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pnminvert

Invert colors of PNM images

TLDR

Invert image colors
$ pnminvert [input.pnm] > [output.pnm]
Invert from stdin
$ cat [image.pnm] | pnminvert > [output.pnm]

SYNOPSIS

pnminvert [file]

DESCRIPTION

pnminvert produces a photographic negative of a PNM image by inverting all pixel values. Each sample value is replaced with the maximum value minus the original value, effectively swapping light and dark.The tool works with all PNM types: PBM (black/white bits are flipped), PGM (grayscale values are inverted), and PPM (each color channel is independently inverted). If no file is given, input is read from stdin. Output is always written to stdout.Part of the Netpbm toolkit. The more general paminvert supersedes this tool and handles PAM images as well.

INSTALL

sudo apt install netpbm
sudo dnf install netpbm
sudo pacman -S netpbm
sudo apk add netpbm
sudo zypper install netpbm
brew install netpbm
nix profile install nixpkgs#netpbm

CAVEATS

`pnminvert` has no options of its own beyond the common libnetpbm options. Output must be redirected to a file; it is always written to stdout.

HISTORY

pnminvert was created as part of the Netpbm package for portable bitmap image manipulation.

SEE ALSO

paminvert(1), pnmarith(1), pnmgamma(1)