Correctly go through property setter when init'ing Timer interval.

anntzer · anntzer · commit 96690e11d24f · 2020-04-17T22:51:07.000+02:00
The setter casts the interval to an int, which is required at least by
the tk backend.

This caught a bug in the wx timer, where just setting the interval would
start the timer.  Fixed that.
diff --git a/doc/api/api_changes_3.3/behaviour.rst b/doc/api/api_changes_3.3/behaviour.rst
@@ -176,3 +176,8 @@ explicitly pass a "%1.2f" as the *valfmt* parameter to `.Slider`.
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 All the functionality of ``CustomCell`` has been moved to its base class
 `~.table.Cell`.
+
+wx Timer interval
+~~~~~~~~~~~~~~~~~
+Setting the timer interval on a not-yet-started ``TimerWx`` won't start it
+anymore.
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -1059,10 +1059,9 @@ def __init__(self, interval=None, callbacks=None):
             `remove_callback` can be used.
         """
         self.callbacks = [] if callbacks is None else callbacks.copy()
-        self._interval = 1000 if interval is None else interval
-        self._single = False
-        # Default attribute for holding the GUI-specific timer object
-        self._timer = None
+        # Set .interval and not ._interval to go through the property setter.
+        self.interval = 1000 if interval is None else interval
+        self.single_shot = False
 
     def __del__(self):
         """Need to stop timer and possibly disconnect timer."""
diff --git a/lib/matplotlib/backends/_backend_tk.py b/lib/matplotlib/backends/_backend_tk.py
@@ -82,9 +82,9 @@ class TimerTk(TimerBase):
     """Subclass of `backend_bases.TimerBase` using Tk timer events."""
 
     def __init__(self, parent, *args, **kwargs):
+        self._timer = None
         TimerBase.__init__(self, *args, **kwargs)
         self.parent = parent
-        self._timer = None
 
     def _timer_start(self):
         self._timer_stop()
@@ -97,7 +97,6 @@ def _timer_stop(self):
 
     def _on_timer(self):
         TimerBase._on_timer(self)
-
         # Tk after() is only a single shot, so we need to add code here to
         # reset the timer if we're not operating in single shot mode.  However,
         # if _timer is None, this means that _timer_stop has been called; so
diff --git a/lib/matplotlib/backends/backend_gtk3.py b/lib/matplotlib/backends/backend_gtk3.py
@@ -52,6 +52,10 @@
 class TimerGTK3(TimerBase):
     """Subclass of `.TimerBase` using GTK3 timer events."""
 
+    def __init__(self, *args, **kwargs):
+        self._timer = None
+        TimerBase.__init__(self, *args, **kwargs)
+
     def _timer_start(self):
         # Need to stop it, otherwise we potentially leak a timer id that will
         # never be stopped.
diff --git a/lib/matplotlib/backends/backend_qt5.py b/lib/matplotlib/backends/backend_qt5.py
@@ -180,12 +180,11 @@ class TimerQT(TimerBase):
     """Subclass of `.TimerBase` using QTimer events."""
 
     def __init__(self, *args, **kwargs):
-        TimerBase.__init__(self, *args, **kwargs)
         # Create a new timer and connect the timeout() signal to the
         # _on_timer method.
         self._timer = QtCore.QTimer()
         self._timer.timeout.connect(self._on_timer)
-        self._timer_set_interval()
+        TimerBase.__init__(self, *args, **kwargs)
 
     def __del__(self):
         # The check for deletedness is needed to avoid an error at animation
diff --git a/lib/matplotlib/backends/backend_webagg_core.py b/lib/matplotlib/backends/backend_webagg_core.py
@@ -489,6 +489,10 @@ def _send_event(self, event_type, **kwargs):
 
 
 class TimerTornado(backend_bases.TimerBase):
+    def __init__(self, *args, **kwargs):
+        self._timer = None
+        super().__init__(*args, **kwargs)
+
     def _timer_start(self):
         self._timer_stop()
         if self._single:
@@ -510,7 +514,6 @@ def _timer_stop(self):
             ioloop.remove_timeout(self._timer)
         else:
             self._timer.stop()
-
         self._timer = None
 
     def _timer_set_interval(self):
diff --git a/lib/matplotlib/backends/backend_wx.py b/lib/matplotlib/backends/backend_wx.py
@@ -70,9 +70,9 @@ class TimerWx(TimerBase):
     """Subclass of `.TimerBase` using wx.Timer events."""
 
     def __init__(self, *args, **kwargs):
-        TimerBase.__init__(self, *args, **kwargs)
         self._timer = wx.Timer()
         self._timer.Notify = self._on_timer
+        TimerBase.__init__(self, *args, **kwargs)
 
     def _timer_start(self):
         self._timer.Start(self._interval, self._single)
@@ -81,7 +81,8 @@ def _timer_stop(self):
         self._timer.Stop()
 
     def _timer_set_interval(self):
-        self._timer_start()
+        if self._timer.IsRunning():
+            self._timer_start()  # Restart with new interval.
 
     def _timer_set_single_shot(self):
         self._timer.Start()
diff --git a/lib/matplotlib/tests/test_backends_interactive.py b/lib/matplotlib/tests/test_backends_interactive.py
@@ -114,7 +114,7 @@ def check_alt_backend(alt_backend):
 
 ax.plot([0, 1], [2, 3])
 
-timer = fig.canvas.new_timer(1)
+timer = fig.canvas.new_timer(1.)  # Test that floats are cast to int as needed.
 timer.add_callback(FigureCanvasBase.key_press_event, fig.canvas, "q")
 # Trigger quitting upon draw.
 fig.canvas.mpl_connect("draw_event", lambda event: timer.start())
