Systems and methods for controlling a display screen of a portable computing device

A system and method for controlling how images are displayed on a display screen of a portable computing device changes the orientation of the images on the display screen when the orientation of the portable computing device changes. The portable computing device is determined to have changed its orientation when it tilts beyond a reference angle that separates a first orientation from a second orientation. If the portable computing device is rapidly tilting back and forth across the reference angle, the value of the reference angle is changed to be either larger or smaller. This prevents the images from rapidly switching back and forth between two different display orientations on a display screen of the portable computing device.