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 dou-
ble hyphen instead of a single hyphen 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 ]8;;index.html#commonoptions\ Common Options]8;;\ ), 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 correspond-
ing 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 im-
ages, 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 distribu-
tion. 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 invoca-
tions.
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 in-
put 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
• ]8;;#synopsis\SYNOPSIS]8;;\
• ]8;;#description\DESCRIPTION]8;;\
• ]8;;#options\OPTIONS]8;;\
• ]8;;#arguments\ARGUMENTS]8;;\
• ]8;;#examples\EXAMPLES]8;;\
• ]8;;#history\HISTORY]8;;\
• ]8;;#author\AUTHOR]8;;\
• ]8;;#seealso\SEE ALSO]8;;\
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)
Generated by dwww version 1.16 on Tue Dec 16 05:10:10 CET 2025.