Topic : ATARI ST Picture formats
Author : David Baggett/Jan K⌐upka
Version : atari_gf.hyp 0.01 (17/09/96)
Subject : Documentation/File formats
Nodes : 52
Index Size : 1328
HCP-Version : 3
Compiled on : Atari
@charset : atarist
@lang :
@default :
@help :
@options : -i -s +y +z
@width : 75GEM Metafile *.GEM
Marcel Boom <mboom@mswe.dnet.ms.philips.nl> recently sent me this
format description. I have reproduced it here, largely unchanged.
The file consists out of a header and the data records. The header has
the following format:
mf_header: should be -1, which indicates a metafile
mf_hlength: The length of the header part (usually 24 words)
mf_version: Version number (usually 101)
mf_ndcrcfl: 0: NDC coordinates, 2: Raster coordinates
mf_extends1: Optional, minimal used x coordinate
mf_extends2: Optional, minimal used y coordinate
mf_extends3: Optional, maximal used x coordinate
mf_extends4: Optional, maximal used y coordinate
mf_width: Optional, page width in 0.1 mm
mf_height: Optional, page height in 0.1 mm
mf_coords1: Optional, coordinate system param 1
mf_coords2: Optional, coordinate system param 2
mf_coords3: Optional, coordinate system param 3
mf_coords4: Optional, coordinate system param 4
mf_imgflag: 0: No images, 1 contains bit images
mf_reserved1: reserved.
.
.
mf_reserved9: reserved.
After the header follows the data records of the following format:
0: VDI command number
1: n: Number of parameters for ptsin array
2: m: Number of parameters for intin array
3: Subopcode
4 to 4+n: ptsin array
4+n to 4+n+m: intin array
A VDI command number of -1 signals the end of file.
The meaning of the arrays can be found in the several GEM programming
books.
NOTE: The qualifier is not the Motorola word, but the Intel word,
so high and low byte are swapped!