Apple has had problems with the plastic screens on its iPods, which tend to show scratches, but the iPhone’s screen is made of optical-quality glass. That’s all the more critical because the screen is the interface. Instead of buttons or a keyboard, the iPhone uses a combination of new software and a unique multitouch screen manufactured by the German company Balda. Users tap “soft” buttons directly on the screen and zoom in or out of images or Web pages with two-fingered gestures (zoom out is a pinch, zoom in is a spread). This new control scheme abandons the WiMP (window, icon, menu, pointer) system that has dominated graphical interfaces on computers for decades.
Like Nintendo’s Wii game console (see Hack, July/August 2007), the iPhone uses miniaturized accelerometers that measure its movement. These sensors detect whether the user is holding the iPhone in its “portrait” or “landscape” orientation; the operating system rotates the display accordingly.