Three-dimensional object tracking to augment display area

In some examples, a surface, such as a desktop, in front or around a portable electronic device may be used as a relatively large surface for interacting with the portable electronic device, which typically has a small display screen. A user may write or draw on the surface using any object such as a finger, pen, or stylus. The surface may also be used to simulate a partial or full size keyboard. The use of a camera to sense the three-dimensional (3D) location or motion of the object may enable use of above-the-surface gestures, entry of directionality, and capture of real objects into a document being processed or stored by the electronic device. One or more objects may be used to manipulate elements displayed by the portable electronic device.