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From: jimomura@lsuc.UUCP
Newsgroups: comp.sys.m6809
Subject: Proposal for Graphics Format Std.
Message-ID: <2117@lsuc.UUCP>
Date: Sat, 31-Oct-87 10:11:13 EST
Article-I.D.: lsuc.2117
Posted: Sat Oct 31 10:11:13 1987
Date-Received: Sun, 1-Nov-87 09:57:37 EST
Reply-To: jimomura@lsuc.UUCP (Jim Omura)
Distribution: na
Organization: Law Society of Upper Canada, Toronto
Lines: 109
Summary: Graphics Format 9 for CoCo3


Proposal for Graphics File Format Standard
For OS-9 / Color Computer Users

     I've been waiting for a while now for some sort of standard
to arise, but nothing has happened.  As such, this is what I'm
going to use for now.  If something better comes along, I state
right now that I intend to abandon this format.  But I'll
only do so if there is an alternative which looks to be better
than this.  I don't like the idea of wasting my efforts, but
I believe more strongly in establishing standards which are
useful in the industry generally.  So if I drop this without
"a fight" that's why.

Proposed Name :

     I've arbitrarily called it 'GF9' for Graphics Format 9.
Files need not use this as an extension, but it wouldn't hurt
if you did.

The Header Format:

     The key is 64 bytes which are, for the most, to be thought
of as 32 "words".  Where a word is 16 bits.  These 32 words make
up the header.  There is no "tail" information defined at this
time.

Offset in Bytes:

0x00        The first byte defines screen mode class.
            0  Old Color Computer
            1  CoCo3 Alphanumerics
            2  CoCo3  Graphics modes

0x01        The 2nd byte is a submode.

            For mode 0 they are:

            0  Alphanumerics
            1  Inverted Alphanumerics
            2  SemiGraphics - 4
            3  64 * 64 Color Graphics
            4  128 * 64 Graphics
            5  128 * 64 Color Graphics
            6  128 * 96 Graphics
            7  128 * 96 Color Graphics
            8  128 * 192 Graphics
            9  128 * 192 Color Graphics
            0x0a  128 * 256 Graphics

            For mode 1 they are:

            0  32 char.
            1  40 char.
            2  80 char.

            For mode 2 they are:

            0  160 * 16
            1  256 * 2
            3  256 * 4
            4  256 * 16
            5  320 * 4
            6  320 * 16
            7  512 * 2
            8  512 * 4
            9  640 * 2
            0x0a  640 * 4

0x02-3      Compression style:  0 is uncompressed.

0x04 - 0x1f  Undefined

0x30    Color Pallette 0 (address FFB0)
0x32    Color Pallette 1 (address FFB1)
0x34    Color Pallette 2 (address FFB2)
0x36    Color Pallette 3 (etc.)
0x38
0x3a
0x3c
0x3e
0x40
0x42
0x44
0x46
0x48
0x4a
0x4c
0x4e    Color Pallette 15 (address FFBF)

     The bytes of the file follow as a straight memory dump
if there is no defined compression.  There are no special
delimiter characters in the uncompressed formats.

     The reason for the "undefined" words is for such
things as animation display timing, color cycling, compression
information and such.  It'll be useful for the future.

     Anyway, as I said, I intend to start using this format
immediately, as far as I've defined it, but I'm willing to abandon
it, so don't think that just because I'm barging ahead with it
that I won't consider something else.  Also there's a lot
to be defined in the future, so post any ideas you have and
we'll see. . . .

-- 
Jim Omura, 2A King George's Drive, Toronto, (416) 652-3880
ihnp4!utzoo!lsuc!jimomura
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