pnmscale(1)

NAME
pnmscale - scale a portable anymap

SYNOPSIS
pnmscale s [pnmfile]
pnmscale -xsize|-width|-ysize| -height s [pnmfile]
pnmscale -xscale|-yscale s [pnmfile]
pnmscale -xscale|-xsize|-width s -yscale|-ysize|-height s [pnmfile]
pnmscale -xysize x y [pnmfile]

DESCRIPTION
Reads a portable anymap as input. Scales it by the specified factor or factors and produces a portable anymap as output. If the input file is in color, the output will be too, otherwise it will be grayscale. You can both enlarge (scale factor > 1) and reduce (scale factor < 1).

You can specify one dimension as a pixel size, and the other dimension will be scaled correspondingly.

You can specify one dimension as a scale, and the other dimension will not be scaled.

You can specify different sizes or scales for each axis.

Or, you can use the special -xysize flag, which fits the image into the specified size without changing the aspect ratio.

All flags can be abbreviated to their shortest unique prefix.

If you enlarge by a factor of 3 or more, you should probably add a pnmsmooth step; otherwise, you can see the original pixels in the resulting image.

SEE ALSO
pbmreduce(1), pnmenlarge(1), pnmsmooth(1), pnm(5)

AUTHOR
Copyright (C) 1989, 1991 by Jef Poskanzer.