Καλησπέρα!
Well, there are lots of pdfs with greek classics around. Viewing PFDs on a 6 inch reader for me needs pre-processing on the PC.
1. The pdfs are modern files that you are able to copy/paste text from. Calibre can convert these to epub, but sometimes headers and footers are a mess. I still prefer to convert the pdf to mobi using the -very old- free software mobipocket creator and then feed the mobi file to calibre for epub conversion. This resulted in most cases correct removal of headers/footers. Nowadays Word opens pdf and also acrobat pro works well to export to doc. If you are lucky enough that header/footers are identified correctly you can simply remove them in word and feed the word file to calibre for conversion to epub.
2. Older pdfs which are essentially photos of pages of old books many times in 2 columns per page. I had a big collection of Greek classics like Kazantzakis etc. in such format. The only solution that made it work was using Papercrop software (see
https://www.mobileread.com/forums/sh...ad.php?t=31677). This is also an old program, but worked rather well. It cropped automatically and put the columns of a page one below the other and also repeated some lines on top and below so that you never missed anything. You then used the ebook readers pdf software.
3. Newly created pdfs even with columns but only text are sometimes well reflowed by the ebook's pdf reader. It's a hit or miss though and depends on each file.
Using the above is ebook reader device agnostic and so long it is calibre compatible you are good to go (practically all).
I haven't read any such pdfs since 2014-2015 so I don't know if there are other solutions available nowadays. For scientific pdfs with figures etc you need minimum 10 inches getting better as you near the real size of an A4 paper so as to have 1:1.