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Keyboard layout

14 Oct 2016 • Leave Comments

ABCs

  1. Emacs users are subject to Emacs pinky. Common solution is to switch Caps and Ctrl or turn off Caps.

    Caps is recommended to turned off as it's only used occasionally. What's more, we can use Shift to shout.

  2. Setting for virtual termnial is different from that of X, and should be set respectively.
  3. In this post, I assume Intel PC and QWERTY keybord.

Virtual Terminal (OpenRC)

In Virtual Terminal, without specific clarification, term layout refers to keymap.

  1. Keyboard layout can be found under /usr/share/keymaps. Keymap compressed in .gz format. Depending on the hardware, they are organized in sub-directories.

    For Intel QWERTY keyboard, the default keymap is i386/qwerty/us.map.gz.

    Among other keymaps, there is a special include directory offer supplemental keymap extensions.

  2. There are two import parameters in /etc/conf.d/keymaps, namely keymap and extended_keymaps.

    keymap=us sets keyboard layout to us.map.gz while extended_keymaps is a comma-listed extensions.

    In this post, we will ignore extended_keymaps.

  3. To switch Caps/Ctrl or turn off Caps, we can modiy the keycode in keymap (decompressed). Before that, let's examine the us.map format:

    include "linux-with-alt-and-altgr"
keycode  29 = Control
keycode  58 = Caps_Lock
keycode  97 = Control
    1. include extends the current keymap.
    2. keycode 29 = Control means the Ctrl key is pressed which also applies to 58 and 97.
    3. Specially 97 means the right Ctrl key while 29 is left Ctrl key.

  4. Switch Caps and left Ctrl:

    keycode  29 = Caps_Lock
keycode  58 = Control

    Just swap the keycode for Control and Caps_Lock. Yeah, right, you can swap 29 and 97 (right Control) as well.

  5. Turn off Caps:

    keycode  58 = Control

  6. Although modification the original default us.map.gz is handy, create a new keymap is preferrable.

    Create caps-off.map:

    include "us.map"
keycode  58 = Control

    Remember to compress the new keymap:

    $ gzip caps-off.map
# mv caps-off.map.gz /usr/share/keymaps/i386/qwerty/

    Then set keymap=caps-off in /etc/conf.d/keymaps.

  7. Finally restart keymaps service:

    # rc-service keymaps restart

  8. Interestingly, someone already compose a customized /usr/share/keymaps/i386/qwerty/emacs.map.gz.

    I have chosen to use this one keymap=emacs. It includes much more customization for Emacs.

  9. Attention: changing /etc/conf.d/keymaps directly affects only Virtual Terminal.

X

  1. Aside from changing keymaps, X supports XKB in /usr/share/X11/xkb/rules/base.lst instead of raw keycode.

    X KeyBoard extension, or XKB, defines the way keyboards codes are handled in X, and provides access to internal translation tables. It is the basic mechanism that allows using multiple keyboard layouts in X.

  2. (deprecated) x11-apps/xmodmap is a somewhat low level tool, similar to OpenRC /etc/conf.d/keymaps.

    xmodmap can temporarily change keymaps on command line (Terminal Emulator). However, for persistent effect, create a configuration file ~/.Xmodmap:

    !
! Swap Caps_Lock and Control_L
!
remove Lock = Caps_Lock
remove Control = Control_L
keysym Control_L = Caps_Lock
keysym Caps_Lock = Control_L
add Lock = Caps_Lock
add Control = Control_L

    Insert xmodmap ~/.Xmodmap command to ~/.xinitrc, ~/.Xresources, ~/.xprofile (Gnome Display Manager) or whatever. Alternatively, we can add it to desktop's autostart list. Most desktops (Xfce4, Gnome, or KDE) supports such setting.

  3. XKB command line tool x11-apps/setxkbmap is a relativelly high level tool. If present, it resets /etc/conf.d/keymap and xmodmap settings.

    Edit ~/.xinitrc or ~/.xprofile and call setxkbmap from there.

    /usr/bin/setxkbmap -option "ctrl:swapcaps"
or
/usr/bin/setxkbmap -option "ctrl:nocaps"

  4. XKB in Xorg configuration

    Without installing setxkbmap package, we can use XKB rules in /etc/X11/xorg.conf.d/10-keyboard.conf:

    Section "InputClass"
    Identifier      "keyboard-all"
    MatchIsKeyboard "on"
    #Option  "XkbOptions"    "ctrl:swapcaps"
    #Option  "XkbOptions"    "terminate:ctrl_alt_bksp"
    Option  "XkbOptions"    "ctrl:nocaps"
EndSection

    Restart X to take effect.

Refs

  1. Keyboard layout switching
  2. Moving the Ctrl key
  3. keybord configuration in Xorg
  4. x keybord extension XKB

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