On Thu, Jun 4, 2009 at 5:10 PM, Timothy W. Grove <tim_grove@[...].org>  wrote:
>  Dear Josiah,
> 
>  This is quite an old posting, but I'm facing a similar problem to Stuart. In
>  your response below you mentioned specifically:
> 
>  "Alternatively (what I would suggest) is to create a secondary thread
>  that uses wx.CallAfter() to call the wx.Timer event handler that you
>  would have written every 10 ms or so..."
> 
>  Could you expand any further on how you would use wxCallAfter, perhaps an
>  example line of code? I think at some point today I was trying to use
>  wxCallLater() in a new thread, but it kept telling me that I needed to call
>  the timer from the main thread instead. I'm using wxPython 2.8 under Windows
>  Vista, if that makes any difference!

You are in luck, I only randomly check threads here. :)

import threading
import wx

_stop = {}
def call_every(function, msdelay, token=None):
    if token is None:
        token = object()
        threading.Thread(target=call_repeatedly, args=(function,
msdelay, token).start()
        _stop[token] = 0
        return token
    time.sleep(msdelay/1000.0)
    while not _stop[token]:
        wx.CallAfter(function, token)
        time.sleep(msdelay/1000.0)
    _stop.pop(token)

def stop(token):
    _stop[token] = 1


Used like:
self.stopper = call_every(self.OnTimer, 10)

Then in OnTimer:
if <condition for stop> :
    stop(self.stopper)

It's a bit of boilerplate, but it might be more convenient for
non-timer-based polls.

For some of my own stuff, I'm actually using a secondary thread to
handle all of my wx.FutureCall() and wx.Timer() replacements.  One
thread for maybe a dozen delayed things.

Though...maybe a wx.FutureCall() is really what you are looking for
(check status, if it's not what you want, wx.FutureCall()).

 - Josiah

>  Josiah Carlson wrote:
> >
> > On Thu, Aug 21, 2008 at 1:43 PM, Stuart Thiessen
> > <thiessenstuart@[...].com> wrote:
> >
> >>
> >> I am working on a program where I want to be able to let a user select a
> >> start and end point in a video using MediaCtrl.Tell() to find the actual
> >> points. Then I want them to be able to click a button and just play that
> >> clip. Finding those points is simple enough, but I am apparently not
> >> doing
> >> it right to start it playing at the start point and tell it to pause or
> >> stop
> >> at the end point.
> >>
> >> Any suggestions?
> >>
> >> Thanks,
> >>
> >> Stuart
> >>
> >> My code is as follows: (where self.startclip is the ms to start playing
> >> and
> >> self.endclip is the ms to end playing. I am assuming as I look at my
> >> code,
> >> that I need to do something with an Event handler somehow instead of what
> >> I'm doing, but I'm not sure how I would do that.
> >>
> >> def OnPlayClip(self, evt):
> >>               self.mc.Seek(self.startclip)
> >>               self.mc.Play()
> >>               while self.mc.Tell() < self.endclip:
> >>                       pass
> >>               self.mc.Stop()
> >>
> >
> > That while loop is going to kill you, which is why things aren't
> > working.  Create a wx.Timer instance and have it signal an event every
> > 100ms or so where you do your check to see if you should stop the
> > video.
> >
> > Alternatively (what I would suggest) is to create a secondary thread
> > that uses wx.CallAfter() to call the wx.Timer event handler that you
> > would have written every 10 ms or so.  Why?  Because wx.Timer()
> > instances are limited depending on the platform, have very limited
> > precision, etc.  I've found that just running a single thread in the
> > background to handle scheduled events to be generally faster (a future
> > release of PyPE uses this method to improve performance on OS X
> > significantly).
> >
> >  - Josiah
> > _______________________________________________
> > wxpython-users mailing list
> > wxpython-users@[...].org
> > http://lists.wxwidgets.org/mailman/listinfo/wxpython-users
> >
> >
> 
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