UIView “suck” animation

Question

I'd like to use the UIView "sucking" transition (view is "sucked" into a point) referenced here:

http://iphonedevwiki.net/index.php/UIViewAnimationState#Using_suckEffect

The method above, however, uses private APIs, which makes it next to useless for an App Store app. How can I recreate a similar effect without relying on private APIs? I'm guessing the answer has to do with OpenGL, although I have zero experience there.

Answer 1

have you checkked out the cocos2d framework. it's an objective c wrapper for openGL and it's done really well. you can check out their demo video which shows all the transition types that the library supports.

Answer 2

Please have a look at my project at git://github.com/rmd6502/Genie.git - it's very slow right now, but improvements are forthcoming.

Answer 3

As long as Apple doesn't publicly document the effect, and you want to avoid the risk of being rejected for using private API's you'll have to roll your own.

A suggestion to start working on this would be using OpenGL ES shaders.

The following blog post includes a demo Quartz Composer patch to create the Genie effect as seen in OS X and iOS: http://www.aderstedtsoftware.com/users/erik/weblog/c7cb9/

A good start for your OpenGL ES shader would be to use the code in the Genie Filter in this QuartzComposer file. The code can almost be copied to a shader for OpenGL as is. The most work would probably be integrating OpenGL in your application: rendering the right view to a OpenGL texture and overlaying OpenGL over your application to perform the animation based on your shader.