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Pamenlarge User Manual(0)						Pamenlarge User Manual(0)

NAME
       pamenlarge - Enlarge a Netpbm image N times

SYNOPSIS
       pamenlarge N [pnmfile]

DESCRIPTION
       This program is part of Netpbm(1)

       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;  other-
       wise, you can see the original pixels in the resulting image.

       For  PBM  images, pamenlarge uses special fast algorithms for scale factors up to 10.  For
       larger factors, it uses a simple but slow algorithm.  As a result, you  can  often  get	a
       significantly  faster  scale by running pamenlarge multiple times.  For example, enlarging
       by 3 and then by 5 is faster than enlarging once by 15.	And because  the  algorithms  are
       different for the different scale factors, some faster than others, the order matters too.
       For example, the following examples all produce the same output -- an image 15 times  big-
       ger  on edge than the input -- but with at different spees, each being faster than the one
       before.

	    $ pamenlarge 15 test.pbm
	    $ pamenlarge 5 test.pbm | pamenlarge 3
	    $ pamenlarge 3 test.pbm | pamenlarge 5

       The special fast cases for factors up to 10 have existed since Release 10.50 (March 2010).
       The  special  cases  for  1, 2, 3, and 5 go back to Release 10.41 (December 2007).  Before
       10.41, there are no special scale factors and PBM enlargement is significantly slower than
       today for all scale factors.

       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 sim-
       ple 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 differ-
       ence is that pamenlarge can enlarge PAM format images in addition to PNM.

SEE ALSO
       pbmreduce(1) , pamscale(1) , pamstretch(1) , pbmpscale(1) , pnmsmooth(1) , pnm(1)

AUTHOR
       Copyright (C) 1989 by Jef Poskanzer.

netpbm documentation			  17 March 2010 		Pamenlarge User Manual(0)
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