Chinese character description language
The Chinese character description languages are several proposed languages to most accurately and completely describe Chinese characters and information such as their list of components, list of strokes, their order, and the location of each of them on a background empty square. They are designed to overcome the inherent lack of information within a bitmap description. This enriched information can be used to identify variants of characters that are unified into one code point by Unicode and ISO/IEC 10646, as well as to provide an alternative form of representation for rare characters that do not yet have a standardized encoding in Unicode or ISO/IEC 10646. Many aim to work for Kaishu style and Song style, as well as to provide the character's internal structure which can be used for easier look-up of a character by indexing the character's internal make-up and cross-referencing among similar characters.
CDL
Character Description Language is a font technology, based on XML, co-created by Tom Bishop and Richard Cook for the Wenlin Institute, designed for describing any CJK character, but suitable for describing any glyph.This XML-based declarative language actually defines the stroke order of each component, as well as assembly of previously defined components to build up ever more complex characters. Many of these components are characters in their own right, in addition to serving as building-block components.
The background looks like a square of 128 pixels on each side. In this background:
- Each of about 50 strokes can be drawn in SVG.
- A basic component is composed by calling several strokes. In this component, each stroke is described by its bottom-left and top-right corner. Transformations are possible. There are more than 1,000 basic components.
- A character is composed by calling several components. In this character, each component is described by its bottom-left and top-right corner. In order for a component to fit into its proper portion of the Chinese character's rectangular block, a component may be transformed upon its use as a building-block embedded within a containing more-complex character.
T. Bishop and R. Cook explain this as follows:
As of spring 2003, over 50,000 Chinese characters had been described via CDL. As of 26 February 2013, 86,416 Chinese characters had been described via CDL.
HanGlyph
A character description language intended for supplying missing rare characters in documents. Documents can contain markup for missing characters, which will automatically trigger the generation of small fonts to provide the characters. The language itself is a simple postfix notation describing strokes and ways to combine them. The prototype software uses Metapost to render the characters and embed them in LaTeX documents. The language was presented by Wai Wong in 1997, and papers about its implementation in Metapost and LaTeX appeared at TeX user group conferences in 2003.Ideographic Description Sequences
Chapter 12 of the Unicode specification defines a syntax for "Ideographic Description Sequences" intended for use in describing characters not included in the standard in terms of combinations of components that do have code points. Twelve special characters in the range U+2FF0 to U+2FFB act as prefix operators to combine other characters or sequences to form larger characters.| Character | Unicode Character Number | Full Unicode Name |
| ⿰ | U+2FF0 | Ideographic description character left to right |
| ⿱ | U+2FF1 | Ideographic description character above to below |
| ⿲ | U+2FF2 | Ideographic description character left to middle and right |
| ⿳ | U+2FF3 | Ideographic description character above to middle and below |
| ⿴ | U+2FF4 | Ideographic description character full surround |
| ⿵ | U+2FF5 | Ideographic description character surround from above |
| ⿶ | U+2FF6 | Ideographic description character surround from below |
| ⿷ | U+2FF7 | Ideographic description character surround from left |
| ⿸ | U+2FF8 | Ideographic description character surround from upper left |
| ⿹ | U+2FF9 | Ideographic description character surround from upper right |
| ⿺ | U+2FFA | Ideographic description character surround from lower left |
| ⿻ | U+2FFB | Ideographic description character overlaid |
These sequences are useful in describing to the reader a character that is not directly printable, either because it is absent in a given font, or is absent from the Unicode standard altogether. For example, the Sawndip character "" can be described as "⿰書史". Another use is for dictionary lookup purposes, as a sort of rough input method for queries.
These sequences can be rendered either by keeping the individual characters separately or by parsing the Ideographic Description Sequence and drawing the ideograph so described They do not, by themselves, provide unambiguous rendering for all characters. For instance, the sequence ⿱十一 represents both 土 and 士.
Unicode's specification for these sequences is based on the characters and syntax of the earlier GBK standard.
The IDSgrep free software package by Matthew Skala extends Unicode's IDS syntax to include additional features for dictionary lookup; it is capable of converting KanjiVG's database to its own extended IDS format, or of searching EIDS files generated by the related Tsukurimashou font family.