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Pamrestack User Manual(1)              General Commands Manual             Pamrestack User Manual(1)

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NAME
       pamrestack - Rearrange rows of a Netpbm image


SYNOPSIS
       pamrestack

       [-width=width]

       [-trim={fill|crop|abort}]

       [-verbose]

       [pamfile]

       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).

       pamrestack  rearranges the pixels of a Netpbm image into different size rows.  E.g. if an im‐
       age is 100 pixels wide and 50 pixels high, you can rearrange it to 125 wide and 40 high.   In
       that  case, 25 pixels from the start of the 2nd row of the input would be moved to the end of
       the 1st row of input, 50 pixels from the 3rd row would be moved to the 2nd row, etc.

       Put another way, pamrestack arranges all the input rows into one long sequence  and  produces
       output rows therefrom, in FIFO order.

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

       Output is to Standard Output.

       pamrestack works on a multi-image stream.  It cuts each image in the stream independently and
       produces a multi-image stream output.



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



       -width=width
              The width of the output.  If this option is not specified, the output will
                consist of a single row wide enough to contain all the pixels of the input
                image.


       -trim={fill|crop|abort}
              This option specifies what to do when the new width does not cleanly divide the number
              of pixels in the input image.



       fill

              (Default) Complete the final row by adding black pixels as necessary.


       crop

              Discard the final partial row.  If this means there is nothing to
                  output, fail the program.


       abort

              Fail the program..



       -verbose
              Print information about the processing to Standard Error.




USAGE
       pamrestack is a general editor with many possible uses.


       •

                  pamrestack can rearrange into rectangles single-dimension images
                  produced by programs such as ppmhist and pamseq.  This makes
                  the output easier to examine with a viewer.  Conversely, pamrestack
                  can be used to convert a normal rectangular image into one wide row or one
                  tall column if that is desirable for compression, conversion, or analysis.


       •

                  pamrestack can repair images corrupted by an incorrect width value
                  in the header.  Images grabbed from the framebuffer device often exhibit
                  this problem.


       •      pamrestack can be used with pamdice, pamundice,
                  pamcat, etc. to divide and combine images in the process of
                  interlacing.




EXAMPLES
       •      Rearrange the one-dimensional output of pamseq into a square:

              pamseq 3 255 | pamrestack -width=4096



       •      Combine two files, each 600 pixels wide, one with the odd rows and
                another with the even rows, to construct an interlaced image:

              pamcat -leftright oddrows.ppm evenrows.ppm | pamrestack -width=600




       •      Like the above, but invert all pixels in the even rows left to right
                to produce a serpentine interlace:

                pamflip -leftright evenrows.ppm |
                  pamcat -leftright oddrows.ppm - |
                    pamrestack -width 600





SEE ALSO
       pamseq(1), ppmhist(1), pnmshear(1), pamscale(1), pamdeinterlace(1), pamdice(1), pamundice(1),
       pamcat(1), pam(1)



HISTORY
       pamrestack was new in Netpbm 10.99 (June 2022).



AUTHOR
       By Akira F. Urushibata.  Contributed to the public domain by the author.

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/pamrestack.html

netpbm documentation                                                       Pamrestack User Manual(1)