[Coco] Sockmaster HiColor and Rascan IMG file format

[Joel Ewy]

John Kowalski wrote:
> At 11:40 PM 06/01/2007 -0600, JCE wrote:
>   
>> I've had a lot of fun playing with Sockmaster's HiColor program, using
>> BMP files I've scaled down and converted from JPEGs using NETPBM.  But
>> the program can ostensibly display significantly more than 256 colors. 
>> I'd like to see if I can tell the difference between a 12-bit source
>> image and an 8-bit source image.  Problem is I don't have any good .IMG
>> files to test it out with.  Ideally, I'd like to be able to convert
>> JPEGs into 4096 color .IMG files myself.
>>     
>
> I don't know of any converters and it's been a while since I looked into
> HiColor, but I seem to recall the "4096" color IMG files may not actually
> stictly be 4096 colors.  The three (R, G and B) pages of the IMG data may
> have been encoded as 640x200 4-shade dithered images - the dithering being
> used to increase the visible shades.  Mathematically it may have only worked
> out to be the equivalent of 512 colors.?  I may be wrong, that's just my
> recollection.
>   
I've seen some .IMG pictures that were actually made on the DS-69 rather
than the Rascan.  These were done in the high-res (4 gray) mode and
dithered, so they certainly aren't anywhere near 4096 "real" colors. 
They look awful.  But it suggests that at one time, somebody had a
program to make .IMG files from sources other than the Rascan.  I
checked last night, and view 4.4 can't do it.  But the Rascan pictures
I've seen, such as the one in the Rainbow review, looked really good,
and I'm sure they used 16 gray shades for each color plane.

I also remember making my own real 12-bit images with my DS-69B.  I did
them in the 4-bit per pixel mode.  When I tried using a b/w video camera
and colored celophane filters the results were pretty bad.  But I did
get good results when a friend brought over his camcorder with a digital
freeze frame, and the color splitter for his Amiga DigiView.  With that
we could capture a still image and individually digitize the red, green,
and blue components on the CoCo.  Then I cooked up a simple C program in
OS-9 that would read in the three .PIX files, rotate them on the fly,
and save them all out as a 15-bit Targa file (easy to implement) with
the LSB unused.  (This is pix2tga on rtsi)  I then used a DOS utility on
the PC to quantize the colors down to 256 and convert the Targa file
into a .GIF which I could view on the PC or the Amiga.  (This was
pre-MM/1, or at least before I got one.)  The results of that process
were very good, though they were rather labor intensive, requiring a lot
of equipment and moving fairly large data files by floppy disk or Zmodem
from RS-DOS to OS-9 to MS-DOS to AmigaDOS, et cetera.
>> Of course, it would also be cool if HiColor could read in some other
>> file formats.  Hey Sock, any chance you'd let the source code out of the
>> bag?  :)
>>
>> JCE
>>     
> You know..  I may as well just post it up on my web page.  It would be cool
> if the code got upgraded/enhanced, or used in other projects - like HiColor
> title pages for new games or something!
>   
Cool!  I can even imagine a few kinds of games that don't require much
processing during play that might even include small HiColor images
during play.  A text adventure with graphics comes to mind.
> I'm going to look into finding where I put it and put it on the web in the
> next day or two.  It might not be the prettiest code to look at, or even
> easy to follow..
>   
Nobody will make fun of you, I promise!
>                                          John Kowalski (Sock Master)
>                                          http://www.axess.com/twilight/sock/
>