Pamcut User Manual(1) General Commands Manual Pamcut User Manual(1)
NAME
pamcut - cut a rectangle out of a PAM, PBM, PGM, or PPM image
SYNOPSIS
pamcut
[-left colnum]
[-right colnum]
[-top rownum]
[-bottom rownum]
[-width cols]
[-height rows]
[-pad]
[-cropleft numcols]
[-cropright numcols]
[-croptop numrows]
[-cropbottom numrows]
[-verbose]
[left top width height]
[pnmfile]
Minimum unique abbreviations of option are 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).
pamcut reads a PAM, PBM, PGM, or PPM image as input and extracts the
specified rectangle, and produces the same kind of image as output.
You can specify either the rectangle to cut out and keep or specify the
edges to crop off and discard, or a combination.
To request edges be cropped off, use options -cropleft, -cropright,
-croptop, and -cropbottom to indicate how many rows or columns to dis-
card.
For example, -cropleft=50 -cropright=200 means to discard the leftmost
50 and rightmost 200 columns.
To specify the rectangle to keep, use -left, -right, -top, -bottom,
-width, -height, and -pad options.
For example, -left=50 -right=200 means to keep the 150 columns between
Columns 50 and 200 inclusive.
You can code any mixture of the options. What you don't specify de-
faults. Those defaults are in favor of minimal cutting and in favor of
cutting the right and bottom edges off. It is an error to overspecify,
i.e. to specify all three of -left, -right, and -width or -top, -bot-
tom, and -height or right as well as -cropright.
There is an older way to specify the rectangle to keep: positional ar-
guments. Arguments were the only way available before July 2000, but
you should not use them in new applications. Options are easier to re-
member and read, more expressive, and allow you to use defaults.
If you use both options and arguments, the two specifications get mixed
in an unspecified way.
To use arguments, specify all four of the left, top, width, and height
arguments. left and top have the same effect as specifying them as the
argument of a -left or -top option, respectively. width and height
have the same effect as specifying them as the argument of a -width or
-height option, respectively, where they are positive. Where they are
not positive, they have the same effect as specifying one less than the
value as the argument to a -right or -bottom option, respectively.
(E.g. width = 0 makes the cut go all the way to the right edge). Be-
fore July 2000, negative numbers were not allowed for width and height.
Input is from Standard Input if you don't specify the input file pnm-
file.
Output is to Standard Output.
pamcut works on a multi-image stream. It cuts each image in the stream
independently and produces a multi-image stream output. Before Netpbm
10.32 (March 2006), it ignored all but the first image in the stream.
If you are splitting a single image into multiple same-size images,
pamdice is faster and easier than running pamcut multiple times.
pamcomp is also useful for cutting and padding an image to a certain
size. You create a background image of the desired frame dimensions
and overlay the subject image on it.
OPTIONS
In addition to the options common to all programs based on libnetpbm
(most notably -quiet, see
Common Options ⟨index.html#commonoptions⟩ ), pamcut recognizes the
following command line options:
-left=colnum
The column number of the leftmost column to be in the output.
Columns left of this get cut out. If a nonnegative number, it
refers to columns numbered from 0 at the left, increasing to the
right. If negative, it refers to columns numbered -1 at the
right, decreasing to the left.
-right=colnum
The column number of the rightmost column to be in the output,
numbered the same as for -left. Columns to the right of this
get cut out.
-top=rownum
The row number of the topmost row to be in the output. Rows
above this get cut out. If a nonnegative number it refers to
rows numbered from 0 at the top, increasing downward. If nega-
tive, it refers to columns numbered -1 at the bottom, decreasing
upward.
-bottom=rownum
The row number of the bottom-most row to be in the output, num-
bered the same as for -top. Rows below this get cut out.
-width=cols
The number of columns to be in the output. Must be positive.
-height=rows
The number of rows to be in the output. Must be positive.
-cropleft
-cropright
-croptop
-cropbottom
These options tell how many rows or columns to crop from the
left, right, top, or bottom edges, respectively.
The value must not be negative.
These option were new in Netpbm 10.85 (December 2018). Before
that, you can achieve the same thing with -left, top, and nega-
tive values for -right and -bottom. Remember to subtract one in
the latter case; e.g. the equivalent of -cropright=1 is
-right=-2.
-pad If the rectangle you specify is not entirely within the input
image, pamcut fails unless you also specify -pad. In that case,
it pads the output with black up to the edges you specify. You
can use this option if you need to have an image of certain di-
mensions and have an image of arbitrary dimensions.
pnmpad also adds borders to an image, but you specify their
width directly.
pamcomp does a more general form of this padding. Create a
background image of the frame dimensions and overlay the subject
image on it. You can use options to have the subject image in
the center of the frame or against any edge and make the padding
any color (the padding color is the color of the background im-
age).
-verbose
Print information about the processing to Standard Error.
SEE ALSO
pnmcrop(1), pamdice(1), pamcomp(1), pnmpad(1), pnmcat(1), pgmslice(1),
pnm(1)
HISTORY
pamcut was derived from pnmcut in Netpbm 9.20 (May 2001). It was the
first Netpbm program adapted to the new PAM format and programming li-
brary.
The predecessor pnmcut was one of the oldest tools in the Netpbm pack-
age.
AUTHOR
Copyright (C) 1989 by Jef Poskanzer.
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/pamcut.html
netpbm documentation 04 October 2019 Pamcut User Manual(1)
Generated by dwww version 1.15 on Sat Jun 29 02:21:45 CEST 2024.