)
+            MouseEvent('scroll_event', self, x, y, step=event['step'],
+                       guiEvent=guiEvent).process()
+        elif e_type == 'motion_notify':
+            MouseEvent(e_type + '_event', self, x, y,
+                       guiEvent=guiEvent).process()
+        elif e_type in ['figure_enter', 'figure_leave']:
+            LocationEvent(e_type + '_event', self, x, y,
+                          guiEvent=guiEvent).process()
     handle_button_press = handle_button_release = handle_dblclick = \
         handle_figure_enter = handle_figure_leave = handle_motion_notify = \
         handle_scroll = _handle_mouse
 
     def _handle_key(self, event):
-        key = _handle_key(event['key'])
-        e_type = event['type']
-        guiEvent = event.get('guiEvent', None)
-        if e_type == 'key_press':
-            self.key_press_event(key, guiEvent=guiEvent)
-        elif e_type == 'key_release':
-            self.key_release_event(key, guiEvent=guiEvent)
+        KeyEvent(event['type'] + '_event', self, _handle_key(event['key']),
+                 guiEvent=event.get('guiEvent')).process()
     handle_key_press = handle_key_release = _handle_key
 
     def handle_toolbar_button(self, event):
@@ -318,7 +312,7 @@ def handle_resize(self, event):
         # identical or within a pixel or so).
         self._png_is_old = True
         self.manager.resize(*fig.bbox.size, forward=False)
-        self.resize_event()
+        ResizeEvent('resize_event', self).process()
 
     def handle_send_image_mode(self, event):
         # The client requests notification of what the current image mode is.
