Methods and devices provide an efficient user interface for providing continuous zoom or magnification of a displayed image on a computing device. A user may initiate a zoom-in or zoom-out function by tracing an ellipsoidal shape (e.g., a circle) using a user interface device, such as a touchscreen, touchpad or mouse. The zoom function continues so long as a touchscreen or touchpad are touched, or a mouse button is depressed, and an ellipsoidal path is traced. Zoom-in or magnification scaling factor may be applied to an image in response to a clockwise path trace and a zoom-out or demagnification scaling factor may be applied to an image in response to a clockwise path trace, or vice versa. A visual aid may be presented on the display that may be followed to conduct the zoom function.