Pamcut User Manual(0) Pamcut User Manual(0)NAMEpamcut - cut a rectangle out of a PAM, PBM, PGM, or PPM image
pamcut
[-left colnum]
[-right colnum]
[-top rownum]
[-bottom rownum]
[-width cols]
[-height rows]
[-pad]
[-verbose]
[left top width height]
[pnmfile]
Minimum unique abbreviation of option is acceptable. You may use dou‐
ble 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.
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.
There are two ways to specify the rectangle to cut: arguments and
options. Options are easier to remember and read, more expressive, and
allow you to use defaults. Arguments were the only way available
before July 2000.
If you use both options and arguments, the two specifications get mixed
in an unspecified way.
In any case, remember that you are specifying the rectangle to keep,
not the bits to discard. Otherwise, you'll be tempted to believe that
-right=9 means to delete the 9 rightmost columns. (It really means
keep the stuff up to Column 9 and delete the rest).
To use options, just code any mixture of the -left, -right, -top, -bot‐
tom, -width, and -height options. What you don't specify defaults.
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, -bottom, and
-height.
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).
Before 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 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.
-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.
To delete N columns at the left edge, specify -left=N.
To delete N columns at the right edge, specify -left=--(N+1).
-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.
To delete N rows at the top, specify -top=N.
To delete N rows at the bottom, specify -bottom=-(N+1).
-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.
-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
dimensions 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
image).
-verbose
Print information about the processing to Standard Error.
pnmcrop(1), pamcomp(1), pnmpad(1), pnmcat(1), pgmslice(1),
pnm(1)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
library.
The predecessor pnmcut was one of the oldest tools in the Netpbm pack‐
age.
Copyright (C) 1989 by Jef Poskanzer.
netpbm documentation 05 April 2005 Pamcut User Manual(0)
