Guide to LaTeX (4th Edition) (Tools and Techniques

G.4. Extended Computer fonts 499
G.4.1 Limitations and deficiencies of the CM fonts
Most of the diacritical marks (accents) used in European languages written
with the Latin alphabet are contained in, or may be generated by, T E X’s
Computer Modern (CM) fonts. A basic set of naked accents is available
for combination with other letters, such as the acute accent ´ with the
letter e to make é. Other combinations may be constructed for diacritical
marks that are not predefined in T E X or L AT E X.
Fashioning diacritical characters as a combination of letters and special
symbols has one great disadvantage for the T E X processing: words containing
such characters cannot take part in the automatic word division
since the hyphenation patterns include only pure letters. The accented
letters, such as those in German and French and most other languages,
must be treated as single characters in the hyphenation patterns, and
must appear as single letters in the character set.
In addition to diacritical characters, a number of special letters are
employed in some European languages, such as ß, Æ, æ, Œ, œ, Ø, and
ø, which are provided in standard T E X with the CM fonts (Section 2.5.6).
However, other special letters, such as Ŋ, ŋ, Þ, þ, and ð, are missing
completely and cannot be easily constructed from existing ones.
G.4.2 The Cork proposal
At the 1990 International T E X Conference in Cork, Ireland, an extension of
the Latin alphabet and its assignments within the 256 character positions
was proposed and accepted. This extension includes the majority of
special and diacritical letters as single characters for many languages
written with the Latin alphabet. Hyphenation patterns for such languages
may include the special and diacritical letters as single letters for optimal
word division by T E X and L AT E X.
Character fonts conforming to the Cork scheme are to bear the identifying
letters ec in their names for ‘Extended Computer’ in place of the
cm for ‘Computer Modern’.
G.4.3 The realization of EC fonts
The Cork proposal for extending the T E X fonts to 256 characters was first
implemented by Norbert Schwarz, who produced an initial set of META-
FONT source files. He also selected the designation dc to emphasize that
this was a preliminary realization of the EC fonts. Some work was still
needed to fine-tune the design of several symbols.
After issuing versions 1.2 and 1.3 of the DC fonts in 1995 and 1996,
Jörg Knappen released the first set of true EC fonts in January, 1997. Font
Layout 9 presents his font ecrm1000, the extended version of cmr10. The
EC fonts are now considered to be stable in that neither their encoding