lt_xspec not working due to QApplication error

[klaudhub]

Trying to open 1D spectra (pypeit version 1.15.0 installed via pip) with the lt_xspec command raises the following issue:

File "/home/user/anaconda3/envs/pypeit/bin/lt_xspec", line 8, in <module>
    sys.exit(main())
             ^^^^^^
File "/home/user/anaconda3/envs/pypeit/lib/python3.11/site-packages/linetools/scripts/lt_xspec.py", line 84, in main
    width = app.desktop().screenGeometry().width()
            ^^^^^^^^^^^
AttributeError: 'QApplication' object has no attribute 'desktop'

Since QApplication is drawn from qtpy.QtWidgets, the issue might be solved by rolling back from the qtpy version 2.4.1, but I am not entirely sure. Thanks!

[freddavies]

The solution to the lt_xspec issue seems to be replacing the offending line in linetools/scripts/lt_xspec.py with the new (QT6?) version from pypeit_show_1dspec,

old:
width = app.desktop().screenGeometry().width()
new:
width = app.screens()[0].geometry().width()

Perhaps a small linetools PR?