qt.qpa.screen: QXcbConnection: Could not connect to display Could not connect to any X display.
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An application that was working fine on MacOS Mojave 10.14.6 was transferred to Ubuntu20.10 running on an i5 pc. The error message in the title of this post resulted. Any help would be appreciated. python 3.7
lcleve
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Thanks for your reply. I open the file with VSCode and open the program with "Run without debugging". This is done directly on the PC. I am not familiar with XServer.
Thanks,
lcleve
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Hi,
One other thing, are you sure your system is running an X server and not Wayland ?
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@jsulm The echo command yielded x11.
I initially started with a conda environment and used conda to install pyqt5 following instructions on the conda website.
Following your post, i installed from the $ prompt Qt6 following instructions from the Qt website.
Is it possible that there is a problem with ubuntu 20.10? Is there an earlier version that is known to work?
One again thank you for your help. As new comer to ubuntu and pyqt, this problem is quite daunting to me.
lcleve
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@jsulm The echo command yielded x11.
I initially started with a conda environment and used conda to install pyqt5 following instructions on the conda website.
Following your post, i installed from the $ prompt Qt6 following instructions from the Qt website.
Is it possible that there is a problem with ubuntu 20.10? Is there an earlier version that is known to work?
One again thank you for your help. As new comer to ubuntu and pyqt, this problem is quite daunting to me.
lcleve
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Thank you for your just-to-be-sure question, as I am a complete newcomer to Linux. Initially, I opened the program as a normal user. After your message, I looked up how to open as root. Using the following, I opened it up as root:
sudo code --user-data-dir="~/.vscode-root". The program then opened up, but the gui was distorted, being too large for a 1920x1080 screen even though the size was set to 1920x1080 pixels. The text was also enlarged and out of expected boundaries. I also opened up the .ui file using the newly installed Qt5Designer on my Ubuntu system. It looked fine - identical to what was seen on Mojave OS. However, no change when the program was opened again from root.
After opening as root, I got the following terminal output:
root@jonathan-HP-Compaq-Elite-8300-USDT:/home/jonathan# source activate anno_env
bash: activate: No such file or directory
root@jonathan-HP-Compaq-Elite-8300-USDT:/home/jonathan# /usr/bin/env /home/jonathan/anaconda3/envs/anno_env/bin/python3.7 /root/.vscode/extensions/ms-python.python-2021.5.842923320/pythonFiles/lib/python/debugpy/launcher 33145 -- /home/jonathan/fullgui9JHC.gyp
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-root'With much appreciation for your help.
lcleve
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Did you try to start your application directly from the command line outside of VSCode ?
As for root it was just to make sure you did not do that as there are additional security restriction to avoid starting GUI application by default.
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Thanks for the clarification re root.
After your message, I opened the program from the command line and got the same distorted gui.
A popup message dialog seems to work. A file selection dialog also opens. Clicking and dragging the title bar doesn't work.
Thanks for your help.
lcleve
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What if you just create a minimal script showing a single QWidget ?
What do you get ?
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@SGaist
I used the same imports and the same conda env. Below is the code and terminal output:from PyQt5 import uic, QtGui, Qt, QtCore
from PyQt5.QtGui import QKeySequence
from PyQt5 import QtWidgets
from PyQt5.QtCore import pyqtSlot
from PyQt5.QtWidgets import QApplication, QWidget, QInputDialog, QLineEdit, QFileDialog, QMessageBox, QLabel
import pandas as pd
import time
import numpy as np
import os
import os.path
import getpassapp = QApplication([])
label = QLabel(' Hello World!')
label.show()
app.exe()
Terminal Output:
(base) jonathan@jonathan-HP-Compaq-Elite-8300-USDT:~$ source /home/jonathan/anaconda3/bin/activate
(base) jonathan@jonathan-HP-Compaq-Elite-8300-USDT:~$ conda activate anno_env
/usr/bin/env /home/jonathan/anaconda3/envs/anno_env/bin/python /home/jonathan/.vscode/extensions/ms-python.python-2021.5.842923320/pythonFiles/lib/python/debugpy/launcher 43883 -- /home/jonathan/PyQtTest.py
(anno_env) jonathan@jonathan-HP-Compaq-Elite-8300-USDT:~$ /usr/bin/env /home/jonathan/anaconda3/envs/anno_env/bin/python /home/jonathan/.vscode/extensions/ms-python.python-2021.5.842923320/pythonFiles/lib/python/debugpy/launcher 43883 -- /home/jonathan/PyQtTest.py
qt.qpa.screen: QXcbConnection: Could not connect to display
Could not connect to any X display.
(anno_env) jonathan@jonathan-HP-Compaq-Elite-8300-USDT:~$ -
What is that debugpy ?
You seem to not have any environment variables set which is a bit surprising.
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What is that debugpy ?
You seem to not have any environment variables set which is a bit surprising.
@SGaist
I don't know what debugpy refers to. However, when I ran the program, I used the run-without-debug option in vscode.I saw on the Qt website that Ubuntu 18.04 was supported, so I tested our program with this version and got the same error message: Could not connect to any X display. I also checked and found that x11 was being used.
Regarding environment variables, I do not recall having to set any when using MacOS Mojave where the program ran fine and I have seen no dialogs for this while setting up the Ubuntu 20.10 system. Any advice on how to explore this would be appreciated, since I do not have prior experience with this.
I have also checked permissions for the various files using the GUI options.
Once again, many thanks.
lcleve
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X11 is Linux only there's nothing here to compare with macOS.
How did you test that on 18.04 ?
One thing that I find really strange is that env seem to return empty which is something that is highly unexpected.
How are you starting your terminal ?
Which one do you use ? -
X11 is Linux only there's nothing here to compare with macOS.
How did you test that on 18.04 ?
One thing that I find really strange is that env seem to return empty which is something that is highly unexpected.
How are you starting your terminal ?
Which one do you use ?I tested for x11 using: echo $XDG_SESSION_TYPE at the $prompt of the terminal. The terminal I used is the default terminal that installed with the operating systems (18.04 and 20.10), presumably gnome-terminal? Should I switch to another?
What is it that you see that indicates that "env seems to return empty"?
Could it be a matter of permissions, given that that a gui (albeit distorted ) did appear on the screen when I opened from root?
Thanks.
lcleve
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I thought you called the env command and did not saw anything printed.
So it was not the case, can you call it and show what you get ?
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I thought you called the env command and did not saw anything printed.
So it was not the case, can you call it and show what you get ?
@SGaist
here is the result for 18.04. If this is not informative, I can send the result for 20.10, but it will take me a few minuttes to change hard drives.(base) william@william-HP-Compaq-Elite-8300-USDT:~$ env
CLUTTER_IM_MODULE=xim
CONDA_SHLVL=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:.zst=01;31:.tzst=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:.wim=01;31:.swm=01;31:.dwm=01;31:.esd=01;31:.jpg=01;35:.jpeg=01;35:.mjpg=01;35:.mjpeg=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:
CONDA_EXE=/home/william/anaconda3/bin/conda
LESSCLOSE=/usr/bin/lesspipe %s %s
XDG_MENU_PREFIX=gnome-
LANG=en_US.UTF-8
DISPLAY=:0
GNOME_SHELL_SESSION_MODE=ubuntu
COLORTERM=truecolor
USERNAME=william
CONDA_PREFIX=/home/william/anaconda3
XDG_VTNR=2
SSH_AUTH_SOCK=/run/user/1000/keyring/ssh
MANDATORY_PATH=/usr/share/gconf/ubuntu.mandatory.path
S_COLORS=auto
_CE_M=
XDG_SESSION_ID=2
USER=william
DESKTOP_SESSION=ubuntu
QT4_IM_MODULE=xim
TEXTDOMAINDIR=/usr/share/locale/
GNOME_TERMINAL_SCREEN=/org/gnome/Terminal/screen/4415aacb_f29d_41fc_969b_1ecfb25dfbd2
DEFAULTS_PATH=/usr/share/gconf/ubuntu.default.path
PWD=/home/william
HOME=/home/william
CONDA_PYTHON_EXE=/home/william/anaconda3/bin/python
TEXTDOMAIN=im-config
SSH_AGENT_PID=2421
QT_ACCESSIBILITY=1
XDG_SESSION_TYPE=x11
XDG_DATA_DIRS=/usr/share/ubuntu:/home/william/.local/share/flatpak/exports/share/:/var/lib/flatpak/exports/share/:/usr/local/share/:/usr/share/:/var/lib/snapd/desktop
_CE_CONDA=
XDG_SESSION_DESKTOP=ubuntu
GJS_DEBUG_OUTPUT=stderr
CONDA_PROMPT_MODIFIER=(base)
GTK_MODULES=gail:atk-bridge
WINDOWPATH=2
TERM=xterm-256color
SHELL=/bin/bash
VTE_VERSION=5202
QT_IM_MODULE=ibus
XMODIFIERS=@im=ibus
IM_CONFIG_PHASE=2
XDG_CURRENT_DESKTOP=ubuntu:GNOME
GPG_AGENT_INFO=/run/user/1000/gnupg/S.gpg-agent:0:1
GNOME_TERMINAL_SERVICE=:1.84
XDG_SEAT=seat0
SHLVL=1
GDMSESSION=ubuntu
GNOME_DESKTOP_SESSION_ID=this-is-deprecated
LOGNAME=william
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
XDG_RUNTIME_DIR=/run/user/1000
XAUTHORITY=/run/user/1000/gdm/Xauthority
XDG_CONFIG_DIRS=/etc/xdg/xdg-ubuntu:/etc/xdg
PATH=/home/william/anaconda3/bin:/home/william/anaconda3/condabin:/home/william/.local/bin:/home/william/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
CONDA_DEFAULT_ENV=base
GJS_DEBUG_TOPICS=JS ERROR;JS LOG
SESSION_MANAGER=local/william-HP-Compaq-Elite-8300-USDT:@/tmp/.ICE-unix/2324,unix/william-HP-Compaq-Elite-8300-USDT:/tmp/.ICE-unix/2324
LESSOPEN=| /usr/bin/lesspipe %s
GTK_IM_MODULE=ibus
_=/usr/bin/env -
Everything looks Ok...
Next test: can you install and test your code with your distribution provided PyQt5 ?
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Everything looks Ok...
Next test: can you install and test your code with your distribution provided PyQt5 ?
@SGaist
The env results I sent before were for ubuntu 18.04. In retrospect, this may have complicated things unnecessarily, since our goal is is to work on ubuntu 20.10. So below is the env output for 20.10. Note that the username for 20.10 is jonathan. For the older version, it is william.(base) jonathan@jonathan-HP-Compaq-Elite-8300-USDT:~$ env
SHELL=/bin/bash
SESSION_MANAGER=local/jonathan-HP-Compaq-Elite-8300-USDT:@/tmp/.ICE-unix/1707,unix/jonathan-HP-Compaq-Elite-8300-USDT:/tmp/.ICE-unix/1707
QT_ACCESSIBILITY=1
COLORTERM=truecolor
XDG_CONFIG_DIRS=/etc/xdg/xdg-ubuntu:/etc/xdg
XDG_MENU_PREFIX=gnome-
GNOME_DESKTOP_SESSION_ID=this-is-deprecated
CONDA_EXE=/home/jonathan/anaconda3/bin/conda
_CE_M=
GNOME_SHELL_SESSION_MODE=ubuntu
SSH_AUTH_SOCK=/run/user/1000/keyring/ssh
XMODIFIERS=@im=ibus
DESKTOP_SESSION=ubuntu
SSH_AGENT_PID=1663
GTK_MODULES=gail:atk-bridge
PWD=/home/jonathan
LOGNAME=jonathan
XDG_SESSION_DESKTOP=ubuntu
XDG_SESSION_TYPE=x11
CONDA_PREFIX=/home/jonathan/anaconda3
GPG_AGENT_INFO=/run/user/1000/gnupg/S.gpg-agent:0:1
XAUTHORITY=/run/user/1000/gdm/Xauthority
GJS_DEBUG_TOPICS=JS ERROR;JS LOG
WINDOWPATH=2
HOME=/home/jonathan
USERNAME=jonathan
IM_CONFIG_PHASE=1
LANG=en_US.UTF-8
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:.dz=01;31:.gz=01;31:.lrz=01;31:.lz=01;31:.lzo=01;31:.xz=01;31:.zst=01;31:.tzst=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:.wim=01;31:.swm=01;31:.dwm=01;31:.esd=01;31:.jpg=01;35:.jpeg=01;35:.mjpg=01;35:.mjpeg=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:.webp=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_CURRENT_DESKTOP=ubuntu:GNOME
VTE_VERSION=6200
CONDA_PROMPT_MODIFIER=(base)
GNOME_TERMINAL_SCREEN=/org/gnome/Terminal/screen/f4b8c0e5_b44e_4a61_8b22_3f26ba220048
GJS_DEBUG_OUTPUT=stderr
LESSCLOSE=/usr/bin/lesspipe %s %s
XDG_SESSION_CLASS=user
TERM=xterm-256color
_CE_CONDA=
LESSOPEN=| /usr/bin/lesspipe %s
USER=jonathan
GNOME_TERMINAL_SERVICE=:1.81
CONDA_SHLVL=1
DISPLAY=:0
SHLVL=1
QT_IM_MODULE=ibus
CONDA_PYTHON_EXE=/home/jonathan/anaconda3/bin/python
XDG_RUNTIME_DIR=/run/user/1000
CONDA_DEFAULT_ENV=base
XDG_DATA_DIRS=/usr/share/ubuntu:/usr/local/share/:/usr/share/:/var/lib/snapd/desktop
PATH=/home/jonathan/anaconda3/bin:/home/jonathan/anaconda3/condabin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
GDMSESSION=ubuntu
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
_=/usr/bin/envI am not entirely clear on what you mean for the next test. The program was previously transferred from Mojave to 20.10 via flash drive and run from vscode without debugging. After testing the code on Mojave to double check that it was working, I ran the code on 20.10 and got the following:
source /home/jonathan/anaconda3/bin/activate
(base) jonathan@jonathan-HP-Compaq-Elite-8300-USDT:~$ source /home/jonathan/anaconda3/bin/activate
conda activate anno_env
(base) jonathan@jonathan-HP-Compaq-Elite-8300-USDT:~$ conda activate anno_env
(anno_env) jonathan@jonathan-HP-Compaq-Elite-8300-USDT:~$ /usr/bin/env /home/jonathan/anaconda3/envs/anno_env/bin/python /home/jonathan/.vscode/extensions/ms-python.python-2021.5.842923320/pythonFiles/lib/python/debugpy/launcher 40389 -- /home/jonathan/fullgui9JHC.gyp
qt.qpa.screen: QXcbConnection: Could not connect to display
Could not connect to any X display.
(anno_env) jonathan@jonathan-HP-Compaq-Elite-8300-USDT:~$ -
The idea is to use what is provided by Ubuntu rather than conda.
But before doing that, can you start your application with the QT_DEBUG_PLUGINS environment variable set to 1 ?
That will give you more information with what is happening with plugins.
