[Coco] OS-9 Font file format

[Bob Devries]

Mike,

the specs are in the OS9 manual.

The font files are made up of escape sequences which are the commands needed 
to activate (if that's the right word) the font.

So, 1B 2B C8 01... is the GPLoad command (page 3-19 of the Windows section 
of the manual).

The bytes after the two-byte command 1B 2B are:

GRP (group number)
BFN (buffer number)
STY (format (screen type?))
HSX/LSX (X dimension of block)
HSY/LSY (Y dimension of block)
HBL/LBL (number of bytes of data following)
DATA......

Hope that helps.

Bob Devries
Dalby, QLD, Australia


----- Original Message ----- 
From: "Mike Rowen" <mike at bcmr3.net>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Tuesday, September 20, 2011 8:03 AM
Subject: [Coco] OS-9 Font file format


> Can anyone point me to detailed information on OS-9 Font files? I have
> conjectured most of it, but wondering if there is any genuine spec for
> these?
> I can find no references to the first, second, and fifth bytes that begin 
> a
> font entry. I found no detailed info in the OS-9 manuals, Multi-Vue, or
> Inside OS-9 LII books. I have not
> encountered any different values for these bytes, so in the end, its not a
> show stopper. However, I like to understand how things work. :) Any
> details on font files is appreciated. Also, my conjecture about the 6th -
> 11th bytes may be incorrect. Perhaps the answer lies in NitrOS9 source 
> code?
>
> For example, the first 11 bytes of the OS-9 stdfonts is:
>
> 1b 2b c8 01 05 00 08 00 08 04 00
>
> Byte 1 ???
> Byte 2 ???
> Byte 3 is the group (c8= group 200)
> Byte 4 is the buffer number (01)
> Byte 5 ???
>
> The rest of this is conjecture based on looking at the different fonts:
>
> Byte 6 & 7 is the font width in pixels (00 08 = 8 pixels wide)
> Byte 8 & 9 is the font height in pixels (00 08 = 8 pixels wide)
> Byte 10 & 11 is the number of bytes in the font (04 00 = 1k or 1024 bytes)
>
> I also see that after the 3rd font in the stdfonts file (pulled from
> NitrOS9), there are references to group 206 (ce) and its not clear what 
> all
> the info after the font 3 bytes is about, though I have not spent any time
> yet attempting to reverse engineer the end bits of the font file. Thanks.
>
> Regards,
> -Mike Rowen
>
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