Hi @JoseyWales ! I just made a thread about this as well and came across yours as I was tagging mine.
I have the Kodi working well with my 8bitdo controller but I am a now looking for a solution for PDFs and CBZ comic books. My thinking is for manuals, guides, tie-in comics for games, even maps!
I have come across a few possibilities concerning Kodi add-ons but they are not likely to be great to use with a game controller on a TV screen so I am looking to see if anyone has done this already. I had requested long ago that we get a wiki-viewer for RetroPie and one was sorted out via lynx/curses/etc but PDFs/epubs/mobi/CBZs will not be renderable in curses/the terminal.
1 - Images in Kodi. Kodi lets you view pictures and you could order each page/sheet into their own folders and view them like that. I need to test the zooming from a controller on a TV screen
2 - Kodi addons for ebooks and PDF files. There are a number of these but I have to test them out as well.
3 - Video conversion - This is a radical idea, but instead of trying to get the PDF/epub/cbz/mobi/etc formats to work properly with zoom and a controller and such, we could instead try to do it by converting these files to VIDEOS! You could then play them in Kodi and have them setup in such a way that they they are zoomed in properly and so forth. They would obviously be pause-able and rather than try and get the RetroPie to conform to what we need, we convert the files to something that the RetroPie would be able to handle better. This is technically the most complicated way but I think it is possible for me to write a script for Mac OS X machines to convert them.