Screen Estate: When apple announced the iPhone 4 with its 960 x 640 ‘retina’ display, my initial thought was why didn’t they launch the iPad and iPhone 4 with a matched resolution, but on reflection they have done something fundamentally different on each. It’s way better for it.
The iPhone 4 doen’t have a larger screen than previous iPhone, it’s identical in size, it’s just got a higher DPI. Ignore the resolution for a minute. The thing is were used to the computing metaphor of packing in more assets when theres a higher resolution, so a 1024x480 screen will show more than a 800x600 screen, you’ll get more menu items on screen, more of an article etc.
But with the iPhone you’ll get exactly the same, just better quality. That’s important for usability, the finger is still the chubster inaccurate digit its always been, and it needs a physical space to select items. On big problem i had with the nokia N900 was it was tying to be a desktop 800x480 display, showing full websites, rather than the mobile version. It was largely unusable because all the ‘hit areas’ were too small to accurately hit without using a stylus. The iPhone SDK will just work as it did before but with a better quality to all text / UIKit elements.
The iPad has only a slightly higher resolution 1024x768 (how old skool \m/ ) most web sites are built with this size in mind. but importantly the screen is much larger. This allows more hit space on the screen. Also iPad introduces a new Interface method, single view in portrait, menu/view in landscape. This split view isn’t valid on the iPhone as theres not enough space for the elements to remain usable.
The only people that will have to start reworking are games devs, who bypass standard UI kit elements. 3D games may need to up texture qualities/model complexity, but should ‘get away with it’. 2D graphics will not look too bad when sized by exactly 2x, but the issue for developers is to probably use two sets of graphics, one for iPhone 3GS and lower, one for iPhone 4/iPad. And two screen ratios, two screen physical sizes, though alot of game may not need much adapation, other than for interface overlays which will have to be larger on iPad than iPhone etc.
There are performance issues with pushing 4 times the pixels, but the beefed up hardware should cope.
So even though the resolutions may be similar, making apps for iPhone and iPad will still have to be different, as its the screen size not the resolution that effects the usability.