GSD

The GSD binary file format

This is my first try to reverse engineer a binary file format. If you like, you could add your thoughts! By comparison between different files with the extention .gsd i try to see what data is stored where. It has some parts in ansi-text and the most parts are just binary numbers of different length. As identification, the file starts with the text "GRAPHTEC PRT&CUT". The next line at offset 0000:0010 starts with binary numbers "03 00 00 00 02 00 00 00 00 00 00 00 00 00 00 00" (I don't know if they make any sense there).

• From offset 0000:0080 to offset 0000:00cf is unknown binary data.
• From offset 0000:00d3 to offset 0000:00de is binary data, which is exactly repeated from offset 0000:00fb to 0000:0107. It starts with the hex numbers 40 6a 40 which seems to be a marker for file seek. It ends with 40 00 04. Inbetween those bytes is data which funktion is still unknown.

• Every object can have a different color in the 8bit-RGB-color-range. E.g. RGB(254,254,254), but most probably it is only black. RGB(0,0,0). The first color is defined as ansi text from position 0000:05cd to 0000:05de.

• The size of the canvas is defined from 0000:0674 to 0000:067f and it ends with a big R. The value could be in upper case letters "ISO A4.....R" or "LETTER.....R" The string must be trunkated after the 11th char and a R must be appended.

• The hex value 40 seems to be the delimiter between chunks of data of different length.