What is a BDF file?
BDF files are human readable form and usually distributed in an ASCII encoding. The file starts with global information relevant to the complete font, followed by the information and bitmaps for the individuals glyphs. The data in it shows for the font for a single size orientation. The metrics to use in more than one direction may be comprised in a single file. In BDF file, each item is contained on a separate line of text in the file. Spaces are used to separate the items on a line.
BDF file format
The BDF shorts for Glyph Bitmap Distribution Format; owned by Adobe is a file format for saving fonts of bitmap type. The content takes the form of a text file intended to be computer as well as human readable. The BDF is particularly used in Unix X Window environments. It has been replaced widely by the PCF font format which is supposed to be more efficient, and by OpenType and TrueType fonts.
BDF file structure
A BDF font file consists of three sections:
- a global section that applies to all glyphs in a font.
- a section with a separate entry for each glyph.
- the ENDFONT statement.
Here is an example font containing one glyph, for ASCII capital ‘A’. Its global declarations start with the “STARTFONT” line and end with the “CHARS” line
STARTFONT 2.1 FONT -gnu-unifont-medium-r-normal--16-160-75-75-c-80-iso10646-1 SIZE 16 75 75 FONTBOUNDINGBOX 16 16 0 -2 STARTPROPERTIES 2 FONT_ASCENT 14 FONT_DESCENT 2 ENDPROPERTIES CHARS 1 STARTCHAR U+0041 ENCODING 65 SWIDTH 500 0 DWIDTH 8 0 BBX 8 16 0 -2 BITMAP 00 00 00 00 18 24 24 42 42 7E 42 42 42 42 00 00 ENDCHAR ENDFONT