Editing Mouse keys (section)

==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>