rawtopgm

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
BUGS
SEE ALSO
AUTHORS

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 program will try to read the entire image to a memory buffer. If you get a message that states that you are out of memory, 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