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

       pnmsmooth - smooth out an image

       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.

       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 invokes pnmconvol with an appropriate convolution matrix.


	      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  val-
	      ues  of  the  -size option, but the modern Netpbm	command	syntax
	      paradigm doesn't allow an	option with multiple  values,  so  in-
	      stead  -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 old
		   pnmsmooth -size 5 5 infile.ppm >outfile.ppm

	      This options makes pnmsmooth only	show you the  convolution  ma-
	      trix.   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 dif-
	      ferent.  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).

       pnmconvol(1), pnm(5)

       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 sign or  double  hy-
       phens 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 convolution 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

       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 pnmconvol -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 -normalize option (new	in 10.50), which made  specifying  the
       convolution  matrix for the kind	of smoothing that pnmsmooth does triv-
       ial, so -dump disappeared from pnmsmooth.

       (There were also	ease of	implementation issues that kept	us from	simply
       keeping	the  original  -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).

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

netpbm documentation	       19 December 2009	      Pnmsmooth	User Manual(0)


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