.TH MBF 5
.SH NAME
mbf \- Monospaced Bitmap Font
.SH DESCRIPTION
A font file using the MBF format consists of a header, a list of ranges and a
list of bitmaps.
.PP
The header, located at the very beginning of the file, is intended to identify
it as a MBF font and specify the number of glyphs as well as the glyph
dimensions.
.PP
.RS
.nf
struct Header {
    char sig[4];            /* signature: "MBF\\x01" */
    uint16_t nglyphs;       /* number of glyphs */
    uint8_t width, height;  /* glyph dimensions */
};
.fi
.RE
.PP
This header is followed by a range list. The list starts with a \fBuint16_t\fR
number indicating how many ranges follow. each range is composed of two numbers,
\fIoffset\fR and \fIlength\fR (both \fBuint16_t\fR). \fIoffset\fR is the code of
the first character in the range. \fIlength\fR is the number of characters in
the range. For example, the ASCII range is represented by the tuple (0, 128).
Ranges must not overlap. Ranges must be sorted by ascending order of
\fIoffset\fR values.
.PP
The list of ranges is followed by a list of \fInglyphs\fR bitmaps. Each bitmap
has \fIheight\fR rows. The number of bytes per row is the minimum necessary to
accomodate \fIwidth\fR bits (this number is known as the \fBstride\fR). Paddings
go in the right (least significant) bits of the last byte in the row.
.PP
.RS
.nf
stride = ceil(width / 8)
.fi
.RE
.PP
Bitmaps must be sorted by ascending order of code point, so that they can be
located by searching the range list.
.SH NOTES
MBF files store 16-bit numbers using the native byte order. For this reason,
they are not portable accross machines of different endianess.