How to add a new keyboard layout (Custom keyboard layout definition)

Creating custom keyboard layout

For example, I'm looking to add a new modified English (international AltGr dead keys) US layout with swapped r,R & t,T. I will name it XY swapped:RT English (international AltGr dead keys).

1. Create new symbols file:

   sudo nano /usr/share/X11/xkb/symbols/xy

    default  partial alphanumeric_keys
    xkb_symbols "basic" {
   
       name[Group1]= "XY swapped:RT English (international AltGr dead keys)";
   
       include "us(altgr-intl)"
   
    // my custom changes:
   
       key <AD04> { [        t, T,           ediaeresis,   Ediaeresis      ] };
       key <AD05> { [        r, R,           thorn,        THORN           ] };
   
   
       include "level3(ralt_switch)"
    };
   

   include "us(altgr-intl)" means it inherits all key from that layout only key overridden here.

   You may use Keyboard Layout Editor which is a GUI program that helps create or edit XKB keyboard layouts. Thanks to @Glutanimate

2. Add the new layout declaration to /usr/share/X11/xkb/rules/evdev.xml (copy & modify us layout section)

   Reference: Make new variant keyboard layout available in Settings?

   sudo gedit /usr/share/X11/xkb/rules/evdev.xml

    ...
    <layout>
      <configItem>
        <name>xy</name>
   
        <shortDescription>en</shortDescription>
        <description>XY swapped:RT English (international AltGr dead keys)</description>
        <languageList>
                 <iso639Id>eng</iso639Id>
                 <iso639Id>fra</iso639Id>
                 <iso639Id>ger</iso639Id>
        </languageList>
      </configItem>
      <variantList>
      </variantList>
    </layout>
    ...
   

3. Delete xkb cache.

    sudo rm /var/lib/xkb/*.xkm
   

   Notes:

   To load changes to the layouts menu simply restart gnome-keyboard-preferences; relaunching the window manager should not be necessary.

   There is a change in Ubuntu version 13.10 which causes the keyboard settings cache to not refresh after files in "/usr/share/X11/xkb/symbols" are modified. It looks like changes just don't get applied. To force the cache refreshing a one should delete *.xkm files from "/var/lib/xkb".

   ^{Reference: Howto: Custom keyboard layout definitions}

   or

    sudo dpkg-reconfigure xkb-data
   

   ^{Reference: Why did 13.10 break my custom keyboard layout?}

   

Reply to fix OP modifications

• (Update #1 wrong parent layout) You have modified xkb_symbols "pes_part_basic" which is in irwinxp file: that's ok.

  but xkb_symbols "pes" in irwinxp file still:

    include "ir(pes_part_basic)"
  

  which should be:

    include "irwinxp(pes_part_basic)"
  

• (Update #2 custom icon) If <shortDescription>en</shortDescription> changed to <shortDescription>xy</shortDescription>. So the new layout will distinct from En and it will appear as Xy.

  Most probably there will be no icon for it in ubuntu-mono. Then the indicator will dynamically generate new one which may not follow current theme.

  1. Copy any layout icons for dark/light mono themes:

      sudo cp /usr/share/icons/ubuntu-mono-dark/status/22/indicator-keyboard-En.svg /usr/share/icons/ubuntu-mono-dark/status/22/indicator-keyboard-Xy.svg
      sudo cp /usr/share/icons/ubuntu-mono-light/status/22/indicator-keyboard-En.svg /usr/share/icons/ubuntu-mono-light/status/22/indicator-keyboard-Xy.svg
     

  2. SVG files are just XML. Open then for editing and change text value from En to Xy:

      sudo nano /usr/share/icons/ubuntu-mono-dark/status/22/indicator-keyboard-Xy.svg
      sudo nano /usr/share/icons/ubuntu-mono-light/status/22/indicator-keyboard-Xy.svg
     

     Example:

      <?xml version="1.0" encoding="UTF-8" standalone="no"?>
      <svg width="22" xmlns="http://www.w3.org/2000/svg" version="1.1" height="22">
       <defs>
        <mask id="m">
         <rect y="0" x="0" style="fill:#fff" height="22" width="22"/>
         <text y="15.5" x="5" style="font-size:12;font-family:Ubuntu;font-weight:500;fill:black">Xy</text>
        </mask>
       </defs>
       <rect style="fill:#dfdbd2" mask="url(#m)" rx="2" height="20" width="20" y="1" x="1"/>
      </svg>
     

  3. Update theme cache:

      sudo update-icon-caches /usr/share/icons/ubuntu-mono-*/            
     

  4. Logout/login

     

Other Helpful References

• How to modify a keyboard layout in Linux (thanks to @Rmano)
• Building an XKB Keyboard (thanks to @Glutanimate)