190 lines
7.1 KiB
ReStructuredText
190 lines
7.1 KiB
ReStructuredText
Unicode support
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===============
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Last update: 2005-01-17, version 1.4
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This file is maintained by H. Peter Anvin <unicode@lanana.org> as part
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of the Linux Assigned Names And Numbers Authority (LANANA) project.
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The current version can be found at:
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http://www.lanana.org/docs/unicode/admin-guide/unicode.rst
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Introduction
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------------
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The Linux kernel code has been rewritten to use Unicode to map
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characters to fonts. By downloading a single Unicode-to-font table,
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both the eight-bit character sets and UTF-8 mode are changed to use
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the font as indicated.
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This changes the semantics of the eight-bit character tables subtly.
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The four character tables are now:
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=============== =============================== ================
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Map symbol Map name Escape code (G0)
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=============== =============================== ================
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LAT1_MAP Latin-1 (ISO 8859-1) ESC ( B
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GRAF_MAP DEC VT100 pseudographics ESC ( 0
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IBMPC_MAP IBM code page 437 ESC ( U
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USER_MAP User defined ESC ( K
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=============== =============================== ================
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In particular, ESC ( U is no longer "straight to font", since the font
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might be completely different than the IBM character set. This
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permits for example the use of block graphics even with a Latin-1 font
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loaded.
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Note that although these codes are similar to ISO 2022, neither the
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codes nor their uses match ISO 2022; Linux has two 8-bit codes (G0 and
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G1), whereas ISO 2022 has four 7-bit codes (G0-G3).
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In accordance with the Unicode standard/ISO 10646 the range U+F000 to
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U+F8FF has been reserved for OS-wide allocation (the Unicode Standard
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refers to this as a "Corporate Zone", since this is inaccurate for
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Linux we call it the "Linux Zone"). U+F000 was picked as the starting
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point since it lets the direct-mapping area start on a large power of
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two (in case 1024- or 2048-character fonts ever become necessary).
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This leaves U+E000 to U+EFFF as End User Zone.
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[v1.2]: The Unicodes range from U+F000 and up to U+F7FF have been
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hard-coded to map directly to the loaded font, bypassing the
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translation table. The user-defined map now defaults to U+F000 to
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U+F0FF, emulating the previous behaviour. In practice, this range
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might be shorter; for example, vgacon can only handle 256-character
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(U+F000..U+F0FF) or 512-character (U+F000..U+F1FF) fonts.
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Actual characters assigned in the Linux Zone
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--------------------------------------------
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In addition, the following characters not present in Unicode 1.1.4
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have been defined; these are used by the DEC VT graphics map. [v1.2]
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THIS USE IS OBSOLETE AND SHOULD NO LONGER BE USED; PLEASE SEE BELOW.
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====== ======================================
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U+F800 DEC VT GRAPHICS HORIZONTAL LINE SCAN 1
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U+F801 DEC VT GRAPHICS HORIZONTAL LINE SCAN 3
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U+F803 DEC VT GRAPHICS HORIZONTAL LINE SCAN 7
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U+F804 DEC VT GRAPHICS HORIZONTAL LINE SCAN 9
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====== ======================================
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The DEC VT220 uses a 6x10 character matrix, and these characters form
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a smooth progression in the DEC VT graphics character set. I have
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omitted the scan 5 line, since it is also used as a block-graphics
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character, and hence has been coded as U+2500 FORMS LIGHT HORIZONTAL.
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[v1.3]: These characters have been officially added to Unicode 3.2.0;
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they are added at U+23BA, U+23BB, U+23BC, U+23BD. Linux now uses the
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new values.
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[v1.2]: The following characters have been added to represent common
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keyboard symbols that are unlikely to ever be added to Unicode proper
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since they are horribly vendor-specific. This, of course, is an
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excellent example of horrible design.
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====== ======================================
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U+F810 KEYBOARD SYMBOL FLYING FLAG
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U+F811 KEYBOARD SYMBOL PULLDOWN MENU
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U+F812 KEYBOARD SYMBOL OPEN APPLE
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U+F813 KEYBOARD SYMBOL SOLID APPLE
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====== ======================================
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Klingon language support
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------------------------
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In 1996, Linux was the first operating system in the world to add
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support for the artificial language Klingon, created by Marc Okrand
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for the "Star Trek" television series. This encoding was later
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adopted by the ConScript Unicode Registry and proposed (but ultimately
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rejected) for inclusion in Unicode Plane 1. Thus, it remains as a
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Linux/CSUR private assignment in the Linux Zone.
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This encoding has been endorsed by the Klingon Language Institute.
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For more information, contact them at:
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http://www.kli.org/
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Since the characters in the beginning of the Linux CZ have been more
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of the dingbats/symbols/forms type and this is a language, I have
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located it at the end, on a 16-cell boundary in keeping with standard
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Unicode practice.
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.. note::
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This range is now officially managed by the ConScript Unicode
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Registry. The normative reference is at:
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http://www.evertype.com/standards/csur/klingon.html
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Klingon has an alphabet of 26 characters, a positional numeric writing
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system with 10 digits, and is written left-to-right, top-to-bottom.
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Several glyph forms for the Klingon alphabet have been proposed.
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However, since the set of symbols appear to be consistent throughout,
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with only the actual shapes being different, in keeping with standard
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Unicode practice these differences are considered font variants.
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====== =======================================================
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U+F8D0 KLINGON LETTER A
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U+F8D1 KLINGON LETTER B
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U+F8D2 KLINGON LETTER CH
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U+F8D3 KLINGON LETTER D
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U+F8D4 KLINGON LETTER E
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U+F8D5 KLINGON LETTER GH
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U+F8D6 KLINGON LETTER H
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U+F8D7 KLINGON LETTER I
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U+F8D8 KLINGON LETTER J
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U+F8D9 KLINGON LETTER L
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U+F8DA KLINGON LETTER M
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U+F8DB KLINGON LETTER N
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U+F8DC KLINGON LETTER NG
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U+F8DD KLINGON LETTER O
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U+F8DE KLINGON LETTER P
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U+F8DF KLINGON LETTER Q
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- Written <q> in standard Okrand Latin transliteration
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U+F8E0 KLINGON LETTER QH
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- Written <Q> in standard Okrand Latin transliteration
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U+F8E1 KLINGON LETTER R
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U+F8E2 KLINGON LETTER S
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U+F8E3 KLINGON LETTER T
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U+F8E4 KLINGON LETTER TLH
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U+F8E5 KLINGON LETTER U
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U+F8E6 KLINGON LETTER V
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U+F8E7 KLINGON LETTER W
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U+F8E8 KLINGON LETTER Y
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U+F8E9 KLINGON LETTER GLOTTAL STOP
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U+F8F0 KLINGON DIGIT ZERO
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U+F8F1 KLINGON DIGIT ONE
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U+F8F2 KLINGON DIGIT TWO
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U+F8F3 KLINGON DIGIT THREE
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U+F8F4 KLINGON DIGIT FOUR
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U+F8F5 KLINGON DIGIT FIVE
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U+F8F6 KLINGON DIGIT SIX
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U+F8F7 KLINGON DIGIT SEVEN
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U+F8F8 KLINGON DIGIT EIGHT
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U+F8F9 KLINGON DIGIT NINE
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U+F8FD KLINGON COMMA
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U+F8FE KLINGON FULL STOP
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U+F8FF KLINGON SYMBOL FOR EMPIRE
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====== =======================================================
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Other Fictional and Artificial Scripts
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--------------------------------------
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Since the assignment of the Klingon Linux Unicode block, a registry of
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fictional and artificial scripts has been established by John Cowan
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<jcowan@reutershealth.com> and Michael Everson <everson@evertype.com>.
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The ConScript Unicode Registry is accessible at:
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http://www.evertype.com/standards/csur/
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The ranges used fall at the low end of the End User Zone and can hence
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not be normatively assigned, but it is recommended that people who
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wish to encode fictional scripts use these codes, in the interest of
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interoperability. For Klingon, CSUR has adopted the Linux encoding.
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The CSUR people are driving adding Tengwar and Cirth into Unicode
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Plane 1; the addition of Klingon to Unicode Plane 1 has been rejected
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and so the above encoding remains official.
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