two pages on one screen

[JumboSK]

Please can you add support for like fold devices / 2 screens devices?

I had Microsoft surface duo with 2 screens (something like fold device) and i want to use it as book, like 2 pages on screen bacouse when its open i have big screen.
I try gallery mode but its not on whole screen

[RobbWatershed]

Duplicate of #623