man > pamcut(1)

Pamcut User Manual(1)                  General Commands Manual                 Pamcut User Manual(1)

NAME
       pamcut - cut a rectangle out of a PAM, PBM, PGM, or PPM image


SYNOPSIS
       pamcut

       [-left colnum]

       [-right colnum]

       [-top rownum]

       [-bottom rownum]

       [-width cols]

       [-height rows]

       [-pad]

       [-cropleft numcols]

       [-cropright numcols]

       [-croptop numrows]

       [-cropbottom numrows]

       [-verbose]

       [left top width height]

       [pnmfile]

       Minimum unique abbreviations of option are 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 sep‐
       arate an option name from its value.


DESCRIPTION
       This program is part of Netpbm(1).

       pamcut reads a PAM, PBM, PGM, or PPM image as input and extracts the specified rectangle, and
       produces the same kind of image as output.

       You can specify either the rectangle to cut out and keep or specify the edges to crop off and
       discard, or a combination.

       To request edges be cropped off, use options -cropleft, -cropright, -croptop, and -cropbottom
       to indicate how many rows or columns to discard.

       For  example,  -cropleft=50 -cropright=200 means to discard the leftmost 50 and rightmost 200
       columns.

       To specify the rectangle to keep, use -left, -right, -top, -bottom, -width, -height, and -pad
       options.

       For example, -left=50 -right=200 means to keep the 150 columns between Columns 50 and 200 in‐
       clusive.

       You can code any mixture of the options.  What you don't specify  defaults.   Those  defaults
       are  in  favor of minimal cutting and in favor of cutting the right and bottom edges off.  It
       is an error to overspecify, i.e. to specify all three of -left, -right, and -width  or  -top,
       -bottom, and -height or right as well as -cropright.

       There is an older way to specify the rectangle to keep: positional arguments.  Arguments were
       the  only  way  available  before July 2000, but you should not use them in new applications.
       Options are easier to remember and read, more expressive, and allow you to use defaults.

       If you use both options and arguments, the two specifications get  mixed  in  an  unspecified
       way.

       To  use  arguments, specify all four of the left, top, width, and height arguments.  left and
       top have the same effect as specifying them as the argument of a -left or  -top  option,  re‐
       spectively.   width  and  height have the same effect as specifying them as the argument of a
       -width or -height option, respectively, where they are positive.  Where they  are  not  posi‐
       tive,  they  have  the same effect as specifying one less than the value as the argument to a
       -right or -bottom option, respectively.  (E.g. width = 0 makes the cut go all the way to  the
       right edge).  Before July 2000, negative numbers were not allowed for width and height.

       Input is from Standard Input if you don't specify the input file pnmfile.

       Output is to Standard Output.

       pamcut  works  on  a  multi-image stream.  It cuts each image in the stream independently and
       produces a multi-image stream output.  Before Netpbm 10.32 (March 2006), it ignored  all  but
       the first image in the stream.

       If  you  are  splitting  a single image into multiple same-size images, pamdice is faster and
       easier than running pamcut multiple times.

       pamcomp is also useful for cutting and padding an image to a  certain  size.   You  create  a
       background image of the desired frame dimensions and overlay the subject image on it.


OPTIONS
       In  addition  to  the options common to all programs based on libnetpbm (most notably -quiet,
       see ]8;;index.html#commonoptions\ Common Options]8;;\ ), pamcut recognizes the following command line options:



       -left=colnum
              The column number of the leftmost column to be in the output.  Columns  left  of  this
              get  cut  out.   If  a nonnegative number, it refers to columns numbered from 0 at the
              left, increasing to the right.  If negative, it refers to columns numbered -1  at  the
              right, decreasing to the left.


       -right=colnum
              The  column  number  of the rightmost column to be in the output, numbered the same as
              for -left.  Columns to the right of this get cut out.


       -top=rownum
              The row number of the topmost row to be in the output.  Rows above this get  cut  out.
              If a nonnegative number it refers to rows numbered from 0 at the top, increasing down‐
              ward.  If negative, it refers to columns numbered -1 at the bottom, decreasing upward.


       -bottom=rownum
              The  row  number  of the bottom-most row to be in the output, numbered the same as for
              -top.  Rows below this get cut out.


       -width=cols
              The number of columns to be in the output.  Must be positive.


       -height=rows
              The number of rows to be in the output.  Must be positive.


       -cropleft

       -cropright

       -croptop

       -cropbottom
              These options tell how many rows or columns to crop from the left, right, top, or bot‐
              tom edges, respectively.

              The value must not be negative.

              These option were new in Netpbm 10.85 (December 2018).  Before that, you  can  achieve
              the  same thing with -left, top, and negative values for -right and -bottom.  Remember
              to subtract one in the latter case; e.g. the equivalent of -cropright=1 is -right=-2.


       -pad   If the rectangle you specify is not entirely within the input image, pamcut fails  un‐
              less  you  also  specify  -pad.  In that case, it pads the output with black up to the
              edges you specify.  You can use this option if you need to have an  image  of  certain
              dimensions and have an image of arbitrary dimensions.

              pnmpad also adds borders to an image, but you specify their width directly.

              pamcomp  does  a  more general form of this padding.  Create a background image of the
              frame dimensions and overlay the subject image on it.  You can use options to have the
              subject image in the center of the frame or against any edge and make the padding  any
              color (the padding color is the color of the background image).


       -verbose
              Print information about the processing to Standard Error.



SEE ALSO
       pnmcrop(1), pamdice(1), pamcomp(1), pnmpad(1), pamcat(1), pgmslice(1), pnm(1)


HISTORY
       pamcut  was  derived  from pnmcut in Netpbm 9.20 (May 2001).  It was the first Netpbm program
       adapted to the new PAM format and programming library.

       The predecessor pnmcut was one of the oldest tools in the Netpbm package.



AUTHOR
       Copyright (C) 1989 by Jef Poskanzer.

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/pamcut.html

netpbm documentation                       04 October 2019                     Pamcut User Manual(1)