Encodings in TEX
The history of TEX font encodings
This document explains the ideas behind LATEX character encodings and the restrictions that apply when defining a new encoding; it also lists the encodings that are already defined. Thus, a group at the TUG Annual General Meeting in Cork, Ireland, defined a uniform 256-glyph font encoding, which contains the accented and non-syllabic letters needed to express most Western European languages ( and some Eastern European ones) without resorting to the \accent command. This "Tape" encoding has since been realized in a series of fonts designed with Metafont, in at least one series of fonts that is available in both Adobe Type 1 and OpenType formats, and in a number of virtual typefaces of others. series.
Since the time of the Cork meeting, much effort has been devoted to designing text font encodings for use with TEX, and the Cork encoding influenced the design of many such encodings. A TUG Technical Working Group was established at the Cork meeting, the aim of which was to define a set of 256 glyph encodings to adjust and extend Knuth's originals, using ideas from several other fonts that had appeared since then, and from recognized needs of researchers in mathematics and mathematical sciences. However, the slow progress of these mathematical encodings has been overtaken by the addition (in the last decade or so) of a large number of mathematical symbols to Unicode [3]; further changes can be expected so that the new mathematical encodings of public fonts will most likely be delayed even further.
Further information
Further details may include the code positions used in the encoding, the variable slots (see below), a sample font (listed later in the document if the relevant fonts are present), and a source for further reference. While the defining feature of an encoding is that every font encoded according to the encoding must have the same glyph set, there are some encodings (most notably OT1 and its descendants) in which a few glyph code slots differ in their content in different fonts. We do not recommend introducing any new encryption names unless careful consideration and discussion in the user community has confirmed the need for the encryption.
The 'OT' series of font encodings begins with Donald Knuth's original text encoding used for text fonts in the earliest releases of TEX itself. Support for this encoding is available in the Cyrillic package, although for all practical purposes it is better to use one of the T2 encodings. The Cork encoding was developed to take advantage of the (then) new TEX 3 capabilities, which allow word splitting in most Western European (and some Eastern European) languages in an unmodified version of TEX.
The encoding was developed in the absence of any existing attempt at typeface design, but instances written in Metafont (the 'EC' typefaces), and more recently Adobe Type 1 instances of the same typefaces have become available. LATEX name: T2A, T2B, T2C Public name: Cyrillic encodings Author: The CyrTUG font team Glyph slots used: 0x00–0xFF. There are too many glyphs in the full Cyrillic complement of languages for all of them to be covered by a single LATEX-compliant encoding (the bottom half of each L2 encoding is identical to that of L1, so each has a conforming LATEX coding — see section 3).
Unfortunately, TS1encoding was developed without reference to the glyphs available in existing commercial fonts.
Other encodings
Local encodings provide the means to develop representation techniques suitable for a specific TEX environment. It is an alternative to the T1 encoding developed by Y&Y and used in their commercial TEX implementation. This encoding does not meet the restrictions for T encodings described in section 3 on page 13, as it has no ascii glyphs at all.
Encodings that are supposed to be used with LATEX for "general purpose text fonts" must have certain fixed glyphs in certain encoding slots. A 'general font' is a font intended for arbitrary text in natural language and not only in special environments (such as the phonetic alphabet) or only for. If there are empty spaces available, then adding all or some of the diacritics will be the best way to fill them.
If there are not enough slots for the required characters, one possible technique is to create a sub-encoding and move non-letter characters into it. Since only "letters" participate in the hyphenation algorithm, this technique does not affect the appearance of the typeset result.
The constraints on upper/lower case tables
This is the case for the following glyphs that must be in their assii positions for general purpose text encodings:. Since only "letters" participate in the hyphenation algorithm, this technique does not affect the appearance of the printed result. different LATEX installations will not be able to communicate with each other due to incompatible font sets). One way to use such slots is to fill them with ligature glyphs, since TEX will not consult these tables for glyphs built by ligature programs, but instead uses the entries for the individual glyphs used to produce the ligature.
For a full list of the upper/lower case mapping tables, see section B (page 39). An encoding-specific command is a command that generates a glyph (or glyphs) to produce a graphical effect that can be implemented differently in different encodings. The encoding-specific command changes execution automatically when the encoding changes over the course of the document.
Special encoding commands are included in the internal LATEX character representation (licr) and are also discussed in [21, Sec. In the table, the first 15 commands are "accent-like" and require as an argument the character to be accented. 7] Matthias Clasen and Ulrik Vieth: Towards a new math font encoding for (La)TEX. mfg-euro-all.ps.gz.
The vnrfont family, developed by the author of pdfTEX, Hàn Thê´ Thành. http://vntex.org/download/vntex. 18] Homepage of the International Phonetic Association.http://www.arts. gla.ac.uk/IPA/ipa.html. The lh fonts for Cyrillic: 〈CTAN〉/fonts/cyrillic/lh. 21] Frank Mittelbach and Michel Goossens. The LATEX Companion second edition.
22] The Unicode Standard.http://unicode.org. 23] Justin Ziegler, Mathematical Font Encoding Technical Report, June 1994, http:. This appendix contains a table of each font mentioned as an "example" font above, provided the font was available when the document was processed with LATEX.
Text symbol encodings
Extended text encodings
Mathematical encodings
Other encodings
The following two sets of tables list the \uppercase and \lowercase values for each position in the LATEX standard 256-character tables.