Our iOS App orientation is landscape (also set up in the plist), but JUCE initially sets up the portrait orientation and then quickly after start up changes to landscape (within the first second or so). It is quite noticeable and in earlier versions of JUCE I could fix this calling this function in our Application constructor.
From what I can tell iOS sends a callback that tells JUCE the orientation has changed after the app has started and the window is displayed. It looks like the following function is responsible for changing the orientation after the iOS callback.
However in the UIViewComponentPeer constructor the window the window’s transform is initially set to the identity.
I tried to patch it myself, but I was only able to make it switch rotations faster and not set it correctly from the beginning.
This issue can also be reproduced in the iOS Simulator.