[luatex] How to color unicode combinging characters.

[Khaled Hosny]

On Fri, Mar 18, 2011 at 03:39:50AM +0200, Khaled Hosny wrote:
> On Thu, Mar 17, 2011 at 10:25:11PM +0200, Simo Ojala wrote:
> > 
> > Hi,
> > 
> > I am really just taking my first steps in TeX world, so forgive me
> > my ignorance. However I already have this quite advanced coloring
> > problem and I have read and been told that LuaTeX might be able to
> > solve this kind of stuff. So thats why I try to ask this here,
> > hopefully found the right place to post this kind of problem...
> > 
> > I am trying to create some ancient hebrew inflection charts and the
> > problem is to be able to paint vowels (and other diacritics) without
> > changing color of the consonants they are combined with. (The vowels
> > are unicode combining characters which are positioned according to
> > and combined with consonants.) I already have got some suggestions
> > that I could do some thing like this:
> > 
> > \textcolor{red}{a}\textcolor{blue}{b} % where 'a' represents a
> > consonant and 'b' a vowel
> > 
> > However this leads to situation where the characters are not
> > actually combined, but just placed separately to the document. That
> > it turn leads to positioning problems and other bad stuff.
> 
> You don't provide any sample files, so one can only guess.
> 
> I think the problem is related to pdfliteral whatsits used to implement
> color, so using luacolor package (check its documentation) in LaTeX or
> using ConTeXt would help, either would get rid of whatsits in favour of
> attributes. But again, without a test file one can only guess.
> 
> ConTeXt have even more "goodies" to automatically color certain glyphs
> without manually inserted color commands, but I never used it, though.

Looks like luacolor is not compatible with luaotfload so opentype
features (needed for mark positioning) will not work.

However, ConTeXt test was successful (as far as my non-Hebrew eye can
tell).

Regards,
 Khaled

-- 
 Khaled Hosny
 Egyptian
 Arab
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