dmb@TIS.COM (David M. Baggett) (10/25/89)
Since there have been some inquiries about picture files, here's the
latest version of "The List". If you have an old version of this,
I strongly suggest you take this new one. Major corrections have been
made to:
NEOchrome (color animation info in header was _completely_ wrong)
DEGAS compressed (bitplane ordering was wrong)
Tiny (complete rewrite of compression scheme description)
I have fully tested NEO, DEGAS (all variants), and Tiny, so I'm fairly
sure these are correct now.
Those of you who have been kind enough to upload this list to archives,
please replace the old crusty versions with this one (oh, and THANKS).
David Baggett
arpa: dmb@TIS.COM
---------------------------------- >8 -----------------------------------------
ST Picture Formats
------------------
Compiled by:
Dave Baggett
(arpanet: dmb@TIS.COM)
(Please report errors or additions)
CONTRIBUTORS
Phil Blanchfield Jason Blochowiak David Brooks Neil Forsyth
Ken MacLeod Jim McCabe Darek Mihocka David Mumper
George Seto Joe Smith Greg Wageman Gerry Wheeler
Contents
--------
NEOchrome NEOchrome Animation DEGAS
DEGAS Elite (Uncompressed) DEGAS Elite (Compressed) Tiny
Spectrum 512 (Uncompressed) C.O.L.R. Object Editor Mural MacPaint
Spectrum 512 (Compressed) Animatic Film
Introductory Information
------------------------
word = 2 bytes
long = 4 bytes
palette = Hardware color palette, stored as 16 words. First word is
color register zero (background), last word is color register
15. Each word has the form:
Bit: (MSB) 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00 (LSB)
-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
0 0 0 0 0 R2 R1 R0 0 G2 G1 G0 0 B2 B1 B0
R2 = MSB of red intensity
R0 = LSB of red intensity
G2 = MSB of green intensity
G0 = LSB of green intensity
B2 = MSB of blue intensity
B0 = LSB of blue intensity
Intensity ranges from 0 (color not present) to 7 (highest
intensity).
Example: { red = 7, green = 3, blue = 5 } -> 0735 (hex)
Caveat: It is wise to mask off the upper four bits of each
palette entry, since a few programs store special
information there (most notably Art Studio).
The Formats
-----------
<NEOchrome>
1 long resolution (0 = loew res, 1 = medium res, 2 = high res)
16 words palette
12 bytes filename (usually " . ")
1 byte unused (usually either 80 hex or 0)
1 byte color animation limits (4 most significant bits are
left/lower limit; 4 least significant bits are
right/upper limit).
1 byte color animation enabled? High bit set if yes.
1 byte color animation speed and direction
x = 0 means animation stopped
x < 0 means colors cycle to the left (decreasing)
x > 0 means colors cycle to the right (ascending)
Number of vblanks between cycles is |x| - 1
19 longs reserved for expansion
16000 words picture data (screen memory)
-----------
32128 bytes total
<NEOchrome Animation>
NOTE: To get this feature on versions 0.9 and later select the Grabber
icon and click the both mouse buttons in the eye of the second R in
the word GRABBER.
Interestingly enough, some versions of NEO only require you
to press the right button, not both. Hmmm...
1 long magic number BABEEBEA (hex) (seems to be ignored)
1 word width of image in bytes (always divisible by 8)
1 word height of image in scan lines
1 word size of image in bytes + 10 (!)
1 word x coordinate of image (must be divisible by 16) - 1
1 word y coordinate of image - 1
1 word number of frames
1 word animation speed (# vblanks to delay between frames)
1 long reserved; should be zero
--------
22 bytes total for header
? words image data (words of screen memory) for each frame, in
order
<DEGAS>
1 word resolution (0 = low res, 1 = medium res, 2 = high res)
Other bits may be used in the future; use a simple bit
test rather than checking for specific word values.
16 words palette
16000 words picture data (screen memory)
-----------
32034 bytes total
<DEGAS Elite (Uncompressed)>
1 word resolution (0 = low res, 1 = medium res, 2 = high res)
Other bits may be used in the future; use a simple bit
test rather than checking for specific word values.
16 words palette
16000 words picture data (screen memory)
4 words left color animtion limit table (starting color numbers)
4 words right color animation limit table (ending color numbers)
4 words animation channel direction flag (0 = left, 1 = off, 2 = right)
4 words animation channel delay in 1/60's of a second. [0 - 128]
-----------
32066 bytes total
<DEGAS Elite (Compressed)>
1 word resolution (same as Degas, but high order bit is set;
i.e., hex 8000 = low res, hex 8001 = medium res,
hex 8002 = high res). Other bits may be used in the
future; use a simple bit test rather than checking
for specific word values.
16 words palette
< 32000 bytes control bytes
4 words left color animtion limit table (starting color numbers)
4 words right color animation limit table (ending color numbers)
4 words animation channel direction flag (0 = left, 1 = off, 2 = right)
4 words animation channel delay in 1/60's of a second. [0 - 128]
-----------
< 32066 bytes total
Control byte meanings:
For a given control byte, x:
0 <= x <= 127 Use the next x + 1 bytes literally (no repetition)
-127 <= x <= -1 Use the next byte -x + 1 times
-128 No operation (ignore)
Compression Scheme:
Each scan line is compressed separately; i.e., all data for a given
scan line appears before any data for the next scan line. The scan lines
are specified from top to bottom (i.e., 0 is first). For each scan line,
all the data for a given bit plane appears before any data for the next
higher order bit plane.
To clarify: The first data in the file will be the data for the highest
order bit plane of scan line zero, followed by the data for the next lower
order bit plane of scan line zero, etc., until all bit planes have been
specified for scan line zero. The next data in the file will be the data
for the highest order bit plane of scan line one, followed by the data for
the next lower order bit plane of scan line one, etc., until all bit planes
have been specified for all scan lines.
<C.O.L.R. Object Editor Mural>
16000 words picture data (screen memory)
(palettes are stored in separate files)
-----------
32000 bytes total
<Tiny>
Several people have reported sightings of mutated Tiny pictures
that do not follow the standard format, so let's be careful out there.
What is described here is the format David Mumper's original TNYSTUFF.PRG
produces.
1 byte resolution (same as NEO, but +3 indicates rotation
information also follows)
If resolution > 2 {
1 byte left and right color animation limits. High 4 bits
hold left (start) limit; low 4 bits hold right (end)
limit
1 byte direction and speed of color animation (negative value
indicates left, positive indicates right, absolute value
is delay in 1/60's of a second.
1 word color rotation duration (number of iterations)
}
16 words palette
1 word number of control bytes
1 word number of data words
3-10667 bytes control bytes
1-16000 words data words
-------------
42-32044 bytes total
Control byte meanings:
For a given control byte, x:
x < 0 Absolute value specifies the number of unique words to
take from the data section (from 1 to 127)
x = 0 1 word is taken from the control section which specifies
the number of times to repeat the next data word (from
128 to 32767)
x = 1 1 word is taken from the control section which specifies
the number of unique words to be taken from the data
section (from 128 - 32767)
x > 1 Specifies the number of times to repeat the next word
taken from the data section (from 2 to 127)
Format of expanded data:
The expanded data is not simply screen memory bitmap data; instead, the
data is divided into four sets of vertical columns. (This results in
better compression.) A column consists of one specific word taken
from each scan line, going from top to bottom. For example, column 1
consists of word 1 on scanline 1 followed by word 1 on scanline 2, etc.,
followed by word 1 on scanline 200.
The columns appear in the following order:
1st set contains columns 1, 5, 9, 13, ..., 69, 73, 77 in order
2nd set contains columns 2, 6, 10, 14, ..., 70, 74, 78 in order
3rd set contains columns 3, 7, 11, 15, ..., 71, 75, 79 in order
4th set contains columns 4, 8, 12, 16, ..., 72, 76, 80 in order
Note that Tiny partitions the screen this way regardless of resolution; i.e.,
these aren't bitplanes. For example, medium resoltion only has two bitplanes,
but Tiny still divides the medium resolution pictures into four parts.
<Spectrum 512 (Uncompressed)>
80 words first scan line of picture (unused) -- should be zeroes
15920 words picture data (screen memory) for scan lines 1 through 199
9552 words 3 palettes for each scan line (the top scan line is
not included because Spectrum 512 can't display it)
-----------
51104 bytes total
<Spectrum 512 (Compressed)>
1 word 5350 (hex) ("SP")
1 word 0 (reserved for future use)
1 long length of data bit map
1 long length of color bit map
<= 32092 bytes compressed data bit map
<= 17910 bytes compressed color bit map
--------------
< 50014 bytes total
Data compression:
Compression is via a modified run length encoding (RLE) scheme,
similar to DEGAS compressed and Tiny. The data map is stored as a
sequence of records. Each record consists of a header byte followed by
one or more data bytes. The meaning of the header byte is as follows:
For a given header byte, x:
0 <= x < 127 Use the next x + 1 bytes literally (no repetition)
-128 <= x < 0 Use the next byte -x + 2 times
The data appears in the following order:
1. Picture data, bit plane 0, scan lines 1 - 199
2. Picture data, bit plane 1, scan lines 1 - 199
3. Picture data, bit plane 2, scan lines 1 - 199
4. Picture data, bit plane 3, scan lines 1 - 199
Decompression of data ends when 31840 data bytes have been used.
Color map compression:
Each 16-word palette is compressed separately. There are three
palettes for each scan line (597 total). The color map is stored as a
sequence of records. Each record starts with a 1-word bit vector which
specifies which of the 16 palette entries are included in the data
following the bit vector (1 = included, 0 = not included; i.e., stays
the same). The least significant bit of the bit vector refers to
palette entry zero, while the most significant bit refers to palette
entry 15. Bit 15 must be zero, since Spectrum 512 does not use palette
entry 15. Bit 0 should also be zero, since Spectrum 512 always makes the
background color black.
The words specifying the values for the palette entries indicated in
the bit vector follow the bit vector itself, in order (0 - 15).
Yes, it is hideously complex.
<Animatic Film>
1 word number of frames
16 words palette
1 word speed (0 - 99; value is 99 - # vblanks to delay between frames)
1 word direction (0 = forwards, 1 = backwards)
1 word end action (what to do after the last frame)
0 = pause, then repeat from beginning
1 = immediately repeat from beginning
2 = reverse
1 word width of film in pixels
1 word height of film in pixels
1 word Animatic version number (major)
1 word Animatic version number (minor)
1 long magic number 27182818 (hex)
3 longs reserved for expansion (should be all zeros)
--------
32 words total for header
? words image data (words of screen memory) for each frame, in order
<MacPaint>
Word has it that this is wrong. Someone please send me a correction!
header {
1 long version number (if zero, entire header is ignored)
38 * 2 longs pattern data (anyone know how to use this?)
83 longs reserved
} (total 160 longwords for header)
< 51200 bytes compressed bitmap data
-------------
< 51716 bytes total
Bitmap compression:
The bitmap data is for a 576 pixel by 720 pixel monochrome image.
The data is stored as a sequence of records. Each record consists of a
control byte followed by one or more data bytes. The meaning of the
control byte is as follows:
For a given control byte, x:
0 < x < 127 Use the next x + 1 bytes literally (no repetition)
-128 <= x <= 0 Use the next byte -x + 1 times
There are 72 bytes per scan line. Each bit represents one pixel; 0 = white,
1 = black.
Version of Wed Oct 25 00:56:54 EDT 1989