Originally Posted by Paul Moews
I don't completely understand the size buttons effect
on PDF files. The page switches between fit "visible" and fit
"width" . It doesn't seem to have anything to do with margins -
An option in Settings allows one to make landscape the default
viewing mode; in landscape the page is about 5 x 7 inches and shown
in 2 halves.
If you hold the size button down for 5 sec, it'll swap into landscape without going through the settings; works for non-PDFs too.