Fabien,
The GUI not being responsive might be my fault, I've never used a timer
of 0 and processEvents(). I think what might be happening is that when
you call processEvents, the timer of 0 calls your principal function
again, which calls processEvents again, and so on. Try a timer of 2
again, that "should" stop the timer from being constantly triggered.
Later today, once I get to work, I'll run some tests of my own and
figure out if that's really the problem. Email me if you make any progress.
-Dave
On 12/13/2011 2:30 AM, Fabien Lafont wrote:
> Hey David,
>
> I'm doing this program to control an experiment, so I want to put the
> voltage on the sample, then wait two seconds to be sure there is no
> current fluctuations then measure the curent with multimeters and
> finally plot the datas. That's why I need the "sleep"... In fact I
> wanted to use in parallel the timer to "refresh" the graph and a while
> loop to "extract" the datas.
>
> If I use startTimer(0) it works but the GUI is almost unresponsive.
> I'm trying to use qApp.processEvents() but up to now I don't manage to
> see the window appears...
>
> Thanks again for your help
>
> Fabien
>
>
>
> 2011/12/12 David Hoese<dho...@gmail.com>:
>> Hey Fabien,
>>
>> So you made your principal function run on a timer every 2 seconds? And by
>> "lag" do you mean that the GUI is unresponsive? I'm still not seeing when
>> the loop stops, but what you can do is set the timer at a 0 interval so it
>> will call the principal function as fast as it can (but with no loop). The
>> problem with this is that you have those 2 sleep calls in the function. I'm
>> not sure why you have the sleeps, but if you need them you have two choices:
>>
>> 1. Make you GUI multi-threaded and you could emit a Qt signal from the data
>> thread when the GUI thread needs to update the GUI. Yes this could get
>> complicated, but if the sleeps are required then its probably the best way.
>>
>> 2. (From what I've been told, the Qt experts don't approve this) You can use
>> app.processEvents() in your loop (after each sleep maybe) and this will
>> pause your function and tell the main event loop to process any queued
>> events (like GUI actions/events) which will make your GUI more responsive.
>>
>> If that doesn't make sense let me know.
>>
>> -Dave
>>
>>
>> On 12/12/11 9:16 AM, Fabien Lafont wrote:
>>>
>>> Hi David! Sorry about the delay I was abroad and without any way to
>>> connect to the internet.
>>>
>>> Thank you very much. I've tried to put the principal inside the
>>> timerEvent. It work but it lags. In fact I've set the interval of the
>>> Timer to 2 seconds because the principal loop takes roughly 2seconds
>>> but it's not very accurate...
>>>
>>> Is there a way to do the principal loop, show it on the screen, then
>>> redo the loop?
>>>
>>> Thanks again!
>>>
>>> Fabien
>>>
>>> 2011/12/5 David Hoese<dho...@gmail.com>:
>>>>
>>>> If I'm understanding your question correctly and reading your code
>>>> correctly, you're asking why the timer method of doing things works, but
>>>> the
>>>> principal() while loop method does not.
>>>>
>>>> I had a couple solutions that involved the main event loop, but I just
>>>> noticed 2 main things that are probably wrong with your code:
>>>> 1. You are calling 'principal' from inside __init__ so you never actually
>>>> return from __init__ which means that you never call "window.show()" and
>>>> therefore never call "qApp.exec_()". If you really want to use the
>>>> 'principal' method you would have to connect it to a one shot timer anyway
>>>> to have it run after you have started the application ('qApp.exec_()'). I
>>>> think the recommended way would be to use the timer the way you did in your
>>>> latest email.
>>>>
>>>> 2. At least in the way my email client reads your original code, your
>>>> calls to the matplotlib drawing functions aren't inside the while loop and
>>>> the while loop never ends...although this doesn't matter if you don't fix
>>>> #1
>>>> above.
>>>>
>>>> Hope that made sense.
>>>>
>>>> -Dave
>>>>
>>>>
>>>> On 12/5/11 1:44 PM, matplotlib-users-requ...@lists.sourceforge.net wrote:
>>>>>
>>>>> Message: 3
>>>>> Date: Mon, 5 Dec 2011 15:46:02 +0100
>>>>> From: Fabien Lafont<lafont.fab...@gmail.com>
>>>>> Subject: Re: [Matplotlib-users] [ploting data] Live data
>>>>> Cc:matplotlib-users@lists.sourceforge.net
>>>>> Message-ID:
>>>>>
>>>>> <CAC9H_cjrgQBE6e6+jzZHyfYHonTeAg0XwU7c_2G-hu=s+z7...@mail.gmail.com>
>>>>> Content-Type: text/plain; charset=ISO-8859-1
>>>>>
>>>>> Thx all for your remarks,
>>>>>
>>>>> I can't understand why this code works (when I use the timer method):
>>>>
>>>>
>>>>
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