Tapworthy

Chapter 3. Tiny Touchscreen

DESIGNING FOR SIZE AND TOUCH

AT FIRST BLUSH, the iPhone’s tiny size might seem its biggest design challenge. When you’re accustomed to creating websites or desktop software for monitors at least a foot across, 3.5 inches is mighty stingy. Yet while designing with a limited supply of pixels is a demanding part of the job, leaving it at that would suggest that your role is only to create efficient screens. The challenge turns out to be more subtle than that, because the iPhone isn’t just small: it’s handheld and works by touch. That means you’re doing something more sophisticated than organizing pixels.

You’re designing a physical interface that will be explored by human hands, directly manipulated in a way that desktop software never is. Of course, there’s nothing literally physical about your app. Your interface is just a virtual representation drawn by so many flickering liquid crystals. But the way it’s used is physical. Unlike phones or desktop computers, the iPhone has practically no physical interface of its own—no keyboard or mouse, just the single Home button. The device is a blank slate, a palm-sized slab of glass onto which you, the app designer, impose whatever interface you might dream up. You define the physical experience of the device. Your app’s buttons may be virtual, but they nevertheless require direct touch and define the device in a very physical way.

Figure 3-1. Photo: Oscar Alonso

This means your project is not only a challenge of visual ...