Re: [matplotlib-devel] Bugs in Qt4 backend with the latest PyQt release

[william r. <wil...@gm...>]

I should mention that the latest test was on a windows 32 bit xp box.

On Mon, Aug 31, 2009 at 11:51 AM, william ratcliff <
wil...@gm...> wrote:

> Ok, I upgraded to python 2.6, installed mpl 0.99 qt 4.5, and the new pyqt
> and things are more responsive...However, the difference between having that
> line in and taking it out are the difference between having pan/zoom events
> being extremely responsive and having an extremely noticeable lag.  I've
> attached a test file from the web which is rather simple.  You can notice
> the lag if you either try to pan/zoom using the toolbar, or if you try to
> use the slider to change the sizes of the horizontal bars.
>
> Sigh, upgrading everything to 2.6 is going to be a chore...
>
>
> Thanks,
> William
>
>
> On Mon, Aug 31, 2009 at 11:30 AM, Darren Dale <dsd...@gm...> wrote:
>
>> I've been using 2.6. It should be fine on windows now, but I can't
>> attest to it since I only use windows when I have to test and make
>> windows installers.
>>
>> On Mon, Aug 31, 2009 at 10:02 AM, william
>> ratcliff<wil...@gm...> wrote:
>> > Let me try to upgrade to PyQt 4.5--I'm currently using 4.4.3 on vista 32
>> > bit.  Btw. are you using python 2.6 or 2.5 (I ask because I'm still on
>> 2.5
>> > and am wondering if anyone has noticed any difficulties with 2.6).
>> >
>> > Cheers,
>> > Wiliam
>> >
>> > On Mon, Aug 31, 2009 at 9:36 AM, Darren Dale <dsd...@gm...>
>> wrote:
>> >>
>> >> Hi William,
>> >>
>> >> On Mon, Aug 31, 2009 at 8:25 AM, william
>> >> ratcliff<wil...@gm...> wrote:
>> >> > Hi!  I just installed matplotlib version .99 (windows vista,
>> python25,
>> >> > 32bit) and found that
>> >> > this line was missing:
>> >> > QtGui.qApp.processEvents()
>> >> >
>> >> > Adding it sped the QT4Agg backend back to reasonable speeds--but it
>> >> > still
>> >> > seems a bit slow.  Otherwise, I am using the excellent Python(x,y)
>> >> > 2.1.14
>> >> > release for my python distribution on this machine.  Could this line
>> be
>> >> > added back?
>> >>
>> >> Unfortunately, no, that line can not be added back in. When that line
>> >> is in place, the backend attempts to process queued events before it
>> >> is finished processing the current event. It was leading to segfaults
>> >> in some cases. processEvents should not be called in the middle of
>> >> processing an event.
>> >>
>> >> I tested the responsiveness of panning and zooming with and without
>> >> that call to processEvents, on Linux and windows and it looked fine.
>> >> Maybe its an issue related to a specific Qt version on windows. Things
>> >> looked fine for me with Qt-4.5/PyQt-4.5 on 64bit Vista.
>> >>
>> >> Darren
>> >
>> >
>>
>>
>>
>> --
>> "In our description of nature, the purpose is not to disclose the real
>> essence of the phenomena but only to track down, so far as it is
>> possible, relations between the manifold aspects of our experience" -
>> Niels Bohr
>>
>> "It is a bad habit of physicists to take their most successful
>> abstractions to be real properties of our world." - N. David Mermin
>>
>> "Once we have granted that any physical theory is essentially only a
>> model for the world of experience, we must renounce all hope of
>> finding anything like the correct theory ... simply because the
>> totality of experience is never accessible to us." - Hugh Everett III
>>
>
>