NAME¶
pnmcrop - crop a portable anymap
SYNOPSIS¶
pnmcrop [
-white|
-black|
-sides] [
-left]
[
-right] [
-top] [
-bottom] [
pnmfile]
All options may be abbreviated to their shortest unique prefix or specified with
double hyphens.
DESCRIPTION¶
Reads a PBM, PGM, or PPM image as input. Removes borders that are the background
color, and produces the same type of image as output.
If you don't specify otherwise,
pnmcrop assumes the background color is
whatever color the top left and right corners of the image are and if they are
different colors, something midway between them. You can specify that the
background is white or black with the
-white and
-black options
or make
pnmcrop base its guess on all four corners instead of just two
with
-sides.
By default,
pnmcrop chops off any stripe of background color it finds, on
all four sides. You can tell
pnmcrop to remove only specific borders
with the
-left,
-right,
-top, and
-bottom options.
If you want to chop a specific amount off the side of an image, use
pnmcut.
If you want to add different borders after removing the existing ones, use
pnmcat or
pnmcomp.
OPTIONS¶
- -white
- Take white to be the background color. pnmcrop removes borders
which are white.
- -black
- Take black to be the background color. pnmcrop removes borders
which are black.
- -sides
- Determine the background color from the colors of the four corners of the
input image. pnmcrop removes borders which are of the background
color.
If at least three of the four corners are the same color, pnmcrop
takes that as the background color. If not, pnmcrop looks for two
corners of the same color in the following order, taking the first found
as the background color: top, left, right, bottom. If all four corners are
different colors, pnmcrop assumes an average of the four colors as
the background color.
The -sides option slows pnmcrop down, as it reads the entire
image to determine the background color in addition to the up to three
times that it would read it without -sides.
- -left
- Remove any left border.
- -right
- Remove any right border.
- -top
- Remove any top border.
- -bottom
- Remove any bottom border.
- -verbose
- Print on Standard Error information about the processing, including
exactly how much is being cropped off of which sides.
SEE ALSO¶
pnmcut(1),
pnmfile(1),
pnm(5)
AUTHOR¶
Copyright (C) 1989 by Jef Poskanzer.