2626import re
2727import sys
2828import time
29+ try :
30+ import threading
31+ except ImportError :
32+ import dummy_threading as threading
2933
3034from cycler import cycler
3135import matplotlib
@@ -177,6 +181,12 @@ def findobj(o=None, match=None, include_self=True):
177181return o .findobj (match ,include_self = include_self )
178182
179183
184+ def _get_required_interactive_framework ():
185+ global _backend_mod
186+ return getattr (
187+ _backend_mod .FigureCanvas ,"required_interactive_framework" ,None )
188+
189+
180190def switch_backend (newbackend ):
181191"""
182192 Close all open figures and set the Matplotlib backend.
@@ -224,8 +234,7 @@ class _backend_mod(matplotlib.backend_bases._Backend):
224234_log .debug ("Loaded backend %s version %s." ,
225235newbackend ,_backend_mod .backend_version )
226236
227- required_framework = getattr (
228- _backend_mod .FigureCanvas ,"required_interactive_framework" ,None )
237+ required_framework = _get_required_interactive_framework ()
229238if required_framework is not None :
230239current_framework = cbook ._get_running_interactive_framework ()
231240if (current_framework and required_framework
@@ -248,6 +257,9 @@ class _backend_mod(matplotlib.backend_bases._Backend):
248257
249258def new_figure_manager (* args ,** kwargs ):
250259"""Create a new figure manager instance."""
260+ if (_get_required_interactive_framework ()
261+ and threading .current_thread ()is not threading .main_thread ()):
262+ cbook ._warn_external ("Don't do this!" )
251263global _backend_mod
252264return _backend_mod .new_figure_manager (* args ,** kwargs )
253265
@@ -276,6 +288,9 @@ def show(*args, **kwargs):
276288 This is experimental, and may be set to ``True`` or ``False`` to
277289 override the blocking behavior described above.
278290 """
291+ if (_get_required_interactive_framework ()
292+ and threading .current_thread ()is not threading .main_thread ()):
293+ cbook ._warn_external ("Don't do this!" )
279294global _backend_mod
280295return _backend_mod .show (* args ,** kwargs )
281296