PTC Inc.
Second touch zoom control

Abstract:

A second touch zoom solution allows maintaining selection control, and movement of a selection point, during zoom operations not possible through traditional pinch-zoom. A first finger touch to a touch screen establishes a hot spot, selection, or one-finger gesture. Before the first finger is lifted from the touch screen, a second finger is placed on the screen and serves as a zoom control. Dragging the second finger away from the first zooms in; toward the first zooms out. Dragging the first finger does not affect the zoom, even if the motion changes the difference between the two fingers. When the second finger is lifted, the zoom level stays where it is. When the first finger is lifted, the zoom returns to the zoom level before the gesture began.