Unicode font

A Unicode font (also known as UCS font and Unicode typeface) is a computer font that contains a wide range of characters, letters, digits, glyphs, symbols, ideograms, logograms, etc., which are collectively mapped into the standard Universal Character Set, derived from many different languages and scripts from around the world. Unlike most conventional computer fonts, which are specific to a particular language or legacy character set and contain only a small subset of the UCS characters, these fonts attempt to include many thousands of possible glyphs, so that they can be used as a single typeface across multilingual documents.

The Unicode standard does not specify or create the font (typeface), a collection of graphical shapes called glyphs, itself. Rather, it defines the abstract characters as a specific number (known as a codepoint) and also defines the required changes of shape depending on the context the glyph is used in (e.g., combining characters, precomposed characters and letter-diacritic combinations). The choice of font, which governs how the abstract characters in the Universal Coded Character Set (UCS) are converted into a bitmap or vector output that can then be viewed on a screen or printed, is left up to the user. If a font is chosen which does not contain a glyph for a codepoint used in the document, typically a question mark, a box, or some other substitute character is displayed.

Computer fonts use various techniques to display characters or glyphs. A bitmap font contains a grid of dots known as pixels forming an image of each glyph in each face and size. Outline fonts (also known as vector fonts) use drawing instructions or mathematical formulæ to describe each glyph. Stroke fonts use a series of specified lines (for the glyph's border) and additional information to define the profile, or size and shape of the line in a specific face and size, which together describe the appearance of the glyph.

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