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 either 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 numbered
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 consistent
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 arguments (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 arguments 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 extract 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
Common Options ), pamcat recognizes the following command line options:

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 handle 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