iOS graphics Introduction: OpenGL ES, Metal, Core Graphics, Core Image, GPUImage, Scene Kit (3D), Sprite Kit (2D), OpenCV
iOS framework related to the graphic image processing all here:
Graphical Interface Framework - UIKit
Core Animation Framework - Core Animation
graphics framework apple package - Core Graphics & Quartz 2D
traditional cross-platform graphical frame - OpenGL ES
graphics framework of Apple's latest push - Metal
suitable picture apples filters framework - Core Image
third-party filters program for video - GPUImage
game engine - Scene Kit (3D) and Sprite Kit (2D)
computer vision applications in iOS - OpenCV for iOS