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Groups > comp.lang.python > #38342

Re: Monitoring updating directory for image for GUI

From Alain Ketterlin <alain@dpt-info.u-strasbg.fr>
Newsgroups comp.lang.python
Subject Re: Monitoring updating directory for image for GUI
Date 2013-02-07 11:25 +0100
Organization Universites Paris VI/Paris VII - France
Message-ID <87ehgs5slb.fsf@dpt-info.u-strasbg.fr> (permalink)
References <8a572770-9cc1-4b65-9053-10fd6c2f543b@googlegroups.com>

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ciscorucinski@gmail.com writes:

> Basically I am creating a program that will stream musical notes into
> a program called Lilypond one-by-one and it will create the sheet
> music for that stream of music via OS command. Your understanding of
> Lilypond is not needed, but you need to know that for each new note
> that is streamed in "real-time", a PNG image file will be created for
> that stream of music up to that point...via Lilypond.
>
> What I am looking at doing is to monitor the directory where the image
> files are being created in real-time, and update the GUI (build with
> gtk.Builder and Glade) with the most recent image file. I have the
> program multithreaded and it appears that all of the images are being
> created sequentially; however, I need to make sure that an older image
> (an image with less notes displayed) is NOT going to be displayed over
> a newer image.

The "canonical" way to monitor file system changes (in Linux) is to use
inotify. There is a python wrapper, at
https://github.com/seb-m/pyinotify

But it would be much simpler to have Lilypond (or a wrapper) write out
the name of the files it produces (e.g., to a fifo) and have your GUI to
synchronize on that.

> I have looked at creating a Stack from the python List, along with
> os.walk(). However, I am not sure if those are adequate with a
> directory that is actively adding new files. Also, how I imagined
> using the Stack with taking the next item off of the stack meant that
> older ones would be replacing new ones...and with a queue, it might be
> updating too slow; especially if the notes being streamed in are
> played fast. So I would like for the most recent image to be used and
> all others discarded.

I'm  lost.

-- Alain.

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Thread

Monitoring updating directory for image for GUI ciscorucinski@gmail.com - 2013-02-06 14:02 -0800
  Re: Monitoring updating directory for image for GUI Chris Angelico <rosuav@gmail.com> - 2013-02-07 17:25 +1100
    Re: Monitoring updating directory for image for GUI ciscorucinski@gmail.com - 2013-02-07 16:48 -0800
      Re: Monitoring updating directory for image for GUI Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-08 02:01 +0000
        Re: Monitoring updating directory for image for GUI ciscorucinski@gmail.com - 2013-02-08 09:09 -0800
          Re: Monitoring updating directory for image for GUI Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-02-09 00:53 +0000
          Re: Monitoring updating directory for image for GUI Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-02-08 20:32 -0500
        Re: Monitoring updating directory for image for GUI ciscorucinski@gmail.com - 2013-02-08 09:09 -0800
    Re: Monitoring updating directory for image for GUI ciscorucinski@gmail.com - 2013-02-07 16:48 -0800
  Re: Monitoring updating directory for image for GUI Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2013-02-07 11:25 +0100
  Re: Monitoring updating directory for image for GUI Piet van Oostrum <piet@vanoostrum.org> - 2013-02-07 18:11 +0100
  Re: Monitoring updating directory for image for GUI ciscorucinski@gmail.com - 2013-02-11 14:50 -0800
    Re: Monitoring updating directory for image for GUI MRAB <python@mrabarnett.plus.com> - 2013-02-11 23:50 +0000
    Re: Monitoring updating directory for image for GUI Piet van Oostrum <piet@vanoostrum.org> - 2013-02-13 17:09 +0100

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