1Pnmsmooth User Manual(0)                              Pnmsmooth User Manual(0)
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NAME

6       pnmsmooth - smooth out an image
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SYNOPSIS

10       pnmsmooth [-width=cols] [-height=rows] [pnmfile] [-size]
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12       Minimum  unique  abbreviations  of  options is acceptable.  You may use
13       double hyphens instead of single hyphen to denote options.  You may use
14       white space in place of the equals sign to separate an option name from
15       its value.
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DESCRIPTION

19       This program is part of Netpbm(1).
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21       pnmsmooth smoothes out an image by replacing each pixel with the  aver‐
22       age  of  its  width  X height neighbors.  It is implemented as a progam
23       that invokes pnmconvol with an appropriate convolution matrix.
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OPTIONS

27       In addition to the options common to all programs  based  on  libnetpbm
28       (most notably -quiet, see
29        Common  Options ⟨index.html#commonoptions⟩ ), pnmsmooth recognizes the
30       following command line options:
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34       -width=cols
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36       -height=rows
37              These options specify the dimensions of the convolution  matrix.
38              Default dimensions are 3 wide and 3 high.
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40              Before  Netpbm  10.49  (December  2009), the maximum size of the
41              convolution matrix is limited by the maxval of  the  image  such
42              that  width  *  height  *  2  must  not exceed the maxval.  (use
43              pamdepth to increase the maxval if necessary).
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45              These options were new in Netpbm 10.32 (February 2006).   Before
46              that, use -size.
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49       -size  This  deprecated  option  exists  in current Netpbm for backward
50              compatibility.  It was obsoleted by -width and -height in Netpbm
51              10.32 (February 2006).
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53              When  you  use  this option, the first two program arguments are
54              the width and height, respectively, of  the  convolution  matrix
55              and  do  the same thing as the -width and -height option values.
56              The third (optional) program argument is the input file name.
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58              In reality, in old pnmsmooth, the width and height are two  val‐
59              ues  of  the  -size option, but the modern Netpbm command syntax
60              paradigm doesn't allow an option with multiple  values,  so  in‐
61              stead  -size is an option with no value and width and height are
62              program arguments.  That has the fortunate effect of making  the
63              following  command  mean the same in current pnmsmooth as in old
64              pnmsmooth:
65                   pnmsmooth -size 5 5 infile.ppm >outfile.ppm
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69       -dump=dumpfile
70              This options makes pnmsmooth only show you the  convolution  ma‐
71              trix.   It  writes to Standard Output a pnmconvol -matrix option
72              value that represents the matrix.  It does not invoke  pnmconvol
73              and does not produce an output image.
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75              Before  Netpbm 10.49 (December 2009), this option is rather dif‐
76              ferent.  It takes a file name as a value, and it writes to  that
77              file  the  convolution  matrix  as a PGM file (as used to be the
78              normal input for pnmconvol).
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SEE ALSO

86       pnmconvol(1), pnm(1)
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HISTORY

90       Before Netpbm 10.32 (February 2006), pnmsmooth did not use  the  modern
91       Netpbm  command line parser, so had an unconventional command line syn‐
92       tax.  Most importantly, you could not use an equal sign or  double  hy‐
93       phens in the options.
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95       Before  Netpbm  10.49  (December 2009), there was a -dump option.  This
96       strange option caused pnmsmooth not to do any smoothing or produce  any
97       output  image  but  instead  write the convolution matrix it would have
98       used, as PGM file such as pnmconvol used to use, to a file you specify.
99       The idea was you could then use that file with a separate invocation of
100       pnmconvol.
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102       Then, in Netpbm 10.49, there was a rather different -dump option with a
103       similar  purpose:  It  caused  pnmsmooth  to  write to Standard Error a
104       string suitable as a value for the pnmconvol -matrix option (an  option
105       that was new in Netpbm 10.49).
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107       But in Netpbm 10.51 (June 2010), pnmconvol started using the even newer
108       pnmconvol -normalize option (new in 10.50), which made  specifying  the
109       convolution  matrix for the kind of smoothing that pnmsmooth does triv‐
110       ial, so -dump disappeared from pnmsmooth.
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112       (There were also ease of implementation issues that kept us from simply
113       keeping  the  original  -dump  around for backward compatibility: As we
114       modified pnmsmooth to take advantage of the new features of  pnmconvol,
115       which  pnmsmooth  uses  internally, the information needed to implement
116       -dump was no longer available in the program).
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DOCUMENT SOURCE

119       This manual page was generated by the Netpbm tool 'makeman'  from  HTML
120       source.  The master documentation is at
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122              http://netpbm.sourceforge.net/doc/pnmsmooth.html
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124netpbm documentation           19 December 2009       Pnmsmooth User Manual(0)