[lltx] Misplaced combined diacritics

[Khaled Hosny]

On Fri, Oct 01, 2010 at 03:24:16PM +0200, Khaled Hosny wrote:
> On Fri, Oct 01, 2010 at 03:11:16PM +0200, Khaled Hosny wrote:
> > On Fri, Oct 01, 2010 at 03:04:16PM +0200, Arthur Reutenauer wrote:
> > >   The more general issue is with fontspec for LuaTeX not enabling the
> > > 'ccmp' OpenType feature by default, I guess.
> > 
> > I'll check, if that is the case it should be easily fixable.
> 
> No, it has nothing to do with ccmp which we already turn on by default,
> actually it wouldn't make any difference since the ccmp table in the
> font is used to decompose pre composed glyphs, not the other way around,
> and all diacritics are positioned by mark positioning, and some bug is
> causing the marks to be positioned on the wrong glyph, something to talk
> with Hans about.

Something odd related to directionality is happening here, I was
wondering why my latest Arabic font with heavy mark positioning is
working fine, now if you set direction to right-to-left the marks are
positioned properly:

\input{luaotfload.sty}
\font\gentr={file:GenBasR.ttf:script=latn;language=dflt}
\leavevmode{\luatextextdir TRT\gentr xäx XÄX}\par
\leavevmode{\luatextextdir TLT\gentr xäx XÄX}\par
\bye

-- 
 Khaled Hosny
 Arabic localiser and member of Arabeyes.org team
 Free font developer