focal (1) pamcut.1.gz

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NAME

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

SYNOPSIS

       pamcut  [-left  leftcol]  [-right  rightcol]  [-top  toprow]  [-bottom bottomrow] [-width width] [-height
       height] [-pad] [-verbose] [ left right width height ] [pnmfile]

       All options may be abbreviated to the shortest unique prefix.

DESCRIPTION

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

       There  are  two  ways  to  specify  the  rectangle  to cut: arguments and options.  Options are easier to
       remember and read, more expressive, and allow you to use defaults.  Arguments were the only way available
       before July 2000.

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

       To  use  options, just code any mixture of the -left, -right, -top, -bottom, -width, and -height options.
       What you don't specify defaults.  It is an error to overspecify, i.e. to  specify  all  three  of  -left,
       -right, and -width or -top, -bottom, and -height.

       To  use  arguments,  specify all four of the left, right, width, and height arguments.  left and top have
       the same effect as specifying them as the argument of a -left or -top option,  respectively.   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  positive,  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.

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

OPTIONS

       -left  The column number of the leftmost column to be in the output.  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 The column number of the rightmost column to be in the output, numbered the same as for -left.

       -top   The row number of the topmost row to be in the output.  If a nonnegative number it refers to  rows
              numbered from 0 at the top, increasing downward.  If negative, it refers to columns numbered -1 at
              the bottom, decreasing upward.

       -bottom
              The row number of the bottom-most row to be in the output, numbered the same as for -top.

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

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

       -pad   If the rectangle you specify is not entirely within the input image, pamcut fails unless 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.

       -verbose
              Print information about the processing to Standard Error.

SEE ALSO

       pnmcrop(1), pnmpad(1), pnmcat(1), pgmslice(1), pnm(5)

AUTHOR

       Copyright (C) 1989 by Jef Poskanzer.

                                                 03 August 2000                                        pamcut(1)