Yes I know. My hope is to make a xcode plugin for xojo iOS from the iV4CC (iv4cc_8_mac.dmg) client library for the Valentina Server. And thereby skip using REST databases.
But I don't know if that's possible.
You can print pre-existing printable content by setting either the printItem or printItems property of UIPrintInteractionController. Images and PDFs can be given either as image data (in a NSData, UIImage, or ALAsset instance) or via any NSURL referencing something that can be loaded into an NSData object.