Ubuntu – How to remap the keyboard to create a lefthand numpad

keyboardremappingshortcut-keysxkbxmodmap

Like many smaller machines, my laptop's keyboard is missing a dedicated numpad.

I can generally type without looking at my keyboard, but I am unable to blindly type numbers with the number row. That's why I thought of converting the left side of my keyboard into a second-level numpad (e.g. Z = 0, X = 1. C = 2, V = 3, S = 4 and so on).

Another advantage would be the possiblity to quickly type numbers without taking the right hand off the mouse or moving the left hand across the entire keyboard.

Now I'm looking for a way to remap those keys to "create" the numpad, at best independent of the desktop environment, as I'm using multiple ones constantly. Also, it would be amazing if that mapping was portable, so I could set it up once and enable it for different keyboards/machines.

I know that it's possible to modify the keymap directly inside /usr/share/X11/xkb/symbols/, but those allow only three modifiers (Shift, AltGr (on European keyboards) and Shift + AltGr) and they're usually in use on the letter keys or require both hands to activate.

I thought of using either Super_L or a combination of Shift_L + Alt as modifier keys to access the numpad layer, since those combinations shouldn't be in use and are easy to reach with one hand.

How could this be accomplished?

Best Answer

I am into custom keyboards running QMK and such which allows to redefine every key and allows advanced behaviours such as layers. I recentley came across Kmonad which is a software tool which allows most of the same features. I haven't tried it myself, but this should allow you to hold down or toggle a key to activate a layer on which you can map numbers to the left side of the keyboard.

Here is a link to the github; https://github.com/david-janssen/kmonad

I think Kmonad is also included in a lot of recent distros so it might already be available in APT.

Original Answer:

This is not attended to be a canonical answer to the question. It could be counted as a work around. Hopping someone writes sophisticated solution for it.

This a simple prototype keyboard modifiers indicator for Unity.

Image starting from left: Icon, Shift, Locked Caps, Ctrl, Alt, Super, Locked AltGr (Small circle to indicate locked state)

screenshot of unity-xkbmod prototype

Source file unity-xkbmod.c:

/*
 * unity-xkbmod.c
 *
 * Copyright 2014 Sneetsher <sneetsher@localhost>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301, USA.
 *
 *
 */

#include <string.h>

#include <X11/XKBlib.h>

#include <glib/gprintf.h>
#include <gtk/gtk.h>
#include <libappindicator/app-indicator.h>

//callback data structure
typedef struct _AppData {
  Display *_display;
  int *_deviceId;
  AppIndicator *indicator;
} AppData;

//menu ui
static GtkActionEntry entries[] = {
  { "Quit",     "application-exit", "_Quit", "<control>Q",
    "Exit the application", G_CALLBACK (gtk_main_quit) },
};

static guint n_entries = G_N_ELEMENTS (entries);

static const gchar *ui_info =
"<ui>"
"  <popup name='IndicatorPopup'>"
"    <menuitem action='Quit' />"
"  </popup>"
"</ui>";

//callback function, get xkb state, update indicator label (icon have limitation)
static gboolean update_xkb_state (gpointer data)
{
  //get xkb state
  XkbStateRec xkbState;
  XkbGetState(((AppData*) data)->_display, *(((AppData*) data)->_deviceId), &xkbState);

  //construct label
  GString *label = g_string_new("");

  register int i;
  unsigned bit;

  //loop taken from xkbwatch source
  for (i = XkbNumModifiers - 1, bit = 0x80; i >= 0; i--, bit >>= 1)
  {
    //printf("base%d %s  ", i, (xkbState.base_mods & bit) ? "on " : "off");
    //printf("latched%d %s  ", i, (xkbState.latched_mods & bit) ? "on " : "off");
    //printf("locked%d %s  ", i, (xkbState.locked_mods & bit) ? "on " : "off");
    //printf("effective%d %s  ", i, (xkbState.mods & bit) ? "on " : "off");
    //printf("compat%d %s\n", i, (xkbState.compat_state & bit) ? "on " : "off");

    //todo: change constant with xkb modifier constant (defined in the headers)
    // show effective modifier stat
    switch (i)
    {
      case 7:
        g_string_prepend (label,  ((xkbState.mods & bit) ? "⎇" : ""));
        break;
      case 6:
        g_string_prepend (label,  ((xkbState.mods & bit) ? "⌘" : ""));
        break;
      case 5:
        g_string_prepend (label,  ((xkbState.mods & bit) ? "5" : ""));
        break;
      case 4:
        g_string_prepend (label,  ((xkbState.mods & bit) ? "①" : ""));
        break;
      case 3:
        g_string_prepend (label,  ((xkbState.mods & bit) ? "⌥" : ""));
        break;
      case 2:
        g_string_prepend (label,  ((xkbState.mods & bit) ? "⋀" : ""));
        break;
      case 1:
        g_string_prepend (label,  ((xkbState.mods & bit) ? "⇬" : ""));
        break;
      case 0:
        g_string_prepend (label,  ((xkbState.mods & bit) ? "⇧" : ""));
        break;
      default:
        break;
    };

    // show if modifier is locked
    g_string_prepend (label,  ((xkbState.locked_mods & bit) ? " ˳" : " "));
  }

  //g_string_prepend (label,  "");
  app_indicator_set_label (((AppData*) data)->indicator, label->str, NULL);

  //g_free(label);
  return TRUE;
}


int main (int argc, char **argv)
{
  AppData appdata;
  Display *_display;
  int _deviceId;

  char* displayName = strdup("");
  int eventCode;
  int errorReturn;
  int major = XkbMajorVersion;
  int minor = XkbMinorVersion;;
  int reasonReturn;


  AppIndicator *indicator;
  GtkWidget *indicator_menu;
  GtkUIManager *uim;
  GtkActionGroup *action_group;
  GError *error = NULL;

  gtk_init (&argc, &argv);


  XkbIgnoreExtension(False);

  g_printf("Xkb client lib ver: %d.%d\n" , major , minor );
  _display = XkbOpenDisplay(displayName, &eventCode, &errorReturn,
                            &major, &minor, &reasonReturn);
  g_printf("Xkb server lib ver: %d.%d\n" , major , minor );

  if (reasonReturn != XkbOD_Success)
  {
    g_printf("Unable to open display!\n");
    return 1;
  }

  XkbDescRec* kbdDescPtr = XkbAllocKeyboard();
  if (kbdDescPtr == NULL)
  {
    g_printf ("Failed to get keyboard description.\n");
    return 2;
  }
  kbdDescPtr->dpy = _display;
  _deviceId = kbdDescPtr->device_spec;

  /*
  //no need for event listener, used gtk_timeout timer
  XkbSelectEventDetails(_display, XkbUseCoreKbd, XkbStateNotify,
                     XkbAllStateComponentsMask, XkbGroupStateMask);
  */


  action_group = gtk_action_group_new ("AppActions");
  gtk_action_group_add_actions (action_group, entries, n_entries, NULL);

  indicator = app_indicator_new_with_path (
                                        "Simple XKB Modifier Indicator",
                                        "icon",
                                        APP_INDICATOR_CATEGORY_HARDWARE,
                                        g_get_current_dir());

  uim = gtk_ui_manager_new ();
  gtk_ui_manager_insert_action_group (uim, action_group, 0);
  if (!gtk_ui_manager_add_ui_from_string (uim, ui_info, -1, &error))
  {
    g_printf ("Failed to build menus: %s\n", error->message);
    g_error_free (error);
    error = NULL;
    return 3;
  }

  indicator_menu = gtk_ui_manager_get_widget (uim, "/ui/IndicatorPopup");
  app_indicator_set_menu (indicator, GTK_MENU (indicator_menu));
  app_indicator_set_status (indicator, APP_INDICATOR_STATUS_ACTIVE);

  //app_indicator_set_label (indicator, " ⇧ ⋀ ⌥ ⎇  ⌘ ", NULL);
  //symbols: shift U21E7 ctrl U22C0 alt/altgr U2325 U2387  cmd U2318
  //from font: DejaVu Sans

  appdata._display = _display;
  appdata._deviceId = &_deviceId;
  appdata.indicator = indicator;
  gtk_timeout_add (120, (GtkFunction) update_xkb_state, &appdata);
  //nice for realtime tasks, to replace gtk_timeout
  //gtk_idle_add ((GtkFunction) idle_func, &appdata);

  gtk_main ();

  XCloseDisplay (_display);
  return 0;
}

Installing needed headers/libs: (Not sure if I miss any)

sudo apt-get install libx11-dev libappindicator-dev libgtk2.0-dev

Compiling:

gcc -Wall unity-xkbmod.c -o unity-xkbmod `pkg-config --cflags --libs appindicator-0.1` -lX11

Run:
```
./unity-xkbmod
```

Note:

libappindicator used for Unity indicators lack an important feature which make easy to ports other desktops indicators. See Bug #812067 API needed: pixbuf icon setting support

Without this feature, let's say we need (Shift, Ctrl, Alt, AltGr, Super) with sticky keys active; we have 3 main status for each (Off, On/Latched, Locked). So 3^5 combined icons should be generated. (Where normal case just 3x5 single icons)

That's why I used indicator label with symbols from DejaVu Sans font.
To put an icon, place it in same folder and name it icon.*. Accepted formats: png, svg, ico, xpm ...

If you don't like any icon, just create a 1x1 px image instead.

References:

The X Keyboard Extension
Application Panel Indicators
Source of xkbwatch & plasma-widget-kbstate

Best Answer

Related Solutions

Ubuntu – How to remap “special” keys in xkb

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Original Answer:

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