Core Image vs Core Graphics

Question

I am making an application that uses basic core Graphics functions . The Application runs reasonably well on Ipad2, but there is a performance hit on Ipad3 due to retina display, which causes drawing to be done on number of pixels 4 times to the earlier. I tried some hacks to improve performance, but since drawing takes place on gestures in my code, I think I will have to switch on to some other alternative. I was wanting to ask if Core Image provides all the functionalities that can be performed using Core Graphics, so that I may use GPU Processing capability. If not, what could be the best alternative so that I can use the same functionalities with a better processing capability.

Answer 1

Core Image and Core Graphics are very different. Core Image is an image processing technology. You can apply pre-made filters like sepia, black and white, and color invert, or you can create custom filters. Core Graphics is a rendering API utilizing Quartz 2D technologies that allows for complex drawing.

Brad Larson's GPUImage is a great alternative/addition to Core Image. You can find it here.

If you want improved performance, you can try a low level API like OpenGL. It's difficult to learn, but here are a few links to get you started:

• iPhone OpenGL ES – 8 Great Resources For Learning - From ManiacDev, self-explanatory
• OpenGL ES Programming Guide for iOS - Apple's own documentation, thorough, a good start
• iOS based OpenGL ES programming - Some more resources for getting started
• OpenGL ES 2.0 for iPhone Tutorial - Good Ray Wenderlich introduction
• Pro OpenGL ES for iOS - Great Apress book but not for beginners