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Commit	Line	Data
	1	#!/usr/bin/env python
	2
	3	"""
	4	Run wxPython in a second thread.
	5
	6	Overview:
	7	Importing this module creates a second thread and starts
	8	wxPython in that thread. Its single method,
	9	add_cone(), sends an event to the second thread
	10	telling it to create a VTK viewer window with a cone in
	11	it.
	12
	13	This module is meant to be imported into the standard
	14	Python interpreter. It also works with Pythonwin.
	15	It doesn't seem to work with IDLE (on NT anyways).
	16	It should also work in a wxPython application.
	17
	18	Applications already running a wxPython app do not
	19	need to start a second thread. In these cases,
	20	viewer creates the cone windows in the current
	21	thread. You can test this by running shell.py
	22	that comes with wxPython, importing viewer and
	23	calling add_cone.
	24
	25	Usage:
	26	[user]$ python
	27	Python 1.5.2 (#1, Sep 17 1999, 20:15:36) ...
	28	Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam
	29	>>> import viewer
	30	>>> viewer.add_cone() # pop up a cone window
	31	>>> a = 1
	32	1
	33	>>> viewer.add_cone() # create another cone window
	34
	35	Why would anyone do this?:
	36	When using wxPython, the call to app.Mainloop() takes over
	37	the thread from which it is called. This presents a
	38	problem for applications that want to use the standard
	39	Python command line user interface, while occasionally
	40	creating a GUI window for viewing an image, plot, etc.
	41	One solution is to manage the GUI in a second thread.
	42
	43	wxPython does not behave well if windows are created in
	44	a thread other than the one where wxPython was originally
	45	imported. ( I assume importing wxPython initializes some
	46	info in the thread). The current solution is to make the
	47	original import of wxPython in the second thread and then
	48	create all windows in that second thread.
	49
	50	Methods in the main thread can create a new window by issuing
	51	events to a "catcher" window in the second thread. This
	52	catcher window has event handlers that actually create the
	53	new window.
	54	"""
	55
	56	class viewer_thread:
	57	def start(self):
	58	""" start the GUI thread
	59	"""
	60	import time
	61	import thread
	62	thread.start_new_thread(self.run, ())
	63
	64	def run(self):
	65	"""
	66	Note that viewer_basices is first imported *here*.
	67	This is the second thread. viewer_basics imports
	68	wxPython. if we imported it at
	69	the module level instead of in this function,
	70	the import would occur in the main thread and
	71	wxPython wouldn't run correctly in the second thread.
	72	"""
	73	import viewer_basics
	74
	75	try:
	76	self.app = viewer_basics.SecondThreadApp(0)
	77	self.app.MainLoop()
	78	except TypeError:
	79	self.app = None
	80
	81	def add_cone(self):
	82	"""
	83	send an event to the catcher window in the
	84	other thread and tell it to create a cone window.
	85	"""
	86	import viewer_basics
	87
	88	if self.app:
	89	evt = viewer_basics.AddCone()
	90	viewer_basics.wxPostEvent(self.app.catcher, evt)
	91	else:
	92	viewer_basics.add_cone()
	93
	94	viewer = viewer_thread()
	95	viewer.start()
	96
	97	def add_cone():
	98	viewer.add_cone()
	99
	100