[Visualpython-users] Re: VPython / python-gtk integration

[James P. R. <u32...@an...>]

I have successfully run a simulation in VPython that had a pygtk 
interface using threads.  The main thread thread ran the GTK main loop, 
then I had a thread for the simulation.  I had issues quitting the 
program (though I often also have the same issues when I'm not using 
threading or pygtk), and there also seemed to be various quirks when I 
tried running it on other platforms.  This is the basic idea:

import threading

class simulator(threading.Thread):
    def __init__(self):
       threading.Thread.__init__(self)
       self.runningEvent = threading.Event()
    def run(self):
       while 1:
          self.runningEvent.wait()
          # simulation stuff

def startStopCallback(widget, data):
    if s.runningEvent.isSet():
       s.runningEvent.clear()
    else:
       s.runningEvent.set()

gtk.threads_init()
# gtk setup stuff including a start/stop button

s = simulator()
s.start()


The gtk.threads_init() must be called if you are using pygtk and threading.

One thing that you need to ensure, if you are ever making GTK calls from 
a thread other than the thread GTK is running in, you must use 
gtk.threads_enter() and gtk.threads_leave() before and after you make 
the call.