netpbm (1)

Netpbm is a package of graphics programs and programming libraries.

There are over 220 separate programs in the package, most of which have "pbm", "pgm", "ppm", or "pnm" in their names. For example, pnmscale and giftopnm.

For example, you might use pnmscale to shrink an image by 10%. Or use pnmcomp to overlay one image on top of another. Or use pbmtext to create an image of text. Or reduce the number of colors in an image with pnmquant.

All of the programs work with a set of graphics formats called the "netpbm" formats. Specifically, these formats are pbm(5), pgm(5), ppm(5), and pam(5). The first three of these are sometimes known generically as pnm. Many of the Netpbm programs convert from a Netpbm format to another format or vice versa. This is so you can use the Netpbm programs to work on graphics of any format. It is also common to use a combination of Netpbm programs to convert from one non-Netpbm format to another non-Netpbm format. Netpbm has converters for over 80 graphics formats, and as a package Netpbm lets you do more graphics format conversions than any other computer graphics facility.

The Netpbm formats are all raster formats, i.e. they describe an image as a matrix of rows and columns of pixels. In the PBM format, the pixels are black and white. In the PGM format, pixels are shades of gray. In the PPM format, the pixels are in full color. The PAM format is more sophisticated. A replacement for all three of the other formats, it can represent matrices of general data including but not limited to black and white, grayscale, and color images.

Programs designed to work with PBM images have "pbm" in their names. Programs designed to work with PGM, PPM, and PAM images similarly have "pgm", "ppm", and "pam" in their names.

All Netpbm programs designed to read PGM images see PBM images as if they were PGM too. All Netpbm programs designed to read PPM images see PGM and PBM images as if they were PPM. See the section "Implied Format Conversion" below.

Programs that have "pnm" in their names read PBM, PGM, and PPM but unlike "ppm" programs, they distinguish between them and their function depends on the format. For example, pnmtogif creates a black and white GIF output image if its input is PBM or PGM, but a color GIF output image if its input is PPM. And pnmscale produces an output image of the same format as the input. A ppmscale program would read all three PNM input formats, but would see them all as PPM and would always generate PPM output.

If it seems wasteful to you to have three separate PNM formats, be aware that there is a historical reason for it. In the beginning, there were only PBMs. PGMs came later, and then PPMs. Much later came PAM, which realizes the possibility of having just one aggregate format.

The formats are described in the man pages pbm(5), pgm(5), ppm(5), and pam(5),

A program that uses the PGM library to read an image can read a PBM image as well as a PGM image. The program sees the PBM image as if it were the equivalent PGM image, with a maxval of 255.

A program that uses the PPM library to read an image can read a PGM image as well as a PPM image and a PBM image as well as a PGM image. The program sees the PBM or PGM image as if it were the equivalent PPM image, with a maxval of 255 in the PBM case and the same maxval as the PGM in the PGM case.

In many graphics format, there's a means of indicating that certain parts of the image are wholly or partially transparent, meaning that if it were displayed "over" another image, the other image would show through there. Netpbm formats deliberately omit that capability, since their purpose is to be extremely simple.

In Netpbm, you handle transparency via a transparency mask in a separate (slightly redefined) PGM image. In this pseudo-PGM, what would normally be a pixel's intensity is instead it an opaqueness value. See pgm(5). pnmcomp is an example of a program that uses a PGM transparency mask.

The Netpbm programs are generally useful run by a person from a command shell, but are also designed to be used by programs. A common characteristic of Netpbm programs is that they are simple, fundamental building blocks. They are most powerful when stacked in pipelines. Netpbm programs do not use graphical user interfaces (in fact, none of them display graphics at all, except for a very simple Linux Svgalib displayer) and do not seek input from a user.

Each of these programs has its own man page.

There are a few options that are present on all programs that are based on the Netpbm libraries, including virtually all Netpbm programs. These are not mentioned in the individual man pages for the programs.

-quiet

Suppress all informational messages that would otherwise be issued to Standard Error. (To be precise, this only works to the extent that the program in question implements the Netpbm convention of issuing all informational messages via the pm_message() service of the Netpbm libraries).

-version

Instead of doing anything else, report the version of the libpbm library linked with the program (it may have been linked statically into the program, or dynamically linked at run time). Normally, the Netpbm programs and the libraries are installed at the same time, so this tells you the version of the program and all the other Netpbm libraries and files it uses as well.

Here is a directory of the Netpbm programs. You can also use man -k to search for a program that does what you want.

Converters

ppmtompeg

convert series of PPM frames to an MPEG movie

jpegtopnm

convert JFIF/JPEG/EXIF file to Netpbm format

pnmtojpeg

convert PPM to JPEG/JFIF/EXIF format

anytopnm

convert any graphics format to Netpbm format

bmptoppm

convert Windows or OS/2 Bitmap file to PPM

ppmtobmp

convert PPM to Windows or OS/2 Bitmap file

winicontoppm

convert Windows icon file to PPM

ppmtowinicon

convert PPM to Windows icon file

giftopnm

convert GIF to portable anymap

ppmtogif

convert PPM to GIF

pnmtopng

convert Netpbm format to Portable Network Graphics

pngtopnm

convert PNG (Portable Network Graphics) to Netpbm formats

palmtopnm

convert Palm pixmap to Netpbm formats

pnmtopalm

convert Netpbm formats to Palm pixmap

jbigtopbm

convert JBIG BIE (compressed bitmap) to PBM

pamtopnm

convert a PAM image to PBM, PGM, or PPM

pbmtojbig

convert PBM to JBIG BIE (compressed bitmap)

pnmtofiasco

convert Netpbm image to Fiasco (wfa) highly compressed format

fiascotopnm

convert Fiasco (wfa) highly compressed format to Netpbm image

hpcdtoppm

convert photo CD to PPM

pbmtonokia

convert PBM to Nokia Smart Messaging Format (SMF)

pbmtowbmp

convert PBM to WAP (Wireless App Protocol) Wireless Bitmap

wbmptopbm

convert WAP (Wireless App Protocol) Wireless Bitmap to PBM

neotoppm

convert Atari Neochrome (.neo) image to PPM

ppmtoneo

convert PPM image to Atari Neochrome (.neo)

pbmtomda

convert from PBM to Microdesign (for Amstrad PCWs)

mdatopbm

convert from Microdesign (for Amstrad PCWs) to PBM

atktopbm

convert Andrew Toolkit raster object to PBM

pbmtoatk

convert PBM to Andrew Toolkit raster object

brushtopbm

convert Xerox doodle brushes to PBM

cmuwmtopbm

convert CMU window manager format to PBM

g3topbm

convert Group 3 FAX to PBM

pbmtog3

convert PBM to Group 3 FAX

icontopbm

convert Sun icon to PBM

pbmtoicon

convert PBM to Sun icon

gemtopnm

convert GEM .img format to PBM or pixmap

macptopbm

convert MacPaint to PBM

pbmtomacp

convert PBM to MacPaint

mgrtopbm

convert MGR format to PBM

pbmtomgr

convert PBM to MGR format

pi3topbm

convert Atari Degas .pi3 to PBM

pbmtopi3

convert PBM to Atari Degas .pi3

xbmtopbm

convert X10 or X11 bitmap to PBM

pbmtoxbm

convert PBM to X11 bitmap

pbmtox10bm

convert PBM to X10 bitmap

ybmtopbm

convert Bennet Yee "face" file into PBM

pbmtoybm

convert PBM into Bennet Yee "face" file

pbmto10x

convert PBM to Gemini 10x printer graphics

pbmtoascii

convert PBM to ASCII graphic form

asciitopgm

convert ASCII character graphics to PGM

pbmtobbnbg

convert PBM to BBN BitGraph graphics

pbmtocmuwm

convert PBM to CMU window manager format

pbmtoepson

convert PBM to Epson printer graphics

pbmtogem

convert PBM into GEM .img file

pbmtogo

convert PBM to GraphOn graphics

pbmtolj

convert PBM to HP LaserJet black and white graphics

ppmtolj

convert PPM to HP LaserJet color graphics (PCL)

pjtoppm

convert HP PaintJet file to PPM

ppmtopj

convert PPM to HP PaintJet file

thinkjettopbm

convert HP Thinkjet printer stream to PBM

pbmtoplot

convert PBM into Unix plot(5) file

pbmtoptx

convert PBM to Printronix graphics

pbmtozinc

convert PBM to Zinc Interface Library icon

fitstopnm

convert FITS format to portable anymap

pnmtofits

convert Netpbm formats to FITS format

fstopgm

convert Usenix FaceSaver(tm) format to PGM

pgmtofs

convert PGM to Usenix FaceSaver(tm) format

hipstopgm

convert HIPS format to PGM

lispmtopgm

convert a Lisp Machine bitmap file into PGM format

pgmtolispm

convert PGM into Lisp Machine format

pnmtops

convert Netpbm formats to Postscript

pstopnm

convert Postscript to Netpbm formats

psidtopgm

convert PostScript "image" data to PGM

pbmtolps

convert PBM image to Postscript using lines

pbmtoepsi

convert a PBM image to encapsulated Postscript preview bitmap

pbmtopsg3

convert PBM images to Postscript using G3 fax compression.

rawtopgm

convert raw grayscale bytes to PGM

pgmtopbm

convert PGM to PBM

gouldtoppm

convert Gould scanner file to PPM

ilbmtoppm

convert IFF ILBM to PPM

ppmtoilbm

convert PPM to IFF ILBM

imgtoppm

convert Img-whatnot to PPM

mtvtoppm

convert MTV ray-tracer output to PPM

pcxtoppm

convert PC Paintbrush format to PPM

pgmtoppm

colorize a portable graymap into a PPM

pi1toppm

convert Atari Degas .pi1 to PPM

ppmtopi1

convert PPM to Atari Degas .pi1

picttoppm

convert Macintosh PICT to PPM

ppmtopict

convert PPM to Macintosh PICT

qrttoppm

convert QRT ray-tracer output to PPM

rawtoppm

convert raw RGB bytes to PPM

sldtoppm

convert an AutoCAD slide file into a PPM

spctoppm

convert Atari compressed Spectrum to PPM

sputoppm

convert Atari uncompressed Spectrum to PPM

tgatoppm

convert TrueVision Targa file to PPM

ppmtotga

convert PPM to TrueVision Targa file

ximtoppm

convert Xim to PPM

xpmtoppm

convert XPM format to PPM

ppmtoxpm

convert PPM to XPM format

yuvtoppm

convert Abekas YUV format to PPM

eyuvtoppm

convert Encoder/Berkeley YUV format to PPM

ppmtoeyuv

convert PPM to Encoder/Berkeley YUV format

ppmtoyuv

convert PPM to Abekas YUV format

ppmtoyuvsplit

convert PPM to 3 subsampled raw YUV files

yuvsplittoppm

merge 3 subsampled raw YUV files to one PPM

ppmtoacad

convert PPM to AutoCAD database or slide

ppmtoicr

convert PPM to NCSA ICR graphics

ppmtopcx

convert PPM to PC Paintbrush format

ppmtopgm

convert PPM to portable graymap

ppmtopuzz

convert PPM to X11 "puzzle" file

rasttopnm

convert Sun raster file to Netpbm formats

pnmtorast

convert Netpbm formats to Sun raster file

tifftopnm

convert TIFF file to portable anymap

pnmtotiff

convert Netpbm formats to TIFF RGB file

pnmtotiffcmyk

convert Netpbm formats to TIFF CMYK file

xwdtopnm

convert X10 or X11 window dump to Netpbm formats

pnmtoxwd

convert Netpbm formats to X11 window dump

pnmtoplainpnm

convert regular Netpbm format image into plain Netpbm format

pbmtopgm

convert PBM file to PGM by averaging areas

411toppm

convert 411 (Sony Mavica) to PPM

ppmtosixel

convert PPM to DEC sixel format

ppmtouil

convert PPM to Motif UIL icon file

sbigtopgm

convert Santa Barbara Instrument Group CCD file to PGM

vidtoppm

convert Parallax XVideo JPEG to sequence of PPM files

pnmtorle

convert PNM to Utah Raster Toolkit (urt/rle) file

rletopnm

convert Utah Raster Toolkit (urt/rle) file to PNM

ppmtoleaf

convert PPM to Interleaf

leaftoppm

convert Interleaf to PPM

bioradtopgm

convert Biorad confocal image to PGM

pbmtoln03

convert PGM image to Dec LN03+ Sixel image

pbmtopk

convert PBM image to packed format (PK) font

pktopbm

convert packed format (PK) font to PBM image

Image Generators

All of these generate Netpbm format output.

pbmmake

create a blank PBM image of a specified size

ppmmake

create a PPM image of a specified size and color

pgmramp

generate a grayscale ramp

ppmpat

create a pretty PPM image

ppmrainbow

create a spectrum-like image with colors fading together.

pgmnoise

create a PGM image of white noise

pbmtext

render text into a PBM image

pbmupc

create a Universal Product Code PBM image

ppmcie

generate a CIE color map PPM image

pbmpage

create a printer test pattern page in PBM format

ppmcolors

create a color map (PPM image) containing all possible colors of given maxval

Image Editors

All of these work on the Netpbm formats

ppmlabel

Add text to an image

pnmshadow

add a shadow to an image so it looks like it's floating

ppmbrighten

brighten or dim an image -- change saturation and value

ppmdim

dim an image - different way from ppmbrighten

pbmreduce

reduce a PBM N times, using Floyd-Steinberg

pgmnorm

normalize contrast in a PGM image

ppmnorm

normalize contrast in a PPM image

pbmpscale

enlarge a PBM image with edge smoothing

pnmscale

scale an image with high precision

pnmscalefixed

scale an image quickly with low precision

pnmenlarge

enlarge an image N times

ppmdither

ordered dither for color images

pnmcolormap

Choose the N best colors to represent an image; create a colormap

pnmremap

Replace colors in an image with those from a color map

ppmquant

quantize colors in a color image down to fewer colors

pnmquant

quantize colors/shades in a color or grayscale image down to fewer

ppmquantall

quantize colors on many files

ppmrelief

run a Laplacian Relief filter on a PPM

pnmarith

perform arithmetic on two images

pnmcat

concatenate images

pnmpad

add borders to an image

pnmcomp

create composite (overlay) of images

ppmmix

mix (overlay) two images.

pnmcrop

crop all like-colored borders off an image

pamcut

select a rectangular region from an image

pnmcut

obsolete version of pamcut (kept because it may have fewer bugs)

pamdice

slice an image into many horizontally and/or vertically

pamdeinterlace

remove every other row from an image

pamchannel

extract a single plane (channel, e.g. R, G, or B) from an image

pnmdepth

change the maxval in an image

pnmflip

perform one or more flip operations on an image

pamstretch

scale up an image by inserting interpolated pixels

pamstretch-gen

scale by non-integer values using pamstretch and pnmscale

pnminvert

invert an image

pnmgamma

perform gamma correction on an image

pnmhisteq

histogram equalize image to increase contrast

pnmmargin

add a margin to an image

pnmpaste

paste a rectangle into an image

pnmrotate

rotate an image

pnmshear

shear an image

pnmsmooth

smooth am image

pnmtile

replicate an image into a specified size

pbmclean

remove lone pixels (snow) from a PBM image

pnmalias

antialias an image

ppmchange

change all of one color to another in PPM image

pnmnlfilt

filter an image by replacing each pixel with a function of nearby pixels

ppmshift

shift lines of PPM image left or right a random amount

ppmspread

move pixels of PPM image a random amount

pnmconvol

general MxN convolution on an image

rgb3toppm

combine three portable graymaps into one PPM

ppmtorgb3

separate a PPM into three portable graymaps

pbmlife

apply Conway's rules of Life to a PBM image

ppmdist

map colors to high contrast grayscales arbitrarily

ppmntsc

adjust colors so they are legal for NTSC or PAL television

Image Analyzers

These all work on the Netpbm formats as input.

pnmfile

describe an image's vital characteristics

pnmpsnr

measure difference between two images

pgmedge

edge-detect a PGM image

pgmenhance

edge-enhance a PGM image

pgmslice

print grayscale values for a row or column of a PGM image

pgmtexture

calculate textural features on a PGM image

pgmhist

print a histogram of the values in a PGM image

ppmhist

print a histogram of a PPM

pnmhistmap

draw a histogram of a PGM or PPM

ppmtomap

generate a map of all colors in an image

ppm3d

generate a blue/green 3D glasses image from two images

Miscellaneous

ppmsvgalib

display a PPM image on a Linux virtual console using Svgalib

pbmmask

create a mask bitmap from a regular bitmap

ppmcolormask

create mask of areas of a certain color in an image

pnmsplit

split a multi-image Netpbm file into multiple 1-image files

pnmindex

build a visual index of a bunch of Netpbm images

pcdindex

build a visual index of a photo CD from PCD overview file

pnmmontage

build multiple Netpbm images into a single montage image

pgmbentley

Bentleyize a PGM image

pgmcrater

create cratered terrain by fractal forgery

pamoil

turn a PNM or PAM image into an oil painting

ppmforge

fractal forgeries of clouds, planets, and starry skies

pgmkernel

generate a convolution kernel

ppmtv

Make an image lined so it looks like an old TV

pbmto4425

Display PBM image on AT&T 4425 ASCII terminal with gfx chars

Uncatalogued As Yet

pnmtoddif

pnmtosgi

pnmtosir

ppmflash

ppmqvga

ppmtomitsu

ppmtopjxl

sgitopnm

sirtopnm

spottopgm

xvminitoppm

zeisstopnm

The Netpbm programming libraries, libpbm(3), libpgm(3), libppm(3), and libpnm(3), make it easy to write programs that manipulate graphic images. Their main function is to read and write files in the Netpbm format, and because the Netpbm package contains converters for all the popular graphics formats, if your program reads and writes the Netpbm formats, you can use it with any formats.

But the libraries also contain some utility functions, such as character drawing and RGB/YCrCb conversion.

The libraries have the conventional C linkage. Virtually all programs in the Netpbm package are based on the Netpbm libraries.

Application Notes

As a collection of primitive tools, the power of Netpbm is multiplied by the power of all the other unix tools you can use with them. These notes remind you of some of the more useful ways to do this. Often, when people want to add high level functions to the Netpbm tools, they have overlooked some existing tool that, in combination with Netpbm, already does it.

Often, you need to apply some conversion or edit to a whole bunch of files.

As a rule, Netpbm programs take one input file and produce one output file, usually on Standard Output. This is for flexibility, since you so often have to pipeline many tools together.

Here is an example of a shell command to convert all your of PNG files (named *.png) to JPEG files named *.jpg:

for i in *.png; do pngtopnm $i | ppmtojpeg >`basename $i .png`.jpg; done

Or you might just generate a stream of individual shell commands, one per file, with awk or perl. Here's how to brighten 30 YUV images that make up one second of a movie, keeping the images in the same files:

ls *.yuv .br | perl -ne 'chomp;

print yuvtoppm $_ | ppmbrighten -v 100 | ppmtoyuv >tmp$$.yuv; ,

mv tmp$$.yuv $_\n

' .br | sh

The tools find (with the -exec option) and xargs are also useful for simple manipulation of groups of files.

Some shells' "process substitution" facility can help where a non-Netpbm program expects you to identify a disk file for input and you want it to use the result of a Netpbm manipulation. Say printcmyk takes the filename of a Tiff CMYK file as input and what you have is a PNG file abc.png. Try:

printcmyk <({ pngtopnm abc.png | pnmtotiffcmyk ; })

It works in the other direction too, if you have a program that makes you name its output file and you want the output to go through a Netpbm tool.

Other Graphics Software

Netpbm contains primitive building blocks. It certainly is not a complete graphics library.

The first thing you will need to make use of any of these tools is a viewer. For the X inclined, there is xzgv. See ftp://metalab.unc.edu/pub/Linux/apps/graphics/viewers/X.

xloadimage and its extension xli are also common ways to display a graphic image in X.

ImageMagick is like a visual version of Netpbm. Using the X/Window system on Unix, you can do basic editing of images and lots of format conversions. The package does include at least some non-visual tools. Convert, Mogrify, Montage, and Animate are popular programs from the ImageMagick package. ImageMagick runs on Unix, Windows, Windows NT, Macintosh, and VMS.

The Gimp is a visual image editor for Unix and X, in the same category as the more famous, less capable, and much more expensive Adobe Photoshop, etc. for Windows. See http://www.gimp.org.

The file program looks at a file and tells you what kind of file it is. It recognizes most of the graphics formats with which Netpbm deals, so it is pretty handy for graphics work. Netpbm's anytopnm program depends on file. See ftp://ftp.astron.com/pub/file.

The Utah Raster Toolkit serves a lot of the same purpose as Netpbm, but without the emphasis on format conversions. This package is based on the RLE format, which you can convert to and from the Netpbm formats. http://www.cs.utah.edu/research/projects/alpha1/urt.html gives some information on the Utah Raster Toolkit, but does not tell where to get it.

There are some Netpbm-like graphics tools distributed by the Army High Performance Computing Research Center at http://www.arc.umn.edu/gvl-software/media-tools.html. These operate directly on non-Netpbm format images, so they aren't included in the Netpbm package. However, you can use them with any image format by using the Netpbm format converters.

Ivtools is a suite of free X Windows drawing editors for Postscript, Tex, and web graphics production, as well as an embeddable and extendable vector graphic shell. It uses the Netpbm facilities. See http://www.ivtools.org.

Ilib is a C subroutine library with functions for adding text to an image (as you might do at a higher level with pbmtext, pnmcomp, etc.). It works with Netpbm input and output. Find it at http://www.radix.net/~cknudsen/Ilib. Netpbm also includes character drawing functions in the libppm library, but they do not have as fancy font capabilities (see ppmlabel for an example of use of the Netpbm character drawing functions).

GD is a library of graphics routines that is part of PHP. It has a subset of Netpbm's functions and has been found to resize images more slowly and with less quality.

pnm2ppa converts to HP's "Winprinter" format (for HP 710, 720, 820, 1000, etc). It is a superset of Netpbm's pbmtoppa and handles, notably, color. However, it is more of a printer driver than a Netpbm-style primitive graphics building block. See http://sourceforge.net/project/?group_id=1322.

The program morph morphs one image into another. It uses Targa format images, but you can use tgatoppm and ppmtotga to deal with that format. You have to use the graphical (X/Tk) Xmorph to create the mesh files that you must feed to morph. morph is part of the Xmorph package. See http://www.colorado-research.com/~gourlay/software/Graphics/Xmorph.

To create an animated GIF, or extract a frame from one, use gifsicle. gifsicle converts between animated GIF and still GIF, and you can use ppmtogif and giftopnm to connect up to all the Netpbm utilities. See http://www.lcdf.org/gifsicle.

To convert an image of text to text (optical character recongition - OCR), use gocr (think of it as an inverse of pbmtext). See http://altmark.nat.uni-magdeburg.de/~jschulen/ocr/.

http://schaik.com/pngsuite contains a PNG test suite -- a whole bunch of PNG images exploiting the various features of the PNG format.

Another version of pnmtopng/pngtopnm is at http://www.schaik.com/png/pnmtopng.html. The version in Netpbm was actually based on that package a long time ago, and you can expect to find better exploitation of the PNG format, especially recent enhancements, in that package. It may be a little less consistent with the Netpbm project and less exploitive of recent Netpbm format enhancements, though.

jpegtran Does some of the same transformations as Netpbm is famous for, but does them specifically on JPEG files and does them without loss of information. By contrast, if you were to use Netpbm, you would first decompress the JPEG image to Netpbm format, then transform the image, then compress it back to JPEG format. In that recompression, you lose a little image information because JPEG is a lossy compression. jpegtran comes with the Independent Jpeg Group's (http://www.ijg.org) JPEG library.

Some tools to deal with EXIF files (see also Netpbm's jpegtopnm and pnmtojpeg): To dump (interpret) an EXIF header: Exifdump ((http://topo.math.u-psud.fr/~bousch/exifdump.py) or Jhead (http://www.sentex.net/~mwandel/jhead).

A Python EXIF library and dumper: http://pyexif.sourceforge.net.

Latex2html converts Latex document source to HTML document source. Part of that involves graphics, and Latex2html uses Netpbm tools for some of that. But Latex2html through its history has had some rather esoteric codependencies with Netpbm. Older Latex2html doesn't work with current Netpbm. Latex2html-99.2beta8 works, though.

Other Graphics Formats

People never seem to tire of inventing new graphics formats, often completely redundant with pre-existing ones. Netpbm cannot keep up with them. Here is a list of a few that we know Netpbm does not handle (yet).

  CAL (originated by US Department Of Defense, favored by architects).

http://www.landfield.com/faqs/graphics/fileformats-faq/part3/section-24.html

  array formats dx, general, netcdf, CDF, hdf, cm

  CGM+

  Windows Meta File (.WMF).  Libwmf converts from WMF to things like

Latex, PDF, PNG. Some of these can be input to Netpbm.

  Microsoft Word, RTF.  Microsoft keeps a proprietary hold on these formats.

Any software you see that can handle them is likely to cost money.

  DXF (AutoCAD)

Netpbm has a long history, starting with Jef Poskanzer's Pbmplus package in 1988. The file HISTORY in the Netpbm source code contains a historical overview as well as a detailed history release by release.

Netpbm is based on the Pbmplus package by Jef Poskanzer, first distributed in 1988 and maintained by him until 1991. But the package contains work by countless other authors, added since Jef's original work. In fact, the name is derived from the fact that the work was contributed by people all over the world via the Internet, when such collaboration was still novel enough to merit naming the package after it.

Bryan Henderson has been maintaining Netpbm since 1999. In addition to packaging work by others, Bryan has also written a significant amount of new material for the package.