opencv GUI does not work

[braindevices]

cv2.namedWindow('test', cv2.WINDOW_AUTOSIZE) results in an error:

QObject::moveToThread: Current thread (0xca9110) is not the object's thread (0x1256140).
Cannot move to target thread (0xca9110)

here is the version:

cv2.__version__
Out[3]: '3.3.0'
QtCore.QT_VERSION_STR
Out[7]: '5.6.2'

[skvark]

On which operating system? This is probably a bug in OpenCV or in your code and there's nothing I can do about it.

And no need to report Qt version, wheels have Qt 4.8.7 embedded inside them. They do not use your system's Qt version.

Are you sure you are using the prebuilt wheels?

[braindevices]

yepp, using prebuilt wheels. It is on ubuntu 14.04

[skvark]

Works fine on Ubuntu 14.04:

Can you post more code?

[TechnoConserve]

I get the same error when attempting cv2.namedWindow('test', cv2.WINDOW_AUTOSIZE), but only when using python3.5

I'm on Ubuntu 16.04.

[techdragon]

@braindevices @TechnoConserve can you provide more information about your Ubuntu environment, the output of which -a python3, which -a pip, pip freeze, env (Always remember to check for any secret information that shouldn't be shared such as API keys or other items before you post the output of env) , and apt list --installed would all prove useful.

[TechnoConserve]

uname -a
Linux ave-GL552VW 4.10.0-35-generic #39~16.04.1-Ubuntu SMP Wed Sep 13 09:02:42 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

which -a python3
/home/ave/venv/opencv/bin/python3
/home/ave/venv/potato/bin/python3
/usr/bin/python3

which -a pip
/home/ave/venv/potato/bin/pip
/home/ave/.local/bin/pip
/usr/local/bin/pip
/usr/bin/pip

That does seem puzzling to me since it only picked up pip in one of my virtual environments regardless of whether I have the opencv virtual environment active or not.

pip freeze
apparmor==2.10.95
apparmor.click==0.3.13.1
apt-xapian-index==0.47
apturl==0.5.2
awscli==1.11.155
beautifulsoup4==4.6.0
blinker==1.3
botocore==1.7.13
Brlapi==0.6.4
certifi==2017.7.27.1
chardet==3.0.4
checkbox-support==0.22
click==0.4.43+16.4.20170613.0ubuntu1
colorama==0.3.7
command-not-found==0.3
cryptography==1.2.3
defer==1.0.6
Django==1.11.5
django-modelcluster==3.1
django-taggit==0.22.1
django-treebeard==4.1.2
djangorestframework==3.6.4
docutils==0.14
feedparser==5.1.3
guacamole==0.9.2
html5lib==0.999
httplib2==0.9.1
idna==2.6
Jinja2==2.8
jmespath==0.9.3
language-selector==0.1
LibAppArmor==2.10.95
louis==2.6.4
lxml==3.5.0
Mako==1.0.3
MarkupSafe==0.23
numpy==1.13.1
oauthlib==1.0.3
onboard==1.2.0
opencv-python==3.3.0.10
padme==1.1.1
pexpect==4.0.1
Pillow==3.1.2
pkg-resources==0.0.0
plainbox==0.25
psycopg2==2.7.3.1
ptyprocess==0.5
pyasn1==0.3.5
pycups==1.9.73
pycurl==7.43.0
pygobject==3.20.0
PyJWT==1.3.0
pyparsing==2.0.3
python-apt==1.1.0b1
python-dateutil==2.6.1
python-debian==0.1.27
python-gnupg==0.3.8
python-systemd==231
pytz==2017.2
pyxdg==0.25
PyYAML==3.12
reportlab==3.3.0
requests==2.18.4
rsa==3.4.2
s3transfer==0.1.11
sessioninstaller==0.0.0
six==1.11.0
system-image==3.1
system-service==0.3
ubuntu-drivers-common==0.0.0
ufw==0.35
unattended-upgrades==0.1
Unidecode==0.4.21
unity-scope-calculator==0.1
unity-scope-chromiumbookmarks==0.1
unity-scope-colourlovers==0.1
unity-scope-devhelp==0.1
unity-scope-firefoxbookmarks==0.1
unity-scope-manpages==0.1
unity-scope-openclipart==0.1
unity-scope-texdoc==0.1
unity-scope-tomboy==0.1
unity-scope-virtualbox==0.1
unity-scope-yelp==0.1
unity-scope-zotero==0.1
urllib3==1.22
usb-creator==0.3.0
uWSGI==2.0.15
wagtail==1.12.2
Willow==0.4
xdiagnose==3.8.4.1
xkit==0.0.0
XlsxWriter==0.7.3

env
XDG_VTNR=7
KDE_MULTIHEAD=false
SSH_AGENT_PID=2482
XDG_SESSION_ID=2
PAM_KWALLET5_LOGIN=/tmp/kwallet5_ave.socket
TERM=xterm
SHELL=/bin/bash
KONSOLE_DBUS_SERVICE=:1.31
GTK2_RC_FILES=/etc/gtk-2.0/gtkrc:/home/ave/.gtkrc-2.0:/home/ave/.config/gtkrc-2.0
KONSOLE_PROFILE_NAME=Green
QT_LINUX_ACCESSIBILITY_ALWAYS_ON=1
GS_LIB=/home/ave/.fonts
GTK_RC_FILES=/etc/gtk/gtkrc:/home/ave/.gtkrc:/home/ave/.config/gtkrc
WINDOWID=58720261
OLDPWD=/home/ave/PycharmProjects/potato-project/potato
SHELL_SESSION_ID=b8195832c1774000aa88ccc122cc6b7b
GTK_MODULES=gail:atk-bridge
XDG_SESSION_CLASS=user
KDE_FULL_SESSION=true
USER=ave
QT_ACCESSIBILITY=1
LS_COLORS=rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lha=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.tzo=01;31:*.t7z=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.lrz=01;31:*.lz=01;31:*.lzo=01;31:*.xz=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.alz=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.cab=01;31:*.jpg=01;35:*.jpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.m4a=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.oga=00;36:*.opus=00;36:*.spx=00;36:*.xspf=00;36:
XDG_SESSION_PATH=/org/freedesktop/DisplayManager/Session1
XDG_SEAT_PATH=/org/freedesktop/DisplayManager/Seat0
SSH_AUTH_SOCK=/tmp/ssh-YXVwNQB4fLBl/agent.2436
SESSION_MANAGER=local/ave-GL552VW:@/tmp/.ICE-unix/2732,unix/ave-GL552VW:/tmp/.ICE-unix/2732
DEFAULTS_PATH=/usr/share/gconf//usr/share/xsessions/plasma.default.path
VIRTUAL_ENV=/home/ave/venv/opencv
XDG_CONFIG_DIRS=/etc/xdg/xdg-/usr/share/xsessions/plasma:/etc/xdg:/usr/share/kubuntu-default-settings/kf5-settings
DESKTOP_SESSION=/usr/share/xsessions/plasma
PATH=/home/ave/venv/opencv/bin:/home/ave/venv/potato/bin:/home/ave/bin:/home/ave/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
QT_IM_MODULE=compose
QT_QPA_PLATFORMTHEME=kde
PWD=/home/ave/venv
XDG_SESSION_TYPE=x11
LANG=en_US.UTF-8
KDE_SESSION_UID=1000
MANDATORY_PATH=/usr/share/gconf//usr/share/xsessions/plasma.mandatory.path
PS1=(opencv) \[\e]0;\u@\h: \w\a\]${debian_chroot:+($debian_chroot)}\u@\h:\w\$ 
KONSOLE_DBUS_SESSION=/Sessions/1
GTK2_MODULES=overlay-scrollbar
COLORFGBG=15;0
HOME=/home/ave
SHLVL=2
XDG_SEAT=seat0
KDE_SESSION_VERSION=5
LANGUAGE=
XCURSOR_THEME=breeze_cursors
LOGNAME=ave
XDG_SESSION_DESKTOP=KDE
DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-UiuOcMuIpB,guid=2d3de9776ef25a2171e6481959c98ad4
XDG_DATA_DIRS=/usr/share//usr/share/xsessions/plasma:/usr/local/share/:/usr/share/:/var/lib/snapd/desktop
LESSOPEN=| /usr/bin/lesspipe %s
XDG_RUNTIME_DIR=/run/user/1000
DISPLAY=:0
PROFILEHOME=
XDG_CURRENT_DESKTOP=KDE
PAM_KWALLET_LOGIN=/tmp/kwallet_ave.socket
LESSCLOSE=/usr/bin/lesspipe %s %s
ZADDR=zcbZsZdkHfGqbgUjZuM7KiJ7x2ayXLLbXfB8eryRqatW64hhqRK7W74Whjq95jFHKzyTYbnTFnNZBRM8cJ9Q6hVcGGWd7BT
XAUTHORITY=/tmp/xauth-1000-_0
_=/usr/bin/env

[dzimmerer]

Same error (also on 16.04 with python 3.5)

[djokjulapfe]

Same error on Ubuntu 16.04 with python 3.5. Beaks at cv2.imshow('Test', img)

[sibojia]

Same error on Ubuntu 16.04 with python 2.7. Prints hundreds of error:

QObject::moveToThread: Current thread (0x5563aa165a20) is not the object's thread (0x5563aa278b20).
Cannot move to target thread (0x5563aa165a20)

When calling cv2.waitKey() for the first time in a process. No other effects but the messages are very annoying.
cv2.__version__ = 3.3.0

[ridho9]

Same here, opencv 3.3.0 and ubuntu 16.04
Trying cv2.namedWindow('test', cv2.WINDOW_AUTOSIZE) with 3.3.0.10 returns the same QObject error, but using 3.2.0.8 returns

<ipython-input-3-2efaecccc8a8> in <module>()
----> 1 cv2.namedWindow('test', cv2.WINDOW_AUTOSIZE)

error: /io/opencv/modules/highgui/src/window.cpp:565: error: (-2) The function is not implemented. Rebuild the library with Windows, GTK+ 2.x or Carbon support. If you are on Ubuntu or Debian, install libgtk2.0-dev and pkg-config, then re-run cmake or configure script in function cvNamedWindow

And I already have installed libgtk2.0-dev and pkg-config

[ibrmora]

Same here, opencv 3.3.0.10 and ubuntu 16.04 with python 3.5.2 cv2.imshow("image", image)

[saeedranjbar12]

GUI problem with opencv 3.4.0 and ubuntu 16.04 - python 2.7

[caixiaofan]

First, uninstall any versions of OpenCV you may have installed. If you installed using pip:

sudo pip uninstall opencv-python
Next, try installing OpenCV using your Linux distro's package manager. For Ubuntu/Debian, this is:

sudo apt-get install libopencv-dev python-opencv

copy from https://reformatcode.com/code/python/how-to-fix-the-error-quotqobjectmovetothreadquot-in-opencv-in-python

[sibojia]

@caixiaofan This simply lets you use the opencv binding shipped in apt-get and stop using this repo. IMHO issues in this repo should focus on how to solve problems in this library.