The |FONT internal file

The |FONT internal file lists the fonts a help file uses. The font-change command in the text picks a descriptor from it by number.

Header

Offset	Size	Type	Name	Description
0	2	u16	`NumFacenames`	How many face names
2	2	u16	`NumDescriptors`	How many font descriptors
4	2	u16	`FacenamesOffset`	Where the face names are, from the start of the file. Also tells the layout: see below
6	2	u16	`DescriptorsOffset`	Where the descriptors are
8	2	u16	`NumStyles`	If `FacenamesOffset` is 12 or more: how many styles
10	2	u16	`StyleOffset`	The same: where the styles are
12	2	u16	`NumCharmaps`	If `FacenamesOffset` is 16 or more: how many character map names
14	2	u16	`CharmapOffset`	The same: where they are

Face names are fixed-width, NUL-padded strings; their width is the room between the two offsets divided by the number of names (usually 20 or 32 bytes).

Descriptors

Files made for Windows 3.0 and 3.1 use 11-byte descriptors, with sizes in half-points. When FacenamesOffset is 12 or more the descriptors are 42 bytes, with sizes in twips.

Offset	Size	Type	Field (11-byte descriptor)
0	1	u8	Attributes: bits 1 bold, 2 italic, 4 underline, 8 strikeout, 16 double underline, 32 small caps
1	1	u8	Size in half-points
2	1	u8	Family: 1 modern, 2 roman, 3 swiss, 4 script, 5 decorative
3	2	u16	Face name number
5	3	bytes	Text colour (RGB)
8	3	bytes	Background colour (RGB)

Of the 42-byte form, HELPDECO’s notes identify the face number (at offset 1), the colours (at 3 and 6), the height (at 14, in twips), the weight (at 30), the italic, underline, strikeout, double-underline and small-caps flags (at 34 to 38) and the pitch and family byte (at 41). The other bytes are not understood. Multimedia Viewer files use a different arrangement of the same size when FacenamesOffset is 16 or more, with the face number at offset 0, a style number at offset 2 and the colours at 6 and 9.

.HLP File Format – |FONT

Header

Descriptors