I18n text input

[Glynn Clements]

Russell Shaw wrote:

> For functions XkbLookupKeySym(), XLookupString(), XKeycodeToKeysym(),
> XKeysymToString etc, how can i tell if the keysym is a graphic printable
> character like "a", or a control character such as "Left" (XK_Left) ?
> 
> I need to tell automatically if it's a normal unicode character that can be
> printed in an entry box for any written language.

For languages other than English, keyboard input isn't as simple as
one keypress => one character. Many Western languages use "dead"
accents (i.e. pressing an accent key causes the next character to be
accented) or compose processing (e.g. Compose,o,/ => ø), and
East-Asian languages typically require far more complex input methods.

> Do these functions return UTF-8 unicode?

XLookupString() uses ISO-8859-1.

XmbLookupString() and XwcLookupString() return strings in a
locale-specific encoding. If X_HAVE_UTF8_STRING is defined,
Xutf8LookupString() returns a UTF-8 string. All three functions
require an input context (see XOpenIM() and XCreateIC() for a starting
point, but you probably aren't going to work it out from manual pages
alone).

Unless you're planning on spending the next few months learning how
text entry works for languages other than English, I'd recommend using
a GUI toolkit rather than trying to do it using bare Xlib. Or at least
steal the code from such a toolkit.

-- 
Glynn Clements <glynn at gclements.plus.com>