unicode.rst 7.1 KB

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  1. Unicode support
  2. ===============
  3. Last update: 2005-01-17, version 1.4
  4. This file is maintained by H. Peter Anvin <unicode@lanana.org> as part
  5. of the Linux Assigned Names And Numbers Authority (LANANA) project.
  6. The current version can be found at:
  7. http://www.lanana.org/docs/unicode/admin-guide/unicode.rst
  8. Introduction
  9. ------------
  10. The Linux kernel code has been rewritten to use Unicode to map
  11. characters to fonts. By downloading a single Unicode-to-font table,
  12. both the eight-bit character sets and UTF-8 mode are changed to use
  13. the font as indicated.
  14. This changes the semantics of the eight-bit character tables subtly.
  15. The four character tables are now:
  16. =============== =============================== ================
  17. Map symbol Map name Escape code (G0)
  18. =============== =============================== ================
  19. LAT1_MAP Latin-1 (ISO 8859-1) ESC ( B
  20. GRAF_MAP DEC VT100 pseudographics ESC ( 0
  21. IBMPC_MAP IBM code page 437 ESC ( U
  22. USER_MAP User defined ESC ( K
  23. =============== =============================== ================
  24. In particular, ESC ( U is no longer "straight to font", since the font
  25. might be completely different than the IBM character set. This
  26. permits for example the use of block graphics even with a Latin-1 font
  27. loaded.
  28. Note that although these codes are similar to ISO 2022, neither the
  29. codes nor their uses match ISO 2022; Linux has two 8-bit codes (G0 and
  30. G1), whereas ISO 2022 has four 7-bit codes (G0-G3).
  31. In accordance with the Unicode standard/ISO 10646 the range U+F000 to
  32. U+F8FF has been reserved for OS-wide allocation (the Unicode Standard
  33. refers to this as a "Corporate Zone", since this is inaccurate for
  34. Linux we call it the "Linux Zone"). U+F000 was picked as the starting
  35. point since it lets the direct-mapping area start on a large power of
  36. two (in case 1024- or 2048-character fonts ever become necessary).
  37. This leaves U+E000 to U+EFFF as End User Zone.
  38. [v1.2]: The Unicodes range from U+F000 and up to U+F7FF have been
  39. hard-coded to map directly to the loaded font, bypassing the
  40. translation table. The user-defined map now defaults to U+F000 to
  41. U+F0FF, emulating the previous behaviour. In practice, this range
  42. might be shorter; for example, vgacon can only handle 256-character
  43. (U+F000..U+F0FF) or 512-character (U+F000..U+F1FF) fonts.
  44. Actual characters assigned in the Linux Zone
  45. --------------------------------------------
  46. In addition, the following characters not present in Unicode 1.1.4
  47. have been defined; these are used by the DEC VT graphics map. [v1.2]
  48. THIS USE IS OBSOLETE AND SHOULD NO LONGER BE USED; PLEASE SEE BELOW.
  49. ====== ======================================
  50. U+F800 DEC VT GRAPHICS HORIZONTAL LINE SCAN 1
  51. U+F801 DEC VT GRAPHICS HORIZONTAL LINE SCAN 3
  52. U+F803 DEC VT GRAPHICS HORIZONTAL LINE SCAN 7
  53. U+F804 DEC VT GRAPHICS HORIZONTAL LINE SCAN 9
  54. ====== ======================================
  55. The DEC VT220 uses a 6x10 character matrix, and these characters form
  56. a smooth progression in the DEC VT graphics character set. I have
  57. omitted the scan 5 line, since it is also used as a block-graphics
  58. character, and hence has been coded as U+2500 FORMS LIGHT HORIZONTAL.
  59. [v1.3]: These characters have been officially added to Unicode 3.2.0;
  60. they are added at U+23BA, U+23BB, U+23BC, U+23BD. Linux now uses the
  61. new values.
  62. [v1.2]: The following characters have been added to represent common
  63. keyboard symbols that are unlikely to ever be added to Unicode proper
  64. since they are horribly vendor-specific. This, of course, is an
  65. excellent example of horrible design.
  66. ====== ======================================
  67. U+F810 KEYBOARD SYMBOL FLYING FLAG
  68. U+F811 KEYBOARD SYMBOL PULLDOWN MENU
  69. U+F812 KEYBOARD SYMBOL OPEN APPLE
  70. U+F813 KEYBOARD SYMBOL SOLID APPLE
  71. ====== ======================================
  72. Klingon language support
  73. ------------------------
  74. In 1996, Linux was the first operating system in the world to add
  75. support for the artificial language Klingon, created by Marc Okrand
  76. for the "Star Trek" television series. This encoding was later
  77. adopted by the ConScript Unicode Registry and proposed (but ultimately
  78. rejected) for inclusion in Unicode Plane 1. Thus, it remains as a
  79. Linux/CSUR private assignment in the Linux Zone.
  80. This encoding has been endorsed by the Klingon Language Institute.
  81. For more information, contact them at:
  82. http://www.kli.org/
  83. Since the characters in the beginning of the Linux CZ have been more
  84. of the dingbats/symbols/forms type and this is a language, I have
  85. located it at the end, on a 16-cell boundary in keeping with standard
  86. Unicode practice.
  87. .. note::
  88. This range is now officially managed by the ConScript Unicode
  89. Registry. The normative reference is at:
  90. https://www.evertype.com/standards/csur/klingon.html
  91. Klingon has an alphabet of 26 characters, a positional numeric writing
  92. system with 10 digits, and is written left-to-right, top-to-bottom.
  93. Several glyph forms for the Klingon alphabet have been proposed.
  94. However, since the set of symbols appear to be consistent throughout,
  95. with only the actual shapes being different, in keeping with standard
  96. Unicode practice these differences are considered font variants.
  97. ====== =======================================================
  98. U+F8D0 KLINGON LETTER A
  99. U+F8D1 KLINGON LETTER B
  100. U+F8D2 KLINGON LETTER CH
  101. U+F8D3 KLINGON LETTER D
  102. U+F8D4 KLINGON LETTER E
  103. U+F8D5 KLINGON LETTER GH
  104. U+F8D6 KLINGON LETTER H
  105. U+F8D7 KLINGON LETTER I
  106. U+F8D8 KLINGON LETTER J
  107. U+F8D9 KLINGON LETTER L
  108. U+F8DA KLINGON LETTER M
  109. U+F8DB KLINGON LETTER N
  110. U+F8DC KLINGON LETTER NG
  111. U+F8DD KLINGON LETTER O
  112. U+F8DE KLINGON LETTER P
  113. U+F8DF KLINGON LETTER Q
  114. - Written <q> in standard Okrand Latin transliteration
  115. U+F8E0 KLINGON LETTER QH
  116. - Written <Q> in standard Okrand Latin transliteration
  117. U+F8E1 KLINGON LETTER R
  118. U+F8E2 KLINGON LETTER S
  119. U+F8E3 KLINGON LETTER T
  120. U+F8E4 KLINGON LETTER TLH
  121. U+F8E5 KLINGON LETTER U
  122. U+F8E6 KLINGON LETTER V
  123. U+F8E7 KLINGON LETTER W
  124. U+F8E8 KLINGON LETTER Y
  125. U+F8E9 KLINGON LETTER GLOTTAL STOP
  126. U+F8F0 KLINGON DIGIT ZERO
  127. U+F8F1 KLINGON DIGIT ONE
  128. U+F8F2 KLINGON DIGIT TWO
  129. U+F8F3 KLINGON DIGIT THREE
  130. U+F8F4 KLINGON DIGIT FOUR
  131. U+F8F5 KLINGON DIGIT FIVE
  132. U+F8F6 KLINGON DIGIT SIX
  133. U+F8F7 KLINGON DIGIT SEVEN
  134. U+F8F8 KLINGON DIGIT EIGHT
  135. U+F8F9 KLINGON DIGIT NINE
  136. U+F8FD KLINGON COMMA
  137. U+F8FE KLINGON FULL STOP
  138. U+F8FF KLINGON SYMBOL FOR EMPIRE
  139. ====== =======================================================
  140. Other Fictional and Artificial Scripts
  141. --------------------------------------
  142. Since the assignment of the Klingon Linux Unicode block, a registry of
  143. fictional and artificial scripts has been established by John Cowan
  144. <jcowan@reutershealth.com> and Michael Everson <everson@evertype.com>.
  145. The ConScript Unicode Registry is accessible at:
  146. https://www.evertype.com/standards/csur/
  147. The ranges used fall at the low end of the End User Zone and can hence
  148. not be normatively assigned, but it is recommended that people who
  149. wish to encode fictional scripts use these codes, in the interest of
  150. interoperability. For Klingon, CSUR has adopted the Linux encoding.
  151. The CSUR people are driving adding Tengwar and Cirth into Unicode
  152. Plane 1; the addition of Klingon to Unicode Plane 1 has been rejected
  153. and so the above encoding remains official.