Pamcat User Manual(1) General Commands Manual Pamcat User Manual(1)
NAME
pamcat - concatenate Netpbm images
SYNOPSIS
pamcat
{-leftright | -lr | -topbottom | -tb}
[-white|-black]
[-jtop|-jbottom|-jcenter] [-jleft|-jright|-jcenter]
[netpbmfile ... | -listfile={filename|-}]
Minimum unique abbreviation of option is acceptable. You may use double
hyphens instead of single hyphen to denote options. You may use white
space in place of the equals sign to separate an option name from its
value.
DESCRIPTION
This program is part of Netpbm(1).
pamcat reads one or more Netpbm images as input, concatenates them ei-
ther left to right or top to bottom, and produces a single Netpbm image
as output.
Options -leftright and -topbottom determine the direction
of the concatenation.
The images do not have to be the same shape: You can concatenate images
of different widths top to bottom and of different heights left to
right.
You can concatenate images of different depths (numbers of planes).
You
can concatenate a PBM image with a PPM image. Et cetera.
The format of the output image is the highest of the formats of the
input images, in the order PBM, PGM, PPM, PAM.
For PAM output, if all of the input images have the same tuple type
(including implied tuple types of PNM images), that is the tuple type
of the
output. If the inputs differ, but are all visual tuple types, the
output's tuple type is the most primitive that can represent all the
input. E.g. if inputs are GRAYSCALE and RGB, the output is RGB, and
if the
inputs are GRAYSCALE_ALPHA and RGB, the output is RGB_ALPHA. If the
inputs
differ and are not all visual, the output tuple type is a null string.
When the output is PAM, its depth is the maximum of the depths of the
inputs (including implied depths of PNM images), but at least enough
to
represent the tuple type specified above. In the case of nonvisual
PAM
output, input images are padded to this output depth with higher num-
bered
planes of all zeroes.
Where the input images are of different widths and you concatenate top
to bottom, pamcat generates output as wide as the widest of the
inputs and pads the narrower ones. The images can be justified either
left, right, or center within this padded field. Use options
-jleft, -jright, and -jcenter to control this.
Similarly, where the input images are of different heights and you
concatenate left to right, pamcat generates output as tall as the
tallest of the inputs and pads the shorter ones. The images can be
justified either top, bottom, or center within this padded field. Use
options
-jtop, -jbottom, and -jcenter to control this.
You can make the padding black or white or let pamcat determine a
likely background color, with possibly different colored padding for
each
input image. Control this with the -black and -white options.
Where the output image contains transparency information (because at
least
one of the input images does), the padding is opaque. (That is con-
sistent
with the result for an output image without transparency information,
because
such an image is defined to be opaque).
The arguments are names of input files. Any one of these, but not more
than one, may be "-" to indicate Standard Input. If you have no argu-
ments (and do not specify -listfile), that means a single input image
from Standard Input (and that is pointless - the output is the same as
the input). You can supply the file names in a file instead of as argu-
ments with a -listfile option.
Regardless of how you specify the input files, you may not concatenate
more files than your system's limit on the number of concurrently
open files by one process. 16 is a typical number for that.
To assemble a regular grid of images, you can use pamundice.
To do the reverse, you might use pamdice to split an image up into
smaller ones of equal size or pamcut to chop off part of an image or ex-
tract part of an image.
pnmtile concatenates a single input image to itself repeatedly.
OPTIONS
In addition to the options common to all programs based on libnetpbm
(most notably -quiet, see ]8;;index.html#commonoptions\ Common Options]8;;\ ), pamcat recognizes the fol-
lowing command line options:
Direction
-topbottom, -tb
Combine images vertically, top to bottom.
-leftright, -lr
Combine images horizontally, left to right.
You must specify the direction by specifying one of the above.
You cannot
specify both.
Justification
-jleft
Left-justify images in a top-bottom concatenation.
You cannot specify this with -jright.
This option is invalid in a left-right concatenation.
-jright
Right-justify images in a top-bottom concatenation.
You cannot specify this with -jleft.
This option is invalid in a left-right concatenation.
-jtop
Top-justify images in a left-right concatenation.
You cannot specify this with -jbottom.
This option is invalid in a top-bottom concatenation.
-jbottom
Bottom-justify images in a left-right concatenation.
You cannot specify this with -jtop.
This option is invalid in a top-bottom concatenation.
-jcenter
Center images (valid for both left-right and top-bottom concate-
nations).
This is the default.
By default, pamcat centers the smaller images. Use
-jleft and -jbottom to override this.
-topbottom -jleft would stack the images on top of each other, flush
with the left edge. -leftright -jbottom would line up the images
left to right with their bottom edges aligned as if sitting on a ta-
ble.
Padding Color
These options specify what color to use to fill in the extra space when
doing the justification. If neither is specified, pamcat chooses
whichever color seems to be right for the images, and the color may be
different for each image.
-white Make all padding white.
You may not specify this with -black
-black Make all padding black.
You may not specify this with -white
Miscellaneous
-listfile={filename|-}
This specifies the name of a file that contains the list of input
files.
Option value - means the list comes from Standard Input.
The file contains one file name per newline-delimited line in
whatever
code the system fopen service expects. You may omit the new-
line
on the last line. Empty lines are ignored. There is no
mechanism for
including comments in the list (so if you want to have a com-
mented list,
preprocess it to remove comments before supplying it to pam-
cat).
You may not specify file names as command line arguments together
with
-listfile
You may not list more files than than your system's limit on the
number of concurrently open files by one process. 16 is a typ-
ical number
for that.
This option was new in Netpbm 11.01 (December 2022).
SEE ALSO
pamundice(1), pamdice(1), pnmtile(1), pamcut(1), pnm(1), pam(1)
HISTORY
pamcat was new in Netpbm 11.00 (September 2022); in earlier versions,
pnmcat does most of the same thing.
Primordial Netpbm/Pbmplus contained concatenation tools, but there were
two
of them: pbmcatlr for left-right concatenation of PBM images
and pbmcattb for top-bottom concatenation. When the PGM and PPM
formats were added, these programs were combined and extended to han-
dle all
three formats, as pnmcat. All of this work was done by Pbmplus
author Jef Poskanzer.
In Netpbm 10.44 (September 2008), Akira F Urushibata added special fast
processing for raw PBM images, exploiting bitstring processing CPU
facilities.
pnmcat was one of the most essential programs in Netpbm, but one
thing it could not concatenate was PAM images with transparency. So
in
Netpbm 11.00 (September 2022), Bryan Henderson wrote pamcat to
replace it. It reused the raw PBM fast path code from pnmcat almost
verbatim.
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/pamcat.html
netpbm documentation 30 November 2022 Pamcat User Manual(1)
Generated by dwww version 1.16 on Tue Dec 16 04:28:49 CET 2025.