multitouch

Multitouch refers to input on a touch‑sensitive surface that can register multiple simultaneous touch points. It enables gestures such as pinch‑to‑zoom, rotate, two‑finger scrolling, and multi‑finger dragging, providing a more natural and efficient way to interact with digital interfaces. Multitouch can be implemented with several technologies, most commonly capacitive sensing, including projected-capacitive and self-capacitance sensors. Capacitive sensors detect changes in electromagnetic fields caused by finger contacts on a grid of electrodes. Other approaches include resistive touch, infrared‑based touch frames, and optical multi‑touch systems that use cameras and light patterns to determine touch positions. Many modern devices combine hardware with software gesture recognition to identify and interpret input from multiple points in real time.

The concept emerged from human–computer interaction research in the 1980s and 1990s and was popularized by consumer devices in the 2000s, especially after being adopted by smartphones and tablets such as the iPhone in 2007. In common designs, a multitouch system tracks each contact point across successive frames and assigns a unique identifier to maintain the touch as it moves; the operating system can then interpret combinations of touches as gestures.

Applications include touchscreens on smartphones and tablets, multi‑touch touchpads on laptops, interactive kiosks, musical instruments, and game interfaces. Advantages include more natural input and support for simultaneous commands; limitations involve hardware cost, difficulty distinguishing intentional touches from accidental ones, palm rejection challenges, calibration needs, and reduced sensitivity in wet or dirty conditions.

Related topics include capacitive touch, resistive touch, gesture recognition, and touchpads.