W3C CSS2 Cascading Style Sheets, level 2 - instructional media + ...

There are also fonts that leave it to the graphic designer to choose from among
various alternative shapes provided. Unfortunately, CSS2 doesn’t yet provide the
means to select those alternatives. Currently, it is always the default shape that
is chosen from such fonts.
15.4.6 Font family name
This specifies the family name portion of the font face name. For example, the
family name for Helvetica-Bold is Helvetica and the family name of ITC Stone
Serif Semibold Italic is ITC Stone Serif. Some systems treat adornments relating
to condensed or expanded faces as if they were part of the family name.
15.4.7 Glyph widths
This is a list of widths, on the design grid, for the glyph corresponding to each
character. The list is ordered by ISO10646 code point. Widths cannot usefully be
specified when more than one glyph maps to the same character or when there
are mandatory ligatures.
15.4.8 Horizontal stem width
This value refers to the dominant stem of the font. There may be two or more
designed widths. For example, the main vertical stems of Roman characters will
differ from the thin stems on serifed "M" and "N", plus there may be different
widths for uppercase and lowercase characters in the same font. Also, either by
design or by error, all stems may have slightly different widths.
15.4.9 Height of uppercase glyphs
This measurement is the y-coordinate of the top of flat uppercase letters in Latin,
Greek, and Cyrillic scripts, measured from the baseline. This descriptor is not
necessarily useful for fonts that do not contain any glyphs from these scripts.
15.4.10 Height of lowercase glyphs
This measurement is the y-coordinate of the top of unaccented, non-ascending
lowercase letters in Latin, Greek and Cyrillic scripts, measured from the baseline.
Flat-topped letters are used, ignoring any optical correction zone. This is usually
used as a ratio of lowercase to uppercase heights as a means to compare font
families.
This descriptor is not useful for fonts that do not contain any glyphs from these
scripts. Since the heights of lowercase and uppercase letters are often
expressed as a ratio for comparing different fonts, it may be useful to set both the
lowercase and uppercase heights to the same value for unicameral scripts such
as Hebrew, where for mixed Latin and Hebrew text, the Hebrew characters are
typically set at a height midway between the uppercase and lowercase heights of
the Latin font.
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