Pnmsmooth User Manual(0) Pnmsmooth User Manual(0)
pnmsmooth - smooth out an image
Deprecated backward-compatibility option:
Minimum unique abbreviation of option is acceptable. You may use dou-
ble hyphens instead of single hyphen to denote options. You may use
white space in place of the equals sign to separate an option name from
This program is part of Netpbm(1).
pnmsmooth smoothes out an image by replacing each pixel with the aver-
age of its width X height neighbors. It is implemented as a progam
that generates a PGM convolution matrix and then invokes pnmconvol with
These options specify the dimensions of the convolution matrix.
Default dimensions are 3 wide and 3 high. Each dimension must
be odd. The maximum size of the convolution matrix is limited
by the maxval of the image such that width * height * 2 must not
exceed the maxval. (use pnmdepth to increase the maxval if nec-
These options were new in Netpbm 10.32 (February 2006). Before
that, use -size.
-size This deprecated option exists in current Netpbm for backward
compatibility. It was obsoleted by -width and -height in Netpbm
10.32 (February 2006).
When you use this option, the first two program arguments are
the width and height, respectively, of the convolution matrix
and do the same thing as the -width and -height option values.
The third (optional) program argument is the input file name.
In reality, in old pnmsmooth, the width and height are two val-
ues of the -size option, but the modern Netpbm command syntax
paradigm doesn’t allow an option with multiple values, so
instead -size is an option with no value and width and height
are program arguments. That has the fortunate effect of making
the following command mean the same in current pnmsmooth as in
pnmsmooth -size 5 5 infile.ppm >outfile.ppm
This options makes pnmsmooth only generate and save the convolu-
tion file. It does not invoke pnmconvol and does not produce an
Before Netpbm 10.32 (February 2006), pnmsmooth did not use the modern
Netpbm command line parser, so had an unconventional command line syn-
tax. Most importantly, you could not use an equal size or double
hyphens in the options.
netpbm documentation 4 December 1994 Pnmsmooth User Manual(0)
Man(1) output converted with