From: Doug Ewell (dewell@adelphia.net)
Date: Mon Oct 28 2002 - 20:37:35 EST
My USD 0.02, as someone who is neither a professional typographer nor a
font designer (more than one, but not quite two, different things)...
Discussions about the character-glyph model often mention the "essential
characteristics" of a given character. For example, a Latin capital A
can be bold, italic, script, sans-serif, etc., but it must always have
that essential "A-ness" such that readers of (e.g.) English can identify
it as an A instead of, say, an O or a 4 or a picture of a duck. (Mark
Davis has a chart showing dozens of different A's in his "Unicode Myths"
presentation.)
Somewhere in between the obvious relationships (A = A, B ≠ A), we have
the case pair A and a. They are not identical, but they are certainly
more similar to each other than are A and B.
It seems to me, as a non-font guy, that calling a font a "Unicode font"
implies two things:
1. It must be based on Unicode code points. For True- and OpenType
fonts, this implies a Unicode cmap; for other font technologies it
implies some more-or-less equivalent mechanism. The point is that
glyphs must be associated with Unicode code points (not necessarily
1-to-1, of course), not merely with an internal 8-bit table that can be
mapped to Unicode only through some other piece of software.
2. The glyphs must reflect the "essential characteristics" of the
Unicode character to which they are mapped. That means a capital A can
be bold, italic, script, sans-serif, etc. A small a can also be
small-caps (or even full-size caps), but I think this is the only
controversial point.
In a Unicode font, U+0041 cannot be mapped to a capital A with macron,
as it is in Bookshelf Symbol 1; nor to a six-pointed star, as in
Monotype Sorts; nor to a hand holding up two fingers, as in Wingdings.
(But it can be mapped to a "notdef" glyph, if the font makes no claim to
supporting U+0041.)
U+0915 absolutely can have snow on it, or be bold or italic or whatever
(or all of these), as long as a Devanagari reader would recognize its
essential "ka-ness." It cannot look like a Latin A, nor for that matter
can U+0041 look like a Devanagari ka.
Font guys, do you agree with this?
Of course, the term "Unicode font" is also often used to mean "a font
that covers all, or nearly all, of Unicode." Font technologies
generally don't even allow this, of course, and even by the standards of
"nearly" we are still limiting ourselves to things like Bitstream
Cyberbit, Arial Unicode MS, Code2000, Cardo, etc. Right or wrong, this
is a commonly accepted meaning for "Unicode font."
-Doug Ewell
Fullerton, California
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