What is PurpleEventCallback?
Solution 1:
Project Purple was the codename for iOS back when it was basically a skunkworks project within Apple. This callback is basically just an event bridge between the CoreFoundation layer (ported from OS X) and the UIKit layer (the next-generation Cocoa framework).
- "How Project Purple Turned into the iPhone"
Solution 2:
Just one more piece of information on PurpleEventCallback.
It's part of Graphics Services. In the case, if you disassemble GraphicsServices framework, you will find the source code of this method.