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

the extras are ignored. [p. 42]
Example(s):
For example:
widths: U+4E00-4E1F 1736 1874 1692
widths: U+1A?? 1490, U+215? 1473 1838 1927 1684 1356 1792
1815 1848 1870 1492 1715 1745 1584 1992 1978 1770
In the first example a range of 32 characters is given, from 4E00 to 4E1F. The
glyph corresponding to the first character (4E00) has a width of 1736, the second
has a width of 1874 and the third, 1692. Because not enough widths have been
provided, the last width replicates to cover the rest of the specified range. The
second example sets a single width, 1490, for an entire range of 256 glyphs and
then explicit widths for a range of 16 glyphs.
This descriptor cannot describe multiple glyphs corresponding to a single character,
or ligatures of multiple characters. Thus, this descriptor can only be used
for scripts that do not have contextual forms or mandatory ligatures. It is nevertheless
useful in those situations. Scripts that require a one-to-many or
many-to-many mapping of characters to glyphs cannot at present use this
descriptor to enable font synthesis although they can still use font downloading or
intelligent matching.
’bbox’ (Descriptor)
Value: , , ,
Initial: undefined
Media: visual
This is the descriptor for the maximal bounding box [p. 229] of the font. The
value is a comma-separated list of exactly four numbers specifying, in order, the
lower left x, lower left y, upper right x, and upper right y of the bounding box for
the complete font.
’definition-src’ (Descriptor)
Value:
Initial: undefined
Media: visual
The font descriptors may either be within the font definition in the style sheet,
or may be provided within a separate font definition resource identified by a URI.
The latter approach can reduce network traffic when multiple style sheets reference
the same fonts.
15.3.8 Descriptors for Alignment: ’baseline’, ’centerline’,
’mathline’, and ’topline’
These optional descriptors are used to align runs of different scripts with one
another.
223