PNMSCALE

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]
      pnmscale -pixels n [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.
      You can use the special -xysize flag, which fits the image into the
      specified size without changing the aspect ratio.
      Or, you can use the -pixels flag, which fits the image into the
      specified number of pixels 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.

DEMONSTRATION

      Let a.pnm be a portable anymap.
      The following command will scale it by a factor of 1.17
	pnmmerge pnmscale .pnm > .pnm

BEFORE

AFTER

s=1.21

-sizexy 300 160 (result size: 300x150)

-xscale 0.707 -yscale 1.414

SEE ALSO

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

AUTHOR

      Copyright (C) 1989, 1991 by Jef Poskanzer.