Create "Add languages" button that show instructions how to add

[MurzNN]

At now users see readonly list of available languages, with no ideas how to add new language. In manual there are described ways, but not all users read it. So will be good to create "Add languages" button that show instructions how to add new languages via installing Tesseract packages.

[al-right]

Yup, linking to the local manual file (Linux):

/usr/share/doc/dpscreenocr/manual.html

or the remote one re. paragraph about installing languages would be helpful:
https://github.com/danpla/dpscreenocr/blob/master/doc/manual.md#installing-languages

And in general a link to the manual, locally or online, would be useful and easy to maintain I think.

Thanks for a great program! :)

[danpla]

The version 1.4.0 now has a language manager button. Only on Windows, though, so it's not a final solution to the problem.

[danpla]

The website now provides a self-contained GNU/Linux bundle (in TAR.XZ) that includes a language manager.