Data Types

The following data types are used in the TrueType font file. All TrueType fonts use Motorola-style byte ordering (Big Endian):

Data type	Description
BYTE	8-bit unsigned integer.
CHAR	8-bit signed integer.
USHORT	16-bit unsigned integer.
SHORT	16-bit signed integer.
ULONG	32-bit unsigned integer.
LONG	32-bit signed integer.
FIXED	32-bit signed fixed-point number (16.16)
FUNIT	Smallest measurable distance in the em space.
FWORD	16-bit signed integer (SHORT) that describes a quantity in FUnits.
UFWORD	Unsigned 16-bit integer (USHORT) that describes a quantity in FUnits.
F2DOT14	16-bit signed fixed number with the low 14 bits of fraction (2.14).

Most tables have version numbers, and the version number for the entire font is contained in the Table Directory (see below). Note that there are two different version number types, each with its own numbering scheme. USHORT version numbers always start at zero (0). Fixed version numbers always start at one (1.0 or 0x00010000).

The Fixed point format consists of a signed, 2's complement mantissa and an unsigned fraction. To compute the actual value, take the mantissa and add the fraction. Examples of 2.14 values are:

Decimal Value	Hex Value	Mantissa	Fraction
1.999939	0x7fff	1	16383/16384
1.75	0x7000	1	0/16384
0.000061	0x0001	0	1/16384
0.0	0x0000	0	0/16384
-0.000061	0xffff	-1	16383/16384
-2.0	0x8000	-2	0/16384