The datpng header looks like this:
| ver | length | width | data ...
|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
struct datpng_header
{
word ver;
dword length;
dword width;
byte c;
byte d;
}
All header data is stored in big endian (network) order.
ver
---
The 'ver' bytes are the version of the data PNG file. This version
indicates the encoded bit depth, existance of a checksum, and other
features.
The least significant 4 bits define the bit depth (up to 16). The most
significant bit (the sign bit) indicates a checksum. All other bits
describe a version of the datpng. This will allow future versions of
the program to continue processing older datpng files.
length
------
The 'length' bytes give the length of the data in bytes.
width
-----
The 'width' bytes give the width of the data chunk in pixels.