Reword docstring of panning callbacks, and pass them a MouseButton.

anntzer · anntzer · commit ecde103bbf5d · 2020-03-13T00:54:01.000+01:00
... rather than a plain int -- this makes the documentation easier, and
MouseButton inherits from int anyways.
diff --git a/lib/matplotlib/axes/_base.py b/lib/matplotlib/axes/_base.py
@@ -4190,17 +4190,16 @@ def start_pan(self, x, y, button):
         """
         Called when a pan operation has started.
 
-        *x*, *y* are the mouse coordinates in display coords.
-        button is the mouse button number:
-
-        * 1: LEFT
-        * 2: MIDDLE
-        * 3: RIGHT
-
-        .. note::
-
-            Intended to be overridden by new projection types.
+        Parameters
+        ----------
+        x, y : float
+            The mouse coordinates in display coords.
+        button : `.MouseButton`
+            The pressed mouse button.
 
+        Notes
+        -----
+        This is intended to be overridden by new projection types.
         """
         self._pan_start = types.SimpleNamespace(
             lim=self.viewLim.frozen(),
@@ -4212,34 +4211,30 @@ def start_pan(self, x, y, button):
 
     def end_pan(self):
         """
-        Called when a pan operation completes (when the mouse button
-        is up.)
-
-        .. note::
-
-            Intended to be overridden by new projection types.
+        Called when a pan operation completes (when the mouse button is up.)
 
+        Notes
+        -----
+        This is intended to be overridden by new projection types.
         """
         del self._pan_start
 
     def drag_pan(self, button, key, x, y):
         """
         Called when the mouse moves during a pan operation.
 
-        *button* is the mouse button number:
-
-        * 1: LEFT
-        * 2: MIDDLE
-        * 3: RIGHT
-
-        *key* is a "shift" key
-
-        *x*, *y* are the mouse coordinates in display coords.
-
-        .. note::
-
-            Intended to be overridden by new projection types.
+        Parameters
+        ----------
+        button : `.MouseButton`
+            The pressed mouse button.
+        key : str or None
+            The pressed key, if any.
+        x, y : float
+            The mouse coordinates in display coords.
 
+        Notes
+        -----
+        This is intended to be overridden by new projection types.
         """
         def format_deltas(key, dx, dy):
             if key == 'control':
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -2877,19 +2877,14 @@ def press(self, event):
 
     def press_pan(self, event):
         """Callback for mouse button press in pan/zoom mode."""
-
-        if event.button == 1:
-            self._button_pressed = 1
-        elif event.button == 3:
-            self._button_pressed = 3
+        if event.button in [1, 3]:
+            self._button_pressed = event.button
         else:
             self._button_pressed = None
             return
-
         if self._nav_stack() is None:
             # set the home button to this view
             self.push_current()
-
         x, y = event.x, event.y
         self._xypress = []
         for i, a in enumerate(self.canvas.figure.get_axes()):
@@ -2900,7 +2895,6 @@ def press_pan(self, event):
                 self.canvas.mpl_disconnect(self._idDrag)
                 self._idDrag = self.canvas.mpl_connect('motion_notify_event',
                                                        self.drag_pan)
-
         self.press(event)
 
     def press_zoom(self, event):
@@ -2917,10 +2911,8 @@ def press_zoom(self, event):
             self._ids_zoom = []
             return
 
-        if event.button == 1:
-            self._button_pressed = 1
-        elif event.button == 3:
-            self._button_pressed = 3
+        if event.button in [1, 3]:
+            self._button_pressed = event.button
         else:
             self._button_pressed = None
             return
