NAME
netpbm - netpbm library overview
Overview Of Netpbm
Netpbm is a package of graphics programs and a programming library.
There are over 330 separate programs in the package, most of which have "pbm", "pgm", "ppm", "pam", or "pnm" in their names. For example, pamscale(1) and giftopnm(1).
For example, you might use pamscale to shrink an image by 10%. Or use pamcomp 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.
Netpbm is an open source software package, distributed via the http://sourceforge.net/projects/netpbm">Sourceforge netpbm project .
Table Of Contents
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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 and do not seek input from a user. The only programs that display graphics at all are the very primitive display programs pamx and ppmsvgalib, and they don’t do anything but that.
Each of these programs has its own manual, as linked in the directory below.
The Netpbm programs can read and write files greater than 2 GiB wherever the underlying system can. There may be exceptions where the programs use external libraries (The JPEG library, etc.) to access files and the external library does not have large file capability. Before Netpbm 10.15 (April 2003), no Netpbm program could read a file that large.
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 manuals for the programs.
You can use two hyphens instead of one on these options if you like.
-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.
-plain
If the program generates an image in PNM format, generate it in the "plain" (aka "ascii") version of the format, as opposed to the "raw" (aka "binary") version.
Note that the other Netpbm format, PAM, does not have plain and raw versions, so this option has no effect on a program that generates PAM output.
This option was introduced in Netpbm 10.10 (October 2002). From Netpbm 10.32 (February 2006) through Netpbm 10.62 (March 2013), the option is invalid with a program that generates PAM output (instead of ignoring the option, the program fails).
Directory
Here is a complete list of all the Netpbm programs (with
links to their manuals):
Netpbm
program directory(1)
How To Use
The Programs 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: 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 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 the hypothetical program
printcmyk takes the filename of a Tiff CMYK file as
input and what you have is a PNG file abc.png. Try: 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. All of the
programs work with a set of graphics formats called the
"netpbm" formats. Specifically, these formats are
pbm(1), pgm(1), ppm(1), and
pam(1). 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 about 100 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 those formats and their function depends on the
format. For example, pnmtopng(1) 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
pnmrotate produces an output image of the same format
as the input. A hypothetical ppmrotate 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 and behave
accordingly, like a "pnm" program does. See
Implied Format Conversion . Finally, there
are subformats of PAM that are equivalent to PBM, PGM, and
PPM respectively, and Netpbm programs designed to read PBM,
PGM, and/or PPM see those PAM images as if they were the
former. For example, ppmhist can analyze a PAM image
of tuple type RGB (i.e. a color image) as if it were
PPM. 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(1),
pgm(1), ppm(1), and pam(1). Implied
Format Conversion 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. A program that
uses the PGM library subroutines to read an image can read a
PAM image as well a PGM image, if the PAM is a grayscale or
black and white visual image. That canonically means the PAM
has a depth of 1 and a tuple type of GRAYSCALE or
BLACKANDWHITE, but most Netpbm programs are fairly liberal
and will take any PAM at all, ignoring all but the first
plane. There is a
similar implied conversion for PPM library subroutines
reading PAM. There is nothing similar for PBM, so if you
need for a PBM program to read a PAM image, run it through
pamtopnm. Netpbm and
Transparency 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(1). pamcomp(1) 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(1). The Netpbm
programming library, libnetpbm(1), 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. In a standard
installation of Netpbm, there is a program named
netpbm-config in the regular program search path. We
don’t consider this a Netpbm program -- it’s
just an ancillary part of a Netpbm installation. This
program tells you information about the Netpbm installation,
and is intended to be run by other programs that interface
with Netpbm. In fact, netpbm-config is really a
configuration file, like those you typically see in the
/etc/ directory of a Unix system. Example: If you write a
program that needs to access a Netpbm data file, it can use
such a shell command to find out where the Netpbm data files
are. netpbm-config
is the only file that must be installed in a standard
directory (it must be in a directory that is in the default
program search path). You can use netpbm-config as a
bootstrap to find all the other Netpbm files. There is no
detailed documentation of netpbm-config. If
you’re in a position to use it, you should have no
trouble reading the file itself to figure out how to use
it. An important
characteristic that varies among graphics software is how
much memory it uses, and how. Does it read an entire image
into memory, work on it there, then write it out all at
once? Does it read one and write one pixel at a time? In
Netpbm, it differs from one program to the next, but there
are some generalizations we can make. Most Netpbm
programs keep one row of pixels at a time in memory. Such a
program reads a row from an input file, processes it, then
writes a row to an output file. Some programs execute
algorithms that can’t work like that, so they keep a
small window of rows in memory. Others must keep the entire
image in memory. If you think of what job the program does,
you can probably guess which one it does. When Netpbm
keeps a pixel in memory, it normally uses a lot more space
for it than it occupies in the Netpbm image file format. The older
programs (most of Netpbm) use 12 bytes per pixel. This is
true even for a PBM image, for which it only really takes
one bit to totally describe the pixel. Netpbm does this
expansion to make implementing the programs easier -- it
uses the same format regardless of the type of image. Newer programs
use the "pam" family of library functions
internally, which use memory a little differently. These
functions are designed to handle generic tuples with a
variable numbers of planes, so no fixed size per-tuple
storage is possible. A program of this type uses 4 bytes per
sample (a tuple is composed of samples), plus a pointer (4-8
bytes) per tuple. In a graphic image, a tuple is a pixel. So
an ordinary color image takes 16-20 bytes per pixel. When
considering memory usage, it is important to remember that
memory and disk storage are equivalent in two ways: • Memory is often virtual, backed
by swap space on disk storage. So accessing memory may mean
doing disk I/O. • Files are usually cached and buffered, so that accessing
a disk file may just mean accessing memory. This means that
the consequences of whether a program works from the image
file or from a memory copy are not straightforward. Note that an
image takes a lot less space in a Netpbm format file, and
therefore in an operating system’s file cache, than in
Netpbm’s in-memory format. In non-Netpbm image
formats, the data is even smaller. So reading through an
input file multiple times instead of keeping a copy in
regular memory can be the best use of memory, and many
Netpbm programs do that. But some files can’t be read
multiple times. In particular, you can’t rewind and
re-read a pipe, and a pipe is often the input for a Netpbm
program. Netpbm programs that re-read files detect such
input files and read them into a temporary file, then read
that temporary file multiple times. A few Netpbm
programs use an in-memory format that is just one bit per
pixel. These are programs that convert between PBM and a
format that has a raster format very much like PBM’s.
In this case, it would actually make the program more
complicated (in addition to much slower) to use
Netpbm’s generic 12 byte or 8 byte pixel
representation. By the way, the
old axiom that memory is way faster than disk is not
necessarily true. On small systems, it typically is true,
but on a system with a large network of disks, especially
with striping, it is quite easy for the disk storage to be
capable of supplying data faster than the CPU can use
it. People
sometimes wonder what CPU facilities Netpbm programs and the
Netpbm programming library use. The programs never depend on
particular features existing (assuming they’re
compiled properly), but the speed and cost of running a
program varies depending upon the CPU features. Note that when
you download a binary that someone else compiled, even
though it appears to be compiled properly for your machine,
it may be compiled improperly for that machine if it is old,
because the person who compiled it may have chosen to
exploit features of newer CPUs in the line. For example, an
x86 program may be compiled to use instructions that are
present on an 80486, but not on an 80386. You would probably
not know this until you run the program and it crashes. But the default
build options almost always build binaries that are as
backward compatible with old CPUs as possible. An exception
is a build for a 64 bit x86 CPU. While the builder could
build a program that runs on a 32 bit x86, it does not do so
by default. A default build builds a program will not run on
an older 32-bit-only x86 CPU. One common
build option is to use MMX/SSE operands with x86 CPUs. Those
are not available on older x86 CPUs. The builder by default
does not generate code that uses MMX/SSE when building for
32 bit x86 CPUs, but does when building for 64 bit x86. One area of
particular importance is floating point arithmetic. The
Netpbm image formats are based on integers, and Netpbm
arithmetic is done with integers where possible. But there
is one significant area that is floating point: programs
that must deal with light intensity. The Netpbm formats use
integers that are proportional to brightness, and brightness
is exponentially related to light intensity. The programs
have to keep the intermediate intensity values in floating
point in order not to lose precision. And the conversion
(gamma function) between the two is heavy-duty floating
point arithmetic. Programs that
mix pixels together have to combine light intensity, so they
do heavy floating point. Three of the most popular Netpbm
programs do that: pamscale(1) (shrink/expand an
image), pamcomp(1) (overlay an image over another
one), and pamditherbw(1) (Make a black and white
image that approximates a grayscale image). The Netpbm
image formats use 16 bit integers. The Netpbm code uses
"unsigned int" size integers to work with
them. The Gimp is a
visual image editor for Unix and X, so it does the kinds of
things that Netpbm does, but interactively in a
user-friendly way. The Gimp knows a variety of graphics file
formats and image transformations, but you can extend it
with plugins. A particularly
easy way to write a Gimp plugin is to write a Netpbm program
(remember that a fundamental mission of Netpbm is make
writing image manipulation programs easy) and then use
http://netpbm2gimp.sourceforge.net/">netpbm2gimp
to compile that same source code into a Gimp plugin. You can turn a
program that converts from a certain graphics file format to
Netpbm format into a Gimp load plugin. Likewise, you
can turn a program that converts to a certain
graphics format from Netpbm format into a Gimp
store plugin. Finally, a program that transforms
images in Netpbm format can become a process
plugin. And the
netpbm2gimp project has already packaged for you a
few hundred of the Netpbm programs as Gimp plugins. With
this package you can, for example, edit an image in any of
the arcane graphics file formats that Netpbm understands but
no other image editor in existence does. PHP-NetPBM
I can’t
actually recommend PHP-NetPBM. I spent some time staring at
it and was unable to make sense of it. Some documentation is
in fractured English and other is in an unusual character
set. But a PHP expert might be able to figure it out and get
some use out of it. Netpbm contains
primitive building blocks. It certainly is not a complete
graphics software library. Command Line
Programs ImageMagick
also contains the program display, which is a
viewer and visual
editor . Image
Viewers 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(1). See the
-s option to zgv. For the X
inclined, there is also xzgv. xwud (X
Window Undump) is a classic application program in the X
Window System that displays an image in an X window. It
takes the special X Window Dump format as input; you can use
Netpbm’s pnmtoxwd(1) to create it. You’re
probably better off just using Netpbm’s
pamx(1). xloadimage
and its extension xli are also common ways to display
a graphic image in X. gqview
is a more modern X-based image viewer. qiv is a
small, very fast viewer for X. To play mpeg
movies, such as produced by ppmtompeg, try
mplayer(1) or
http://sourceforge.net/projects/xine">xine
. See
ftp://metalab.unc.edu/pub/Linux/apps/graphics/viewers/X">ftp://metalab.unc.edu/pub/Linux/apps/graphics/viewers/X
. Image
Capturers Visual
Graphics Software xv is a
very old and very popular simple image editor in the Unix
world. It does not have much in the way of current support,
or maintenance, though. Gimp is a
visual image editor for Unix and the X Window System, in the
same category as the more famous, less capable, and much
more expensive Adobe Photoshop, etc. for Windows. See
http://www.gimp.org">http://www.gimp.org
. And you can add most of Netpbm’s function to Gimp
using
http://netpbm2gimp.sourceforge.net/">Netpbm2gimp
. ImageMagick
contains the program display, which is another visual
image editor. It has fewer functions than Gimp. This program
uses the X Window System. The package also contains
command line graphics
programs. Electric Eyes,
kuickshow, and gthumb are also visual editors
for the X/Window system, and KView and
gwenview are specifically for KDE. Programming
Tools You can easily
run any Netpbm program from a C program with the
pm_system function from the Netpbm programming
library, but that is less efficient than gd functions
that do the same thing. Ilib is
a C subroutine library with functions for adding text to an
image (as you might do at a higher level with
pbmtext, pamcomp, etc.). It works with Netpbm
input and output. Find it at
http://www.k5n.us/Ilib.php">k5n.us
. Netpbm also includes character drawing functions in the
libnetpbm(1) library, but they do not have as fancy
font capabilities (see ppmdraw(1) for an example of
use of the Netpbm character drawing functions). Pango and Cairo
complement each other and work well together. 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. Tools For
Specific Graphics Formats 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 pamtogif and
giftopnm to connect up to all the Netpbm utilities.
See
http://www.lcdf.org/gifsicle">http://www.lcdf.org/gifsicle
. To convert an
image of text to text (optical character recognition - OCR),
use gocr (think of it as an inverse of
pbmtext). See
http://jocr.sourceforge.net/">http://jocr.sourceforge.net/
. Other versions
of Netpbm’s pnmtopng/pngtopam are at
http://www.schaik.com/png/pnmtopng.html"; (1). 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">http://www.ijg.org) JPEG
library. Some tools to
deal with EXIF files (see also Netpbm’s
jpegtopnm(1) and pnmtojpeg(1)): To dump
(interpret) an EXIF header: Exifdump ((
http://www.math.u-psud.fr/~bousch/exifdump.py">http://www.math.u-psud.fr/~bousch/exifdump.py)
) or
http://www.sentex.net/~mwandel/jhead">Jhead
. A Python EXIF
library and dumper:
http://pyexif.sourceforge.net.">http://pyexif.sourceforge.net. Here’s
some software to work with IOCA (Image Object Content
Architecture):
http://www.forminnovation.com">ImageToolbox
(2500,ドル demo available). This can convert from TIFF ->
IOCA and back again. 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/projects/pnm2ppa">The
Pnm2ppa /Sourceforge Project DjVuLibre
is a package of software for using the DjVu format. It
includes viewers, browser plugins, decoders, simple
encoders, and utilities. The encoders and decoders can
convert between DjVu and PNM. See
http://djvu.sourceforge.net/"> the DjVu
website. Document/Graphics
Software First, we look
at where Netpbm meets document processing. pstopnm
converts from Postscript and PDF to PNM. It effectively
renders the document into images of printed pages.
pstopnm is nothing but a convenient wrapper for
http://www.ghostscript.com/">Ghostscript , and
in particular Netpbm-format device drivers that are part of
it. pnmtops and pbmtoepsi convert a PNM image
to a Postscript program for printing the image. But to
really use PDF and Postscript files, you generally need more
complex document processing software. Adobe invented
Postscript and PDF and products from Adobe are for many
purposes the quintessential Postscript and PDF tools. Adobe’s
free Acrobat Reader displays PDF and converts to Postscript.
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. "Distill" is a program
that converts Postscript to PDF. GSview,
ghostview, gv, ggv, and kghostview are some other viewers
for Postscript and PDF files. The program
ps2pdf, part of Ghostscript, converts from Postscript
to PDF. bmpp(1)
converts from Netpbm and other formats to PDF. Two packages
that produce more kinds of Encapsulated Postscript than the
Netpbm programs, including compressed kinds, are
bmpp(1) and
http://imgtops.sourceforge.net/">imgtops . dvips
converts from DVI format to Postscript. DVI is the format
that Tex produces. Netpbm can convert from Postscript to
PNM. Thus, you can use these in combination to work with
Tex/Latex documents graphically. 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
The Utah Raster
Toolkit from the Geometric Design And Computation group in
the Department of Computer Science at University of Utah
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. Ivtools
is a suite of free X Window System 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">http://www.ivtools.org
. Chisato
Yamauchi <cyamauch [AT] ir.jp> has written a free
c/Fortran graphic library:
http://www.ir.isas.jaxa.jp/~cyamauch/eggx_procall/">EGGX/ProCall
. He says he tried to write the ultimate easy-to-use graphic
kit for X. It is for drawing upon an X11 window, but for
storage, it outputs PPM. He suggests Netpbm to convert to
other formats. 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://xmorph.sourceforge.net/">http://xmorph.sourceforge.net/
. 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). Various
commercial Windows software handles dozens of formats that
Netpbm does not, especially formats typically used with
Windows programs. ImageMagick is probably the most used free
image format converter and it also handles lots of formats
Netpbm does not. • WebP was announced by Google in
October 2010 as a more compressed replacement for JFIF (aka
JPEG) on the web. • JPEG-LS is similar to JFIF (aka JPEG) except that it is
capable of representing all the information in any raster
image, so you could convert from, say, PNM, without losing
any information. CharLS is a programming library for
JPEG-LS. • Lossless JPEG is a similarly lossless variation of JPEG.
It predates every other lossless JPEG variation, but had
only brief interest. You can find code for encoding and
decoding Lossless JPEG on
https://github.com/thorfdbg/libjpeg">GitHub
. • JPEG XR offers greater dynamic range, a wider range of
colors, and more efficient compression than JFIF (aka JPEG).
Windows and Internet Explorer understand this format,
starting with Windows 7 and Internet Explorer 9, along with
many other programs. This format was previously known as
Windows Media Photo and HD Photo. • Direct Draw Surface (DDS)is the de facto standard
wrapper format for S3 texture compression, as used in all
modern realtime graphics applications. Besides Windows-based
tools, there is a Gimp plugin for this format. • DjVu is a web-centric format and software platform for
distributing documents and images. Promoters say it is a
good replacement for PDF, PS, TIFF, JFIF(JPEG), and GIF for
distributing scanned documents, digital documents, or
high-resolution pictures, because it downloads faster,
displays and renders faster, looks nicer on a screen, and
consumes less client resources than competing formats. For more
information, see http://djvu.sourceforge.net/"> the
DjVu website. • http://www.web3d.org/x3d/specifications/vrml">VRML
(Virtual Reality Modelling Language) • CALS (originated by US Department Of Defense, favored by
architects). It is described in this 1997 listing of
graphics formats:
http://www.faqs.org/faqs/graphics/fileformats-faq/part3/">
http://www.faqs.org/faqs/graphics/fileformats-faq/part3/
. CALS has at times been an abbreviation of various things,
all of which appear to be essentially the same format, but
possibly slightly different: • Computer Aided Logistics Support • Computer Aided Acquisition and Logistics Support • Continuous Acquisition and Life-cycle Support • Commerce At Light Speed The US Navy
publishes
https://www.navsea.navy.mil/Home/Warfare-Centers/NSWC-Carderock/Resources/Technical-Information-Systems/IETMs/Specifications-Standards/CALS-Standards/">specs
for it. • array formats dx, general,
netcdf, CDF, hdf, cm • CGM+ • HDR formats OpenEXR, SGI TIFF LogLuv, floating point
TIFF, Radiance RGBE • Windows Meta File (.WMF). Libwmf converts from WMF to
things like Latex, PDF, PNG. Some of these can be input to
Netpbm. • Microsoft Word .doc format. Microsoft keeps a
proprietary hold on this format. Any software you see that
can handle it is likely to cost money. • RTF • DXF (AutoCAD) • IOCA (Image Object Content Architecture) The
specification of this format is documented by IBM:
http://publibz.boulder.ibm.com/epubs/pdf/c3168055.pdf">
Data Stream and Object Architectures: Image Object Content
Ar- chitecture Reference . See above for software that
processes this format. • OpenEXR is an HDR format (like PFM(1)). See
http://www.openexr.com"> http://www.openexr.com
. • Xv Visual Schnauzer thumbnail image. This is a rather
antiquated format used by the Xv program. In Netpbm circles,
it is best known for the fact that it is very similar to
Netpbm formats and uses the same signature ("P7")
as PAM because it was developed as sort of a fork of the
Netpbm format specifications. • YUV 4:2:0, aka YUV 420, and the similar YUV 4:4:4, YUV
4:2:2, YUV 4:1:1, YUV 4:1:1s, and YUV 4:1:0. Video systems
often use this. • http://en.wikipedia.org/wiki/MJPEG">MJPEG
movie format. • YUV4MPEG2 is a movie format whose purpose is similar to
that of the Netpbm formats for still images. You use it for
manipulating movies, but not for storing or transmitting
them. The only known use of the format is with
http://mjpeg.sourceforge.net">MJPEGTools
. The programs pnmtoy4m and y4mtopnm (and
predecessors ppmtoy4m and y4mtoppm) in that
package convert between a Netpbm stream and a YUV4MPEG2
stream. As you might guess from the name, YUV4MPEG2 uses a
YUV representation of data, which is more convenient than
the Netpbm formats’ RGB representation for working
with data that is ultimately MPEG2. Netpbm has a
long history, starting with Jef Poskanzer’s Pbmplus
package in 1988. See the Netpbm web site(1) for
details. The file
doc/HISTORY in the Netpbm source code contains a
detailed change 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. This manual
page was generated by the Netpbm tool ’makeman’
from HTML source. The master documentation is at
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.
for i in *.png; do pngtopam $i | ppmtojpeg
>’basename $i .png’.jpg; done
| perl -ne ’chomp;
print yuvtoppm $_ | pambrighten -value +100 | ppmtoyuv
>tmp$$.yuv;
mv tmp$$.yuv $_
’
| sh
printcmyk <({ pngtopam abc.png | pnmtotiffcmyk ; })The Netpbm Formats
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.
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.The Netpbm Library
netpbm-config
$netpbm-config --datadir
/usr/local/netpbm/dataMemory Usage
CPU Usage
Netpbm For Gimp
Companion Software
If you’re using Netpbm to do graphics for a website,
you can invoke the Netpbm programs from a PHP script. To
make this even easier, check out
http://sourceforge.net/projects/phpnetpbm">PHP-NetPBM
, a PHP class that interacts with Netpbm. Its main goal is
to decrease the pain of using Netpbm when working with
images in various formats. It includes macro commands to
perform manipulations on many files.Other Graphics Software
ImageMagick does many of the same things - mainly the
more popular ones - that Netpbm does, including conversion
between popular formats and basic editing. convert,
mogrify, montage, and animate are
popular programs from the ImageMagick package.
ImageMagick runs on Unix, Windows, Windows NT,
Macintosh, and VMS.
The first thing you will want to make use of any of these
tools is a viewer. (On GNU/Linux, you can use Netpbm’s
pamx or 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">ftp://ftp.ibiblio.org/pub/Linux/apps/graphics/viewers/svga
.
xwd (X Window Dump), a classic application program in
the X Window System, captures the contents of an X window,
in its own special image format, called X Window Dump File.
You can use Netpbm’s xwdtopnm(1) to turn it
into something more useful.
http://www.rcdrummond.net/fbdump/">fbdump
Capturers the current contents of a video display on the
local computer and generates a PPM image of it. It works
with Linux framebuffer devices.
Visual graphics software is modern point-and-click software
that displays an image and lets you work on it and see the
results as you go. This is fundamentally different from what
Netpbm programs do.
If you’re writing a program in C to draw and
manipulate images, check out
https://github.com/libgd/libgd">gd . Netpbm
contains a C library for drawing images
(libnetpbm’s "ppmd" routines), but it
is not as capable or documented as gd. There are
wrapper libraries available for Perl, PHP, and other
language.
http://cairographics.org/">Cairo is
similar.
http://www.pango.org/">Pango is another text
rendering library, with an emphasis on
internationalization.
mencode, which is part of the mplayer(1) package,
creates movie files. It’s like a much more advanced
version of ppmtompeg(1), without the Netpbm building
block simplicity.
http://mjpeg.sourceforge.net">MJPEGTools
is software for dealing with the MJPEG movie format.
http://schaik.com/pngsuite">http://schaik.com/pngsuite
contains a PNG test suite -- a whole bunch of PNG images
exploiting the various features of the PNG format.
http://pngwriter.sourceforge.net">pngwriter
is a C++ library for creating PNG images. With it, you plot
an image pixel by pixel. You can also render text with the
FreeType2 library.
https://ameri-imager.software.informer.com/">Ameri-Imager
is an image and video editor. (40ドル Windows only).
There is a large class of software that does document
processing, and that is somewhat related to graphics because
documents contain graphics and a page of a document is for
many purposes a graphic image. Because of this slight
intersection with graphics, I cover document processing
software here briefly, but it is for the most part beyond
the scope of this document.
http://www.foolabs.com/xpdf/">xpdf also
reads PDF files.
http://wvware.sourceforge.net">wvware
converts a Microsoft Word document (.doc file) to various
other formats. While the web page doesn’t seem to
mention it, it reportedly can extract an embedded image in a
Word document as a PNG.
http://www.verypdf.com/artprint">Document
Printer converts various print document formats
(Microsoft Word, PDF, HTML, etc.) to various graphic image
formats. (38,ドル 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(1) program
depends on file. See
ftp://ftp.astron.com/pub/file">ftp://ftp.astron.com/pub/file
.Other Graphics Formats
History
Author
DOCUMENT SOURCE