https://www.temlib.org/AtariForumWiki/index.php?action=history&feed=atom&title=QuantumPaint_file_formatQuantumPaint file format - Revision history2026-07-27T11:13:16ZRevision history for this page on the wikiMediaWiki 1.39.2https://www.temlib.org/AtariForumWiki/index.php?title=QuantumPaint_file_format&diff=16585&oldid=prev>Lp: New page2017-01-03T00:07:11Z<p>New page</p>
<p><b>New page</b></p><div><pre><br />
QuantumPaint *.PBX (low and medium resolution)<br />
<br />
3 bytes 0<br />
1 byte mode, 0x00 = 128 color low resolution pciture, <br />
0x01 = 32 color medium resolution picture,<br />
0x80 = 512 color picture low resolution picture<br />
0x81 = 4096 color picture low resolution picture<br />
1 word 0x8001 = compressed<br />
Quantumpaint v2.00 sets it to 0x8000 for uncompressed files<br />
Quantumpaint v1.00 seems to use 0x0000 for lowras and 0x0333<br />
for medium res bytes. The PBX viewer only tests for 0x8001.<br />
122 bytes ??<br />
total 128 header bytes<br />
?? bytes palette data;<br />
for uncompressed normal pictures 8 pallete datasets follow:<br />
16 words: 16 palettes<br />
1 word: number of the first line this pallet is used<br />
1 word: 0 the palette is not active, else this pallete is active<br />
1 word: first color of color cycle<br />
1 word: last color of color cycle<br />
1 word: cycle speed, number of vbl's between steps, 0 = fastest<br />
1 word: 0: no cycling, 1 cycle right, 0xffff cycle left<br />
2 word: ?? should be zero<br />
__<br />
48 bytes per palette<br />
The first palette should always be active and start on line 0<br />
___<br />
384 bytes palette data for low (128 color) and medium (32 color) pictures<br />
for uncompressed 512 color pictures 6400 words (32 colors per scanline)<br />
for uncompressed 4096 color pictures 12800 words (32 colors per scanline,<br />
2 palette sets for alternating screens, two 6400 word blocks)<br />
?? bytes screen data, for uncompressed pictures this is 32000 bytes for all modes<br />
--------<br />
> 128 bytes total<br />
<br />
Compression scheme<br />
Palette and screen data are compressed into one block using packbits compression.<br />
The expanded screen data is not simply screen memory bitmap data; instead, the <br />
data is divided into four sets of vertical columns. (This results in<br />
better compression.) A column consists of one specific word taken<br />
from each scan line, going from top to bottom. For example, column 1 <br />
consists of word 1 on scanline 1 followed by word 1 on scanline 2, etc., <br />
followed by word 1 on scanline 200.<br />
The columns appear in the following order:<br />
<br />
1st set contains columns 1, 5, 9, 13, ..., 69, 73, 77 in order<br />
2nd set contains columns 2, 6, 10, 14, ..., 70, 74, 78 in order<br />
3rd set contains columns 3, 7, 11, 15, ..., 71, 75, 79 in order<br />
4th set contains columns 4, 8, 12, 16, ..., 72, 76, 80 in order<br />
This colmn ordering is just the same as in the Tiny format.<br />
for medium res it is the same only with two stes for the two medium res bitplanes.<br />
<br />
/*<br />
* Given an x-coordinate and a color index, returns the corresponding<br />
* QuantumPaint palette index.<br />
*<br />
* by Hans Wessels; placed in the public domain January, 2008.<br />
*/<br />
int find_pbx_index(int x, int c)<br />
{<br />
int x1 = 10 * c;<br />
if (1 & c)<br />
{ /* If c is odd */<br />
x1 = x1 - 5;<br />
}<br />
else<br />
{ /* If c is even */<br />
x1 = x1 + 1;<br />
}<br />
if(c>7)<br />
{<br />
x1+=12;<br />
}<br />
if(x>=(x1+75))<br />
{<br />
c = c + 16;<br />
}<br />
return c;<br />
}<br />
</pre><br />
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