Precomposed character
From Wikipedia, the free encyclopedia
A precomposed character (alternatively decomposable character) is a Unicode entity that can be decomposed into a canonically equivalent string of several other characters. Typically, a precomposed character is decomposed into the main character and a combining diacritical mark.
On most computer systems with incomplete Unicode support, the precomposed characters are easier to handle, and also they look better on displays and in print.
For example, the two strings
- ḱṷṓn (U+006B U+0301 U+0075 U+032D U+006F U+0304 U+0301 U+006E) and
- ḱṷṓn (U+1E31 U+1E77 U+1E53 U+006E)
are canonically equivalent and should render identically. In practice, however, most rendering engines still have difficulties with displaying the composed string.
In principle, most Chinese characters as encoded by Han unification and similar schemes may be considered precomposed characters, since they can be reduced to their constituent strokes. Similarly, ligatures are precompositions of their constituent graphemes.
OpenType has the ccmp "feature tag" to define glyphs that are compositions or decompositions involving combining characters.
[edit] See also
[edit] External links
- Free Idg Serif, a derivative of the FreeSerif font with added declarations of precomposed characters.
