NAME

       pammixmulti - blend together multiple PAM images

SYNOPSIS

       pammixmulti
         [--blend=average|random|mask]
         [--maskfile=filename]
         [--stdev=number]
         [--randomseed integer]
         filename ...

       Minimum  unique  abbreviation  of  an  option  is  acceptable. You can use a single hyphen
       instead of double hyphens to denote options. You can use  white  space  in  place  of  the
       equals sign to separate an option name from its value.

DESCRIPTION

       This file is part of Netpbm(1).

       pammixmulti mixes two or more images to produce a new image. The program provides multiple
       ways to interpret "mix."

OPTIONS

       In addition to the options common to all programs based on libnetpbm (most notably -quiet,
       see
        Common Options ⟨index.html#commonoptions⟩ ), pammixmulti recognizes the following command
       line options:

       --blend=average|random|mask

              This option specifies how the input images should be mixed to  produce  the  output
              image.  With --blend=average (the default), each pixel in the output is produced by
              averaging the corresponding pixels from all the input images.  With --blend=random,
              each  pixel in the output is produced by selecting the corresponding pixel from one
              of the input images, chosen at random on a  per-pixel  basis.   With  --blend=mask,
              each  pixel  in  the  output is produced by a weighted average of the corresponding
              pixels from all the input images based on the grayscale level of an additional mask
              image.

       --maskfile=filename

              In  conjunction  with  --blend=mask,  this  option  names  a grayscale mask file to
              control the blending of each pixel.  (If the  file  is  not  grayscale,  the  first
              channel  is  treated  as  gray).   Where the mask file is black, the first image is
              selected. Where the mask file is white, the last image is  selected.   Intermediate
              levels of gray select intermediate images.

       --stdev=number

              When  used  with  --blend=mask, this option controls how smoothly the various input
              images are mixed to produce each  output  pixel.   For  example,  consider  running
              pammixmulti  with  three input images and a mask image that uses gray levels from 0
              to 255. Given --stdev=0.0, gray levels  0-84  produce  exclusively  image  1;  gray
              levels  85-170  produce  exclusively  image  2;  and  gray  levels  171-255 produce
              exclusively image 3.  If the argument to --stdev is positive,  images  are  blended
              according to a normal distribution.  Hence, gray levels around 85 produce an output
              pixel that includes roughly equal amounts of the corresponding pixel from images  1
              and  2  but  less of the corresponding pixel from image 3.  As number tends towards
              the number of input images (going beyond that has diminishing impact),  the  output
              tends to look more like --blend=average. number defaults to 0.25.

       --randomseed integer
              This is the seed for the random number generator used with --blend=random

              Use this to ensure you get the same image on separate invocations.

ARGUMENTS

       You supply the names of the files to mix as non-option arguments.

EXAMPLES

       Average a bunch of PPM images to produce a new PAM image:
           pammixmulti input*.ppm >output.ppm

       Mix these same images by taking each pixel from a randomly selected input image:

           pammixmulti --blend=random input*.ppm >output.ppm

       Use a mask image to control the fading among input images on a pixel-by-pixel basis:

           pammixmulti --blend=mask --maskfile=mask.pgm >output.pam \
              one.pam two.pam three.pam four.pam

       Do the same but with more abrupt transitions:

           pammixmulti --blend=mask --maskfile=mask.pgm --stdev=0.0 >output.pam \
              one.pam two.pam three.pam four.pam

       and now with more gradual transitions:

           pammixmulti --blend=mask --maskfile=mask.pgm --stdev=1.0 >output.pam \
              one.pam two.pam three.pam four.pam

HISTORY

       pammixmulti was new in Netpbm 10.85 (December 2018).

AUTHOR

       Copyright 2018 Scott Pakin, scott+pbm@pakin.org.

SEE ALSO

       pamcomp(1), ppmmix(1), pamarith(1), pnm(1), pam(1)

Table Of Contents

       •

              SYNOPSIS ⟨#synopsis⟩

       •

              DESCRIPTION ⟨#description⟩

       •

              OPTIONS ⟨#options⟩

       •

              ARGUMENTS ⟨#arguments⟩

       •

              EXAMPLES ⟨#examples⟩

       •

              HISTORY ⟨#history⟩

       •

              AUTHOR ⟨#author⟩

       •

              SEE ALSO ⟨#seealso⟩

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/pammixmulti.html