Bedstead is an outline font based on the characters produced by the
Mullard SAA5050 series of Teletext Character Generators. The
SAA5050 is familiar to those of a certain age as the chip that
MODE 7 display on the BBC
Microcomputer. It generates characters from a 5 × 9 pixel
matrix, smoothing diagonal lines to produce an interlaced 10 ×
18 matrix for each character. Bedstead extends that algorithm to
continuity, converting a 5 × 9 pixel grid into an outline with
Bedstead includes all the character designs from the SAA5050 and its various sister chips, including Cyrillic and Hebrew alphabets. It also has a large number of custom-designed glyphs, all of them of course based on the same 5 × 9 pixel grid.
The standard version of Bedstead is based on a square pixel grid. This is good for displays with square pixels, but not entirely faithful to the SAA5050. There is a second version, Bedstead Extended, that more accurately reflects the character shapes generated by an SAA5050 driving a 576i display.
The outline version of Bedstead is generated by an ANSI C program which emits a Spline Font Database file for use with Fontforge, which can convert it into most reasonable font formats.
bedstead-001.001.zip– Full source and binary distribution containing everything below.
bedstead.c– The C program that generates the font.
bedstead.sfd– The Spline Font Database file for use with Fontforge.
bedstead.otf– The finished font in OpenType format.
bedstead-ext.otf– Spline Font Database and OpenType versions of the extended font.
bedstead-20.bdf– Bitmap versions at 10 and 20 pixels high.
bedstead-20-df.png– 10-pixel and 20-pixel tilesets for use with Dwarf Fortress.
The code to generate Bedstead is held in Bazaar. You can get your own copy by running
bzr branch http://bjh21.me.uk/bedstead/