Computer Science
rawtopgm(1) rawtopgm(1)
NAME
rawtopgm - convert raw grayscale bytes into a portable
graymap
SYNOPSIS
rawtopgm [-headerskip N] [-rowskip N] [-tb|-topbottom]
[width height] [imagedata]
DESCRIPTION
Reads raw grayscale bytes as input. Produces a portable
graymap as output. The input file is just grayscale
bytes. If you don't specify the width and height on the
command line, the program will check the size of the image
and try to make a quadratic image of it. It is an error to
supply a non quadratic image without specifying width and
height. The maxval is assumed to be 255.
OPTIONS
-headerskip
If the file has a header, you can use this flag to
skip over it.
-rowskip
If there is padding at the ends of the rows, you
can skip it with this flag. Note that rowskip can
be a real number. Amazingly, I once had an image
with 0.376 bytes of padding per row. This turned
out to be due to a file-transfer problem, but I was
still able to read the image.
-tb -topbottom
Flips the image upside down. The first pixel in a
pgm file is in the lower left corner of the image.
For conversion from images with the first pixel in
the upper left corner (e.g. the Molecular Dynamics
and Leica confocal formats) this flips the image
right. This is equivalent to rawtopgm [file] |
pnmflip -tb .
BUGS
If you don't specify the image width and height, the pro-
gram will try to read the entire image to a memory buffer.
If you get a message that states that you are out of mem-
ory, try to specify the width and height on the command
line. Also, the -tb option consumes much memory.
SEE ALSO
pgm(5), rawtoppm(1), pnmflip(1)
AUTHORS
Copyright (C) 1989 by Jef Poskanzer.
Modified June 1993 by Oliver Trepte, oliver@fysik4.kth.se
15 June 1993 1
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