One of the lesser noticed changes in the iOS 7 beta 3 is the ability to use Retina assets in iPhone-only apps to improve the experience in “2x” mode on non-Retina iPads.
Since the launch of the iPad, Apple has supported the use of iPhone-only apps on its tablet platform, allowing users to toggle between a “1x” mode where the app appears in an iPhone-sized window in the center of the iPad screen and a “2x” mode where pixels are doubled to allow the app to fill more of the iPad’s screen. But up until iOS 6, this 2x pixel doubling has been performed on the non-Retina iPhone versions of the apps for non-Retina iPads, expanding a 480×320 app to fill a 960×640 space on the iPad display and resulting in jagged text and blurry images.
The advent of the Retina display on the iPhone which supports apps at 960×640 has allowed Apple to take advantage of the higher-quality assets in the apps to improve the viewing experience of iPhone-only apps on the iPad. Since the introduction of the first iPad with Retina display, Apple’s Retina iPads have been able to tap into the Retina assets in iPhone apps to improve the display with 2x app viewing. Now, the iOS 7 beta 3 allows non-Retina iPads to do the same.
In the iOS 7 beta, users are no longer even presented with a 1x/2x toggle switch on non-Retina devices, as iPhone apps are merely presented as a 960×640 app on the iPad’s 1024×768 screen. Retina capable iPads, however, still continue to offer the 1x/2x toggle switch.