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. This font is generated by an
extension of the SAA5050’s smoothing algorithm. In addition to
the characters available from the SAA5050 itself, the font
includes characters from the other chips in the family
(including Cyrillic and Hebrew alphabets), an Arabic alphabet
found in an EBU document, and various other useful glyphs. All
glyphs are drawn on the same 5 × 9 pixel grid, albeit with a
slight variation to let the Arabic characters join up.
The outline version of the font 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.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.
The code to generate Bedstead is held in Bazaar. You can get your own copy by running
bzr branch http://bjh21.me.uk/bedstead/