iPhone how to get Magnified effect on certain part of the screen?

Question

Hi all,

The images above are taken from the "Nike Boom" App. I am wondering how to do a magnified effect on the number list as shown in the images. I also want to point out that it is very very smooth animation, so screen capturing certain part of a screen and projected it back on UIView may not work (I tried that)

Thankz in advance, Pondd

Update: Hey,

Just so for anyone who might comes across this topic, I've made a simple sample based on Nielsbot's suggestion and posted up on github here

Please feel free to fork it, improve it and pass it on :)

Best,

Pondd

Answer 1

It's done with 2 scroll views, one in front of the other. One scroll view (A) contains the small numbers. The second scroll view (B) contains the zoomed numbers. The frame of (B) is the transparent window. When you scroll (A), you scroll (B) programmatically, but you move it farther than (A). (I.e. if (A) scrolls 10 pixels, you might scroll (B) 20 pixels.)

Make sense?

If you've ever used Convert.app from TapTapTap they use a similar effect.