Why high resolution screens matter for Apple's iPad 2
Focusing on interface resolution, not screen resolution
At the same time, when Apple introduced the iPad and its 9.7 inch, 1024x768 screen, it did not simply deliver a bigger version of the existing iPhone interface. Instead, it created a distinct user interface that took advantage of its physically larger screen real estate, displaying the iPhone's familiar column view across multiple columns in its Mail and Settings apps, for example.
Apple did allow existing iPhone apps to run unmodified on the iPad, using pixel doubling to fill out most of the iPad's screen. However, while a transitional convenience, iPad users have clearly expressed a preference to seek out apps optimized to take full advantage of its larger display size rather than being content with existing iPhone apps blown up to fill the screen.
With iPad's enhanced user interface optimized to fit its 9.7 inch display, Apple's chief executive Steve Jobs warned that it would be impractical to scale down the iPad experience to fit into the 7 inch displays being favored by competitors, unless those small tablets were also packaged with files to whittle down users' fingers, he quipped.
Just as the Mac desktop's user interface elements shrink toward being invisible at higher pixel densities, the iPad's touch targets would grow unusably small were the display to simply scale down physically at the same pixel resolution.
Samsung's 7 inch Galaxy Tab offers a 1024x600 resolution similar to the iPad's, but introduces problems with trying to scale or stretch existing Android apps to fit that resolution.
While some apps are customized to take advantage of its larger (than a smartphone) screen, web developer Sencha complained that the Galaxy Tab oddly offered a tweener device pixel ratio that effectively made it "slightly bigger than a regular phone screen in CSS pixels, but not really big enough to handle what people want to put in a tablet screen."
More pixels, same interface
While Apple's competitors are planning to roll out devices that offer comparable display features to last year's iPad, ranging from the Motorola Xoom's 10.1 inch screen at 1280x800 to RIM's PlayBook with a 7 inch display and a 1024x600 resolution (similar to the Galaxy Tab), Apple is reportedly planning to double the iPad's resolution, just as it did with iPhone 4.
This would result in a very high 2048x1536 resolution on the next iPad, higher than the company's largest 17 inch MacBook Pro and in the ballpark of its 27 inch, 2560x1440 LED Cinema Display, which the company promotes as "supersize" and "huge," with an "astonishing" resolution.
What could such a high resolution possibly be used to do? Some observers are wondering what the benefit might be, including John Biggs of TechCrunch, who called the idea of such a pixel jump a "pipe dream," while referencing a blog entry by Jack Deneut pointing out that there's simply no video format with content currently available to fill all those pixels.
Deneut drew a diagram showing that DVD video would fill just a corner of the screen at its native resolution, while 720p video (from, say, iTunes) would fill just a quarter of the screen. Even 1080p video, which takes up tremendous gigabytes of storage space, would only fill most of the screen at full resolution. "Most people don't expect pixel-doubling when watching HD video," he wrote.
iPad is not just a video player
In reality, video playback is simply not very demanding in terms of resolution, with consumer televisions having now settled on 720p and 1080p resolutions all the way from 27 inch sets to huge 60 inch and larger televisions. All of these sets also scale standard HDTV resolutions up or down to fit their native display resolutions, typically 1360x768 or 1920x1080.
However, the iPad isn't primarily targeted at playing back video. Unlike most other tablet devices, it wasn't given an HDTV aspect ratio of 1280x720, instead using a 1024x768 resolution more closely suited to general computing applications.
Additionally, anyone with a large monitor is capable of scaling HD video up to play full screen, which is why everything from YouTube to Netflix to QuickTime to Flash Player has a "full screen" playback button, regardless of the size or display resolution of the user's monitor.
Apple's 30" Cinema Display, for example, has a 2560x1600 resolution but has no problem playing back full screen 1080p HD video. It doesn't need native resolution video to make movies look spectacular, and users can't really discern a higher resolution than 1080p (or really, 720p) when watching a screen from a typical viewing distance. Video is clearly not a big reason for needing extremely high resolution displays, and certainly not on a relatively small mobile device like iPad.
On page 3 of 3: When displays go Retina, Leveraging resolution independence.