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we13ster

Member

Registered: 2014-09-01

Posts: 2

[SOLVED] ipython2, qt5 upgrade issue

I just updated to qt5, and ipython2 seems to have some issues with this...

andrey% ipython2 --pylab
Python 2.7.8 (default, Jul  1 2014, 17:30:21)
Type "copyright", "credits" or "license" for more information.

IPython 2.2.0 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.
Using matplotlib backend: Qt5Agg

In [1]: plot(range(10))
This application failed to start because it could not find or load the Qt platform plugin "xcb".

Available platform plugins are: eglfs, kms, linuxfb, minimal, minimalegl, offscreen, xcb.

Reinstalling the application may fix this problem.
zsh: abort (core dumped)  ipython2 --pylab

I couldn't find anything on forum/google. Any ideas how to fix this?

It looks like I have xcb

andrey% pacman -Q | grep xcb
libxcb 1.11-1
xcb-proto 1.11-1
xcb-util 0.3.9-2
xcb-util-image 0.3.9-2
xcb-util-keysyms 0.3.9-2
xcb-util-wm 0.4.1-1

Qt, Ipython packages installed

andrey% pacman -Q | grep qt
pyqt5-common 5.3.1-1
python-pyqt5 5.3.1-1
python2-pyqt5 5.3.1-1
qt4 4.8.6-1
qt5-base 5.3.1-1
qtchooser 41-1

andrey% pacman -Q | grep ipython
ipython 2.2.0-1
ipython2 2.2.0-1

andrey% cat /var/log/pacman.log | grep qt
[2014-07-08 11:53] [PACMAN] installed qt4 (4.8.6-1)
[2014-07-08 11:53] [PACMAN] installed qtwebkit (2.3.3-1)
[2014-07-08 11:53] [PACMAN] installed pyqt4-common (4.11.1-1)
[2014-07-08 11:53] [PACMAN] installed python2-pyqt4 (4.11.1-1)
[2014-08-13 12:13] [PACMAN] installed python-pyqt4 (4.11.1-1)
[2014-09-01 09:05] [PACMAN] installed qtchooser (41-1)
[2014-09-01 09:05] [PACMAN] installed qt5-base (5.3.1-1)
[2014-09-01 09:05] [PACMAN] installed pyqt5-common (5.3.1-1)
[2014-09-01 09:05] [PACMAN] installed python-pyqt5 (5.3.1-1)
[2014-09-01 09:05] [PACMAN] installed python2-pyqt5 (5.3.1-1)
[2014-09-01 09:08] [PACMAN] Running 'pacman -Rns python-pyqt4 python2-pyqt4'
[2014-09-01 09:08] [PACMAN] removed python2-pyqt4 (4.11.1-1)
[2014-09-01 09:08] [PACMAN] removed python-pyqt4 (4.11.1-1)
[2014-09-01 09:08] [PACMAN] removed qtwebkit (2.3.3-1)
[2014-09-01 09:08] [PACMAN] removed pyqt4-common (4.11.1-1)
[2014-09-01 11:20] [PACMAN] Running 'pacman --color auto -S extra/python2-pyqt4'
[2014-09-01 11:20] [PACMAN] installed qtwebkit (2.3.3-1)
[2014-09-01 11:20] [PACMAN] installed pyqt4-common (4.11.1-1)
[2014-09-01 11:20] [PACMAN] installed python2-pyqt4 (4.11.1-1)
[2014-09-01 11:20] [PACMAN] Running 'pacman -Rss python2-qt4'
[2014-09-01 11:20] [PACMAN] Running 'pacman -Rss python2-pyqt4'
[2014-09-01 11:20] [PACMAN] removed python2-pyqt4 (4.11.1-1)
[2014-09-01 11:20] [PACMAN] removed qtwebkit (2.3.3-1)
[2014-09-01 11:20] [PACMAN] removed pyqt4-common (4.11.1-1)
[2014-09-01 11:23] [PACMAN] Running 'pacman --color auto -S extra/qtchooser'
[2014-09-01 11:23] [PACMAN] reinstalled qtchooser (41-1)

Last edited by we13ster (2014-09-01 18:51:24)

we13ster

Member

Registered: 2014-09-01

Posts: 2

Re: [SOLVED] ipython2, qt5 upgrade issue

I did a cursory examination of the IPython source, and it looks like this is an upstream issue. From what I can tell, the IPython 2.x code does not support PyQt5 (though apparently matplotlib is detecting it as a backend). The IPython 3.x line looks like it does add support for qt5, but there is no stable release yet. In any case, this issue can be fixed by forcing IPython to continue to use qt4 (ensure python2-pyqt4 is installed)

andrey% ipython2 --pylab=qt4

BlairNZ

Member

Registered: 2014-09-02

Posts: 1

Re: [SOLVED] ipython2, qt5 upgrade issue

If you want this to be set by default, then add the following line to your matplotlibrc file at .config/matplotlib/matplotlibrc (this isn't created by default):

backend : qt4agg

tlawren

Member

From: Colorado, US

Registered: 2009-04-06

Posts: 80

Re: [SOLVED] ipython2, qt5 upgrade issue

I want to add some more info to this post for others who might be experiencing similar problems. 

I too was experiencing issues with ipython2 and Qt5Agg, but they weren't the same as what we13ster was seeing.  If I ran plot(), a figure would pop-up, but no plot (canvas) would be shown.  Moreover, when I tried to close the window, I would get a "not responding" error and the window would freeze for a few seconds and then close.  close(fig) or close('all') from the ipython2 shell worked as normal though.  Switching ipython2 back to Qt4Agg fixed all of this.

Last edited by tlawren (2014-09-27 13:20:49)