.TH vdmpc 5
.SH NAME
vdmpc \- format of vdmpc color bitmaps (raster images for printing)
.SH SYNTAX
\fI(none)\fR
.br
.SH DESCRIPTION
.NXR "vdmpc" "format"
.NXR "file" "color printing"
.PP
Vdmpc color bitmap files are processed by the vdmpc filter, which comes 
with the Magic VLSI layout editor from Berkeley.
.PP
A vdmpc file consists of 5 parts:  a 1024 byte header and four bitmaps, one for
each of the following colors in order:  black, cyan, magenta, and yellow.
This format is inspired by the 3000-series Versatec color plotters.
.PP
The 1024 byte header starts with a 1-word magic number:  0xA5CF4DFB.
Thus, the first 4 bytes of the file are:  0x4D, 0xFB, 0xA5, 0xCF.
The second word (four bytes) contain the length of the bitmap in pixels.
The third word gives the width of the bitmap.
The width must be a multiple of 8.
It does not have to match the physical width of the plotter, as it will
be clipped or padded as needed.
The remaining words of the header are currently unused, and should be set to
zero.
.PP
The rest of the file contains the bitmaps.  There are no separation or
formatting characters between the bitmaps -- they follow immediately after
the header block and are packed back-to-back.
Each bitmap is of size width*height bits,
where width and height are defined in the header.
Each bitmap consists of a sequence of bits packed into bytes.  The bits are
ordered from the top-left of the image moving towards the top-right.  After
a complete scan-line is represented this way, the data for the next lower
scan line
is represented.  Bits are packed into bytes such that the leftmost bit
on the physical device is placed into the high-order bit position of the byte.
.SH "SEE ALSO"
vdmpc(8)
.SH AUTHOR
Bob Mayo