Interesting, in the years the viewer has existed you are the first person to ask, no demand, tap to turn screens. And yet judging by your level of hyperbole, the viewer has no touch controls and is a complete mess. Refrain from that kind of hyperbole in the future if you want people to pay attention to you.
And here you go:
https://github.com/kovidgoyal/calibr...7c0cf5ed287776