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On many older laptops and some compact keyboards there is an integrated numeric keypad in the main keyboard area. This alternate keypad is activated with a special 'Fn' key next to the left Ctrl key.

As a programmer I learned to use the cursor movement keys (arrows, PgUp, PgDn etc.) and found it greatly improved my programming speed. And the benefits were not bound to just a single application as is the case with specialised shortcut keys.

On conventional PC keyboards, the 'Windows Key' can be used to emulate the 'Fn' key and a corresponding integrated numeric keypad. When I used to use MS Windows I found Autohotkey was able to map the keys using a simple script.

Recently I learned about xkb and how it can be used to map keystrokes at a very low level.

What is the xkb keyboard mapping profile that will emulate an integrated numeric keypad using the windows key as the fn key?

Hint(?): I suspect the file will look a lot like the '/usr/share/X11/xkb/symbols/keypad' file on a Debian-derivative linux distro. This 'keypad' file is included at the top of the '/usr/share/X11/xkb/symbols/pc' file.

The corresponding autohotkey script for reference (# == WinKey):

#8::Up
#k::Down
#u::Left
#o::Right

#7::Home
#j::End
#9::PgUp
#l::PgDn

#m::Insert
#.::Delete

;(Scroll with the left-over keys)
#i::WheelUp
#,::WheelDown

Note that all these keys need to work with any combination of Ctrl, Alt, Shift as well as the Windows Key.

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Peter L
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  • I've made some progress on this but I lack the expertise with xkb. A more specific, [related question](http://unix.stackexchange.com/questions/236089) has been asked on the unix site. – Peter L Oct 20 '15 at 23:30

1 Answers1

2

Steps to install numeric keypad-like cursor keys on the main keyboard in Linux / XKB...

  1. xkbcomp $DISPLAY original.xkb (just in case ;)
  2. xkbcomp $DISPLAY custom.xkb
  3. Edit custom.xkb

  4. Add the following at the end of section: xkb_types "..." {

    type "WinKeyAsFnKey" {
  modifiers = Shift+Super;
  map[Shift] = level2;
  map[Super] = level3;
  map[Super+Shift] = level3;
  level_name[Level1] = "Base";
  level_name[Level2] = "Caps";
  level_name[Level3] = "Fn";
};

  5. Add the following at the end of section xkb_symbols "..." {

     key <AE07> {type="WinKeyAsFnKey",symbols[Group1]=[7,ampersand,NoSymbol],actions=[NoAction(),NoAction(),RedirectKey(key=<HOME>,clearmods=Super)]};
 key <AE08> {type="WinKeyAsFnKey",symbols[Group1]=[8,asterisk,NoSymbol],actions=[NoAction(),NoAction(),RedirectKey(key=<UP>,clearmods=Super)]};
 key <AE09> {type="WinKeyAsFnKey",symbols[Group1]=[9,parenleft,NoSymbol],actions=[NoAction(),NoAction(),RedirectKey(key=<PGUP>,clearmods=Super)]};
 key <AD07> {type="WinKeyAsFnKey",symbols[Group1]=[u,U,NoSymbol],actions=[NoAction(),NoAction(),RedirectKey(key=<LEFT>,clearmods=Super)]};
 key <AD09> {type="WinKeyAsFnKey",symbols[Group1]=[o,O,NoSymbol],actions=[NoAction(),NoAction(),RedirectKey(key=<RGHT>,clearmods=Super)]};
 key <AC07> {type="WinKeyAsFnKey",symbols[Group1]=[j,J,NoSymbol],actions=[NoAction(),NoAction(),RedirectKey(key=<END>,clearmods=Super)]};
 key <AC08> {type="WinKeyAsFnKey",symbols[Group1]=[k,K,NoSymbol],actions=[NoAction(),NoAction(),RedirectKey(key=<DOWN>,clearmods=Super)]};
 key <AC09> {type="WinKeyAsFnKey",symbols[Group1]=[l,L,NoSymbol],actions=[NoAction(),NoAction(),RedirectKey(key=<PGDN>,clearmods=Super)]};
 key <AB07> {type="WinKeyAsFnKey",symbols[Group1]=[m,M,NoSymbol],actions=[NoAction(),NoAction(),RedirectKey(key=<INS>,clearmods=Super)]};
 key <AB09> {type="WinKeyAsFnKey",symbols[Group1]=[period,greater,NoSymbol],actions=[NoAction(),NoAction(),RedirectKey(key=<DELE>,clearmods=Super)]};

  6. Save custom.xkb

  7. xkbcomp custom.xkb $DISPLAY

I'm still working on the mouse scroll with 'i' and ','.

EDIT: The above solution does not play nice with Google Chrome and Chrome-based apps (like Slack).

Alternative approach is to use a programmable keyboard. I use an after-market PCB for a CoolerMaster Masterkeys S keyboard. The Easy AVR layout is available online (although currently the left win-key now doesn't work by itself...I use the right one).

Peter L
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