Maxximuscool.

I think the following text is as good as it gets. Found in the /doc/howto in the ukeyboard sourcecode

How to create a custom keyboard layout for Nokia internet tablets
================================================== ===============

1. Making a layout compiler
---------------------------

First, you need to compile a compiler. You don't need the scratchbox (an
environment used for Maemo development) to do that - any Linux distribution
would do. For creating a .deb package the scratchbox is needed, though.

Simply unpack the ukeyboard package and run "make" in the ukeyboard
directory:
tar -xjf ukeyboard-VERSION.tar.bz2
cd ukeyboard-VERSION
make
(replace VERSION by the version you've downloaded)

2. Using the layout compiler
----------------------------

Run vkb_compiler created in the previous step. As parameters, supply
a layout source file and name of the destination file. The name of the
destination file must have a .vkb extension.
./vkb_compiler my_layout.def xx_XX.vkb

For rules for naming of destination files, see the section 4.1.

3. Testing the layout
---------------------

Make sure ukeyboard package is installed on the device. It does not have to
include your new layout.

Copy the compiled .vkb file to the /usr/share/ukeyboard/ directory on the
device. Ukeyboard will pick up the new layout automatically. Just go to
Text input settings in the Control panel and set your layout in the
Languages tab.

If you update the .vkb file, just go to Text input settings again and
confirm the dialog without changing anything.

4. Limitation of the maemo keyboard layouts
-------------------------------------------

4.1 Allowed names of .vkb files
-------------------------------

The system limits the name of the compiled (.vkb) file in a way that it has
to match the name defined in the "lang" clause in the source (.def) file
(see section 6.2). You do not need to worry about that if you put your
layout into /usr/share/ukeyboard/, ukeyboard will do the necessary magic for
you. Just be sure the name of the file has the .vkb extension.

4.2 Allowed language codes
--------------------------

The name specified in the "lang" clause in the source file cannot be one of
da_DK, de_DE, el_GR, en_GB, en_US, es_ES, es_MX, fi_FI, fr_CA, fr_FR, it_IT,
nl_NL, no_NO, pt_BR, pt_PT, ru_RU and sv_SE. This is a limitation of
ukeyboard and may be relaxed in the future. If you put one of these codes
into the "lang" clause, ukeyboard will give you a warning.

In general, the name in the "lang" clause should be a valid language code.
Ukeyboard permits the country code part to be anything (e.g. you can specify
en_DV for a Dvorak layout). To be safe, it's better to specify exactly two
letters in the country code part, though.

5. Different types of keyboards and layouts
-------------------------------------------

There are three types of .vkb files. The first one is an on-screen keyboard
corresponding to a selected language, the second one is a special keyboard
activated by pressing the "&!e" button, the third one is a "scv" keyboard,
which is displayed by pressing the "Chr" key on the sliding keyboard.
Although vkb_compiler is able to compile all of them, this document covers
the first type only. By a "keyboard" or "keyboard layout" the first type of
the keyboard is meant through the whole document. For a "scv" type, read
this document and then look at the examples in keyboards-scv/ directory.

Each keyboard file contains two keyboard layouts - one for a normal (stylus)
and one for a thumb keyboard.

A normal layout has two parts, alpha and numeric keyboard, in two variants,
lowercase and uppercase. This gives four "sublayouts" for a normal layout.

A thumb layout has two mandatory "sublayouts", lowercase and uppercase alpha
keyboard, and an arbitrary number of "special" sublayouts. They are
presented as tabs.

Remember, both layouts (normal+thumb) have to be defined.

6. Description of the .def file format
--------------------------------------

6.1 Basics
----------

Every keyword, symbol, etc. has to be separated by a whitespace (a space,
a tab or a newline). Especially, be aware that a whitespace is required
before and after { and }.

A # character starts a comment; everything following the # character is
ignored until the end of line. This has one exception, though. If
a character in a key definition is expected, # is considered a valid
character and doesn't have a special meaning.


6.2 The header
--------------

A .def file has to start with a header section:
header {
...header definition...
}

Inside the header, few global things are defined:
- a descriptive name of the keyboard
- a language code
- default word completion dictionary
- dimensions of keys

6.2.1 Descriptive name of the keyboard
--------------------------------------

A descriptive name of the keyboard is defined by:
name "descriptive name"

Ukeyboard uses this name in the list of kayboards in Text input settings
applet. The OS itself seems to just ignore the name, though.

6.2.2 Language code
-------------------

The locale name of the keyboard. See section 4.2 for allowed values of this
field and section 4.1 for a discussion about allowed .vkb file names.

Example:
lang "en_GB"

6.2.3 Word completion dictionary
--------------------------------

When selecting the keyboard layout in the Control panel, a corresponding
word completion dictionary is preselected. This is specified by this clause.

Example:
wc "en_GB"

6.2.4 Key dimensions
--------------------

Each key in the keyboard has its dimensions. These dimensions are not
specified in the key definition, though. Instead, each key has a single
"size number" assigned. The actual dimensions for the "size number" are
specified in the header.

The header can contain an arbitrary number of key sizes. The key size
definition looks like this:
size 0 { width 35 height 35 textpos 26 left 0 top 0 }

The number after the "size" keyword (0 in the example) specifies the size
number. You'll use this number in key definitions to specify the size of the
particular key.

"width" and "height" specify the dimensions of the key in pixels. (Note that
if the sum of widths of keys in a row is more or less than the expected
width, it is proportionally enlarged/shrinked. The same applies to heights.)

"texpos" denotes vertical position of the text on the key (the baseline).

"left" and "top" specify left and top padding of the key (i.e. the empty
space between the previous and this key).

6.3 Layouts and sublayouts
--------------------------

After the header, layout sections are present. They are defined as:
kbd_normal {
...normal keyboard layout definition...
}

kbd_thumb {
...thumb keyboard layout definition...
}

Inside kbd_normal, the following sections are defined:
kbd_normal {
lowercase {
...alpha lowercase keyboard...
}
lowercase_num {
...numeric lowercase keyboard...
}
uppercase {
...alpha uppercase keyboard...
}
uppercase_num {
...numeric uppercase keyboard...
}
}

Inside kbd_thumb section, the following sections are defined:
kbd_thumb {
lowercase {
...alpha lowercase keyboard...
}
uppercase {
...alpha uppercase keyboard...
}
special {
...keyboard on the second tab...
}
special {
...keyboard on the third tab...
}
...
}

Definitions in the sublayout sections are the same for normal and thumb
keyboard, except the "name" clause, which can be present only in the thumb
keyboard sublayouts.

6.4 Sublayout definition
------------------------

A sublayout definition contains the following clauses (the numbers and
values are just examples):
name "abc"
margin 0 0 0 0
default_size 3
row {
...
}
row {
...
}
...

6.4.1 Name of the sublayout
---------------------------

The "name" clause can (and must) be present in thumb keyboard sublayouts
only. It specifies the name displayed on the corresponding tab.

6.4.2 Margins
-------------

Folowing the "margin" clause, four numbers are specified. They denotes
margins of the keyboard starting from top and going clock-wise (i.e. top,
right, bottom, left).

The margins are used for separating of the numerical from alpha keyboard.

6.4.3 Default size
------------------

The "default_size" clause specifies the default size number for keys in this
sublayout. By specifying this, you don't need to add the "size" attribute to
each of the keys.

Remember, the value refers to the dimensions specified in the header.

6.4.4 Row definitions
---------------------

An arbitrary number of rows of keys can be present in each sublayout. See
the section 6.5.

6.5 Key rows
------------

Each key row consists of several keys. The number of keys can be different
for different rows.

The row definition looks like this:
row {
...key 1...
...key 2...
...
...key n...
}

There are several ways to define a key, depending on a type of the key:
key X
white
slide { key X key X key X }

Independently on the type, each key can have attributes. The attributes are
given after the key definition, e.g.:
key c alpha hexa

The order of the attributes is not important. The recognized attributes are:
alpha
num
hexa
tele
special
dead
size N

6.5.1 Key types
---------------

There are three key types:
1. regular keys
2. a space key
3. slide keys (repeated pressing of the slide key cycles through a set of
characters)

6.5.2 Key definition
--------------------

After the "key" keyword, the whitespace is required, followed by a single,
UTF-8 encoded, character (*). This character will be displayed on the key
and printed when the key is pressed by user.

After the "slide" keyword, a new section ({...}) has to be started,
containing a "key" keyword followed by a character, followed by a "key"
keyword, etc. A slide key can contain an arbitrary number of keys.

After the "white" keyword, there is (of course) no character specified.

(*) That's not exactly true. You can specify a bunch of characters, as long
as they don't contain a whitespace. It should work as expected, i.e.
outputting all the characters when the key is pressed. The author hasn't
tested it, though.

6.5.3 Key attributes
--------------------

The "alpha" attribute denotes an alpha key (i.e. letters A to Z plus
equivalents in other languages, including characters with a diacritic).

The "num" attribute denotes a numeric key (i.e. 0 to 9 and the minus sign).

The "hexa" attribute denotes a key that can be used in a hexadecimal input
(i.e. 0 to 9 and A to Z).

The "tele" attribute denotes a key present on a telephone keypad (i.e.
0 to 9, *, #, and few other keys).

The "special" attribute denotes a non-alphanumeric key (i.e. key that is
neither a letter nor a number).

The "dead" attribute denotes the key is a combining diacritical mark
(a so-called "dead key").

The "size" attribute is used when the size of the key should be different
than the default size for this sublayout. Again, remember that the value
refers to the dimensions specified in the header.

7 Contact, legal stuff
----------------------

The document is (c) Jiri Benc, <jbenc@upir.cz>. It is licensed under the
GPLv2.

If you find an error in this document, please contact the author.

maemo is an unregistered trademark of Nokia Corporation.