Reads a portable anymap as input.
Scales it by the specified factor or factors and produces a portable
anymap as output.
shrinking
enlarging
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
pnmsmooth
step; otherwise, you can see the original pixels in the resulting image.
