BITFILE(9.5) BITFILE(9.5)
NAME
bitfile - format of bitmap file
DESCRIPTION
Binary files produced by blitblt(9.1), twid(9.6) and other
bitmap-generating programs are formatted as follows:
Byte no. Description
0, 1: Zero.
2, 3: X-coordinate of the rectangle origin (low-order
byte, high-order byte).
4, 5: Y-coordinate of the rectangle origin (low-order
byte, high-order byte).
6, 7: X-coordinate of the rectangle corner (low-order
byte, high-order byte).
8, 9: Y-coordinate of the rectangle corner (low-order
byte, high-order byte).
remainder: Compressed raster data. Each raster is
exclusive-or'd with the previous one, and zero-
extended (if necessary) to a 16-bit boundary. It
is then encoded into byte sequences, each of
which consists of a control byte followed by two
or more data bytes:
Control Data
2*n bytes of raster data, running from left to
right.
0x80 + n 2 bytes of raster data, to be replicated from
left to right n times.
There are also two ASCII formats in current use. Textures
and 16×16 icons, typically created by icon(9.1), are encoded
as a Texture declaration with initializer, to be copied
unchanged into C program source; see types(9.5). Faces and
other large icons are without any surrounding C syntax. In
either case, each scan line of the bitmap is a comma-
separated list of C-style short hexadecimal constants; scan
lines are separated by newlines.
SEE ALSO
blitblt(9.1), icon(9.1), twid(9.1), types(9.5), sysmon(9.1),
can(1)