Redo LibreOffice support using UNO

[benzea]

The current LibreOffice support is not very nice for a couple of reasons:

• it requires parsing both ODT and PDF files. Because of this:
  • prone to break if PDF export changes
  • no support for right to left languages
  • no support for multicolumn layouts
• Style based system is hard to use

The idea is to move over to use python-uno (either as a macro, or launching libreoffice externally). Using a macro would have the advantage that one might be able to extend the LibreOffice UI to simplify questionnaire creation.

[benzea]

After some trail and error, which did not work out ...

It appears that the API required to do this might not even be available. So, instead we might need to retrieve the information from an XML layout dump. This might work by exporting twice (embedding metainformation in hidden text) and then retrieving first metadata, and later layout information from the XML files.

We might be able to embed all the metadata using hidden text to begin with. That way we don't need styles at all. Though I do not know how to nicely switch between having the text visible/hidden and such.

[reviczky]

https://github.com/mstamy2/PyPDF2

• Support for Python 3

That should do it!

[reviczky]

https://github.com/MrLeeh/pdftools

[benzea]

Quite likely, I am going to drop support for ODT for SDAPS 2.x for a start. Don't want this to become a roadblock in the whole project, and moving to Python 3 would make sense at the same time.

[benzea]

Support has been removed now.