X logical font description

X logical font description (XLFD) is a font standard used by the X Window System. It 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 and operating or file system implementations
* arbitrarily complex font matching or substitution
* extensibility

One prominent XFLD convention is to refer to individual fonts including any variations using their unique "FontName". It comprises a sequence of fourteen hyphen-prefixed, X-registered fields:

#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)
#POINT_SIZE: Size of characters, in pixels; 0 (Zero) means a scalable font
#PIXEL_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: Horizontal resolution, in DPI
#SPACING: monospace, proportional, or "character cell"
#AVERAGE_WIDTH: Average width of characters of this font; 0 means scalable font
#CHARSET_REGISTRY: Registry defining this
#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.)

References

*cite web|url= http://www.xfree86.org/current/xlfd.pdf |title= X Logical Font Description Conventions |accessdate= 2008-02-02 |author= Jim Flowers |coauthors= Stephen Gildea |date= 1994 |format= PDF |work= Digital Equipment Corporation |publisher= X Consortium
*cite book|last= Mansfield |first= Niall |title= The Joy of X - An overview of the X Window System |publisher= Addison-Wesley |origyear= 1992 |year= 1994 |location= Cambridge |pages= pp.266-267 |chapter= System Administration |url= |doi= |id= |isbn= 0-201-56512-9