Rumours continued to strengthen this week that Apple are having 4″ (~10cm) screens manufactured for a new generation of iPhone. Current iPhone displays measure 3.5″ (~9cm) across the diagonal. Apple and rumours go together like salt and pepper of course (and many of them can be taken with a pinch of the former) but reports from a respected news agency like Reuters add significant credance to the prospect of a new iPhone design later this year.
Where rumours are less clear is on the question of the aspect ratio of a larger screen. While some sources expect the aspect ratio to remain at 2:3, there is also speculation that the increase in size would be in the longer dimension only.
If this is true, and I should stress it is no more than a rumour about a rumour, what would this mean to us as developers?
At the moment I see three levels of complexity in terms of creating user interfaces for iOS devices:
The user interface for the iPhone and iPod touch is the simplest because the screen size, as far as developers are concerned, is fixed at 320×480 pixels and there is only ever one view visible at any given time. Although retina displays on the iPhone 4 and 4S are physically 640×960 pixels, we create layouts based on the 320×480 resolution of the iPhone 3 and the device uses the finer resolution to improve font smoothing and image quality.
User interfaces for the iPad are slightly more complex because of iPad specific controls like the split-view (as used in the standard iPad Mail app), popovers and alternate sizes for modal views. As with the transition from iPhone 3 to 4, the retina display on the new iPad is still 768×1024 from a developer perspective, despite the physical resolution of 1536×2048.
Universal applications, designed to run on iPhone, iPod touch and iPad from the same code-base, are the most complex applications to write because they usually involve maintaining two user interface layouts. They may also need to take into account different quirks of widget presentation on the device: Picking photos from the photo library is one example–where the iPad uses a popover and the iPhone and iPod touch use a modal view.
A completely new ”mini” iPad would probably use the 768×1024 resolution that we are used to, but if we throw a 4″ (~10cm) iPhone into the mix with a modified aspect ratio, we may have to consider a layout resolution somewhere in the region of 320×576 in addition to the existing standard of 320×480.
Mockups indicate that this increase on the portrait vertical dimension would be sufficient to add another row of icons on the home screen. That would certainly create a headache with apps that have view layouts using fixed-size components. Universal applications with three storyboards anyone? As developers we would need to pay a lot more attention to scrolling layouts and adjusting the dimensions of controls in our applications. Personally I don’t think it will happen — the App Store has been a huge success and I think Apple will be reticent to make application development more difficult by adding additional variants to a tried and tested formula.
I was teaching Learning Tree’s Building iPhone® and iPad® Applications: Extended Features course in London last week and we had an interesting discussion at the start of class on day four about these rumours, how likely they are to come to fruition, and what they might mean to us.
One of my students speculated that Apple could use the extra height to move a tab bar to the left side of a landscape layout on iPhone, a bit like moving the Mac OS dock to the left side of the screen. I think this is a great idea, even without extra screen height. I encouraged him to raise it as an enhancement suggestion with Apple and you never know–maybe we’ll see this appear in an upcoming version of iOS!