Will OpenGL give me any FPS improvement over CoreAnimation for scrolling a large image?

Question

Hi, I'm considering re-writing the menu system of my iPhone app to use Open GL just to improve the smoothness of scrolling a big image (480x1900px) across the screen.

I'm looking at doing this as a way to improve on using the method/solution as described here (http://stackoverflow.com/questions/1443140/smoother-uiview). This solution was a big improvement over the previous implementation but it's still not perfect and as this is the first thing the user will see I'd like it to be as flawless as possible.

Will switching to OpenGL give me the sort of smooth scrolling I'm looking for? I've stayed clear of OpenGL until now as this is my first app and core animation has handled everything else I've thrown at it well enough, would be good to know if this alternative implementation is likely to work! thanks

Answer 1

You should be using CATiledLayer for images that big. From the UIView docs:

Regardless of which version of iPhone OS is running, you should consider using a CATiledLayer object if you need to create views larger than 1024 x 1024 in size.

Bill Dudney posted the CATiledLayer example from his Core Animation book on his blog. Unless you're building a graphics intensive game, you shouldn't need to drop down into OpenGL. Core Animation should give you all of the performance you need.