pnmcut(1)pnmcut(1)NAMEpnmcut - cut a rectangle out of a PBM, PGM, or PPM image
SYNOPSISpnmcut [-left leftcol] [-right rightcol] [-top toprow]
[-bottom bottomrow] [-width width] [-height height] [-pad]
[-verbose] [ left top width height ] [pnmfile]
All options may be abbreviated to the shortest unique pre
fix.
DESCRIPTION
Reads a PBM, PGM, or PPM image as input. Extracts the
specified rectangle, and produces the same kind of image
as output.
There are two ways to specify the rectangle to cut: argu
ments 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 specifica
tions get mixed in an unspecified way.
To use options, just code any mixture of the -left,
-right, -top, -bottom, -width, and -height options. What
you don't specify defaults. It is an error to overspec
ify, 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 pnmfile.
Output is to Standard Output.
OPTIONS-left The column number of the leftmost column to be in
the output. If a nonnegative number, it refers to
columns numbered from 0 at the left, increasing to
the right. If negative, it refers to columns num
bered -1 at the right, decreasing to the left.
-right The column number of the rightmost column to be in
the output, numbered the same as for -left.
-top The row number of the topmost row to be in the out
put. If a nonnegative number it refers to rows
numbered from 0 at the top, increasing downward.
If negative, it refers to columns numbered -1 at
the bottom, decreasing upward.
-bottom
The row number of the bottom-most row to be in the
output, numbered the same as for -top.
-width The number of columns to be in the output. Must be
positive.
-height
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, pnmcut fails unless you also spec
ify -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 dimen
sions.
pnmpad can also fill an image out to a specified
dimension, and gives you more explicit control over
the padding.
-verbose
Print information about the processing to Standard
Error.
SEE ALSOpnmcrop(1), pnmpad(1), pnmcat(1), pgmslice(1), pnm(5)AUTHOR
Copyright (C) 1989 by Jef Poskanzer.
29 June 2000 pnmcut(1)
