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