Simplify redisplay-x/separate_textual_runs

[Olivier Galibert]

On Fri, Mar 30, 2007 at 05:14:47PM +0200, Aidan Kehoe wrote:
>  > +      int ucs = ichar_to_unicode(ch);
>  > +
>  > +      /* If UCS is less than zero or greater than 0xFFFF, set ucs2 to
>  > +	 REPLACMENT CHARACTER. */
>  > +      /* That means we can't handle characters outside of the BMP for now */
>  > +      ucs = (ucs & ~0xFFFF) ? 0xFFFD : ucs;
> 
> You???ve just done that Unicode conversion to throw away the result. That???s
> not very constructive, since the XFT redisplay routines *require* that the
> supplied strings are Unicode. I???m fighting with Cygwin right now to get it
> to usefully install fontconfig so I can check this out for certain, but I
> believe strongly that this will break redisplay with non-Latin-1 characters
> under XFT and Mule.

Ok, I don't see how.  Did you miss the '~' ?  The line keeps the value
as-is if it is in the 0000-ffff range, sets it to fffd otherwise.  So
that breaks non-BMP characters indeed, but not non-latin1 ones.  The
rest of the Xft code wants an ucs-2 representation at that point.

It's code that was there in the first place.  I have no issue with
going to ucs-4 or utf-8 but I didn't want to change things outside of
separate_textual_runs in this patch.

  OG.