---
name: "pnmalias"
section: "1"
platform: "linux"
package: "netpbm"
version: "10.86.51-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/pnmalias"
---

# pnmalias(1)

antialias a PNM image

## NAME

pnmalias - antialias a PNM image

## SYNOPSIS

**pnmalias**

\[**-bgcolor** *color*\]

\[**-fgcolor** *color*\]

\[**-bonly**\]

\[**-fonly**\]

\[**-balias**\]

\[**-falias**\]

\[**-weight** *w*\]

\[*pnmfile*\]

## DESCRIPTION

This program is part of **Netpbm**(1) .

**pnmalias** reads a PNM image as input, and applies anti-aliasing to background and foreground pixels.  If the input file is a PBM, **pnmalias** promotes the output anti-aliased image to a PGM, and prints a message informing the user of the change in format.

## OPTIONS

In addition to the options common to all programs based on libnetpbm (most notably **-quiet**, see \
  Common Options ⟨index.html#commonoptions⟩ ), **pnmalias** recognizes the following command line options:

**-bgcolor** *colorb* sets the background color the *colorb*.

**-fgcolor** *colorf* sets the foreground color to *colorf*.

Pixels with these values will be anti-aliased.  By default, **pnmalias** takes the background color to be black, and foreground color to be white.

Specify the color (*color*) as described for the  argument of the **pnm\_parsecolor()** library routine ⟨libnetpbm\_image.html#colorname⟩ .

Note that even when dealing with PGMs, background and foreground colors need to be specified in the fashion described above.  In this case, **pnmalias** takes the background and foreground pixel values to be the value of the red component for the specified color.

**-bonly** says to apply anti-aliasing only to the background pixels.

**-fonly** says to apply anti-aliasing only to the foreground pixels.

**-balias** says to apply anti-aliasing to all pixels surrounding background pixels.

**-falias** says to apply anti-aliasing to all pixels surrounding foreground pixels.

If you specify neither **-balias** nor **-falias**, **pnmalias** applies anti-aliasing only among neighboring background and foreground pixels.

**-weight** *w* says to use *w* as the central weight for the aliasing filter.  *w* must be a real number in the range 0 \< *w* \< 1.  The lower the value of *w* is, the "blurrier" the output image is.  The default is w = 1/3.

## SEE ALSO

[**pbmtext**(1)](/pbmtext/1.md) , [**pnmsmooth**(1)](/pnmsmooth/1.md) , **pnm**(1)

## AUTHOR

Copyright (C) 1992 by Alberto Accomazzi, Smithsonian Astrophysical Observatory.

## DOCUMENT SOURCE

This manual page was generated by the Netpbm tool 'makeman' from HTML source.  The master documentation is at

-

  **http://netpbm.sourceforge.net/doc/pnmalias.html**