Editing Mouse keys

{{Short description|Feature of some graphical user interfaces that uses the keyboard as a pointing device}}
'''Mouse keys''' is a feature of some [[graphical user interface]]s that uses the keyboard (especially [[numeric keypad]]) as a [[pointing device]] (usually replacing a [[Computer mouse|mouse]]). Its roots lie in the earliest days of [[visual editor]]s when line and column navigation was controlled with [[arrow keys]].
Today, mouse keys usually refers to the numeric keypad layout standardized with the introduction of the [[X Window System]] in 1984.<ref>[https://www.xfree86.org/current/XKBproto.pdf The X Keyboard Extension: Protocol Specification]</ref><ref>[https://www.xfree86.org/current/XKBlib.pdf The X Keyboard Extension: Library Specification]</ref>

==Layout==

[[Image:X window system MouseKeys default numpad layout.svg|thumb|left|X window system MouseKeys default numpad layout]]

{| class="wikitable"
|-
! key
! action
|-
! {{Key press|Num Lock}}
| with {{Key press|[[Alt key|Alt]]|[[Shift key|Shift]]}}
enable/disable MouseKeys
|-
! {{Key press|8}}
| cursor up
|-
! {{Key press|2}}
| cursor down
|-
! {{Key press|6}}
| cursor right
|-
! {{Key press|4}}
| cursor left
|-
! {{Key press|7}}
| cursor up and left
|-
! {{Key press|9}}
| cursor up and right
|-
! {{Key press|3}}
| cursor down and right
|-
! {{Key press|1}}
| cursor down and left
|-
! {{Key press|/}}
| [[X Window System core protocol#Mappings|select primary button]]
|-
! {{Key press|*}}
| [[X Window System core protocol#Mappings|select modifier button]]
|-
! {{Key press|-}}
| [[X Window System core protocol#Mappings|select alternate button]]
|-
! {{Key press|5}}
| [[Point and click|click selected button]]
|-
! {{Key press|+}}
| [[Double-click|double click selected button]]
|-
! {{Key press|0}}
| [[Drag and drop|depress selected button]]
|-
! {{Key press|.}}
| [[Drag and drop|release selected button]]
|-
! {{Key press|Enter}}
| [[enter key]]
|}

==History==

Historically, MouseKeys supported GUI programs when many [[Computer terminal#Graphical terminals|terminals]] had no dedicated [[pointing device]]. As pointing devices became ubiquitous, the use of mouse keys narrowed to situations where a pointing device was missing, unusable, or inconvenient. Such situations may arise from the following:
*precision requirements (e.g., [[technical drawing]])
*[[accessibility|disabled user]] or ergonomics issues
*environmental limits (e.g., vibration in car or plane)
*broken/missing/unavailable equipment

In 1987, Macintosh Operating System 4.2 Easy Access provided MouseKeys support to all applications. Easy access was (de)activated by clicking the {{Key press|shift}} key five times.{{citation needed|date=August 2024}}

By the early 2020s, with [[Graphics tablet|graphics tablets]] becoming more common, a configuration change may be required before enabling MouseKeys.{{citation needed|date=August 2024}}

==MouseKeysAccel==

[[Image:X Protocol MouseKeysAccel Control Trajectory.svg|thumb|left|X window system MouseKeysAccel trajectory]]

{| class="wikitable"
|-
! parameter
! meaning
|-
! mk_delay
| milliseconds between the initial key press and first repeated motion event
|-
! mk_interval
| milliseconds between repeated motion events
|-
! mk_max_speed
| steady speed (in action_delta units) applied each event
|-
! mk_time_to_max
| number of events (count) accelerating to steady speed
|-
! mk_curve
| ramp used to reach maximum pointer speed
|}

The [[X Window System]] MouseKeysAccel control applies action (usually cursor movement) repeatedly while a direction key {1,2,3,4,6,7,8,9} remains depressed.<ref>The X Keyboard Extension: Library Specification, Library Version 1.0/Document Revision 1.1, X Consortium Standard, X Version 11 / Release 6.4, Keyboard Controls, 10.5.2, [https://www.x.org/releases/X11R7.6/doc/libX11/specs/XKB/xkblib.html#the_mousekeysaccel_control The MouseKeysAccel Control]</ref> When the key is depressed, an ''action_delta'' is immediately applied.  If the key remains depressed, longer than ''mk_delay'' milliseconds, some action is applied every ''mk_interval'' milliseconds until the key is released. If the key remains depressed, after more than ''mk_time_to_max'' actions have been applied, ''action_delta'' magnified ''mk_max_speed'' times, is applied every ''mk_interval'' milliseconds.

The first ''mk_time_to_max'' actions increase smoothly according to an exponential.

<math>
\mathrm{action\_delta} \times \mathrm{mk\_max\_speed} \times \left(
 \frac{ i } { \mathrm{mk\_time\_to\_max} } \right)
^{\frac{ 1000 + \mathrm{mk\_curve} } { 1000 }}
</math>

{| class="wikitable"
|-
! mk_curve
! result
|-
! -1000
| uniform speed, linearly increasing action
|-
! 0
| uniform acceleration, linearly increasing speed
|-
! 1000
| uniform jerk, linearly increasing acceleration
|}

These five parameters are configurable.<ref>[http://library.gnome.org/users/gnome-access-guide/stable/dtconfig-mousekeys.html.en GNOME Documentation Library, Configuring a Keyboard-Based Mouse] {{webarchive|url=https://web.archive.org/web/20100612115254/http://library.gnome.org/users/gnome-access-guide/stable/dtconfig-mousekeys.html.en |date=2010-06-12 }}</ref>

==Enabling==

Under the [[X Window System]]s [[X.Org Server|X.Org]] and [[XFree86]] used on [[Unix-like]] systems such as [[Linux]], [[Berkeley Software Distribution|BSD]], and [[IBM AIX|AIX]], MouseKeys (and MouseKeysAccel), when available, is nominally (de)activated by {{key press|Alt}}+{{key press|Shift}}+{{key press|Num Lock}}.<ref>The X Keyboard Extension: Library Specification, Library Version 1.0/Document Revision 1.1, X Consortium Standard, X Version 11 / Release 6.4, Keyboard Controls, 10.5.1, [https://www.x.org/releases/X11R7.6/doc/libX11/specs/XKB/xkblib.html#the_mousekeys_control The MouseKeys Control]</ref> MouseKeys without acceleration (also known as plot mode) is sometimes available with {{key press|Shift}}+{{key press|Num Lock}}. This is nominally independent of the [[window manager]] in use, but may be overridden, or even made unavailable by a [[configuration file]].

Before enabling, it may be necessary to change system configuration. The [https://www.x.org/archive/X11R7.7/doc/man/man1/setxkbmap.1.xhtml setxkbmap] utility can be used to change the configuration under Xorg:<ref>{{cite web |url=https://manpages.ubuntu.com/manpages/jammy/en/man7/xkeyboard-config.7.html |title=xkeyboard-config manual page |date=2012 |access-date=15 March 2015}}</ref>

<code>setxkbmap -option keypad:pointerkeys</code>

There are also various utilities to allow more precise control via user-configurable key bindings, such as [https://beesbuzz.biz/code/269-xmousekeys xmousekeys] and [https://www.semicomplete.com/projects/xdotool/ xdotool].

Since [[KDE Plasma 5|KDE 5]], MouseKeys is enabled and configured by systemsetting5<ref>[https://docs.kde.org/trunk5/en/systemsettings/systemsettings/general.html KDE.org, Using System Settings, System Settings Categories and Modules]</ref> (Hardware → Input Devices → Mouse → Keyboard Navigation)

MouseKeys for [[Apple Inc.]]'s [[macOS]] is enabled and configured via the [[Accessibility]]<ref>[https://www.apple.com/accessibility/macosx/physical.html Apple.com, Mac OS X, Accessibility]</ref> ([apple] → System Preferences → Accessibility → Mouse & Trackpad).

[[Microsoft]] changed the method of enabling between [[Windows 2000]],<ref>Microsoft.com, Accessibility Tutorials, Windows 2000, [http://www.microsoft.com/enable/training/windows2000/default.aspx Turning MouseKeys On and Off]</ref> [[Windows XP]] (added diagonal cursor movement and MouseKeysAccel),<ref>Microsoft.com, Accessibility Tutorials, Windows XP, [http://www.microsoft.com/enable/training/windowsxp/mousekeys.aspx MouseKeys: Control the Mouse Pointer Using the Numeric Keypad]</ref> and [[Windows Vista]].<ref>Microsoft.com, Accessibility Tutorials, Windows Vista, [http://www.microsoft.com/enable/training/windowsvista/mousekeys.aspx Control the mouse pointer with the keyboard (Mouse Keys)]</ref>

==Common usage==
===Replacing the mouse keys===
 
Replacing the mouse keys by the numeric keypad is as follows:
 
Typing {{key press|5}} (with the numeric keypad) is equivalent to clicking the selected button. By default, the selected button is the primary button (nominally under [[index finger]], left button for most right-handed people and right button for most left-handed people). Typing {{key press|-}} (with the numeric keypad) selects the alternate button (nominally under [[ring finger]], right button for most right-handed people and left button for most left-handed people). Typing {{key press|*}} (with the numeric keypad) selects the modifier button (nominally under the [[middle finger]], middle button of a 3-button mouse). Typing {{key press|/}} (with the numeric keypad) selects the primary button. The selection remains in effect until a different button is selected.

Assignment of left/middle/right button to primary/modifier/alternate, alternate/modifier/primary, or something else is settable by many means. Some mice have a switch, that swaps assignment of right and left keys. Many laptop bioses have a setting for mouse button assignment. Many window managers have a setting that permutes the assignment. Within the [[X Window System core protocol]], permutation can be applied by [https://www.x.org/archive/X11R7.7/doc/man/man1/xmodmap.1.xhtml xmodmap].

===Moving the pointer by keys===

Other than {{key press|5}}, all other numeric keys from the numeric keypad are used to move the pointer on the screen. For example, {{key press|8}} will move the pointer upwards, while {{key press|1}} will move it diagonally downwards to the left.

== See also ==

*{{annotated link|FilterKeys}}
*{{annotated link|Sticky keys}}
*{{annotated link|ToggleKeys}}
*{{annotated link|Virtual keyboard}}

==References==

{{Reflist}}

{{DEFAULTSORT:Mouse Keys}}
[[Category:Computer accessibility]]
[[Category:Computing input devices]]
[[Category:User interface techniques]]
[[Category:Ergonomics]]