pnmsmooth(1) - phpMan

Pnmsmooth User Manual(0)                                                 Pnmsmooth User Manual(0)



NAME
       pnmsmooth - smooth out an image


SYNOPSIS
       pnmsmooth [-width=cols] [-height=rows] [pnmfile] [-size]

       Minimum unique abbreviations of options is acceptable.  You may use double 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 its value.


DESCRIPTION
       This program is part of Netpbm(1).

       pnmsmooth  smoothes  out  an image by replacing each pixel with the average of its width X
       height neighbors.  It is implemented as a progam that invokes pnmconvol with an  appropri-
       ate convolution matrix.


OPTIONS
       -width=cols

       -height=rows
              These options specify the dimensions of the convolution matrix.  Default dimensions
              are 3 wide and 3 high.

              Before Netpbm 10.49 (December 2009), 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 pamdepth to increase the maxval if necessary).

              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  values  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 com-
              mand mean the same in current pnmsmooth as in old pnmsmooth:
                   pnmsmooth -size 5 5 infile.ppm >outfile.ppm


       -dump=dumpfile
              This options makes pnmsmooth only show you the convolution matrix.   It  writes  to
              Standard  Output  a  pnmconvol -matrix option value that represents the matrix.  It
              does not invoke pnmconvol and does not produce an output image.

              Before Netpbm 10.49 (December 2009), this option is rather different.  It  takes  a
              file  name  as  a value, and it writes to that file the convolution matrix as a PGM
              file (as used to be the normal input for pnmconvol).






SEE ALSO
       pnmconvol(1), pnm(1)


HISTORY
       Before Netpbm 10.32 (February 2006), pnmsmooth did not use the modern Netpbm command  line
       parser, so had an unconventional command line syntax.  Most importantly, you could not use
       an equal sign or double hyphens in the options.

       Before Netpbm 10.49 (December 2009), there was a -dump option.  This strange option caused
       pnmsmooth not to do any smoothing or produce any output image but instead write the convo-
       lution matrix it would have used, as PGM file such as pnmconvol used to use, to a file you
       specify.   The idea was you could then use that file with a separate invocation of pnmcon-
       vol.

       Then, in Netpbm 10.49, there was a rather different -dump option with a  similar  purpose:
       It  caused  pnmsmooth to write to Standard Error a string suitable as a value for the pnm-
       convol -matrix option (an option that was new in Netpbm 10.49).

       But in Netpbm 10.51 (June 2010), pnmconvol started using the even newer pnmconvol -normal-
       ize  option  (new  in 10.50), which made specifying the convolution matrix for the kind of
       smoothing that pnmsmooth does trivial, so -dump disappeared from pnmsmooth.

       (There were also ease of implementation issues that kept us from simply keeping the origi-
       nal -dump around for backward compatibility: As we modified pnmsmooth to take advantage of
       the new features of pnmconvol, which pnmsmooth uses internally, the information needed  to
       implement -dump was no longer available in the program).

DOCUMENT SOURCE
       This  manual page was generated by the Netpbm tool 'makeman' from HTML source.  The master
       documentation is at

              http://netpbm.sourceforge.net/doc/pnmsmooth.html

netpbm documentation                     19 December 2009                Pnmsmooth User Manual(0)

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