man > pamstack(1)

Pamstack User Manual(1)                General Commands Manual               Pamstack User Manual(1)

NAME
       pamstack - stack planes of multiple PAM images into one PAM image


SYNOPSIS
       pamstack [-tupletype tupletype] [-firstmaxval,-lcmmaxval] [inputfilespec ...]

       All  options  may  be abbreviated to the shortest unique prefix.  You may use two hyphens in‐
       stead of one.  You may separate an option from its value with a space instead of =.


DESCRIPTION
       This program is part of Netpbm(1).

       pamstack reads multiple PAM or PNM images as input and produces a PAM image as  output,  con‐
       sisting of all the planes (channels) of the inputs, stacked in the order specified.

       It can also just change the tuple type of a single PAM image.


       For  any  one  (but not more) of the input files, you may specify "-" to mean Standard Input.
       If you specify no arguments at all, the input is one file: Standard Input.

       The output is the same dimensions as the inputs, except that the depth is
         the sum of the depths of the inputs.  The maxval is the same as the inputs
         if they are all alike, and controlled by -firstmaxval
         and -lcmmaxval if not.  The tuple type is a null string unless you
         specify the -tupletype option.


        pamstack fails if the inputs are not all the same width and height.  It also fails  if  they
       do not all have the same maxval, unless you specify -firstmaxval or -lcmmaxval.

       pamstack works with multi-image streams.  It stacks the 1st image in all the streams into one
       output  image  (the  first  one  in  the output stream), then stacks the 2nd image in all the
       streams into the 2nd image in the output stream, and so on, until one  of  the  streams  runs
       dry.  It's like a matrix operation.

       Before  Netpbm  10.32 (February 2006), pamstack ignored all but the first image in each input
       stream.

       pamchannel does the opposite of pamstack:  It extracts individual planes from a single PAM.

       Use pamtopnm(1) to convert a suitable PAM image to a more traditional PNM (PBM, PGM, or  PPM)
       image.  (But there's no need to do that if you're going to feed it to a modern Netpbm program
       -- they all take suitable PAM input directly).

       One  example of using pamstack is that some Netpbm programs accept as input a PAM that repre‐
       sents graphic image with transparency information.  Taking a color image  for  example,  this
       would be a PAM with tuple type "RGB_ALPHA".  In Netpbm, such images were traditionally repre‐
       sented  as  two  images  -  a PPM for the color and a PGM for the transparency.  To convert a
       PPM/PGM pair into PAM(RGB_ALPHA) input that newer programs require, do something like this:

       $ pamstack -tupletype=RGB_ALPHA myimage.ppm myalpha.pgm | \
             pamtouil >myimage.uil



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




       -tupletype tupletype
              This  specifies  the  tuple  type  name to be recorded in the output.  You may use any
              string up to 255 characters.  Some programs recognize some names.  If  you  omit  this
              option, the default tuple type name is null.


       -firstmaxval
              This  says  to make the maxval of the output the same as the maxval of the first image
              of the input; the program scales sample values of other images are as necessary.

              By default, pamstack requires all the input images to have the same maxval.   If  they
              don't, it fails.

              You cannot specify this with -lcmmaxval.

              This option was new in Netpbm 11.03 (June 2023).


       -lcmmaxval
              This says to make the maxval of the output the least common multiple of the maxvals of
              the input images, limited to 65535 if the LCM is above that; the program scales sample
              values of other images are as necessary.

              By  default,  pamstack requires all the input images to have the same maxval.  If they
              don't, it fails.

              You cannot specify this with -firstmaxval.

              This option was new in Netpbm 11.03 (June 2023).




SEE ALSO
       pam(1) pamchannel(1)


HISTORY
       pamstack was new in Netpbm 10.0 (June 2002).

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/pamstack.html

netpbm documentation                         18 May 2023                     Pamstack User Manual(1)