Question

I’m creating an interactive e-book for the iPad. This book will contain multiple pages that will consist of a lot of animations (frame and motion animations), transitions,… I was wondering what my development options are, should I use OpenGL, Quartz,…?

I’ve use UIImageView.animationImages before and found that it had really bad performance. What’s the best way to draw frame based animations?

Does anybody have some good pointers to resources on this?

thanks in advance,
Thomas

Answer 1

I guess that depends a bit on what you’ll be drawing. If you have a need for 3D, then OpenGL is the way to go, but it doesn’t sound like it. I have a feeling Quartz2D is going to be just fine for your 2D drawing needs. I’ve done drawing with both and they have a very similar API. I think the downside of using all the raw power of OpenGL is that you have then signed up for doing most of the work yourself. I don’t recommend attempting to using Core Animation high level APIs to manipulate OpenGL views.

If you do use Quartz2D and “normal” UIViews instead of OpenGL/EAGLView, then you can take advantage the many pre-canned animations Apple already build with Core Animation. This include the card flip left/right, resizing, moving (x/y translation), rotation and the ever popular e-book page curl.

The best example of iBook like custom page curl functionality I could find is this example code from High Caffeine Content. However, you don’t have to bring that much math to the table if you just want to use the out of the box Core Animation stuff. The bad performance you may have encountered could have been due to anything, including older/slower hardware. They have revved the graphics chips on the new devices.