pamstack – stack planes of multiple PAM images into one PAM image
pamstack [-tupletype tupletype] [inputfilespec]
All options may be abbreviated to the shortest unique prefix.
Reads multiple PAM or PNM images as input. Produces a PAM image as out‐
put, consisting of all the planes (channels) of the inputs, stacked in
the order specified.
The output is the same dimensions as the inputs, except that the depth
is the sum of the depths of the inputs. It has the same maxval. pam‐
stack fails if the inputs are not all the same width, height, and max‐
val. The tuple type is a null string unless you specify the -tupletype
pamchannel does the opposite of pamstack: It extracts individual planes
from a single PAM.
Use pamtopnm to convert a suitable PAM image to a more traditional PNM
(PBM, PGM, or PPM) image.
One example of using pamstack is that some Netpbm programs accept as
input a PAM that represents graphic image with transparency information
— tuple type “RGBA”. In Netpbm, such images were traditionally repre‐
sented as two images – a PPM for the color and a PGM for the trans‐
parency. To convert a PPM/PGM pair into PAM(RGBA) input that newer pro‐
grams require, do something like this:
pamstack -tupletype=RGBA myimage.ppm myalpha.pgm | pamtouil >myim‐
This specified the tuple type name to be recorded in the output.
You may use any string up to 255 characters. Some programs rec‐
ognize some names. If you omit this option, the default tuple
type name is null.
Copyright (C) by Bryan Henderson, San Jose CA 2000.08.05
01 May 2002 pamstack