Re: How to convert char from Emacs-20 internal to UTF-8?

[Adrian Robert <arobert@cogsci.ucsd.edu>]

On Mar 16, 2005, at 12:19 PM, Stefan Monnier wrote:

>> I apologize for the "retro" question, but I was wondering if there 
>> was an
>> easy way to convert a character in the Emacs-20 internal 19-bit 
>> encoding
>> (from FAST_GLYPH_CHAR(glyph)) to UTF-8 (preferable) or straight 
>> Unicode.
>> I'd like to do it fully within C if possible, and it needs to be 
>> efficient.

I found a way to do this using parts of the C program available at:

http://tclab.kaist.ac.kr/~otfried/Mule/

Basically it uses a large table to convert from charset/byte1/byte2 to 
unicode then UTF-8.  I call SPLIT_NON_ASCII_CHAR() to get that info out 
of the 19-bit internal representation stored in the glyph.  CCL was not 
needed, though maybe it would have provided a more compact way to solve 
the problem than a 250K table.

However, I still have an issue: for 2-byte characters, such as Big5 or 
JIS Chinese characters, emacs (20) is giving me two glyphs for each 
character, with identical values.    Does this have something to do 
with it thinking the font needs a double wide horizontal space to 
render the character?

thanks,
Adrian