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Commit	Line	Data
	1	#!/usr/bin/env python
	2	#
	3	# 11/15/2003 - Jeff Grimmett (grimmtooth@softhome.net)
	4	#
	5	# o Updated for wx namespace
	6	#
	7
	8	"""
	9	Run wxPython in a second thread.
	10
	11	Overview:
	12	Importing this module creates a second thread and starts
	13	wxPython in that thread. Its single method,
	14	add_cone(), sends an event to the second thread
	15	telling it to create a VTK viewer window with a cone in
	16	it.
	17
	18	This module is meant to be imported into the standard
	19	Python interpreter. It also works with Pythonwin.
	20	It doesn't seem to work with IDLE (on NT anyways).
	21	It should also work in a wxPython application.
	22
	23	Applications already running a wxPython app do not
	24	need to start a second thread. In these cases,
	25	viewer creates the cone windows in the current
	26	thread. You can test this by running shell.py
	27	that comes with wxPython, importing viewer and
	28	calling add_cone.
	29
	30	Usage:
	31	[user]$ python
	32	Python 1.5.2 (#1, Sep 17 1999, 20:15:36) ...
	33	Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam
	34	>>> import viewer
	35	>>> viewer.add_cone() # pop up a cone window
	36	>>> a = 1
	37	1
	38	>>> viewer.add_cone() # create another cone window
	39
	40	Why would anyone do this?:
	41	When using wxPython, the call to app.Mainloop() takes over
	42	the thread from which it is called. This presents a
	43	problem for applications that want to use the standard
	44	Python command line user interface, while occasionally
	45	creating a GUI window for viewing an image, plot, etc.
	46	One solution is to manage the GUI in a second thread.
	47
	48	wxPython does not behave well if windows are created in
	49	a thread other than the one where wxPython was originally
	50	imported. ( I assume importing wxPython initializes some
	51	info in the thread). The current solution is to make the
	52	original import of wxPython in the second thread and then
	53	create all windows in that second thread.
	54
	55	Methods in the main thread can create a new window by issuing
	56	events to a "catcher" window in the second thread. This
	57	catcher window has event handlers that actually create the
	58	new window.
	59	"""
	60
	61	class viewer_thread:
	62	def start(self):
	63	""" start the GUI thread
	64	"""
	65	import time
	66	import thread
	67	thread.start_new_thread(self.run, ())
	68
	69	def run(self):
	70	"""
	71	Note that viewer_basices is first imported *here*.
	72	This is the second thread. viewer_basics imports
	73	wxPython. if we imported it at
	74	the module level instead of in this function,
	75	the import would occur in the main thread and
	76	wxPython wouldn't run correctly in the second thread.
	77	"""
	78	import viewer_basics
	79
	80	try:
	81	self.app = viewer_basics.SecondThreadApp(0)
	82	self.app.MainLoop()
	83	except TypeError:
	84	self.app = None
	85
	86	def add_cone(self):
	87	"""
	88	send an event to the catcher window in the
	89	other thread and tell it to create a cone window.
	90	"""
	91	import viewer_basics
	92
	93	if self.app:
	94	evt = viewer_basics.AddCone()
	95	viewer_basics.wxPostEvent(self.app.catcher, evt)
	96	else:
	97	viewer_basics.add_cone()
	98
	99	viewer = viewer_thread()
	100	viewer.start()
	101
	102	def add_cone():
	103	viewer.add_cone()
	104
	105