X logical font description
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X logical font description (XLFD) is a font standard used by the X Window System. Modern X software typically relies on the newer Fontconfig system instead, but XLFDs are still supported in current X window implementations for compatibility with legacy software.
XLFD is intended to support:
- unique, descriptive font names that support simple pattern matching
- multiple font vendors, arbitrary character sets, and encodings
- naming and instancing of scalable and polymorphic fonts
- transformations and subsetting of fonts
- independence of X server and operating or file system implementations
- arbitrarily complex font matching or substitution
- FOUNDRY: Type foundry - vendor or supplier of this font
- FAMILY_NAME: Typeface family
- WEIGHT_NAME: Weight of type
- SLANT: Slant (upright, italic, oblique, reverse italic, reverse oblique, or "other")
- SETWIDTH_NAME: Proportionate width (e.g. normal, condensed, narrow, expanded/double-wide)
- ADD_STYLE_NAME: Additional style (e.g. (Sans) Serif, Informal, Decorated)
- PIXEL_SIZE: Size of characters, in pixels; 0 (Zero) means a scalable font
- POINT_SIZE: Size of characters, in tenths of points
- RESOLUTION_X: Horizontal resolution in dots per inch (DPI), for which the font was designed
- RESOLUTION_Y: Vertical resolution, in DPI
- SPACING: monospaced, proportional, or "character cell"
- AVERAGE_WIDTH: Average width of characters of this font; 0 means scalable font
- CHARSET_REGISTRY: Registry defining this character set
- CHARSET_ENCODING: Registry's character encoding scheme for this set
The following sample is for a 75-dpi, 12-point, Charter font:
-bitstream-charter-medium-r-normal--12-120-75-75-p-68-iso8859-1[65 70 80_90]
(which also tells the font source that the client is interested only in characters 65, 70, and 80-90.)
- Jim Flowers; Stephen Gildea (1994). "X Logical Font Description Conventions" (PDF). Digital Equipment Corporation. X Consortium. Retrieved 2015-11-22.
- Mansfield, Niall (1994) . "System Administration". The Joy of X - An overview of the X Window System. Cambridge: Addison-Wesley. pp. 266–267. ISBN 0-201-56512-9.
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