Multitouch systems

The word multitouch refers to the ability to distinguish between two or more fingers touching a touch-sensing surface, such as a touch screen or a touch pad. Typical multitouch devices include tablets, mobile phones, pads, and even powerwalls with images projected from their back.

A single touch is usually done by a finger or a pen (stylus). The touch sensor will detect its X/Y coordinates and generate a touch point for user-level applications to use. If the device simultaneously detects and resolves multiple touches, user applications can thus efficiently recognize and handle complex inputs.

Gestures also play an important role in multitouch systems. A gesture is considered as a standardized motion, which can be used distinctly to represent a certain purpose. For example, the "tap" gesture (hit the surface lightly and release) always means to select and start a program on mobile phones, and the "zoom" gesture (move two fingers towards or apart from each other), or sometimes...