Some modifiers update key values. If the old values are unsupported
(e.g. "¢") but the new values are supported (e.g. "c"), the keyboard
should let the user press the new value. Check if the new key value
is supported instead of the old one.
Some characters, such as U+03A3 (GREEK CAPITAL LETTER SIGMA) don't
convert directly to the proper key symbol. Use a xkeysym library
function to do correct conversions.
The main layout (e.g. latn_bone.xml and latn_neo2.xml) may disable the
bottom row by adding a property to the XML keyboard tag. Omit the bottom
row when this is the case.
In the Unexpected Keyboard, the bottom row always has the width of the
main layout despite being defined with a width of 10 units. Resize the
bottom row according to the main layout to improve layouts like
arab_pc.xml and numeric.xml.
Some fields in the layout can be abandoned when parsing is complete. The
code for opening and parsing a file is partially duplicated for the main
layout and bottom row. Separate the parsing into a new struct to make
the individual results easier to work with.
Some applications have features (like typing Unicode codepoints in foot)
that can only be used with key presses. Add a Meta key to allow the user
to always send a keypress.
If the key value can emit text, it should put the text to be emitted in
the text field. It should not put any special symbol for the key label,
and it should instead be a special case in the display_label() method.
Some keys may have no XKB key symbol, but still have the ability to emit
text. Examples include the "‹" (U+2039) and "›" (U+203A) characters. Add
the text property to key parts so they can emit text even with no key
symbol.
Also, for keys that were not modified by the Function key because they
had no XKB key symbol name, modify them.
Keeping the keys pressed can confuse some compositors, and the key codes
may change. Release any keys that are pressed while the keymap is
changing, and press them again afterwards.
