In contrast, the character width for a fixed-pitch Latin font like Courier is generally 3/5 of an Em. While an Em is customarily the height of the letter “M”, it is the same as the unit width in East Asian fonts, because in these fonts the standard character cell is square. A common name for this unit width is “Em”. Narrow characters are kept together in words or runs that are rotated sideways in vertical text layout.įor a traditional East Asian fixed pitch font, this width translates to a display width of either one half or a whole unit width. Wide characters behave like ideographs they tend to allow line breaks after each character and remain upright in vertical text layout. Layout and line breaking (to cite only two examples) in East Asian context show systematic variations depending on the value of this East_Asian_Width property. For traditional mixed-width East Asian legacy character sets, this classification into narrow and wide corresponds with few exceptions directly to the storage size for each character: a few narrow characters use a single byte per character and all other characters (usually wide) use two or more bytes. This width takes on either of two values: narrow or wide. When dealing with East Asian text, there is the concept of an inherent width of a character.
6.1 Unassigned and Private-Use Characters.4.1 Relation to the Terms “Fullwidth” and “Halfwidth”.For any errata which may apply to this annex, see. For more information about versions of the Unicode Standard, see. For a list of current Unicode Technical Reports, see. Related information that is useful in understanding this annex is found in Unicode Standard Annex #41, “ Common References for Unicode Standard Annexes.” For the latest version of the Unicode Standard, see. Please submit corrigenda and other comments with the online reporting form. The version number of a UAX document corresponds to the version of the Unicode Standard of which it forms a part. The Unicode Standard may require conformance to normative content in a Unicode Standard Annex, if so specified in the Conformance chapter of that version of the Unicode Standard. This is a stable document and may be used as reference material or cited as a normative reference by other specifications.Ī Unicode Standard Annex (UAX) forms an integral part of the Unicode Standard, but is published online as a separate document. This document has been reviewed by Unicode members and other interested parties, and has been approved for publication by the Unicode Consortium. This annex presents the specifications of a normative property for Unicode characters that is useful when interoperating with East Asian Legacy character sets. Unicode® Standard Annex #11 East Asian Width Version