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Pamstack User Manual
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pamstack
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Updated: 10 January 2006
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Table Of Contents
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NAME
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pamstack - stack planes of multiple PAM images into one PAM image
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SYNOPSIS
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\fBpamstack\fR
[\fB-tupletype \fR\fItupletype\fR]
[\fIinputfilespec\fR ...]
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All options may be abbreviated to the shortest unique prefix.  You
may use two hyphens instead of one.  You may separate an option from
its value with a space instead of \fB=\fR.
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DESCRIPTION
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This program is part of Netpbm.
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\fBpamstack\fR reads multiple PAM or PNM images as input and
produces a PAM image as output, consisting of all the planes
(channels) of the inputs, stacked in the order specified.
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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.
\fBpamstack\fR fails if the inputs are not all the same width, height,
and maxval.  The tuple type is a null string unless you specify the
\fB-tupletype\fR option.
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\fBpamstack\fR 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.
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Before Netpbm 10.32 (February 2006), \fBpamstack\fR ignored all but
the first image in each input stream.
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\fBpamchannel\fR does the opposite of \fBpamstack\fR:  It extracts
individual planes from a single PAM.
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Use pamtopnm 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).
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One example of using \fBpamstack\fR is that some Netpbm programs
accept as input a PAM that represents 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 represented 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:
.DS L
\f(CW$ pamstack -tupletype=RGB_ALPHA myimage.ppm myalpha.pgm | \
      pamtouil >myimage.uil
\fR.DE
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OPTIONS
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.RS
.IP "\fB-tupletype \fR\fItupletype\fR"
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.
.RE
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SEE ALSO
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\fBpam\fR
\fBpamchannel\fR
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HISTORY
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\fBpamstack\fR was new in Netpbm 10.0 (June 2002).
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Table Of Contents
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SYNOPSIS
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DESCRIPTION
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OPTIONS
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SEE ALSO
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