[luatex] How to color unicode combinging characters.

[Khaled Hosny]

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.

Regards,
 Khaled

-- 
 Khaled Hosny
 Egyptian
 Arab