FNT Font File Format

FNT is a simple binary font format used by Rockbox. It is a fixed-size raster font format that supports unicode.

In this context a 'long' is intended to mean a 32 bit unit regardless of target architecture.

Header

The FNT header is exactly 36 bytes long consisting of the following fields:

Field	length (bytes)	description
* UCHAR version[4]	4	magic number and version bytes (currently 'RB12')
* USHORT maxwidth	2	font max width in pixels
* USHORT height	2	font height in pixels
* USHORT ascent	2	font ascent (baseline) in pixels
* USHORT pad	2	unused, pad to 32-bit boundary
* ULONG firstchar	4	first character code in font
* ULONG defaultchar	4	default character code in font
* ULONG size	4	# characters in font
* ULONG nbits	4	# bytes imagebits data in file
* ULONG noffset	4	# longs offset data in file
* ULONG nwidth	4	# bytes width data in file

Gyphs

(to be written)