Editing Touchpad (section)

== Operation and function ==
Touchpads operate in several ways, including [[capacitive sensing]] or [[resistive touchscreen]]. The most common technology used in the 2010s senses the change of [[capacitance]] where a finger touches the pad. Capacitance-based touchpads will not sense the tip of a pencil or other similar ungrounded or non-conducting implements. Fingers insulated by a glove may also be problematic, and capacitive touchpads are rarely used as pointing devices for medical hardware.<ref>{{Cite web|title=VersaPad Plus resistive touchpads target medical, rugged environments|url=https://www.microcontrollertips.com/versapad-plus-resistive-touchpad-touchpads-medical-rugged-environments/|access-date=2021-07-06|website=www.microcontrollertips.com}}</ref>

Like [[touchscreen|touchscreens]], touchpads sense absolute position but their resolution is limited by their size. For common use as a pointer device, the dragging motion of a finger is translated into a finer, relative motion of the cursor on the output to the display on the operating system, analogous to the handling of a [[mouse (computing)|mouse]] that is lifted and put back on a surface. Hardware buttons equivalent to a standard mouse's left and right buttons are sometimes positioned adjacent to the touchpad.

Some touchpads and associated [[device driver]] software may interpret tapping the pad as a [[mouse click]], and a tap followed by a continuous pointing motion (a "click-and-a-half") can indicate dragging.<ref name="MacBook">{{cite web |title=Tap and drag | url=http://movies.apple.com/movies/us/apple/mac/macbookair/2008/apple_macbookair_clickdrag_20080115_r320-13cie.mov| publisher=Apple.com}}</ref> Tactile touchpads allow for clicking and dragging by incorporating button functionality into the surface of the touchpad itself.<ref name="The Tactile Touchpad">{{cite web|url=http://www.sigchi.org/chi97/proceedings/short-talk/sm.htm|title=The Tactile Touchpad|publisher=sigchi.com|access-date=2011-03-21|archive-date=2011-10-01|archive-url=https://web.archive.org/web/20111001071602/http://www.sigchi.org/chi97/proceedings/short-talk/sm.htm|url-status=dead}}</ref><ref name="yorku.ca">{{cite web |url=http://www.yorku.ca/mack/p336-mackenzie.pdf|title=A Comparison of Three Selection Techniques for Touchpads| publisher=yorku.ca}}</ref> To select, one presses down on the touchpad instead of a physical button. To drag, instead of performing the "click-and-a-half" technique, the user presses down while on the object, drags without releasing pressure, and lets go when done. Touchpad drivers can also allow the use of multiple fingers to emulate the other mouse buttons (commonly two-finger tapping for right click).

Touchpads are called clickpads if they rely on software buttons rather than physical buttons. Physically the whole clickpad formed a button, logically the driver interprets a click as a left or right button click depending on the placement of fingers.<ref>{{Cite web |title=Libinput features: Clickpad software button behavior |url=https://wayland.freedesktop.org/libinput/doc/latest/clickpad-softbuttons.html |publisher=wayland.freedesktop.org}}</ref>

Some touchpads have "hotspots", locations on the touchpad used for functionality beyond a mouse. For example, on certain touchpads, moving the finger along an edge of the touch pad will act as a [[scroll wheel]], controlling the [[scrollbar]] and scrolling the [[Window (computing)|window]] that has the [[Focus (computing)|focus]], vertically or horizontally. Many touchpads use two-finger dragging for [[Scrolling TrackPad|scrolling]]. Also, some touchpad drivers support tap zones, regions where a tap will execute a function, for example, pausing a media player or launching an [[Application software|application]]. All of these functions are implemented in the touchpad [[device driver]] software, and can be disabled.