Re: Symbol font mappings

From: Robert Herzog (Robert.Herzog@cern.ch)
Date: Fri Oct 22 1999 - 06:33:11 EDT


Hello,

On Thu, 21 Oct 1999 03:07:42 -0700 (PDT) Kevin Bracey wrote:

> In message <199910210949.CAA14247@unicode.org>
> Markus Kuhn <Markus.Kuhn@cl.cam.ac.uk> wrote:
>
> > Robert Herzog wrote on 1999-10-15 09:51 UTC:
> > > http://partners.adobe.com/asn/developer/typeforum/glyphlist.txt
> > > (Of which the following lines might also have to be changed to
> > > reflect the unicode 3.0 glyph swap:
> > > 03C6;phi;GREEK SMALL LETTER PHI
> > > 03D5;phi1;GREEK PHI SYMBOL)
> >
> > Has there already been any progress within Adobe to make this
> > swap in the table? Who is in charge of Adobe's glyphlist.txt?
> >
>
> I can't see how that swap makes any sense at all.

The reasoning goes as follows:

1. In mathematics there is a _semantic_ difference between
   'open phi' and 'closed phi'. It's NOT just a glyph variant.

2. This semantic difference should be _unambiguously_ encoded
   in Unicode

3. The Greek seem to prefer the 'open phi' in their texts, which
   suggests to use 'open phi' at U+03C6, greek letter phi. For
   the mathematicians it does not matter if 'open phi' is at
   U+03C6 and 'closed phi' at U+03D5 (greek phi symbol) or the
   other way around as long as the assignment is fixed (for ever).

4. Unfortunately the 'closed phi' was depicted at U+03C6 in
   Unicode 2.0 and prior, with the result that 'Unicode fonts'
   (e.g. Lucida Unicode and Arial Unicode MS) followed
   Unicode, wheras fonts for the Greek market (among them
   all WGL4 fonts) had the 'open phi' at U+03C6. I think many
   will agree that this is exactly the encoding mess which
   Unicode was meant to prevent.

5. To keep Unicode unambigous (just about) AND follow Greek practice
   the 'open phi' glyph will be shown at U+03C6 and and the
   'closed phi' at U+03D5 in Unicode 3.0.
   (I would have liked an unambigous name for the characters as well,
    eg. 'Greek small letter phi' and 'Greek small letter closed phi',
    but I guess this is politically [also technically?] impossible.)

6. http://partners.adobe.com/asn/developer/typeforum/glyphlist.txt
   is a GLYPHlist. Unless it is changed PostScript 'phi' means 'closed phi'
   and PS 'phi1' 'open phi', because that's how they appear in the Symbol font.

7. Hence from 5 and 6 follows for Unicode 3.0
   U+03C6 -> 'open phi' -> PostScript name 'phi1' and
   U+03D5 -> 'closed phi' -> PS name 'phi',
   which is different from the current Adobe glyphlist.

> Any Greek font will have its phi called /phi, not /phi1, and it will be
> the curly form. If it had the alternate, upright form, it would be /phi1.
>
> The Symbol font has an upright phi called /phi, which is also fine, because
> that's the glyph variant used for phi in mathematics. The alternate curly
> form in this context is /phi1.
>
> It's just a glyph variant, isn't it?

No, there is a semantic difference in mathematics.

> The Symbol font has the glyphs for "phi" and "phi symbol" one way round,
> reflecting mathematics usage, and a Greek language font would have them
> the other way round reflecting Greek usage.

I thought that's exactly what Unicode was conveived for to avoid. In any
case there are many fonts which will be used for Greek texts AND mathematics,
under MS Windows certainly all WGL4 fonts.

Regards, Robert

PS: Is there really nobody from Adobe on this list?

----------------------
Robert Herzog
LHC division, CERN (European Laboratory for Particle Physics)
1211 Geneva 23, Switzerland



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