XGetImage() failed when using mss

General information:

• OS name: _Debian GNU/Linux_Ubuntu
• OS version: 18.10
• OS architecture: 64 bits
• Resolutions:
  • Monitor 1: 1920x1080
  • Monitor 2: 1920x1080
• Python version: 3.7.1
• MSS version: 4.0.2

For GNU/Linux users:

• Display server protocol and version, if known: X server wayland
• Desktop Environment: Unity
• Composite Window Manager name and version: [not sure, it’s gonna be whatever ubuntu 18.10 uses by default - I haven’t configured any of this stuff]

Description of the warning/error

When I use any screen capture command (grab(), shot()), I get an error that XGetImage failed. code: pipenv install mss

and in file process.py, I have taken some code straight the examples in documentation:

import mss
with mss.mss() as sct:
    try:
        filename = sct.shot(mon=-1, output='fullscreen.png')
        print(filename)
    except Exception as e:
        print(e, "\n", e.details)

The above code outputs this:

XGetImage() failed
 {'retval': <mss.linux.LP_XImage object at 0x7fc72d567bf8>, 'args': (<mss.linux.LP_Display object at 0x7fc72db7d1e0>, <mss.linux.LP_Display object at 0x7fc72d567950>, 0, 0, 1920, 1080, 16777215, 2)}

And the stracktrace looks like this:

Traceback (most recent call last):
  File "process.py", line 3, in <module>
    filename = sct.shot(mon=-1, output='fullscreen.png')
  File "/home/f41lurizer/.local/share/virtualenvs/poker-TAtsjijf/lib/python3.7/site-packages/mss/base.py", line 140, in shot
    return next(self.save(**kwargs))
  File "/home/f41lurizer/.local/share/virtualenvs/poker-TAtsjijf/lib/python3.7/site-packages/mss/base.py", line 129, in save
    sct = self.grab(monitor)
  File "/home/f41lurizer/.local/share/virtualenvs/poker-TAtsjijf/lib/python3.7/site-packages/mss/linux.py", line 430, in grab
    ZPIXMAP,
  File "/home/f41lurizer/.local/share/virtualenvs/poker-TAtsjijf/lib/python3.7/site-packages/mss/linux.py", line 171, in validate
    raise ScreenShotError(err, details=details)
mss.exception.ScreenShotError: XGetImage() failed

Other details

I have also tried running as root, and running outside of tmux. Neither of these things changed the error I’m getting. I wonder if this has something to do with using wayland? On pyscreenshot, they seem to have limited support for screenshots on wayland.

[nubonics]

Another way to reproduce this error is to use another display besides :1 in linux suchas export DISPLAY=:2 (with a vncserver running on this display)

CORRECTION: giving the size of a window larger than the vncserver has set as its geometry will result in this error, however, works fine when you specify the correct geometry 😄

[pertinency]

Another way to reproduce this error is to use another display besides :1 in linux suchas export DISPLAY=:2 (with a vncserver running on this display)

CORRECTION: giving the size of a window larger than the vncserver has set as its geometry will result in this error, however, works fine when you specify the correct geometry 😄

I just have solve this issue with this reply. I’m using vnc server and I don’t know why resolution of my display is set by 1900x1200 rather than 1920x1080. The way how I found my resolution of display is followed by this method. After that, sct.grab({"top": 0, "left": 0, "width": 1900, "height": 1200}) has works correctly to me.

Thanks a lot!!