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 produced the 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/