Table of Contents

Name

netpbm - package of graphics manipulation programs and libraries

Description

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 ppmquant.

The Netpbm Formats

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) ,

Implied Format Conversion

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.

The Netpbm Programs

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) and do not seek input from a user.

Each of these programs has its own man page.

Common Options

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
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

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
ppmdither
ordered dither for color images
ppmquant
quantize colors in an image down to a specified number
ppmquantall
quantize colors down to a specified number 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
pnmcut
select a rectangular region from an image
pnmdepth
change the maxval in an image
pnmenlarge
enlarge an image N times
pnmflip
perform one or more flip operations on an image
pnminterp
scale up an image by interpolating between pixels
pnminterp-gen
scale by non-integer values using pnminterp and pnmscale
pnminvert
invert an image
pnmgamma
perform gamma correction on an image
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
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
ppmtomap
generate a map of all colors in an

image

Miscellaneous

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

pnmhisteq
pnmhistmap
pnmnlfilt
pnmtoddif
pnmtosgi
pnmtosir
ppm3d
ppmflash
ppmqvga
ppmtomitsu
ppmtopjxl
sgitopnm
sirtopnm
spottopgm
xvminitoppm
zeisstopnm

The Netpbm Libraries

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 keeping the images in the same files:
| perl -ne 'chomp;
print "yuvtoppm $_ | ppmbrighten -v 100 | ppmtoyuv >tmp$$.yuv;",
mv tmp$$.yuv $_0
' "mv tmp$$.yuv $_0
| 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. zgv is a good viewer to use on a GNU/Linux system with the SVGALIB graphics display driver library. You can find zgv at ftp://ftp.ibiblio.org/pub/Linux/apps/graphics/viewers/svga .

zgv even has a feature in it wherein you can visually crop an image and write an output file of the cropped image using pnmcut. See the -s option to zgv.

For the X inclined, there is also 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).

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.

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.

History

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.

Author

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.


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