Designing Gestural Interfaces

ROTATE TO CHANGE STATE

WHAT

Turning or tilting an object changes either the functionality of the object or the feedback/display of items on that object.

USE WHEN

Use Rotate to Change State on devices that can be used for multiple purposes or to display content that might be better viewed in portrait or landscape view.

WHY

Particularly useful on devices with limited, rectangular screen real estate, Rotate to Change State allows content to be viewed in ways that best display the content, given the screen size.

HOW

Rotate to Change State requires a gyroscope or a multiaxis accelerometer to determine the position of the device. The threshold for the change in state (e.g., 90 degrees, 180 degrees, etc.) needs to be determined.

If the device lays flat (e.g., on a table), accelerometers may not pick up the rotation.

EXAMPLES

Figure 4-16. Nokia's newer N series phones, such as the N95 (pictured), are equipped with accelerometers and can change views from portrait to landscape based on how they are held. Courtesy Nokia.

Figure 4-17. The "Bar of Soap" changes its functionality (from camera to PDA to phone to gaming device) based on how it is held, switching modes when rotated. Courtesy Brandon Thomas Taylor and MIT Media Lab.

Figure 4-18. Canon's PowerShot SD1000 changes its display (to portrait or landscape) based on how the user is holding it. Courtesy Canon.