Because OS X is built from the ground up to be resolution
independent, all the default iOS interface elements are already
vectorized graphics (PDFs, to be specific). This means that when
iOS scales the elements in physical size to fit the 3.5-inch
iPhone 4 screen, they take up the same amount of space as the
elements drawn on the iPhone 3GS but they use four times the
number of pixels.
In theory, you could create an app specifically for the iPhone 4 that increases the information density of the display by putting more (smaller) elements on screen. But the right way to do it is to design with the same information density, and render all elements with double the resolution.
(Curtis is wrong about PDFs/vector graphics being used for most UI elements. They’re usually highly optimized PNGs. iPhone 4-optimized apps will include double-size versions alongside the originals. But the main point of his piece stands.)
★ Monday, 14 June 2010