NAME¶
pamcut - cut a rectangle out of a PAM, PBM, PGM, or PPM image
SYNOPSIS¶
pamcut [
-left leftcol] [
-right
rightcol] [
-top toprow] [
-bottom
bottomrow] [
-width width] [
-height
height] [
-pad] [
-verbose] [
left right
width height ] [
pnmfile]
All options may be abbreviated to the shortest unique prefix.
DESCRIPTION¶
Reads a PAM, 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: 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.
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 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,
right,
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.
If you are splitting a single image into multiple same-size images,
pamdice is faster than running
pamcut multiple times.
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
numbered -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 output. 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, 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.
- -verbose
- Print information about the processing to Standard Error.
SEE ALSO¶
pnmcrop(1),
pnmpad(1),
pnmcat(1),
pgmslice(1),
pnm(5)
AUTHOR¶
Copyright (C) 1989 by Jef Poskanzer.