pamenlarge reads a Netpbm image as input, replicates its pixels
N times, and produces a Netpbm image as output. The output is
the same type of image as the input.
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.
pamenlarge can enlarge only by integer factors. The slower
but more general pamscale can enlarge or reduce by arbitrary
factors. pamscale allows you to enlarge by resampling, which
gives you smoother enlargements. But it is much slower.
pamstretch is another enlarging program that enlarges by
integer factors. It does a simple kind of resampling that gives you a
smoothed enlargement with less computational cost.
pbmreduce can reduce by integer factors, but only for PBM
images.
HISTORY
pamenlarge was new in Netpbm 10.25 (October 2004). It is
designed as a replacement for pnmenlarge by Jef Poskanzer,
which was in Pbmplus as far back as 1989. The major difference is that
pamenlarge can enlarge PAM format images in addition to PNM.