1. Field
This disclosure relates generally to a touchscreen and, more specifically to techniques for controlling operation of a device with a virtual touchscreen.
2. Related Art
Traditionally, a touchscreen has been a display that is configured to detect a presence and location of a touch (or near touch) input to an area of the touchscreen. Many touchscreens are configured to sense contact by an instrument, such as a stylus or a finger. Other touchscreens are configured to sense both passive objects (e.g., a finger, a pencil eraser, or a passive stylus) and active objects (e.g., an active stylus such as a digitizer pen) that may not physically contact the touchscreen. Touchscreens may be configured to concurrently sense a single point of contact or multiple points of contact. In general, touchscreens facilitate user interaction with what is displayed directly on the touchscreen, as contrasted with indirect interaction through, for example, a mouse or a touchpad.
Touchscreens are frequently incorporated within devices such as personal digital assistants (PDAs), satellite navigation equipment, point-of-sale systems, kiosk systems, automatic teller machines (ATMs), portable gaming consoles, mobile phones, smart phones, etc. A wide variety of different technologies may be employed in touchscreens. For example, traditional touchscreens may implement resistive, surface acoustic wave (SAW), capacitive, infrared, strain gauge, optical imaging, or dispersive signal technologies, among other technologies, depending on an application. A tablet personal computer (PC) is an example of a mobile computer system that may employ a touchscreen to facilitate user input (via a stylus, digital pen, fingertip, or other instrument) to operate the tablet PC.
A wide variety of systems (e.g., notebook computer systems (notebooks), personal digital assistants (PDAs), laptop computer systems (laptops), and portable media players) have implemented touchpads. A touchpad is a pointing device that can translate motion and position of a finger of a user to a relative position on a display screen. When implemented in a notebook, touchpads have usually been incorporated on a surface of the notebook, adjacent a keypad. Touchpads (and associated buttons) are frequently provided as a substitute for a mouse. Touchpads vary in size but are normally smaller than three square inches. Touchpads are relative motion devices, similar to a mouse, with a cursor on a display screen moving in a same direction as a finger moving across a surface of the touchpad. In a typical touchpad implementation, buttons adjacent (e.g., below or above) the touchpad serve as standard mouse buttons.
Depending on the touchpad and associated driver, a tap of a finger on the touchpad may correspond to a mouse click. Touchpad drivers may enable the use of multiple fingers to facilitate other mouse buttons (e.g., two-finger tapping for a center mouse button). Some touchpads also implement hotspots (i.e., locations on the touchpad that indicate user intentions other than pointing). For example, on certain touchpads, moving a finger along an edge of the touchpad initiates a scroll wheel for scrolling an in-focus window vertically or horizontally, depending on which edge of the touchpad is stroked. Certain touchpad drivers also allow for tap zones (i.e., regions in which a tap executes a function). In this case, tapping in a tap zone may, for example, pause a media player or launch an application.