GoKawiilApple exposes iPhone Duo hinge-angle API to developers, Federighi says
Craig Federighi told Donald Decodes that Apple has built an API letting developers read the iPhone Duo's hinge angle to within about five degrees, as well as detect the device's overall 'pose,' such as book, table or tent positions. He also described the outer screen's translucent preview effect when opening the device as a deliberate, subtle design choice meant to create continuity between the closed and open states.