In FOCA font structure, a character set corresponds to the definition of a font; it contains the characters of a single type family, typeface, and type size. In addition, a character set specifies character properties and printing attributes (see Figure 1).

The character set components are:

Characters

Characters are letters, numerals, punctuation marks, or other symbols of a font.

Character properties

Character properties detail how a character is positioned relative to the characters around it. Some character properties include:

• The baseline of a character that shows its general alignment
• The dimensions of space in which the character is printed
• The position of the character in that space
• The identifier of the character

Printing attributes

The printing attributes define how the character set is printed. Some printing attributes include rotation of characters, maximum ascender, and point size.

One of the character properties is the character ID (or graphic character ID). Each character is assigned a character ID; for example, the character "A" is assigned the character ID LA020000. The purpose of a character ID is to distinguish the character from similar characters. For example, these characters look similar, but are assigned different character IDs:

Minus sign (-)

Character ID SA000000

Hyphen (-)

Character ID SP100000

Em dash (—)

Character ID SM900000