MNT: implement direct calls to draw_idle

tacaswell · tacaswell · commit 985721e4cf44 · 2015-08-01T00:58:31.000-04:00
This is the result of a phone discussion with @medhoon

The idea is to not rely on pyplot knowing to check if the figure
needs to be re-drawn, but just have the Figure object directly
kick the canvas to draw_idle.

This does not currently work with nbagg due to the first draw_idle
being fired before it is finished building it's self.  There maybe
similar race conditions in the other backends.
diff --git a/lib/matplotlib/figure.py b/lib/matplotlib/figure.py
@@ -55,6 +55,11 @@ def _stale_figure_callback(self, val):
     self.figure.stale = val
 
 
+def _stale_canvas_callback(self, val):
+    if rcParams['interactive'] and self.canvas is not None and val:
+        self.canvas.draw_idle()
+
+
 class AxesStack(Stack):
     """
     Specialization of the Stack to handle all tracking of Axes in a Figure.
@@ -351,6 +356,11 @@ def __init__(self,
         self._axstack = AxesStack()  # track all figure axes and current axes
         self.clf()
         self._cachedRenderer = None
+        self.stale_callback = Figure._stale_callback
+
+    def _stale_callback(self, val):
+        if val and self.canvas is not None:
+            self.canvas.stale = val
 
     # TODO: I'd like to dynamically add the _repr_html_ method
     # to the figure in the right context, but then IPython doesn't
@@ -559,7 +569,7 @@ def set_canvas(self, canvas):
         ACCEPTS: a FigureCanvas instance
         """
         self.canvas = canvas
-        self.stale = True
+        self.stale_callback = _stale_canvas_callback
 
     def hold(self, b=None):
         """
diff --git a/lib/matplotlib/pyplot.py b/lib/matplotlib/pyplot.py
@@ -108,84 +108,6 @@ def _backend_selection():
 from matplotlib.backends import pylab_setup
 _backend_mod, new_figure_manager, draw_if_interactive, _show = pylab_setup()
 
-_IP_REGISTERED = None
-_INSTALL_FIG_OBSERVER = False
-
-def install_repl_displayhook():
-    """
-    Install a repl display hook so that any stale figure are automatically
-    redrawn when control is returned to the repl.
-
-    This works with both IPython terminals and vanilla python shells.
-    """
-    global _IP_REGISTERED
-    global _INSTALL_FIG_OBSERVER
-
-    class _NotIPython(Exception):
-        pass
-
-    # see if we have IPython hooks around, if use them
-
-    try:
-        from IPython import get_ipython
-        ip = get_ipython()
-        if ip is None:
-            raise _NotIPython()
-
-        if _IP_REGISTERED:
-            return
-
-        def post_execute():
-            if matplotlib.is_interactive():
-                draw_all()
-
-        # IPython >= 2
-        try:
-            ip.events.register('post_execute', post_execute)
-        except AttributeError:
-            # IPython 1.x
-            ip.register_post_execute(post_execute)
-
-        _IP_REGISTERED = post_execute
-        _INSTALL_FIG_OBSERVER = False
-
-    # import failed or ipython is not running
-    except (ImportError, _NotIPython):
-        _INSTALL_FIG_OBSERVER = True
-
-
-def uninstall_repl_displayhook():
-    """
-    Uninstalls the matplotlib display hook.
-
-    .. warning
-
-       Need IPython >= 2 for this to work.  For IPython < 2 will raise a
-       ``NotImplementedError``
-
-    .. warning
-
-       If you are using vanilla python and have installed another
-       display hook this will reset ``sys.displayhook`` to what ever
-       function was there when matplotlib installed it's displayhook,
-       possibly discarding your changes.
-    """
-    global _IP_REGISTERED
-    global _INSTALL_FIG_OBSERVER
-    if _IP_REGISTERED:
-        from IPython import get_ipython
-        ip = get_ipython()
-        try:
-            ip.events.unregister('post_execute', _IP_REGISTERED)
-        except AttributeError:
-            raise NotImplementedError("Can not unregister events "
-                                      "in IPython < 2.0")
-        _IP_REGISTERED = None
-
-    if _INSTALL_FIG_OBSERVER:
-        _INSTALL_FIG_OBSERVER = False
-
-
 draw_all = _pylab_helpers.Gcf.draw_all
 
 
@@ -245,13 +167,11 @@ def isinteractive():
 def ioff():
     'Turn interactive mode off.'
     matplotlib.interactive(False)
-    uninstall_repl_displayhook()
 
 
 def ion():
     'Turn interactive mode on.'
     matplotlib.interactive(True)
-    install_repl_displayhook()
 
 
 def pause(interval):
@@ -532,9 +452,6 @@ def make_active(event):
         fig = figManager.canvas.figure
         fig.number = num
 
-        if _INSTALL_FIG_OBSERVER:
-            fig.stale_callback = _auto_draw_if_interactive
-
     return fig
 
 
@@ -2483,13 +2400,6 @@ def spy(Z, precision=0, marker=None, markersize=None, aspect='equal', hold=None,
         sci(ret)
     return ret
 
-# just to be safe.  Interactive mode can be turned on without
-# calling `plt.ion()` so register it again here.
-# This is safe because multiple calls to `install_repl_displayhook`
-# are no-ops and the registered function respect `mpl.is_interactive()`
-# to determine if they should trigger a draw.
-install_repl_displayhook()
-
 ################# REMAINING CONTENT GENERATED BY boilerplate.py ##############
 
 
