[Error] _tkinter.TclError: no display name and no $DISPLAY environment variable

[dr-nugget]

Type of Issue (Enhancement, Error, Bug, Question)

Error

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Operating System

Windows Subsystem for Linux (practically Linux in most cases)

PySimpleGUI Port (tkinter, Qt, Wx, Web)

tkinter (PySimpleGUI)

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Versions

Version information can be obtained by calling sg.main_get_debug_data()
Or you can print each version shown in ()

Python version (sg.sys.version)

3.9.6

PySimpleGUI Version (sg.__version__)

4.47.0

GUI Version (tkinter (sg.tclversion_detailed), PySide2, WxPython, Remi)

8.6.10

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Your Experience In Months or Years (optional)

1 Years Python programming experience

2 Years Programming experience overall

Have used another Python GUI Framework? (tkinter, Qt, etc) (yes/no is fine) Not really

Anything else you think would be helpful?

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Troubleshooting

These items may solve your problem. Please check those you've done by changing - [ ] to - [X]

• [X ] Searched main docs for your problem www.PySimpleGUI.org
• [X ] Looked for Demo Programs that are similar to your goal Demos.PySimpleGUI.org
• [N/A ] If not tkinter - looked for Demo Programs for specific port
• [N/A ] For non tkinter - Looked at readme for your specific port if not PySimpleGUI (Qt, WX, Remi)
• [X ] Run your program outside of your debugger (from a command line)
• [X ] Searched through Issues (open and closed) to see if already reported Issues.PySimpleGUI.org
• [X ] Tried using the PySimpleGUI.py file on GitHub. Your problem may have already been fixed but not released

Detailed Description

Hello,
I am trying out PySimpleGUI, so I made a "Hello World" program (below). When I ran it, I got the following error:
_tkinter.TclError: no display name and no $DISPLAY environment variable
So I try the demo Hello World on GitHub. And I got the same thing. It seems any PySimpleGUI program I run raises that error.

Code To Duplicate

import PySimpleGUI as sg
sg.Window(title="Hello World", layout=[[]], margins=(100, 50)).read()

Screenshot, Sketch, or Drawing

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Watcha Makin?

If you care to share something about your project, it would be awesome to hear what you're building.

[jason990420]

Know nothing about Linux system.

Just found something may help

The problem is that whatever you are doing when your program starts, the X-window system has not yet initialized and you get that error.

An application that creates an X-windows client can only usefully be run in an environment where it has access to an X-windows server to render the display in a graphical form.

$ printenv grep DISPLAY
localhost:0.0

if not specified, try to add following code before your run PySimpleGUI or tkinter code.

import os

if os.environ.get('DISPLAY','') == '':
    print('no display found. Using :0.0')
    os.environ.__setitem__('DISPLAY', ':0.0')

Not for users for following code
Not sure if it will work if X-windows not yet initialized

setting = os.environ.__getitem__('DISPLAY')
window = tk.Tk(screenName = setting)

[dr-nugget]

This didn't work. I got the following error:
_tkinter.TclError: couldn't connect to display ":0.0"

[jason990420]

Ok, it looks like you use Ubuntu LTS
Maybe you can refer
https://askubuntu.com/questions/993225/whats-the-easiest-way-to-run-gui-apps-on-windows-subsystem-for-linux-as-of-2018

WSL (Windows 10 Subsystem for Linux)) is not a full Linux installation with a Linux kernel, it allows you to run some native linux commands / binaries on a Windows (Microsoft) kernel and has limitations.
Install a 3rd party X server.

Tried to Install vcxsrv and start the server, and set the DISPLAY, then it OK for me.
https://sourceforge.net/projects/vcxsrv/

Maybe you can modify the environment

export DISPLAY=localhost:0.0

or

import os
import PySimpleGUI as sg

if os.environ.get('DISPLAY','') == '':
    os.environ.__setitem__('DISPLAY', ':0.0')

sg.Window(title="Hello World", layout=[[]], margins=(100, 50)).read(close=True)

[dr-nugget]

X connection to :0.0 broken (explicit kill or server shutdown).
I have no experience with X-servers. It's probably easier to just develop on Windows.

[jason990420]

First, it's not issue about PySimpleGUI or tkinter, but Windows Subsystem for Linux.
I also have no experience with X-servers.

Follow steps in your WIN10, and it work on my WIN10 and not sure if it work for everyone for maybe different configuration of WIN10.

1. Install vcxsrv on your WIN10 from https://sourceforge.net/projects/vcxsrv/
   Maybe vcxsrv-64.1.20.9.0.installer.exe (41.783M)

2. Start server (Maybe C:\Program Files\VcXsrv\xlaunch.exe) by click on Next, Keep everything default in it, don’t make changes. When you complete the display settings setup by clicking on next. VcXsrv icon will appear in the system tray, and, the Application will keep running in the background.
   
   

3. Start Ubuntu in your WIN10,

jason990420@DESKTOP-ST6UJK4:~$ python3 hello.py
Traceback (most recent call last):
  File "hello.py", line 7, in <module>
    sg.Window(title="Hello World", layout=[[]], margins=(100, 50)).read(close=True)
  File "/home/jason990420/.local/lib/python3.8/site-packages/PySimpleGUI/PySimpleGUI.py", line 8753, in read
    results = self._read(timeout=timeout, timeout_key=timeout_key)
  File "/home/jason990420/.local/lib/python3.8/site-packages/PySimpleGUI/PySimpleGUI.py", line 8819, in _read
    self._Show()
  File "/home/jason990420/.local/lib/python3.8/site-packages/PySimpleGUI/PySimpleGUI.py", line 8578, in _Show
    StartupTK(self)
  File "/home/jason990420/.local/lib/python3.8/site-packages/PySimpleGUI/PySimpleGUI.py", line 14746, in StartupTK
    Window.hidden_master_root = tk.Tk()
  File "/usr/lib/python3.8/tkinter/__init__.py", line 2270, in __init__
    self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)
_tkinter.TclError: no display name and no $DISPLAY environment variable
jason990420@DESKTOP-ST6UJK4:~$ export DISPLAY=localhost:0.0
jason990420@DESKTOP-ST6UJK4:~$ python3 hello.py

# hello.py
import PySimpleGUI as sg

sg.Window(title="Hello World", layout=[[]], margins=(100, 50)).read(close=True)

[tomplatner]

OK , I am a newbie but I Using PyCharm in Windows 11 and SSH to Raspberry Pi and I was getting the above error...this code suggested by Jason above did the trick for me.. specifically I added this code to the very beginning of my code:
import os
import PySimpleGUI as sg

if os.environ.get('DISPLAY','') == '':
os.environ.setitem('DISPLAY', ':0.0')

sg.Window(title="Hello World", layout=[[]], margins=(100, 50)).read(close=True)