Font (information technology)

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Font sample of an open source font , here Linux Libertine

In information technology, a font is generally used to denote any font set digitally available on a computer or connected peripherals . Depending on the intended representation, a font can either be in a raster-oriented format as a bitmap or as a freely scalable vector font . Fonts are auxiliary components of information and communication technologies .

From a technical point of view, a font is understood to mean the raster font-specific or vector font-specific “image and instruction information” of a font set stored in digital form. While stored in Schrifttyensätzen, graphically differently designed typefaces in classical printing technology in the form of sets of metal-cast letters , in flasks were kept, they are in the world of electronic data processing - or, more generally, in the world of information technology systems - as fonts stored in digital data formats . The font is the electronic counterpart to the mechanical type set. It can be used to convert a character set table into specific characters of a peripheral device (such as a monitor or printer ).

Typology based on technical properties

There are various techniques for representing characters in computers and information technology systems. According to these, fonts are divided into:

  • (Also known as raster fonts pixel fonts designated or bitmap fonts), in which each pixel of a glyph - this is the concrete appearance of a character - is set individually.
  • Vector fonts in which the glyphs are displayed by specifying vectors for their outlines.

The term vector font is an umbrella term that also includes outline fonts. Until the early 1980s, vector fonts were mainly fonts in whose stored information (on a level abstracted from digital zeros and ones) the glyphs were simple "full lines" and sections of the glyphs were only identified by simple vectors, the reference points to straight lines and arcs formed. They were especially intended and suitable for output on vector displays and on plotters .

A well-known early representative of the vector font formats is METAFONT .

Today the word vector font is often used as a synonym for outline font. In the stored information of an outline font (on a level abstracted from digital zeros and ones) the individual glyph itself does not consist of simple point vectors of full lines; rather, the outline of the glyph is described as a collection of complex reference point vectors, which can point to Bézier curves and splines in addition to straight lines and arcs . The individual glyph then consists of one or more closed lines, depending on which letter, number or other character is being implemented. (In the special case of using ligatures , the lines can then extend over several glyphs.)

In contrast to raster fonts, vector fonts as well as vector graphics are defined independently of the resolution of the output device and can be output scaled as required without any loss of quality. Since most output devices are based on rasterization and the output is in the form of pixels, a conversion is necessary and only an approximate output is possible, which can cause problems with output units with only a low image resolution. Hinting and other font technologies are used to improve the output in this regard .

Well-known outline font formats are the TrueType font format, various PostScript font formats and the OpenType font format. With the help of special graphics and font technologies, among other things, the same appearance of the screen and printer output is made possible within the framework of the possible resolution . (This is known as the “What you see is what you get” technique.) It is also possible, within limits, to obtain new font sizes and styles (bold, italic) by simply converting the vector data, but custom-made ones are usually made for professional purposes Font styles used.

A specialty among the outline font formats is the ScalableVectorGraphics font format. This is designed exclusively for screen displays, not for printing.

See also

literature

  • Jacques André: Caractères numériques: introduction. In: Cahiers GUTenberg. Vol. 26, May 1997, ISSN  1257-2217 , pp. 5-44, (in French).
  • Johannes Bergerhausen, Siri Poarangan: decodeunicode: The characters of the world. Verlag Hermann Schmidt, Mainz 2011, ISBN 978-3874398138 . All 109,242 characters of typography according to the Unicode standard.
  • Yannis Haralambous: Fonts & encodings. From Unicode to advanced typography and everything in between. Translated by P. Scott Horne. O'Reilly, Beijing et al. 2007, ISBN 978-0-596-10242-5 (in English).
  • Peter Karow: Digital Fonts. Presentation and formats. 2nd improved edition. Springer, Berlin et al. 1992, ISBN 3-540-54917-X .
  • Mai-Linh Thi Truong, Jürgen Siebert, Erik Spiekermann (Eds.): FontBook. Digital Typeface Compendium. (= FontBook 4). 4th revised and expanded edition. FSI FontShop International, Berlin 2006, ISBN 3-930023-04-0 (in English).

Web links

Individual evidence

  1. ^ Donald E. Knuth : The METAFONTbook. Addison-Wesley, Reading, Mass. 1986, p. 6 ff., P. 22 ff.
  2. ↑ Gordon Müllejans: METAFONT: A Reference. Addison-Wesley, Bonn 1992, p. 10 ff.
  3. ^ Donald E. Knuth: The METAFONTbook. [Computers & Typesetting, Part C] Addison-Wesley, Reading, Mass. 1986, ISBN 0-201-13445-4
  4. ^ Donald E. Knuth: METAFONT: The Program. [Computers & Typesetting, Part D] Addison-Wesley, Reading, Mass. 1986, ISBN 0-201-13438-1