Re: [OpenType] PS glyph `phi' vs `phi1'

From: Werner LEMBERG (
Date: Thu Feb 20 2003 - 05:01:13 EST

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    > The Unicode 3.2 text states:
    > <quote>
    > With Unicode 3.0 and the concurrent second edition of ISO/IEC
    > 10646-1, the representative glyphs for U+03C6 GREEK LETTER SMALL PHI
    > and U+03D5 GREEK PHI SYMBOL were swapped. In ordinary Greek text,
    > the character U+03C6 is used exclusively, although this characters
    > has considerably glyphic variation, sometimes represented with a
    > glyph more like the representative glyph shown for U+03C6 (the
    > `loopy' form) and less often with a glyph more like the
    > representative glyph shown for U+03D5 (the `straight' form).

    I didn't know that, sorry. Perhaps a small note should be added to
    the descriptions of U+03C6 and U+03D5 (on page 374 of Unicode 3.2)
    noting that change -- many people (including me) will miss the
    explanatory text.

    > For mathematical and technical use, the straight form of the small
    > phi is an important symbol and needs to be consistently
    > distinguishable from the loopy form. The straight form phi glyph is
    > used as the representative glyph for the symbol phi at U+03D5 to
    > satisfy this distinction.
    > The reversed assignment of representative glyphs in versions of the
    > Unicode Standard prior to Unicode 3.0 had the problem that the
    > character explicitly identified as the mathematical symbol did not
    > have the straight form of the character that is the preferred glyph
    > for that use. Furthermore, it made it unnecessarily difficult for
    > general purpose fonts supporting ordinary Greek text to also add
    > support for Greek letters used as mathematical symbols. This
    > resulted from the fact that many of those fonts already used the
    > loopy form glyph for U+03C6, as preferred for Greek body text; to
    > support the phi symbol as well, they would have had to disrupt glyph
    > choices already optimized for Greek text.
    > When mapping symbol sets or SGML entities to the Unicode Standard,
    > it is important to make sure that codes or entities that require the
    > straight form of the phi symbol be mapped to U+03D5 and not to
    > U+03C6. Mapping to the latter should be reserved for codes or
    > entities that represent the small phi as used in ordinary Greek
    > text.
    > Fonts used primarily for Greek text may use either glyph form for
    > U+03C6, but fonts that also intend to support technical use of the
    > Greek letters should use the loopy form to ensure appropriate contrast
    > with the straight form used for U+03D5.
    > </quote>

    Virtually all fonts I know of use the pre-3.0 glyph representations.
    Sigh. Any suggestion how to fix this mess?

    Thomas Phinney asks:

    > So, if I understand correctly: this means you no longer think
    > Adobe's glyph naming/encoding is in error?

    I no longer know what I shall think. It really depends on how the AGL
    names `phi' and `phi1' look like, and whether Adobe plans to
    distinguish between pre-3.0 and post-3.0 Unicode mapping. If `phi' is
    the stroked glyph and `phi1' the curly version (as used e.g. in the
    Symbol font version 001.007), then the mapping is wrong.

    IMHO, the decision to flip the glyph shapes was a shot into the leg.
    But it's too late...


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