It would be very useful to have a feature that ideally allows to navigate forwards, such that only the the last part previously visible at the bottom is then at the top. That would be the ideal option, very flexible towards zoom. Alternatively having an option to go half a page forwards instead of a full page would already help a lot. This is mostly useful when reading dense multi-page e.g. A4 documents, which don't fit fully on a screen in a readable size. And line scrolling is just very cumbersome. I assume I am on 1.7.2, I didn't find those tags on git, only the KDE ones: I compiled v19.04.2 (debian provided package is ancient).
It's already there. https://docs.kde.org/stable5/en/kdegraphics/okular/configgeneral.html "Page Up/Down overlap Here you can define the percentage of the current viewing area that should be visible after pressing Page Up/Page Down keys. "