DuneGraph
From Just Solve the File Format Problem
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<code>.dg1</code> files begin with ASCII "{{magic|DGU}}". | <code>.dg1</code> files begin with ASCII "{{magic|DGU}}". | ||
| + | |||
| + | <pre> | ||
| + | PaintShop plus *.PSC (st high resolution) | ||
| + | *.DA4 (st high resolution, double height) | ||
| + | |||
| + | *.DA4 files are simple screen dumps: | ||
| + | |||
| + | 64000 bytes image data (uncompressed, thus 640x800) | ||
| + | ----------- | ||
| + | 64000 bytes total for file | ||
| + | |||
| + | *.PSC files are compressed: | ||
| + | |||
| + | 6 bytes file id ["tm89PS"] | ||
| + | 1 word version [0xCB = 2.03] | ||
| + | 1 byte ? [always 2] | ||
| + | 1 byte ? [always 1] | ||
| + | 1 word image width in pixels - 1 [always 639] | ||
| + | 1 word image height in pixels - 1 [always 399] | ||
| + | -------- | ||
| + | 14 bytes total for header | ||
| + | |||
| + | ? image data: | ||
| + | The image data is not compressed based on pixels, but rather scan lines. Starting at the | ||
| + | top and working downward. There are 9 unique codes: | ||
| + | |||
| + | Codes: | ||
| + | 0 set current line all white (0x00) | ||
| + | 10 copy line above (next byte + 1) times | ||
| + | 12 copy line above (next byte + 256 + 1) times | ||
| + | 99 copy from stream 80 * 400 lines (full image) | ||
| + | 100 fill next line with (next byte) as line style [(b << 8 ) | b] | ||
| + | 102 fill next line with (next 2 bytes) as line style [(b1 << 8) | b2] | ||
| + | 110 copy from stream 80 bytes to current line | ||
| + | 200 set current line all black (0xFF) | ||
| + | 255 marks end of file (stop process codes) | ||
| + | |||
| + | 'line style' mentioned above is a reference to VDI function vsl_udsty(), set user-defined | ||
| + | line style pattern. Essentially, fill that line with the bit pattern. | ||
| + | </pre> | ||
== Software == | == Software == | ||
Revision as of 20:47, 10 August 2020
DuneGraph is a graphics program for the Atari ST line of computers. .dc1 files are compressed .dg1 files.
Contents[hide] |
Identification
.dc1 files begin with ASCII "DGC".
.dg1 files begin with ASCII "DGU".
PaintShop plus *.PSC (st high resolution)
*.DA4 (st high resolution, double height)
*.DA4 files are simple screen dumps:
64000 bytes image data (uncompressed, thus 640x800)
-----------
64000 bytes total for file
*.PSC files are compressed:
6 bytes file id ["tm89PS"]
1 word version [0xCB = 2.03]
1 byte ? [always 2]
1 byte ? [always 1]
1 word image width in pixels - 1 [always 639]
1 word image height in pixels - 1 [always 399]
--------
14 bytes total for header
? image data:
The image data is not compressed based on pixels, but rather scan lines. Starting at the
top and working downward. There are 9 unique codes:
Codes:
0 set current line all white (0x00)
10 copy line above (next byte + 1) times
12 copy line above (next byte + 256 + 1) times
99 copy from stream 80 * 400 lines (full image)
100 fill next line with (next byte) as line style [(b << 8 ) | b]
102 fill next line with (next 2 bytes) as line style [(b1 << 8) | b2]
110 copy from stream 80 bytes to current line
200 set current line all black (0xFF)
255 marks end of file (stop process codes)
'line style' mentioned above is a reference to VDI function vsl_udsty(), set user-defined
line style pattern. Essentially, fill that line with the bit pattern.
