3535implicit and explicit interfaces.
3636"""
3737
38+ from enum import Enum
3839import functools
3940import importlib
4041import inspect
@@ -108,8 +109,15 @@ def _copy_docstring_and_deprecators(method, func=None):
108109
109110## Global ##
110111
111- _IP_REGISTERED = None
112- _INSTALL_FIG_OBSERVER = False
112+
113+ # The state controlled by {,un}install_repl_displayhook().
114+ _ReplDisplayHook = Enum ("_ReplDisplayHook" , ["NONE" ,"PLAIN" ,"IPYTHON" ])
115+ _REPL_DISPLAYHOOK = _ReplDisplayHook .NONE
116+
117+
118+ def _draw_all_if_interactive ():
119+ if matplotlib .is_interactive ():
120+ draw_all ()
113121
114122
115123def install_repl_displayhook ():
@@ -119,30 +127,25 @@ def install_repl_displayhook():
119127
120128 This works both with IPython and with vanilla python shells.
121129 """
122- global _IP_REGISTERED
123- global _INSTALL_FIG_OBSERVER
130+ global _REPL_DISPLAYHOOK
124131
125- if _IP_REGISTERED :
132+ if _REPL_DISPLAYHOOK is _ReplDisplayHook . IPYTHON :
126133return
134+
127135# See if we have IPython hooks around, if so use them.
128136# Use ``sys.modules.get(name)`` rather than ``name in sys.modules`` as
129137# entries can also have been explicitly set to None.
130138mod_ipython = sys .modules .get ("IPython" )
131139if not mod_ipython :
132- _INSTALL_FIG_OBSERVER = True
140+ _REPL_DISPLAYHOOK = _ReplDisplayHook . PLAIN
133141return
134142ip = mod_ipython .get_ipython ()
135143if not ip :
136- _INSTALL_FIG_OBSERVER = True
144+ _REPL_DISPLAYHOOK = _ReplDisplayHook . PLAIN
137145return
138146
139- def post_execute ():
140- if matplotlib .is_interactive ():
141- draw_all ()
142-
143- ip .events .register ("post_execute" ,post_execute )
144- _IP_REGISTERED = post_execute
145- _INSTALL_FIG_OBSERVER = False
147+ ip .events .register ("post_execute" ,_draw_all_if_interactive )
148+ _REPL_DISPLAYHOOK = _ReplDisplayHook .IPYTHON
146149
147150from IPython .core .pylabtools import backend2gui
148151# trigger IPython's eventloop integration, if available
@@ -161,16 +164,12 @@ def uninstall_repl_displayhook():
161164 this will reset `sys.displayhook` to what ever function was there when
162165 Matplotlib installed its displayhook, possibly discarding your changes.
163166 """
164- global _IP_REGISTERED
165- global _INSTALL_FIG_OBSERVER
166- if _IP_REGISTERED :
167+ global _REPL_DISPLAYHOOK
168+ if _REPL_DISPLAYHOOK is _ReplDisplayHook .IPYTHON :
167169from IPython import get_ipython
168170ip = get_ipython ()
169- ip .events .unregister ('post_execute' ,_IP_REGISTERED )
170- _IP_REGISTERED = None
171-
172- if _INSTALL_FIG_OBSERVER :
173- _INSTALL_FIG_OBSERVER = False
171+ ip .events .unregister ("post_execute" ,_draw_all_if_interactive )
172+ _REPL_DISPLAYHOOK = _ReplDisplayHook .NONE
174173
175174
176175draw_all = _pylab_helpers .Gcf .draw_all
@@ -810,7 +809,7 @@ def figure(num=None, # autoincrement if None, else integer from 1-N
810809# FigureManager base class.
811810draw_if_interactive ()
812811
813- if _INSTALL_FIG_OBSERVER :
812+ if _REPL_DISPLAYHOOK is _ReplDisplayHook . PLAIN :
814813fig .stale_callback = _auto_draw_if_interactive
815814
816815if clear :