Question

I want to build an animated transition between two view controllers in iOS, resembling the “Box” transition in PowerPoint or the “Reflection” transition in Keynote.

You can see it here, at 2:10:
http://youtu.be/1fLQg5hFQQg?t=2m10s

What’s the best way to do this?

Thanks!

Answer 1

That would be a complex animation to recreate. You’d need to use a CAAnimationGroup that grouped several different animations running at once. You’d want to animate a rotation around the y axis with the center of rotation lifted off the screen, on both the view controller that is animating away and the view that your are animating into place.

You would have to tweak the transform to make it draw with perspective (you add a small value to the .m34 record in the transform). That’s because CA animations are orthographic by default (they don’t show perspective.)

The reflections could be created using a special subclass of CALayer that lets you create duplicates of a layer. I’m blanking on the name of that layer subclass at the moment. You’d set up 1 duplicate with a scale of -1 on the y axis to flip it upside down, and a darkening effect. I’ve never done it myself, but I’ve seen several examples in books and online.