Manual: pammixmulti

Pammixmulti User Manual(1)			   General Commands Manual			  Pammixmulti User Manual(1)

NAME
       pammixmulti - blend together multiple PAM images

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

       Minimum	unique	abbreviation of an option is acceptable. You can use double hyphen instead of a single hyphen to de‐
       note 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  ),
       pammixmulti recognizes the following command line options:

       -blend=average|alpha-weighted|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=alpha-weighted, each pixel in the output is produced by taking a weighted average of the
	      corresponding pixels from all the input images, using each pixel's alpha (opaqueness)  level  as	its  weight.
	      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.

	      -alpha-weighted was new in Netpbm 11.09 (December 2024).

       -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 pro‐
	      duce 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 be‐
	      yond 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 2018–2024 Scott Pakin, scott+pbm@pakin.org.

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

Table Of Contents
       •      SYNOPSIS

       •      DESCRIPTION

       •      OPTIONS

       •      ARGUMENTS

       •      EXAMPLES

       •      HISTORY

       •      AUTHOR

       •      SEE ALSO

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

netpbm documentation				      18 December 2024				  Pammixmulti User Manual(1)