Quote Originally Posted by dflat View Post
You might be referring to these or similar:
iOS - forScore or Unrealbook or iGigbook
Android - MobileSheets
(PC - MobileSheets)

Designed for musicians, they display PDFs (and other formats, depending on the app) and can be used in the foreground (iReal Pro playing in the background). You can use them for notation, lyrics, exported charts from iReal Pro, etc. You add metadata to each song (like composer, key, style, band name) then sort, organise, categorise, make set lists, search ... and make annotations with stylus, finger or on recent models of iPad, use Apple pencil.

https://forscore.co
http://www.diystompboxes.com/unrealbook/
http://www.zubersoft.com/mobilesheets/
Thanks, I've been checking these out and also found an (Android only) app called 'Fakebook Pro'. If Ireal Pro was to incorporate the best features of that app (Photo and PDF import into indexed locations and annotations)it would blast those other apps out of the water.