Re: Greek Prosgegrammeni

From: Kenneth Whistler (
Date: Tue Nov 21 2000 - 15:00:58 EST

Lukas wrote:

> Sorry I'm going on about this again, but I feel still puzzled, so bear with
> me once more.
> I'm not quite sure if Mark's answer solves my problem. I can see that the
> case mappings and decompositions as defined in the charts are internally
> contradiction-free, no problem so far. Only, there still seems to be a
> mismatch between what the charts show and what users will probably expect to
> see. Let me repeat: as far as I can gather, there are several different
> typographical traditions, but roughly speaking there are two: In one
> tradition, readers expect to see full-size, spacing glyphs for mute iotas
> *both* in titlecase and in uppercase (usually a small iota glyph in
> titlecase, a small or capital iota glyph in uppercase). In the other
> tradition, readers expect to see smaller, diacritic-like glyphs (either
> centered under, or near the right corner of, the base letter), again *both*
> in titlecase and in uppercase. All the printing I've seen so far seems to
> adhere either to the one major pattern or the other; they apparently don't
> often get mixed. And as we've seen, many people who are used to the one
> pattern aren't even aware that the other exists.

At the risk of repeating what Asmus has said about this topic, it is
important to remember that the Unicode Standard is not a guide to
typography, but a guide to character interpretation and usage.

Greek fonts should be designed to match expectations of typography, and
then Greek rendering systems will need to map characters and character
combinations appropriately onto the relevant glyphs to produce the
expected effects for one tradition or another.

The Greek polytonic extensions in the Greek Extended block, U+1F00..U1FFF
were added to 10646 (and hence to the Unicode Standard as well) in 1991 at the
insistence of the Greek national body, ELOT, to match their polytonic
standard. Unfortunately, that standard was not developed with sufficient
attention to implementation details, and as a result, we are left with
these problems of case identification (lower, upper, title), case mapping,
decomposition, and representative glyph choice in dealing with the
precomposed polytonic Greek.

The UTC wrangled over this during the years, and has finally settled, for
Unicode 3.0, on what seems to be the most consistent set of case mappings,
decompositions, and representative glyphs we can devise. The goal is
internal consistency, so that despite the edge cases and special cases,
it is possible to write software to handle the characters.

This is a *compromise*, however, making the best of the bad repertoire
we were dealt. It is not ever going to be possible to please everyone
about polytonic Greek in the standard, since people are looking for
different things when they come to the standard in the first place.

> The Unicode charts, somehow arbitrarily, seem to dictate in favour of the
> one tradition in the one case and of the second tradition in the other. In
> titlecase you get some sort of a non-spacing diacritic, while in uppercase
> you *must* use the full-size capital iota glyph. Users who want full-size
> iota glyphs throughout will find it difficult to live with the decomposition
> to u+0345 in titlecase,

Not if the fonts they use map capital letter + ypogegrammeni character
combinations into capital letter + full-size iota glyph sequences.

Of course, if the fonts they use are not designed for correct use with
polytonic Greek, then the default rendering behavior of the ypogegrammeni
will not be what they expect or want. Time to upgrade the fonts.

> while users who want small diacritic glyphs
> throughout will see no sense in the u+0399 (capital iota) in uppercase.
> Without some *very* sophisticated rendering machine, neither group will be
> able to get it all displayed to their taste.

This is not all that sophisticated. It should be a matter that can be
wholly encapsulated within the fonts:

                            Font I Font II

A. 0397 0313 0345 ==> 'H iota adscript 'H iota subscript

B. 1F98 ==> 'H iota adscript 'H iota subscript

> People will prefer encoding
> their texts in ways deviating from the norm, rather sacrificing case
> equivalence than what each of them will consider "correct" display.

Many of us have felt all along that polytonic Greek should always be
represented decomposed, and that the ELOT polytonic "character" encoding
was a dangerous conflation of glyph design and character encoding concerns.

Implementations that use full decomposition for polytonic Greek and fonts
that correctly map the accentual and diacritic combinations are the
best bet for consistency *and* good presentation in the long run.


> Lukas

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