Re: Latin ligatures and Unicode

From: Christopher John Fynn (cfynn@dircon.co.uk)
Date: Sun Dec 19 1999 - 21:09:06 EST


Eberhard Pehlemann wrote:

> I am dealing with so-called "Fraktur" or "Blackletter"
> fonts that encode character shapes used in historical
> european typesetting, especially in german typesetting
> of the last century. These fonts must contain glyphs for
> the long s and for several ligatures, at minimum for ch,
> ck, ff, fi, fl, ft, ll, sch, si, ss, st (all using the long s), tt
> and tz.

> All of you know about the problems of handling such
> glyphs with traditional 8-bit-fonts. So I try to find out
> the best way to handle these glyphs with Unicode and
> 16-bit-fonts.

Eberhard,

IMO the best way of handling ligatures for "Fraktur" typefaces
is by creating OpenType (or Apple's AAT) fonts with the proper
table information. If the combinations of characters you list
*must* be displayed by ligatures when text is set in your
Fraktur font you can specify this in the OpenType substitution
tables or you can make the substitution optional.

The substitution (whether ligatures are formed or not) may
be specified on a language by language basis or you can
make it the default (non-language specific) behaviour for
your font.

(Of course all this will only work in OT or AAT savvy applications.)

I'd handle all ligatures glyphs this way even in the cases
where a ligature character exists in Unicode. I think it best
to make the primary way of forming ligatures through
OpenType layout tables rather than relying on the user to
enter a precomposed-ligature character - or the proposed
"zero-width ligator" character.

A place where zero-width ligator (or non-ligator) characters
might be required is where the presence or abscence of
a ligature affects the meaning or other information being
conveyed by the text. For instance applications where
different manuscripts or editions are being compared
there may be a real need to encode exactly where ligatures
occur in on example of a text but not in another.

- Chris

BTW are you subscribed to the OpenType discussion list?
http://www.microsoft.com/typography/otspec/otlist.htm



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