Tessdata prefix is hardcoded in the app (Linux)

[LFd3v]

Hey, there.

First of all, thank you for creating and maintaining the (free and OSS) app! I forgot to thank you in the previous issue I opened, sorry.

This is more like a heads up, not exactly a bug: it seems that the app looks for Tesseract .trainedata files only in the Ubuntu (Debian too, probably?) default location: /usr/share/tesseract-ocr/5/tessdata, both the AppImage and the AUR file, that is based on the .deb package, cannot file the files in the default installation on ArchLinux, that is simply /usr/share/tessdata.

The good news is that it honors TESSDATA_PREFIX environment variable, so launching the app while setting TESSDATA_PREFIX=/usr/share/tessdata actually works.

So I thought I would just add an issue here to help other users, and maybe this can be added to the documentation, although I did not find a good place where it could be added.

Thanks again. Regards

[LFd3v]

The fix should check TESSDATA_PREFIX at startup (which Tesseract itself respects), and fall back to a bundled path only when the env var is not set and the system path does not exist.

This sounds good to me, some maybe a two step implementation:

1. Fox the hard-coded path using the logic above
2. Add an env variable for customization