# netpbm

Index

## NAME

netpbm - package of graphics manipulation programs and subroutine library

## DESCRIPTION

Netpbm is a package of graphics programs and a programming library.

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.

## The Netpbm Formats

All of the programs work with a set of graphics formats called the "netpbm" formats. Specifically, these formats are pbm, pgm, ppm, and pam. 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 Implied Format Conversion.

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, pmmtopng creates a black and white PNG output image if its input is PBM or PGM, but a color PNG output image if its input is PPM. And pnmscale produces an output image of the same format as the input. A hypothetical ppmscale program would also read all three PNM input formats, but would see them all as PPM and would always generate PPM output.

Programs that have "pam" in their names read all the Netpbm formats: PBM, PGM, PPM, and PAM. They sometimes treat them all as if they are PAM, using an implied conversion, but often they recognize the individual formats an behave accordingly, like a "pnm" program does. See Implied Format Conversion.

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 specifications of pbm, pgm, ppm, and pam.

## Implied Format Conversion

A program that uses the PGM library subroutines 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. note: This sometimes confuses people who are looking at the formats at a lower layer than they ought to be because a zero value in a PBM raster means white, while a zero value in a PGM raster means black.

A program that uses the PPM library subroutines 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.

A program that uses the PAM library subroutines to read an image can read a PBM, PGM, or PPM image as well as a PAM image. The program sees a PBM image as if it were the equivalent PAM image with tuple type BLACKANDWHITE. It sees a PGM image as if it were the equivalent PAM image with tuple type GRAYSCALE. It sees a PPM image as if it were the equivalent PAM image with tuple type RGB. But the program actually can see deeper if it wants to. It can tell exactly which format the input was and may respond accordingly. For example, a PAM program typically produces output in the same format as its input.

## Netpbm and Transparency

In many graphics formats, 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 an opaqueness value. See pgm. pnmcomp is an example of a program that uses a PGM transparency mask.

Another means of representing transparency information has recently developed in Netpbm, using PAM images. In spite of the argument given above that Netpbm formats should be too simple to have transparency information built in, it turns out to be extremely inconvenient to have to carry the transparency information around separately. This is primarily because Unix shells don't provide easy ways to have networks of pipelines. You get one input and one output from each program in a pipeline. So you'd like to have both the color information and the transparency information for an image in the same pipe at the same time.

For that reason, some new (and recently renovated) Netpbm programs recognize and generate a PAM image with tuple type RGB_ALPHA or GRAYSCALE_ALPHA, which contains a plane for the transparency information. See the PAM specification.

## 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, 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.

## Common Options

There are a few options that are present on all programs that are based on the Netpbm library, 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 library).
-version
  Instead of doing anything else, report the version of the libnetpbm 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 library are installed at the same time, so this tells you the version of the program and all the other Netpbm files it uses as well.

  Here is a directory of the Netpbm programs.

### Converters

pnmtoplainpnm
  convert regular Netpbm format image into plain Netpbm format
pgmtopgm
  convert PGM or PBM image to PGM
ppmtoppm
  convert PPM, PGM, or PBM image to PPM
pbmtopgm
  convert PBM image to PGM by averaging areas
pgmtoppm
  colorize a PGM into a PPM
ppmtopgm
  convert PPM image to PGM
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
bmptopnm
  convert Windows or OS/2 Bitmap file to PPM or PGM
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
jbigtopnm
  convert JBIG BIE (compressed bitmap) to PNM
pamtopnm
  convert a PAM image to PBM, PGM, or PPM
pnmtojbig
  convert PNM 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
pcdovtoppm
  Convert a photo CD PCD overview file 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
pbmtoepson
  convert PBM to Epson printer graphics
pbmto10x
  convert PBM to Gemini 10x printer graphics
pnmtopclxl
  convert PNM to HP PCL-XL (PCL 6) printer language
ppmtopjxl
  convert from PPM to HP Paintjet XL PCL printer stream
pbmtolj
  convert PBM to HP LaserJet black and white graphics
ppmtolj
  convert PPM to HP LaserJet color graphics (PCL 5)
pjtoppm
  convert HP PaintJet file to PPM
ppmtopj
  convert PPM to HP PaintJet file
thinkjettopbm
  convert HP Thinkjet printer stream to PBM
ppmtomitsu
  convert from PPM to Mitsubishi S340-10 printer stream
ppmtoterm
  Display PPM image on ANSI standard text terminal
pbmto4425
  Display PBM image on AT&T 4425 ASCII terminal with gfx chars
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
pbmtogem
  convert PBM into GEM .img file
pbmtogo
  convert PBM to GraphOn graphics
pbmtoplot
  convert PBM into Unix plot 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
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
pamtotga
  convert PAM 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
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
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
pamtohdiff
  convert PAM image to horizontal difference version of same
hdifftopam
  convert horizontal difference PAM back to original image
pnmtoddif
  convert from Netpbm formats to DDIF
pnmtosgi
  convert from Netpbm formats to SGI format
sgitopnm
  convert from SGI format to Netpbm formats
pnmtosir
  convert from Netpbm formats to Solitaire Image Recorder file (MGI Type 11 or 17)
sirtopnm
  convert from Solitaire Image Recorder file to Netpbm formats.
spottopgm
  convert SPOT satellite image to PGM
xvminitoppm
  convert Xv "thumbnail" picture to PPM
zeisstopnm
  convert a Zeiss confocal file to Netpbm format

### 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.
ppmrough
  create PPM image of two colors with a ragged border between them
pgmnoise
  create a PGM image of white noise
pbmtext
  render text into a PBM image
pbmtextps
  render text into a PBM image using a Postscript interpreter
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
pamseq
  create a PAM image of all possible tuple values. E.g. a color map containing all possible colors of given maxval

### Image Editors

All of these work on the Netpbm formats

ppmlabel
  Add text to an image
ppmshadow
  add a shadow to an image so it looks like it's floating
ppmbrighten
  brighten or dim an image -- change saturation and value
ppmflash
  brighten an image
ppmdim
  dim an image - different way from ppmbrighten
ppmfade
  Produce series of images fading from one to another
pbmreduce
  reduce a PBM N times, using Floyd-Steinberg
pnmnorm
  normalize contrast
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
pamfunc
  apply simple arithmetic function to samples in an image
pamarith
  apply simple arithmetic binary function to samples in 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
pnmstitch
  stitch together panoramic (side-by-side) photographs
pamchannel
  extract individual planes (channel, e.g. R, G, or B) from an image
pamstack
  stack the planes of multiple PAM images into a single output image
pnmdepth
  change the maxval in an image
pamendian
  Swap bytes in multi-byte samples of a PAM 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
pgmabel
  create cross-section of an image using Abel integration for deconvolution
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
pgmmorphconv
  perform morphological convolutions on a PGM image: dilation and erosion.
pgmminkowski
  Compute Minkowski integral over a PGM image
pgmedge
  edge-detect a PGM image
rgb3toppm
  combine three portable graymaps into one PPM
ppmtorgb3
  separate a PPM into three portable graymaps
pgmenhance
  edge-enhance a PGM image
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
pamslice
  print a row or column of an image in ASCII decimal
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
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

### Obsolete Names

There used to be programs by the following names. Each has been either renamed to a more illustrative name, or superseded by a more general function. In most cases, Netpbm is installed with symbolic links that allow old programs and procedures to use these names but run the replacement programs:

- ppmtotga
- pnmnoraw
- gemtopbm
- pnminterp
- pgmoil
- ppmtojpeg
- bmptoppm
- pgmnorm

## The Netpbm Library

The Netpbm programming library, libnetpbm, makes it easy to write programs that manipulate graphic images. Its main function is to read and write files in the Netpbm formats, 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 library also contain some utility functions, such as character drawing and RGB/YCrCb conversion.

The library has the conventional C linkage. Virtually all programs in the Netpbm package are based on the Netpbm library.

### 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
       | perl -ne 'chomp;
       print yuvtoppm $_ | ppmbrighten -v 100 | ppmtoyuv >tmp$$.yuv;
       mv tmp$$.yuv $_
       '
       | 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 &lt;({ 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 want to make use of any of these tools is a viewer. (On GNU/Linux, you can use ppmsvgalib in a pinch, but it is pretty limiting). zgv is a good full service 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 pamcut. 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.

To play mpeg movies, such as produced by ppmtompeg, try xine.

The free Acrobat Reader from Adobe displays PDF and converts to Postscript. You can sort of read PDF files with Netpbm by using Pstopnm. Pstopnm uses Ghostscript to read what is usually a Postscript file, but because Ghostscript also understands PDF, Pstopnm also converts from PDF to PNM. But Acrobat Reader may do it better. The Acrobat Reader for unix has a program name of "acroread" and the -toPostScript option (also see the -level2 option) is useful.

Other software from Adobe, available for purchase, interprets and creates Postscript and PDF files better than Netpbm can. "Distill" is a program that converts Postscript to PDF.

Here's some software to work with IOCA (Image Object Content Architecture): ImageToolbox ($2500, demo available). This can convert from TIFF -> IOCA and back again. Ameri-Imager ($40 Windows only).

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 libnetpbm 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. Of course, only a few kinds of lossless transformation are possible. 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)
- IOCA (Image Object Content Architecture) The specification of this format is documented by IBM: Data Stream and Object Architectures: Image Object Content Architecture Reference. See above for software that processes this format.

## 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.

## Index

NAME
DESCRIPTION
The Netpbm Formats
Implied Format Conversion
Netpbm and Transparency
The Netpbm Programs
Common Options
  Converters
  Image Generators
  Image Editors
  Image Analyzers
  Miscellaneous
The Netpbm Library
  Application Notes
  Other Graphics Software
  Other Graphics Formats
HISTORY
AUTHOR