[Kst] kst 2.0 : No auto update?

Peter Milne Peter.Milne at d-tacq.com
Mon Aug 16 16:17:23 CEST 2010

Hi Barth, Peter

Thanks a lot for your answers.

Peter K. said that: kst 2.0 uses QFileSystemWatcher
Barth said that: update works on their system.

QFileSystemWatcher should be a nice OS independent solution, better than 
a custom timer polling hack.

However, looks like I didn't give enough information.

My data source is an intelligent digitizer featuring an embedded Linux
system. To export data to MS-Win users we can drop a subset of the 
captured data onto a SAMBA export. The data is in DirFile format, any 
host system  the directory mounted can plot it directly using Kst.

It works well, other than in Kst2.0, it doesn't update dynamically, and 
that's probably due to Qt:


> QFileSystemModel along with QFileSystemWatcher are only for local
> host usage. Mounts and remote access will probably need to be handled
> differently through something like a threaded timer that might check
> the cksum of a mounted directory

It's a shame, because Kst 1.8, on a Linux SAMBA mount does update 
correctly. I guess it's the price of portability.

We'll get by with pressing the "Reload" button so long, I'll try the 
threaded timer hack some time.

Thanks again for your excellent support.

Best regards


On 08/15/2010 11:15 PM, Barth Netterfield wrote:
> This is strange.  We've been doing real time dirfiles all summer
> under Linux with no troubles.
> Do you have the vectors in 'count from end'?

> C. Barth Netterfield University of Toronto 416-845-0946
> On Aug 15, 2010 4:56 PM, "Peter Kümmel" <syntheticpp at gmx.net
> <mailto:syntheticpp at gmx.net>> wrote:
>> Am Sonntag, den 15.08.2010, 15:44 +0100 schrieb Peter Milne:
>>> Data source is a DirFile that gradually grows in time.
>>> Plotting this with kst 1.8 (FC), the plot updates at a
>>> respectable rate.
>>> Plotting with kst 2.0 results in a static plot, FC or MS-Win,
>>> it's necessary to press the RELOAD button to get a new update.
>>> Is this a feature that hasn't been activated yet in kst 2.0?.
>>> The parameter Settings|General|Update-ms looks promising, but
>>> doesn't seem to have an effect.
>>> What should drive this update - is it a timer in KST or perhaps a
>>> event (like inotify) from the OS?.
>> Looks like a bug.
>> There is a QFileSystemWatcher which should trigger an update,
>> DirFileSource::init() in dirfilesource.cpp:
>> _watcher = new QFileSystemWatcher(); if (_fieldList.count() > 1) {
>> QString filePath = _dirfile->ReferenceFilename();
>> _watcher->addPath(filePath); } connect(_watcher, SIGNAL(fileChanged
>> ( const QString & )), this,
> SLOT(checkUpdate()));
>> connect(_watcher, SIGNAL(directoryChanged ( const QString & )),
>> this,
> SLOT(checkUpdate()));
>> Maybe Barth knows immediately what's going wrong.
>> Peter
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Peter Milne			Peter.Milne at d-tacq.com
D-TACQ Solutions Ltd		www.d-tacq.com

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