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Remapping keyboard

Revision as of 21:55, 22 April 2010

If you are not satisfied with your hardware keyboard layout, with root access (through rootsh or ssh) you can modify that as follows.

Permanent remap

You need to edit this file on your N900:

/usr/share/X11/xkb/symbols/nokia_vndr/rx-51

You should however make a copy first in case something goes wrong, but do not place the copy in the nokia_vndr folder or it will stop your phone from booting.

After modifying the rx-51 file, type `setxkbmap' to apply any changes for English keyboards, `setxkbmap de' for German keyboards, etc. If you see an error you should replace the rx-51 file with your backup - if you don't the device will fail to boot and you'll have to reflash it!

If you are satisfied with your new rx-51 file, do also backup that. The next firmware upgrade might restore it to the factory default.

Remapping keyboard arrows

In the English variant of the N900 keyboard arrow keys have no extra symbols attached to them.

You can remap those keys to add things such as accents, umlauts or other useful symbols (e.g. `|', `<' or `>' for the X terminal).

The arrow keys are located at the end of the file. This example shows how to add dead acute, grave, tilde and circumflex accents (useful for writing in Portuguese) Press Fn+Up/Down/Left/Right to use these accents.

xkb_symbols "arrows_4btns" {
    key <UP>   { type[Group1] = "PC_FN_LEVEL2", symbols[Group1] = [ Up, dead_circumflex ] };
    key <LEFT> { type[Group1] = "PC_FN_LEVEL2", symbols[Group1] = [ Left, dead_acute ] };
    key <DOWN> { type[Group1] = "PC_FN_LEVEL2", symbols[Group1] = [ Down, dead_tilde ] };
    key <RGHT> { type[Group1] = "PC_FN_LEVEL2", symbols[Group1] = [ Right, dead_grave ] };
};

This example adds German umlauts:

xkb_symbols "arrows_4btns" {
    key <UP>   { type[Group1] = "PC_FN_LEVEL2", symbols[Group1] = [ Up, udiaeresis ] };
    key <LEFT> { type[Group1] = "PC_FN_LEVEL2", symbols[Group1] = [ Left, odiaeresis ] };
    key <DOWN> { type[Group1] = "PC_FN_LEVEL2", symbols[Group1] = [ Down, adiaeresis ] };
    key <RGHT> { type[Group1] = "PC_FN_LEVEL2", symbols[Group1] = [ Right, ssharp ] };
};

This one adds Page Up, Page Down, Home and End:

xkb_symbols "arrows_4btns" {
    key <UP>   { type[Group1] = "PC_FN_LEVEL2", symbols[Group1] = [ Up, Page_Up ] };
    key <LEFT> { type[Group1] = "PC_FN_LEVEL2", symbols[Group1] = [ Left, Home ] };
    key <DOWN> { type[Group1] = "PC_FN_LEVEL2", symbols[Group1] = [ Down, Page_Down ] };
    key <RGHT> { type[Group1] = "PC_FN_LEVEL2", symbols[Group1] = [ Right, End ] };
};

Of couse all these are just examples. You can add any other symbol you like, or you can remap any other key, not just the arrows.

If you want to know the name of a symbol, just take a look at this list of standard PC keyboard layouts as an example:

http://cgit.freedesktop.org/xkeyboard-config/tree/symbols/

An alternative approach for getting custom special characters is to edit the Special characters view.

Note: the pipe symbol is called "bar".

Example for keyboard with only two arrow keys

Non-English keyboards typically have only two keys for arrows, with Up and Down composed as Fn+Left and Fn+Right, respectively.

In this situation it may be useful to remap keys with characters carrying accents such that one of it is a dead accent, freeing other keys for special characters that you want to have on the hardware keyboard.

For example, on a German keyboard there are three keys occupied by umlauts ä, ö, and ü. The following modification changes ü into dead diaeresis, so that ä, ö, and ü are produced by pressing ü followed by a, o, and u. This way one can also put diaeresis on e, i, and y which occur in other languages.

partial alphanumeric_keys
xkb_symbols "de" {
    include "nokia_vndr/rx-51(english_base)"
    include "nokia_vndr/rx-51(arrows_2btns)"

    name[Group1] = "German";

    // 1. row
    key <AD06>  { [ z, Z, 6, 6 ] };
    // key <AB08> { [ udiaeresis, Udiaeresis, ssharp, ssharp ] };
    key <AB08>  { [ dead_diaeresis, asciicircum, ssharp, ssharp ] };

    // 2. row
    key <AC08>  { [ k,  K, semicolon, semicolon ] };
    key <AC09>  { [ l,  L, colon, colon ] };
    //key <AB09>  { [ odiaeresis, Odiaeresis, exclam, exclam ] };
    key <AB09>  { [ bracketleft, braceleft, exclam, exclam ] };
    //key <UP>  { [ adiaeresis, Adiaeresis, question, question ] };
    key <UP>    { [ bracketright, braceright, question, question ] };

    // 3. row
    key <AB01>  { [ y, Y, EuroSign, EuroSign ] };
    key <AB03>  { [ c, C, equal, equal ] };
    // key <SPCE>  { [ space, space, at, at ] };
    key <SPCE>  { [ space, asciitilde, at, at ] };
    //key <LEFT>  { [ period, comma, comma, comma ] };
    key <LEFT>  { [ period, bar, comma, comma ] };
};

In this example, brackets and braces have then be mapped on ö, ä, Ö, and Ä. Shift-ü has been used for "^". Moreover, Shift-Space has been mapped to tilde (a character that often occurs in URLs), and Shift-. has been mapped to "|". (The previous assignments are commented out by adding "//" in the beginning of a line.)

setxkbmap de

then tests and installs the new keyboard mapping. The new keymap will be used until the rx-51 file is modified again, which may happen after a firmware upgrade. So keep also a backup copy of your modified rx-51!

Temporary remap

Keys can be also remapped temporarily by loading keymap to a file, edit that file and then reload changed file to N900 X server; like this (on an X terminal):

xkbcomp :0
vi server-0.xkb
xkbcomp server-0.xkb :0

This has the advantage that if keymap get screwed out, running just setxkbmap will fix it back to original. If this cannot be done, rebooting will fix things for sure.

For arrow key remapping the following script can be handy:

Just noticed that this makes N900 drain battery !!! (N900 was shutdown in the morning). After executing this maemo-xinput-sounds takes >90% of cpu time. Killing the process will be a temporary fix; I'll look for better solution...

#!/bin/sh

set -eux

# busybox mktemp is sooo strict: 6 X:s at the end is the only option...
tf=`mktemp xkb-XXXXXX`
trap "rm $tf.0 $tf" 0

xkbcomp :0 $tf.0

perl -pe '
 sub out ($$$) {
        print qq(    key <$_[0]> { type[Group1] = "PC_FN_LEVEL2",);
        print qq( symbols[Group1] = [ $_[1], $_[2] ] };);
        return if s/.*};//; while (<>) { last if s/.*};//; };
 }
 s/controls=\)/controls=SlowKeys\)/; # hmm...
 out "UP", "Up", "Odiaeresis" if (/key\s+<UP>/);
 out "DOWN", "Down", "adiaeresis" if (/key\s+<DOWN>/);
 out "LEFT", "Left", "odiaeresis" if (/key\s+<LEFT>/);
 out "RGHT", "Right", "Adiaeresis" if (/key\s+<RGHT>/);
' $tf.0 > $tf

xkbcomp $tf :0

This one maps Up, Down, Left and Right to Ö, ä, ö, Ä, respectively (for finnish/scandinavian users), and is easy to tune for other purposes. Copy this as xk to home directory on N900 and execute it as sh xk whenever (seldom) you reboot N900.