UDG.BAS by John P Stevenson

UDG.BAS is a 1987 program by John P Stevenson which allows the PCW character set to be redefined: a forerunner of LetaEdit. It is supplied with 10 example fonts. Some of these are raw 2048-byte font files (with the file type .UDG); others are .COM files that install the font when run.

Before UDG.BAS can be used, UDG.COM must be run. This copies a number of machine-code helper functions into memory, which are then called by UDG.BAS. UDG.BAS does not check that its machine-code helper routines are present before trying to call them, so it's left up to the user to get this right.

Both UDG.BAS and the .COM files are specific to the PCW, and don't check that they are running on the PCW before attempting to use PCW features.

A number of the fonts contain "icons" in the range 127-142 — that is, two 32x16 graphics each composed of eight character tiles. At the PCW aspect ratio, they look like this:

There appears to have been a bug in the process used to generate the icons, in that the first line of the following character (number 143) has also been blanked.

In the supplied .PSF files, characters used in icons have been mapped to the Unicode Private Use Area.

Files

Fonts

The self-loading .COM files have been rebuilt to support operation on the CPC, Spectrum +3 and PcW16.

The fonts define only characters 0-249, leaving 250-255 either containing random data or a placeholder bitmap.

Font	Download	Notes
Bold	BOLD.COM: Self-loading font for PCW, CPC, Spectrum +3 and PcW16 BOLD.UDG: Font in raw .UDG format BOLD.PSF: Font in PSF format
Charset 1	CHARSET1.COM: Self-loading font for PCW, CPC, Spectrum +3 and PcW16 CHARSET1.UDG: Font in raw .UDG format CHARSET1.PSF: Font in PSF format
Charset 2	CHARSET2.COM: Self-loading font for PCW, CPC, Spectrum +3 and PcW16 CHARSET2.UDG: Font in raw .UDG format CHARSET2.PSF: Font in PSF format	Identical to the standard PCW character set, except for the copyright sign and the undefined characters 250-255.
Charset 3	CHARSET3.COM: Self-loading font for PCW, CPC, Spectrum +3 and PcW16 CHARSET3.UDG: Font in raw .UDG format CHARSET3.PSF: Font in PSF format
Chunkee	CHUNKEE.COM: Self-loading font for PCW, CPC, Spectrum +3 and PcW16 CHUNKEE.UDG: Font in raw .UDG format CHUNKEE.PSF: Font in PSF format
Fatty	FATTY.COM: Self-loading font for PCW, CPC, Spectrum +3 and PcW16 FATTY.UDG: Font in raw .UDG format FATTY.PSF: Font in .PSF format	FATTY.COM only defines the first 128 characters, hence the abbreviated preview image.
Fenice 2	FENICE2.COM: Self-loading font for PCW, CPC, Spectrum +3 and PcW16 FENICE2.UDG: Font in raw .UDG format FENICE2.PSF: Font in .PSF format
Fenice B	FENICEB.COM: Self-loading font for PCW, CPC, Spectrum +3 and PcW16 FENICEB.UDG: Font in raw .UDG format FENICEB.PSF: Font in .PSF format
Tidy mk2	TIDYMK2.COM: Self-loading font for PCW, CPC, Spectrum +3 and PcW16 TIDYMK2.UDG: Font in raw .UDG format TIDYMK2.PSF: Font in .PSF format
UDGFin	UDGFIN.COM: Self-loading font for PCW, CPC, Spectrum +3 and PcW16 UDGFIN.UDG: Font in raw .UDG format UDGFIN.PSF: Font in .PSF format	Almost identical to Tidy Mk2, except for a few differences in the digits and the icons.

Other files

UDG.BAS: Original BASIC listing
UDG.TXT: Original documentation
UDG.ZIP: Original UDG distribution

John Elliott 2021-01-09