There are several facilities available for the display of text information:
Your application can specify two attributes that affect the interpretation and display of text information: the character set identifier (CSID) and the font identifier. When the application specifies a character to be displayed, the CSID and font identifier together determine the symbol that is displayed to represent the character.
A CSID is a number that identifies a set of graphic characters (numbers, letters, and special characters) that is treated as an entity. For example, a CSID may specify characters that represent the alphabet of a language (for example, English or Kanji).
Each character within a CSID has assigned to it a code point, which is a unique bit pattern used to represent the character. For example, the letter "A" has been assigned the EBCDIC code point X'C1' and the ASCII code point X'41'screen Character sets that use 8 bits (1 byte) to represent the character are referred to as single-byte character sets (SBCS). Character sets that use 16 bits (2 bytes) to represent the character are referred to as double-byte character sets (DBCS). The code points assigned to letters, numbers, and certain common symbols follow the EBCDIC or the ASCII encoding sequences.
Character sets can differ from each other in two ways: different sets may vary in the code points used in the set; they may also vary in the symbol displayed for a given code point.
Your application program specifies CSIDs as integer values. The API divides CSID values into the following ranges:
A font identifier is a number that identifies an appearance of the characters in the character set. For example, US English (CSID 1) has fonts that display characters in Italic, Script, Gothic, etc.
Fonts differ from each other only in the appearances of the symbols displayed for a given character. Different fonts within a character set all maintain the same correspondence between characters and code points.
Within each CSID, the API defines these font identifier values:
Although CSIDs and font identifiers are used with geometric text, annotation text, and input devices, these facilities have different restrictions in supporting various character sets and fonts.
You can create your own character sets and fonts for use with geometric text; you cannot define your own character sets and fonts for annotation text and input device processing.
Some workstations may support only one CSID (or one CSID at a time) for annotation text and input devices.
For input device processing, you may specify only the CSID, not the font identifier.