Slide to unlock: an iPhone dance in three acts
When you unlock the iPhone, a subtle three-act choreography plays out in under three-quarters of a second, an example of the remarkable new Core Animation and playful spirit powering the device.
Prelude
Apple hasn’t said so yet, but your iPhone will probably auto-lock after a while to display your desktop picture with the date and time, then eventually fade to black to conserve battery power if at rest. When you nudge or move the iPhone, your desktop picture and date and time will reappear, along with the shimmering words, “slide to unlock”.
Slide that lock to begin the choreography.
If you want to follow along at full-size, watch Apple’s iPhone ad online. When the movie starts playing, pause it, rewind to the beginning, then move frame-by-frame using the left and right arrow keys on your keyboard.
Act One
1. The words “slide to unlock” disappear, wiped from the screen by the slider.
2. The status bar at the top (where the Mac’s menubar lives) switches immediately to a black background, the tiny lock icon replaced by the current time.
3. Your desktop picture fades out, until the flaming pinks, cobalt blues, or brilliant yellows are gone.
4. The screen is now a neutral tone, with the status bar, date/time, and slider still visible.
Act Two
1. The date/time and slider leave the stage, one rising, the other falling. They accelerate until they disappear altogether.
2. The screen is now completely black, except for the status bar.
3. Now the four-button task bar fades in with the distinctive colors of the iPhone palette.
Act Three
1. The application buttons animate in, chaotically and playfully, like school children lining up after recess. There’s a clear sense of play.
That’s a lot of animation, and all you did was turn the thing on. The animation is fun but not frivolous, and though they pass quickly, each act plays a distinct role:
- Act One unlocks the screen and clears away any wild colors in your custom desktop picture.
- Act Two transitions to your desktop.
- Act Three fills your desktop.
Animation is the rule, not the exception, in the new iPhone user interface. When Apple publishes the iPhone Human Interface Guidelines, it will almost certainly place a strong emphasis on animations like these and others.
Read more about animation in Apple’s Mac OS X.