Re: How to walk a Lisp_String?

[Po Lu]

Manuel Giraud <manuel@ledu-giraud.fr> writes:

> Finally, I'd like to walk this Lisp_String and call FACE_FOR_CHAR for
> each charater of this frame.  And then be able to call XftDrawStringUtf8
> (or XmbDrawString) on each substring/font pair.  WDYT?

That won't work correctly since glyphs do not correspond to characters.

After you obtain the substring containing characters that can be
displayed with a single font, you should pass it to the font driver's
`shape' function, and then give the resulting glyphs and offsets to
XftDrawGlyphs.

Using XftDrawStringUtf8 is a bad idea, along with any other "UTF-8"
interface provided by an X library.  They simply don't work very well,
and cannot handle complicated things such as character compositions and
shaping.

Using XmbDrawString in conjunction with the Emacs face machinery is
probably a bad idea too, since both have differing notions of "fontset"
and "font".