[pygtk] gobject.timeout_add()

Sun Jan 24 18:12:01 WST 2010

Il giorno sab, 23/01/2010 alle 15.51 -0800, dj ha scritto:
> Thanks for your continued help on this, Pietro.
> 
> Here is a very basic look at what the program does:
> 1. At a specified time, tune the radio and launch ecasound to make a recording.
> 2. After the recording has finished, tune the radio to another frequency and launch ecasound again.
> 
> The version of the program I had been using launched ecasound in a
>  thread so that the GUI would not be blocked.  gobject.timeout_add()
>  was used to stop the program from immediately re-tuning and trying to
>  record again before the previous recording was finished.  This happens
>  hourly plus an additional 0-4 schedules within each hour.  When I
>  tried to add another schedule within the hour, I couldn't get
>  gobject.timeout_add() to work with it.
> 
> The threaded version uses os.system() to launch ecasound.  I've been
>  experimenting with subprocess.Popen and subprocess.call in the
>  non-threaded version, but I don't understand those too well, and they
>  both block the GUI.  I understand that nobody has suggested that I
>  block the GUI, but I can live with that as long as the rest of the
>  program works.

import sys
import subprocess
p = subprocess.Popen(['sleep', '10'])
sys.exit(0)

Run the above and you'll see Popen() _doesn't_ block the code flow. You
must be doing something else strange. Maybe you don't care about
blocking the GUI, but you certainly care about understanding what's
wrong.

> 
> How I monitor the clock: Every 5 seconds I call time.gmtime() and check
>  the hour and minute.  When those correspond with the waiting schedule,
>  the tuning a recording sequence starts.

Can't you run gobject.timeout_add_seconds() _with_ the number of seconds
which the recording must last?!

Anyway your solution seems reasonable also to me.

Pietro

> 
> westli
> 
> --- On Sat, 1/23/10, Pietro Battiston <toobaz a email.it> wrote:
> 
> > From: Pietro Battiston <toobaz a email.it>
> > Subject: Re: [pygtk] gobject.timeout_add()
> > To: "PYGTK" <pygtk a daa.com.au>
> > Date: Saturday, January 23, 2010, 5:51 AM
> > Il giorno ven, 22/01/2010 alle 21.44
> > -0800, dj ha scritto:
> > > Thank you John and Pietro for your observations and
> > advice.
> > > 
> > > Because of them, I did some rethinking of my
> > program.  Threading has
> > >  worked okay for a couple of years in this
> > program as I continually
> > >  improved it.  But the GUI I started with
> > had to be useful while
> > >  recordings were taking place.  I use the to
> > tune a radio receiver
> > >  according to a schedule and record what was
> > found there, and I needed
> > >  to be able to make adjustments on the fly. 
> > I use a different radio
> > >  and GUI now, and except for Start and Quit
> > buttons, the GUI is just to
> > >  supply information.  So I don't need
> > threading or the timeouts to
> > >  pause the program until the recording is
> > finished.  I'm not thrilled
> > >  with seeing the GUI go dark during recording,
> > but it's okay.
> > 
> > Notice I was not at all suggesting to you to block the
> > GUI... How do you
> > call your external processes?
> > 
> > 
> > > Now
> > >  there is only one 5-second timeout to check the
> > clock between
> > >  scheduled recordings.
> > > 
> > > Is there a better way to monitor the clock?  I
> > have to use time-of-day
> > >  rather than time periods, and I haven't figured
> > out a better way than
> > >  executing time.gmtime() every 5 seconds.
> > > 
> > 
> > I unfortunately cannot understand _what_ type of monitoring
> > you need,
> > and hence how you are currently implementing it.
> > 
> > Pietro
> > 
> > > westli
> > > 
> > > --- On Thu, 1/21/10, Pietro Battiston <toobaz a email.it>
> > wrote:
> > > 
> > > > From: Pietro Battiston <toobaz a email.it>
> > > > Subject: Re: [pygtk] gobject.timeout_add()
> > > > To: pygtk a daa.com.au
> > > > Date: Thursday, January 21, 2010, 1:56 PM
> > > > Il giorno gio, 21/01/2010 alle 08.56
> > > > +0100, John Stowers ha scritto:
> > > > > On Wed, 2010-01-20 at 21:22 -0800, dj
> > wrote:
> > > > > > I hope this is the right place to ask
> > this...
> > > > > > 
> > > > > > I have a python program (using Glade to
> > create
> > > > the gui) that periodically launches ecasound to
> > make audio
> > > > recordings of various lengths.  In order to
> > keep the
> > > > gui viable, ecasound runs in a separate
> > thread.  In
> > > > order to keep the program from getting ahead of
> > itself and
> > > > trying to launch ecasound before the current
> > recording
> > > > process has finished, I use gobject.timeout_add()
> > for the
> > > > length of the recording (plus a second or two for
> > safety).
> > > > > > 
> > > > > > Most of the calls to
> > gobject.timeout_add() are in
> > > > separate functions with different
> > intervals.  All but
> > > > one of them work.  The last one only works
> > if
> > > > gobject.timeout_add(..., ...)/return False is
> > appended to
> > > > the end of the function that needs it, rather
> > than calling
> > > > it.
> > > > > 
> > > > > This doesn't sound like a particuarly nice
> > design,
> > > > 
> > > > More specifically: are you sure you need threads
> > at all?!
> > > > subprocess.call will block the GUI, but
> > subprocess.Popen
> > > > won't.
> > > > 
> > > > Pietro
> > > > 
> > > > _______________________________________________
> > > > pygtk mailing list   pygtk a daa.com.au
> > > > http://www.daa.com.au/mailman/listinfo/pygtk
> > > > Read the PyGTK FAQ: http://faq.pygtk.org/
> > > > 
> > > 
> > > 
> > >       
> > > 
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> > 
> > 
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> > 
> 
> 
>       
> 
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