When I was younger my goal was always to make computer games. Whether on an Apple IIe, or when in 7th grade we got a 386 DX 33Mhz, I would always work on games. One problem I had was creating graphics. Making a picture pixel by pixel and line by line with graph paper took forever. But I was using GW-BASIC and knew no better way.
So in 1992 (when I was in 9th grade) I had a revelation. I would write my own paint program, that could create pictures and then load them into BASIC. I did just that. In Turbo Pascal 5.0 (which I had just learned) I created a paint program. Not knowing what to call it, I saved it as PAINTPROGRAM.PAS Thanks to Bill Gates and the 8 letter dos file limit, this was truncated to PAINTPRO.PAS and hence the paintpro format was born.
The original paintpro was an extremely crude program, using the borland BGI and allowing 16 color editing in VGA and EGA modes. Some clever design work on my part eventually got a pretty good interface going (no mouse, and cryptic commands) with lines, circles, magnification and my own fill routines. The PAINTPRO format from versions 1.0-4.0 was a text file. (A very large text file usually).
I used RLE encoding ( I didn't realize I used RLE encoding until 1996. I always thought it was a nifty algorythm I invented). Basically you start in the upper left corner of the picture, get the color, and count how many pixels across the color stays the same. When the color changes, you save to disk the color and the number across. Do this for the whole picture and you have it saved. As I was saying, versions 1.0-4.0 of paintpro saved it as a text file of integers, with each integer being color*1000+numacross.
This was extremely bulky and slow, but easy to import into C, pascal, and most of all basic. By this time I stopped using Basic, leaning more to Turbo Pascal. But my friend, Jeff, was an amazing artist and he used the program to create graphics for Basic programs. My friend John used paintpro to make C programs.
About this time I finished version 4.0 of paintpro. This version used Borland's VGA256.BGI to implement a 256 colot 320x200 mode. The only problem was with 256 colors the integer size would be overflown with color*1000. I was stumbling; further devolpment was halted.
My friend Jeff created his own program, using the Paintpro format, in visual basic and continued using it.
Then I discoveres TSR's and I developed a screen-capture utility. Goodbye Paintpro, hello Deluxe-Paint and screen capture. This lasted me through two games I never finished, AITAS and SPACEWAR III.
Finally in 1994 I went to Germany as an exchange student. There I got the PCGPE (PC Game Programmers Encyclopedia). In it I learned all about assembly and MCGA mode 13h (320x200x256) and from then on I was programming in this mode. But I needed a new format.
Paintpro version 4.1 was invented. It was a crude attempt to create binary files. It packed the files smaller, but it wasted a lot of space. Using this and a 256 color screen capture I developed I started work on Tom Bombem, my best game ever.
About a year later I revised the paintpro format, version 5.0. This version was much improved, didn't waste space, and incuded pallete information. Development continued.
Finally in the Summer of 1996, after working on loading paintpro images on Unix machines (sgi's and others) I refined the format one more time. Since I haven't talked to Jeff in a year and John uses paintpro sporadically, I never felt the need to be backwards compatible. I also now have a pcx to paintpro converter, because after years of ignorance I finally got a book and realized that the paintpro format is amazingly similar to the PCX format. Oh well. I like it.
Paramaters: A graphics file, semi-compressed.
Maximum Dimensions : 4096x4096
Maximum Colors: 2048
24 bit color
Encoding: Integer to 3 bytes
Many of the paramaters are stored this way to save room.
Basically an integer is 2 bytes long (16 bits).
so the integer 266 is $010A hex or 0000 0001 0000 1010 binary.
What integer to 3 bytes does is strip the top 4 bits off
of two integers (limiting the size of each to 4096, hence
the maximum values of the file) and runs them together
two 12 bit intgers together is 24 bits, or 3 bytes.
So these two stripped integers are saved as 3 bytes.
e.g say the integers 320 and 200 are to be stored this way.
320 = $0140 hex 200 = $00C8
| |
0000|0001 0010 0000 0000|0000 1100 1000
! !
First 4 bits stripped 0001 0010|0000 0000|1100 1000
! ! !
0001 0010 0000 0000 1100 1000
$14 $00 $C8
so the leading 0 is stripped off of each, and
the three bytes $14 $00 $c8
This is a little confusing, but this is the method I chose
and it works pretty well.
The Format:
Header:
PAINTPRO 8 bytes,file type
V6.0 4 bytes,version
xsize,ysize 3 bytes (2 integers two 3 bytes. see above)
(max value 4095 for each)
numcolors,0 3 bytes (2 integers two 3 bytes)
(max value 2047 for colors. 0 is space holder)
palette
[0..(numcolors-1)] of 3 byte (r,g,b)
(24 bit color)
The actual file:
color,numacross 3bytes (2 integers two 3 bytes)
repeated until screen is full.
Optimizations:
here are some optimizations you have to watch for the decreased
file size over v5.0 by at least 10%
wrapping: If a numacross goes past the right edge of the screen,
wrap it to the next line.
e.g if the first one is decoded (5,540) then the color
5 is drawn until the end (at 320) and 320 is
subtracted and then the remaining 220 goes on the
next line).
single pixel: If a value is over 2048, then it is a single pixel
of the value-2048.
e.g if color or numacross is 2148, then put one pixel of 100.
(these only occur in pairs of 2 to make the
file saving faster)
This is the basic format. It is used extensively in Tom Bombem.
It is a standard application of RLE (run-length encoding) and
co-incidently similar to a PCX file.
Feel free to use the format for any application.
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