Gesture-enhanced single-touch
Encyclopedia
Gesture-Enhanced Single-Touch, also known as "Dual Control", "Gesture Touch" and often "Dual-Touch" describes the ability of a touchscreen
to register certain two-finger gestures
, even though the display hardware does not have full Dual-Touch capabilities. A very common application is the pinch-to-zoom gesture, which allows the user to zoom in or out by moving two fingers farther apart or closer together while touching the display.
is the type of sensor hardware in the display. Many touchscreen technologies obtain two independent measurements per touch to acquire a 2-Dimensional position. Given two distinct touches, however, this returns two pairs of measurements, which can be combined in two ways, producing an ambiguous result. Thus, it is not possible to exactly determine the position of two distinct touches. Still, the average position can be approximated, as well as the distance between the touches, which suffices for some gesture applications.
Touchscreen
A touchscreen is an electronic visual display that can detect the presence and location of a touch within the display area. The term generally refers to touching the display of the device with a finger or hand. Touchscreens can also sense other passive objects, such as a stylus...
to register certain two-finger gestures
Gesture recognition
Gesture recognition is a topic in computer science and language technology with the goal of interpreting human gestures via mathematical algorithms. Gestures can originate from any bodily motion or state but commonly originate from the face or hand. Current focuses in the field include emotion...
, even though the display hardware does not have full Dual-Touch capabilities. A very common application is the pinch-to-zoom gesture, which allows the user to zoom in or out by moving two fingers farther apart or closer together while touching the display.
Technical Background
An important technical reason for the limitation to Gesture-Enhanced Single-Touch instead of allowing Dual- or Multi-TouchMulti-touch
In computing, multi-touch refers to a touch sensing surface's ability to recognize the presence of two or more points of contact with the surface...
is the type of sensor hardware in the display. Many touchscreen technologies obtain two independent measurements per touch to acquire a 2-Dimensional position. Given two distinct touches, however, this returns two pairs of measurements, which can be combined in two ways, producing an ambiguous result. Thus, it is not possible to exactly determine the position of two distinct touches. Still, the average position can be approximated, as well as the distance between the touches, which suffices for some gesture applications.