|Editor||Eric Muller (firstname.lastname@example.org)|
|Latest Proposed Update||http://www.unicode.org/reports/tr50/proposed.html|
The Unicode code charts generally show characters in the orientation in which they appear in horizontal lines. However, there are a few exceptions, mostly for characters or scripts which are normally written in vertical lines. This report describes a property that documents that situation.
When text is presented in vertical lines, there are various conventions for the orientation of the characters with respect to the line. In many parts of the world, most characters are upright. In East Asia, Kanji and Kana characters are upright, Latin letters of acronyms are upright, while words and sentences in the Latin script are typically sideways. This report describes two Unicode character properties which can be used to determine a default orientation of characters in those two scenarios.
This is a draft document which may be updated, replaced, or superseded by other documents at any time. Publication does not imply endorsement by the Unicode Consortium. This is not a stable document; it is inappropriate to cite this document as other than a work in progress.
A Unicode Technical Report (UTR) contains informative material. Conformance to the Unicode Standard does not imply conformance to any UTR. Other specifications, however, are free to make normative references to a UTR.
Please submit corrigenda and other comments with the online reporting form [Feedback]. Related information that is useful in understanding this document is found in References. For the latest version of the Unicode Standard see [Unicode]. For a list of current Unicode Technical Reports see [Reports]. For more information about versions of the Unicode Standard, see [Versions].
The Unicode code charts generally show characters in the same orientation as in horizontal lines. However, there are a few exceptions, mostly for characters or scripts which are normally written in vertical lines; in those cases, the code charts show the characters in the same orientation as in vertical lines. Futhermore, those vertical characters and scripts are often rotated when displayed in horizontal lines; figure 1 shows an example of Mongolian text in horizontal lines, where the Mongolian characters are rotated 90 degree counter-clockwise with respect to the code charts. The property Horizontal Orientation documents that situation.
When text is displayed in vertical lines, there are various conventions for the orientation of the characters with respect to the line. In many parts of the world, most characters are upright, that is appear with the same orientation as in the code charts, as can be seen in figure 2. The property Stack Vertical Orientation documents the default orientation of characters in his scenario.
In East Asia, Kanji and Kana characters are upright, Latin letters of acronyms are upright, while words and sentences in the Latin script are typically sideways, as can be seen in figure 3. The property Mixed Vertical Orientation documents the default orientation of characters in his scenario.
The properties and algorithms presented in this report are informative. The intent is to provide a reasonable determination of the orientation of characters which can be used in the absence of other information, but can be overridden by the context, such as markup in a document or preferences in a layout application. This default determination is based on the most common use of a character, but in no way implies that that character is used only in that way.
For more information on the conformance implications, see [Unicode], section 3.5, Properties, in particular the definition (D35) of an informative property.
The properties share the same set of values, which are given in table 1.
|U||characters which are displayed upright, with the same orientation as they appears in the code charts.|
|R||characters which are displayed sideways, rotated 90 degrees clockwise compared to the code charts.|
|L||characters which are displayed sideways, rotated 90 degrees counter-clockwise compared to the code charts.|
|T, Tu, Tr||characters which are not just upright or sideways, but require a different glyph than in the code charts when used in vertical texts. In addition, Tu indicates that as a fallback, the character can be displayed with the code chart glyph upright; similarly, Tr indicates a possible fallback using the code chart glyph rotated 90 degrees clockwise.|
Note that the orientation is described with respect to the appearance in the code charts.
Currently, there are no code points with Horizontal Orientation property value L, T, Tu or Tr; there are no code points with Stacked and Mixed Orientation property value L.
The Horizontal Orientation (short name ho) property is intented to be used for horizontal lines.
The Stacked Vertical Orientation (short name svo) property is intended to be used for vertical lines in those parts of the world where characters are mostly upright.
The Mixed Vertical Orientation (short name mvo) property is intended to be used for vertical lines in East Asia, and more specifically in Japan, China and Korea.
The scope of these properties is limited by the scope of Unicode itself. For example, Unicode does not support directly the representation of texts and inscriptions using Egyptian Hieroglyphs. Instead, Unicode provides characters intended for use when writing about such texts or inscriptions, or for use in conjunction with a markup system such as the Manuel de Codage. While the properties are defined for Egyptian Hieroglyphs, they are meaningful only for occurrences of these characters in discursive texts; when the characters are used with markup, the markup controls the orientation. See [Unicode], section 14.8 for a more complete discussion of the scope of Egyptian Hieroglyph characters.
As in all matters of typography, the interesting unit of text is not the character, but a grapheme cluster: it does not make sense to use a base character upright and a combining mark attached to it sideways.
It is expected that the client of the properties defined here will select a notion of grapheme cluster, and is interested in obtaining an orientation for the cluster as a whole.
A possible choice for the notion of grapheme cluster is either that of legacy grapheme cluster or that of extended grapheme cluster, as defined in [UAX29].
The orientation for a grapheme cluster as a whole is then determined by taking the orientation of the first character in the cluster, with the following exceptions:
if the cluster contains an enclosing combining mark (general category Me), then the whole cluster has ho, svo and mvo orientation U.
to handle combining marks displayed in isolation:
if the cluster is made of U+00A0 NO-BREAK SPACE and some combining mark(s), then the whole cluster has ho and svo orientation U and mvo orientation R.
if the cluster is made of U+3000 IDEOGRAPHIC SPACE and some combining mark(s), then the whole cluster has ho, svo and mvo orientation U.
The properties are intended to provide only a default orientation, rather than to handle correctly all situations. It is expected by when used in the context of a markup system, the user will be able to 1) have some control over which property is used and 2) specify an explicit orientation. For example, one could have an attribute orientation with possible values auto, 0, 90, 180 and 270; when the value of the attribute is not auto, the explicit orientation is used; when the value is auto, the property values are used.
The property values, if used, are intended to be used directly.
To facilitate tailorings, this reports identifies sets of characters which behave similarly, and for which it can useful to tailor the orientation as a group.
This set contains brackets, which while they appear rotated, are commonly implemented as if they were transformed.
This set contains arrows.
Table 4 provides representative glyphs for the horizontal and vertical appearance of characters with the property value T.
|U+2018 LEFT SINGLE QUOTATION MARK|
|U+2019 RIGHT SINGLE QUOTATION MARK|
|U+3001 IDEOGRAPHIC COMMA|
|U+3002 IDEOGRAPHIC STOP|
|U+301C WAVE DASH|
|U+301D REVERSED DOUBLE PRIME QUOTATION MARK|
|U+301E DOUBLE PRIME QUOTATION MARK|
|U+301F LOW DOUBLE PRIME QUOTATION MARK|
|U+30FC KATAKANA-HIRAGANA PROLONGED SOUND MARK|
|U+3041 HIRAGANA LETTER SMALL A|
|U+3043 HIRAGANA LETTER SMALL I|
|U+3045 HIRAGANA LETTER SMALL U|
|U+3047 HIRAGANA LETTER SMALL E|
|U+3049 HIRAGANA LETTER SMALL O|
|U+3063 HIRAGANA LETTER SMALL TU|
|U+3083 HIRAGANA LETTER SMALL YA|
|U+3085 HIRAGANA LETTER SMALL YU|
|U+3087 HIRAGANA LETTER SMALL YO|
|U+308E HIRAGANA LETTER SMALL WA|
|U+3095 HIRAGANA LETTER SMALL KA|
|U+3096 HIRAGANA LETTER SMALL KE|
|U+30A1 KATAKANA LETTER SMALL A|
|U+30A3 KATAKANA LETTER SMALL I|
|U+30A5 KATAKANA LETTER SMALL U|
|U+30A7 KATAKANA LETTER SMALL E|
|U+30A9 KATAKANA LETTER SMALL O|
|U+30C3 KATAKANA LETTER SMALL TU|
|U+30E3 KATAKANA LETTER SMALL YA|
|U+30E5 KATAKANA LETTER SMALL YU|
|U+30E7 KATAKANA LETTER SMALL YO|
|U+30EE KATAKANA LETTER SMALL WA|
|U+30F5 KATAKANA LETTER SMALL KA|
|U+30F6 KATAKANA LETTER SMALL KE|
|U+31F0 KATAKANA LETTER SMALL KU|
|U+31F1 KATAKANA LETTER SMALL SI|
|U+31F2 KATAKANA LETTER SMALL SU|
|U+31F3 KATAKANA LETTER SMALL TO|
|U+31F4 KATAKANA LETTER SMALL NU|
|U+31F5 KATAKANA LETTER SMALL HA|
|U+31F6 KATAKANA LETTER SMALL HI|
|U+31F7 KATAKANA LETTER SMALL HU|
|U+31F8 KATAKANA LETTER SMALL HE|
|U+31F9 KATAKANA LETTER SMALL HO|
|U+31FA KATAKANA LETTER SMALL MU|
|U+31FB KATAKANA LETTER SMALL RA|
|U+31FC KATAKANA LETTER SMALL RI|
|U+31FD KATAKANA LETTER SMALL RU|
|U+31FE KATAKANA LETTER SMALL RE|
|U+31FF KATAKANA LETTER SMALL RO|
|U+3300 SQUARE APAATO|
|U+3301 SQUARE ARUHUA|
|U+3302 SQUARE ANPEA|
|U+3303 SQUARE AARU|
|U+3304 SQUARE ININGU|
|U+3305 SQUARE INTI|
|U+3306 SQUARE UON|
|U+3307 SQUARE ESUKUUDO|
|U+3308 SQUARE EEKAA|
|U+3309 SQUARE ONSU|
|U+330A SQUARE OOMU|
|U+330B SQUARE KAIRI|
|U+330C SQUARE KARATTO|
|U+330D SQUARE KARORII|
|U+330E SQUARE GARON|
|U+330F SQUARE GANMA|
|U+3310 SQUARE GIGA|
|U+3311 SQUARE GINII|
|U+3312 SQUARE KYURII|
|U+3313 SQUARE GIRUDAA|
|U+3314 SQUARE KIRO|
|U+3315 SQUARE KIROGURAMU|
|U+3316 SQUARE KIROMEETORU|
|U+3317 SQUARE KIROWATTO|
|U+3318 SQUARE GURAMU|
|U+3319 SQUARE GURAMUTON|
|U+331A SQUARE KURUZEIRO|
|U+331B SQUARE KUROONE|
|U+331C SQUARE KEESU|
|U+331D SQUARE KORUNA|
|U+331E SQUARE KOOPO|
|U+331F SQUARE SAIKURU|
|U+3320 SQUARE SANTIIMU|
|U+3321 SQUARE SIRINGU|
|U+3322 SQUARE SENTI|
|U+3323 SQUARE SENTO|
|U+3324 SQUARE DAASU|
|U+3325 SQUARE DESI|
|U+3326 SQUARE DORU|
|U+3327 SQUARE TON|
|U+3328 SQUARE NANO|
|U+3329 SQUARE NOTTO|
|U+332A SQUARE HAITU|
|U+332B SQUARE PAASENTO|
|U+332C SQUARE PAATU|
|U+332D SQUARE BAARERU|
|U+332E SQUARE PIASUTORU|
|U+332F SQUARE PIKURU|
|U+3330 SQUARE PIKO|
|U+3331 SQUARE BIRU|
|U+3332 SQUARE HUARADDO|
|U+3333 SQUARE HUIITO|
|U+3334 SQUARE BUSSYERU|
|U+3335 SQUARE HURAN|
|U+3336 SQUARE HEKUTAARU|
|U+3337 SQUARE PESO|
|U+3338 SQUARE PENIHI|
|U+3339 SQUARE HERUTU|
|U+333A SQUARE PENSU|
|U+333B SQUARE PEEZI|
|U+333C SQUARE BEETA|
|U+333D SQUARE POINTO|
|U+333E SQUARE BORUTO|
|U+333F SQUARE HON|
|U+3340 SQUARE PONDO|
|U+3341 SQUARE HOORU|
|U+3342 SQUARE HOON|
|U+3343 SQUARE MAIKURO|
|U+3344 SQUARE MAIRU|
|U+3345 SQUARE MAHHA|
|U+3346 SQUARE MARUKU|
|U+3347 SQUARE MANSYON|
|U+3348 SQUARE MIKURON|
|U+3349 SQUARE MIRI|
|U+334A SQUARE MIRIBAARU|
|U+334B SQUARE MEGA|
|U+334C SQUARE MEGATON|
|U+334D SQUARE MEETORU|
|U+334E SQUARE YAADO|
|U+334F SQUARE YAARU|
|U+3350 SQUARE YUAN|
|U+3351 SQUARE RITTORU|
|U+3352 SQUARE RIRA|
|U+3353 SQUARE RUPII|
|U+3354 SQUARE RUUBURU|
|U+3355 SQUARE REMU|
|U+3356 SQUARE RENTOGEN|
|U+3357 SQUARE WATTO|
|U+337B SQUARE ERA NAME HEISEI|
|U+337C SQUARE ERA NAME SYOUWA|
|U+337D SQUARE ERA NAME TAISYOU|
|U+337E SQUARE ERA NAME MEIZI|
|U+337F SQUARE CORPORATION|
|U+FF61 HALFWIDTH IDEOGRAPHIC FULL STOP|
|U+FF64 HALFWIDTH IDEOGRAPHIC COMMA|
|U+FF67 HALFWIDTH KATAKANA LETTER SMALL A|
|U+FF68 HALFWIDTH KATAKANA LETTER SMALL I|
|U+FF69 HALFWIDTH KATAKANA LETTER SMALL U|
|U+FF6A HALFWIDTH KATAKANA LETTER SMALL E|
|U+FF6B HALFWIDTH KATAKANA LETTER SMALL O|
|U+FF6C HALFWIDTH KATAKANA LETTER SMALL YA|
|U+FF6D HALFWIDTH KATAKANA LETTER SMALL YU|
|U+FF6E HALFWIDTH KATAKANA LETTER SMALL YO|
|U+FF6F HALFWIDTH KATAKANA LETTER SMALL TU|
|U+1F200 SQUARE HIRAGANA HOKA|
|U+1F201 SQUARED KATAKANA KOKO|
The data file, in UCD syntax.
Thanks to the reviewers: Julie Allen, Ken Lunde, Nat McCully, Ken Whistler, Taro Yamamoto, htakenaka, John Cowan, Fantasai, Asmus Freytag, Van Anderson, Ishi Koji, sikeda, Shinyu Murakami, Tokushige Kobayashi, Addison Phillips, Martin Dürst, the W3C Internationalization Core Working Group, the W3C I18N Interest group, the W3C CSS Working group, Michael Everson, John Daggett, Laurentiu Iancu, Dwayne Robinson.
|[JLREQ]||Requirements for Japanese Text layout, W3C Working Group Note|
|[Errata]||Updates and Errata
For reporting errors and requesting information online.
|[Reports]||Unicode Technical Reports
For information on the status and development process for technical reports, and for a list of technical reports.
|[UAX29]||UAX #29: Unicode Text Segmentation
|[Unicode]||The Unicode Standard, Version 6.1.0,
defined by: The Unicode Standard, Version
6.1.0 (Mountain View, CA: The Unicode Consortium, 2012. ISBN 978-1-936213-02-3)
|[Versions]||Versions of the Unicode Standard
For details on the precise contents of each version of the Unicode Standard, and how to cite them.
This section indicates the changes introduced by each revision.
TR renamed to include “Horizontal”.
New property for horizontal text. The current assignment is L for Mongolian and Phags-pa, U for all the other characters.
Proposal B has been accepted; removed proposal A.
Characters moved from U or R to T: 3008..3011 3014..301B 301D..301F 309B..309E 20A0 FF01 FF08..FF09 FF0C..FF0E FFaA..FF1E FF3B FF3F FF5b..FF60 FF62..FF63 FF70 FFE3, on the basis of small shift in the box, similar to small kana.
T moved to Tr or Tu, following MS proposal. The only T characters remaining are 2018 and 2019, which are R/R in MS proposal.
Arrow set introduced, as in MS proposal.
Yi blocks changed from svo/mvo R to U.
UCAS changed from mvo R to U, except for U+1400 ᐀ CANADIAN SYLLABICS HYPHEN.
Properties renamed to Stacked Vertical Orientation (previously Default Vertical Orientation) and Mixed Vertical Orientation (previously East Asian Vertical Orientation)
Introduced sets of characters for tailoring.
Property value S renamed to R.
Property value Sb merged with R; set created for brackets.
Mongolian and Egyptian Hieroglyphs changed to U.
Implementation of the UTC decisions made during meeting #130, February 2012.
Removal of the East Asian Class property
East Asian Orientation renamed East Asian Vertical Orientation
New property, Default Vertical Orientation. The initial assignment is: T if EAVO=T, SB if EAVO=SB and the bracket is specific to CJK, S to align with CSS Sv value except for vertical presentation forms, Tibetan, Mongolian, sup/sub parens, sup punctuation, FD3E, FD3F, which remain U.
Clarification of the status of the properties (end of section 1)
Clarification of the handling of grapheme clusters
Removed the "comments" column in table 3.
Hangul characters: new class cl-19.4, hangul, orientation U
Yijing Hexagram symbosl are now cl-19-3, symbols, orientation U.
Small forms variants are treated like their fullwidth counterparts.
Superscripts and subscript characters are now cl-27, western, orientation S
Small kana: orientation U; class split in cl-11.1, smallHiragana and cl-11.2, smallKatakana
U+3030 〰 WAVY DASH has orientation T.
The two alternatives for math, etc. are described.
First working draft.
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