[pdftex] ToUnicode map and virtual fonts

[Thanh Han The]

I admit that I didn't follow Adobe recommendations but wrote
the code based on some examples. Most of
the problems mentioned can be solved by following
http://partners.adobe.com/public/developer/opentype/index_glyph.html,
which is not very hard.

>   . I dislike the automatic handling of `small', `oldstyle',
>     `inferior', and `superior' suffixes which is against the AGL
>     rules.  Fonts which don't follow the AGL need a bundle of calls to
>     \pdfglyphtounicode anyway, so why does this exception exist?

I cannot see why this is bad. I stole the idea from
somewhere in the Internet (sorry I cannot exactly recall
where it is; I only remember it comes from some
documentation about an XSL-FO processor). This actually saves
us from many calls to \pdfglyphtounicode, as such names
are pretty common in opentype fonts and cannot be considered
as exceptions IMO. Do you have an example when this causes
problem?

>   . Finally, \pdfglyphtounicode can't handle Unicode values outside of
>     the BMP (this is, values >= U+FFFF) -- for example, old Vietnamese
>     (using CJKV glyphs) needs that...
>
> I consider the last item a real design error in \pdfglyphtounicode.

yes it is.

Thanh


On Sun, Oct 01, 2006 at 07:09:15AM +0200, Werner LEMBERG wrote:
>
> > see
> > http://sarovar.org/tracker/index.php?func=detail%26aid=580%26group_id=106%26atid=495
>
> Uh, oh, looking into tounicode3.zip, there are the following severe
> problems.
>
>   . Automatic recognition of `uXXXXX' and `uniXXXX' glyph names is
>     missing.  For big CJKV subfonts, it's simply unreasonable to add
>     more than 20000 calls to \pdfglyphtounicode!
>
>   . pdftex should automatically recognize AGL ligatures like `f_i_i',
>     *without* a special \pdfglyphtounicode rule.  All such rules
>     should be removed from glyphtounicode.tex.
>
>     Is there any reason why pdftex doesn't implement the complete AGL
>     algorithm?
>
>   . I dislike the automatic handling of `small', `oldstyle',
>     `inferior', and `superior' suffixes which is against the AGL
>     rules.  Fonts which don't follow the AGL need a bundle of calls to
>     \pdfglyphtounicode anyway, so why does this exception exist?
>
>   . Finally, \pdfglyphtounicode can't handle Unicode values outside of
>     the BMP (this is, values >= U+FFFF) -- for example, old Vietnamese
>     (using CJKV glyphs) needs that...
>
> I consider the last item a real design error in \pdfglyphtounicode.
>
>
>     Werner