Re: error in pangoLayout->index_to_pos() ?

[David Nečas (Yeti) <yeti physics muni cz>]

On Wed, Feb 28, 2007 at 11:32:58PM +0100, thom_schu gmx de wrote:
> I changed my Glib::ustring::insert method to 
> text.insert(position++, 1, gdk_keyval_to_unicode(event->keyval));
> and called the PangoLayout::index_to_pos() with the byte-position,
> instead of the character position. So far it works.
> Unfortunately Glib::ustring doesnt support methods to convert
> a byte-to-character and character-to-byte position. :-(

The C API has g_utf8_offset_to_pointer() and
g_utf8_pointer_to_offset().

> I would like to integrate input methods, but dont have any idea.
> Isnt there a small example for that ?

The only working examples I know about are in Gtk+ code
(e.g. in GtkEntry).  I didn't study it enough to give
a comprehensive explanation (also, the most complex thing
I use myself is the composition of accents and letters to
accented letters -- but even this would not work with your
approach).

You can get the basic idea by glancing over gtkentry.c.
The text to enter is not obtained from "key-press-event"s at
all, instead it is received in input method "commit"
callback.  But there's more: the surrounding stuff, LTR vs.
RTL, knowing when to reset the im context, ...  I doubt one
can get all this right without actually using it himself.
Therefore I would create a new text widget by modification
of an existing one (it it's possible legally) instead of
writing it from scratch.

Yeti


--
Whatever.