iPhone “slide to unlock” animation

Question

Any ideas as to how Apple implemented the \"slide to unlock\" (also, \"slide to power off\" is another identical example) animation?

I thought about some sort of ani

Answer 1

First, a HUGE thank you to marcio for his solution. This worked almost perfectly, saved me hours of effort, and made a huge splash in my app. My boss loved it. I owe you beer. Or several.

One small correction for iPhone 4 only. I mean the hardware itself, not just iOS 4. They changed the system font on the iPhone 4 from Helvetica (iPhone 3Gs and below) to Helvetic Neue. This caused the translation you're doing from character to glyphs to be off by exactly 4 spots. For example the string "fg" would appear as "bc". I fixed this by explicitly setting the font to "Helvetica" rather than using "systemFontofSize". Now it works like a charm.

Again...THANK YOU!