MNT: Deprecate idle_event and remove it from all but wx backends

This commit removes code related to `idle_event` in the gtk backend,
where it caused spurious warnings, and adds a deprecation warning
on any use of idle_event. Idle event still works in wx for now.

Fixes matplotlib#4534.

Author: ahaldane

doc/api/api_changes/2015-06-21_idle_event.rst

@@ -0,0 +1,9 @@
+deprecated idle_event
+`````````````````````
+
+The `idle_event` was broken or missing in most backends and causes spurious
+warnings in some cases, and its use in creating animations is now obsolete due
+to the animations module. Therefore code involving it has been removed from all
+but the wx backend (where it partially works), and its use is deprecated.  The
+animations module may be used instead to create animations.
+

examples/event_handling/idle_and_timeout.py

@@ -2,6 +2,8 @@
 """
 Demonstrate/test the idle and timeout API
 
+WARNING: idle_event is deprecated. Use the animations module instead.
+
 This is only tested on gtk so far and is a prototype implementation
 """
 import numpy as np

lib/matplotlib/backend_bases.py

@@ -2331,6 +2331,10 @@ def on_press(event):
             cid = canvas.mpl_connect('button_press_event', on_press)
 
         """
+        if s == 'idle_event':
+            warnings.warn("idle_event is only implemented for the wx backend, "
+                          "and will be removed in matplotlib 2.1. Use the "
+                          "animations module instead.", mplDeprecation)
 
         return self.callbacks.connect(s, func)
 

lib/matplotlib/backends/backend_gtk.py

@@ -243,14 +243,11 @@ def __init__(self, figure):
         self.set_flags(gtk.CAN_FOCUS)
         self._renderer_init()
 
-        self._idle_event_id = gobject.idle_add(self.idle_event)
-
         self.last_downclick = {}
 
     def destroy(self):
         #gtk.DrawingArea.destroy(self)
         self.close_event()
-        gobject.source_remove(self._idle_event_id)
         if self._idle_draw_id != 0:
             gobject.source_remove(self._idle_draw_id)
 

lib/matplotlib/backends/backend_gtk3.py

@@ -210,15 +210,11 @@ def __init__(self, figure):
         self.set_double_buffered(True)
         self.set_can_focus(True)
         self._renderer_init()
-        self._idle_event_id = GLib.idle_add(self.idle_event)
         default_context = GLib.main_context_get_thread_default() or GLib.main_context_default()
-        self._idle_event_source = default_context.find_source_by_id(self._idle_event_id)
 
     def destroy(self):
         #Gtk.DrawingArea.destroy(self)
         self.close_event()
-        if not self._idle_event_source.is_destroyed():
-            GLib.source_remove(self._idle_event_id)
         if self._idle_draw_id != 0:
             GLib.source_remove(self._idle_draw_id)
 

lib/matplotlib/backends/backend_qt4.py

@@ -73,8 +73,6 @@ def __init__(self, figure):
         self.figure = figure
         self.setMouseTracking(True)
         self._idle = True
-        # hide until we can test and fix
-        # self.startTimer(backend_IdleEvent.milliseconds)
         w, h = self.get_width_height()
         self.resize(w, h)
 

lib/matplotlib/backends/backend_qt5.py

@@ -240,15 +240,9 @@ def __init__(self, figure):
         self.figure = figure
         self.setMouseTracking(True)
         self._idle = True
-        # hide until we can test and fix
-        # self.startTimer(backend_IdleEvent.milliseconds)
         w, h = self.get_width_height()
         self.resize(w, h)
 
-    def __timerEvent(self, event):
-        # hide until we can test and fix
-        self.mpl_idle_event(event)
-
     def enterEvent(self, event):
         FigureCanvasBase.enter_notify_event(self, guiEvent=event)