Re: manipulate ttf-fonts loaded with luatex

From: Taco Hoekwater <taco@elvenkind.com>
To: mailing list for ConTeXt users <ntg-context@ntg.nl>
Cc: Hans Hagen <pragma@wxs.nl>, news3@nililand.de
Subject: Re: manipulate ttf-fonts loaded with luatex
Date: Thu, 28 Oct 2010 17:48:12 +0200	[thread overview]
Message-ID: <4CC99B3C.9070709@elvenkind.com> (raw)
In-Reply-To: <4CC98FD6.2010100@wxs.nl>

On 10/28/2010 04:59 PM, Hans Hagen wrote:
>
> if the font is okay, accessing by glyph name will work ok

The font is an 8-bit encoding-indexed Macintosh Roman font
presenting itself as TrueType, and that is why it is so
confusing.

Because the font says it is in MacRoman encoding, and the glyph
names are pointless affairs like /c140 (which is the king symbol)
instead of sane names, fontforge takes that the '140' part of
the name is a decimal code point in MacRoman encoding.

This is correct behavior on fontforge's part, but it means that
the Unicode remap becomes slightly messy, as /c140 maps to
'LATIN SMALL LETTER A WITH RING ABOVE'., and the glyph named
/c229 (which is in fact the aring symbol) maps to 'LATIN CAPITAL A
WITH CIRCUMFLEX', and /194 (which is the Acirc) maps to 'NOT SIGN',
etc. etc. In short: the font's glyph naming is anemic.

Now, it appears that luaotfload produces a rubbish .lua file, probably
because it dumps both the MacRoman and the Unicode assignment at the
same time as a merged table. That is a bug, but that is an issue for
the luaotfload maintainers, not something for the context mailing list.

In context itself, \char140  actually and correctly produces the king
symbol.

Incidentally, in context, you can get a dump of the actually used
unicode slots by running:

   \starttext
   \showfont[PIRAT.TTF][all] % grid table
   \stoptext

or

   \usemodule[fnt-10]
   \starttext
   \ShowCompleteFont{PIRAT.TTF}{12pt}{1} % number&names table
   \stoptext

Now, about fixing it: I don't think there is much you can do with
a feature file in this case. If you want to make glyph (name) changes,
it is better to do so in the actual font file, because the fea file
will get hopelessly confusing. (and it will be specific to this
particular font file anyway), and more importantly: if you use a fea
file, you will keep hitting that luaotfload bug. So either clean up
the font yourself, or report a luaotfload bug and wait for it to be
fixed ...

Best wishes,
Taco

___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________