I just read John Gruber’s genius take on the rumours of a 4-inch 16:9 iPhone screen, and I agree that this solution makes the most sense for Apple. If they plan on increasing the size of the iPhone screen, they need to do so in a way that requires little to no work for developers to adapt their applications, while retaining the Retina display quality of 326ppi and keeping the iPhone small.
A 4-inch 16:9 iPhone screen accomplishes all of these things.
1) Developers need only update their apps to auto-adjust to a taller screen. Most apps like Facebook and Twitter can accomplish this by showing more information between the top and bottom navigation bars. Game developers can choose to stretch their apps to the new 16:9 resolution, or simply have their game letterboxed, meaning it will look and play exactly as it does on the current 3.5” iPhone screen.
2) The quality of the Retina display won’t be affected by the added 176 pixels in height. While Apple could simply stretch the display to 4-inches, increasing height and width, this would sacrifice the pixel density of the Retina display, something Apple will not do.
3) As Gruber points out:
If Apple indeed increases the size of the next iPhone’s display to 4 inches, I do not expect them to increase the physical size of the device itself. There is plenty of room on the current iPhone for the rumored 4-inch display — just shrink the non-display areas on the front face.
A taller display at 4-inches should fit on a device the same physical size as the current iPhone 4S. This means Apple can keep the iPhone small and thin, while giving users a larger screen.
Win, win, win. If Apple is going to increase the size of the iPhone screen this year, this is how they’re going to do it.