It is a very nice feature to change the viewed file orientation by turning the device, but sometimes it should be able to turn off, or the app should be able to change the file orientation.
sometimes the image (or the created pdf) has made by wrong orientation information, and it requires 90 or 180 degree rotate. currently it seems there is no rotation option, and there is no possibility to lock the screen.
this means I can not read the file yet.
All in all, the app is great and worth the price