plotutils
Package
The GNU plotutils
package contains software
for both programmers and technical users. Its centerpiece is
libplot
, a powerful C/C++ function library for
exporting 2-D vector graphics in many file formats, both
vector and raster. It can also do vector graphics
animations.
libplot
is device-independent in the sense
that its API (application programming interface) does not depend
on the type of graphics file to be exported.
Besides libplot
, the package contains
command-line programs for plotting scientific data. Many of
them use libplot
to export graphics.
The current version is 2.4.1, released July 2000. It can be installed on GNU/Linux, FreeBSD, and Unix systems.
libplot
, and applications built on it, can
now export graphics files in SVG format. SVG
(Scalable Vector Graphics) is a new, XML-based format for Web
graphics, which is being standardized by the Graphics Activity of the
W3 Consortium.
The libplot
API has been extended to support the
drawing of Postscript-style compound paths.
The plotutils
package comes with a 175-page manual.
Here is an older
version of the manual.
The package is free software. Its source code is distributed as a gzipped tar file, 3.3 megabytes in size. Here is how you can get it.
It includes
graph
, which plots 2-D datasets or data
streams in real time. Being designed for command-line use, it
can be used in shell scripts. It produces output on an
X Window System display, in SVG format, in PNG format, in PNM
format, in pseudo-GIF format, in WebCGM format, in Illustrator
format, in Postscript format, in PCL 5 format, in
HP-GL/2 format, in Fig format
(editable with the xfig
drawing editor), in ReGIS format, in Tektronix format, or in
GNU Metafile format. Output in Postscript format may be
edited with the idraw
drawing editor.
idraw
is available in the ivtools
package from Vectaport, Inc. Both xfig
and
idraw
are free software.
plot
, which translates GNU Metafile format to
any of the other formats.
tek2plot
, for translating legacy Tektronix
data to any of the above formats.
pic2plot
, for translating the
pic
language (a scripting language for
designing box-and-arrow diagrams) to any of the above formats.
The pic
language was designed at Bell
Laboratories as an add-on to the troff
text
formatter.
plotfont
, for displaying
character maps of the fonts that are available in the above
formats.
spline
, which does spline interpolation of
data. It normally uses either cubic spline interpolation
or exponential splines in tension, but it can function as a
real-time filter under some circumstances.
ode
, which numerically integrates a system
consisting of one or more ordinary differential equations.
We developed these command-line programs to replace the Unix
command-line programs graph
, plot
, and
spline
. The GNU versions are far more powerful,
and are free software.
GNU libplot
, a C/C++ function library for
device-independent 2-D vector graphics. GNU
libplot
is compatible with the traditional Unix
libplot
library, but is far more powerful.
It is installed as part of the package. On systems
that support shared libraries, it is installed as a shared
library. A C++ class library called
libplotter
, which provides an object-oriented
interface to libplot
's functionality, is optionally
installed as well.
GNU libplot
and libplotter
support all
the output formats mentioned above (X11, SVG, PNG, PNM, pseudo-GIF,
WebCGM, Illustrator
format, idraw
-editable Postscript, PCL 5,
Fig
format, HP-GL/2, ReGIS, Tektronix, and GNU Metafile).
They can produce animated pseudo-GIFs, and smooth,
double-buffered animations on any X Window System display.
The libplot
imaging model is similar to
Postscript's. In any output format, they can draw the
following.
xfig
drivers support
the 35 standard Postscript fonts, and the SVG, Illustrator,
PCL 5 and HP-GL/2 drivers support the 45 standard
PCL 5 fonts. All drivers support a set of
22 Hershey vector fonts. This includes HersheyCyrillic,
a Russian font that uses the KOI8-R
encoding, and HersheyEUC, a Japanese font that uses the
8-bit EUC-JP encoding. Japanese text strings may include both
syllabic characters (Hiragana and Katakana) and ideographic
characters (Kanji). A library of over 600 Kanji is
built in.
When using libplot
or libplotter
, a
programmer draws vector graphics in a `user frame', rather than
in the device frame. As in Postscript, the user frame may be
transformed into the device frame by an arbitrary affine map.
Scaling, rotation, shearing, and translation are all
supported.
Even though the plotutils
package can produce what
appear to be GIFs and animated GIFs, it does not transgress the
patents covering the LZW compression algorithm. The reason is
that instead of LZW encoding, it uses run-length encoding, which
is not patentable. To avoid confusion, we call the files
produced by the package `pseudo-GIF files'.
A simple piechart plotting program that illustrates the use of
GNU libplot
is available here.
It was contributed by Bernhard
Reiter. Chris
Elliott has developed a libplot
-based program
called ascii_chart
,
which takes data in a two-column format and prepares a piechart
plot or a line plot. Jam
Marukawa has written a shell script that allows GNU
graph
to produce bar graphs. It is available on his freeware
page.
Also, Juergen
Pfeifer has developed an Ada95 binding for
libplot
. Mike
Miller has developed a SWIG wrapper for
libplot
, which lets libplot
functions
be called from Python. It is available here.
A separate Python wrapper, developed by Mike Nolta, is here. Recently, Piotr Klaban has
developed a Perl
module for libplot
.
plotutils
package?
The two primary authors of the plotutils
package
are Robert Maier
and Nick Tufillaro
(who developed ode
). Many other people
contributed, however. The rasterization code used by the export
filters, which is distributed as a separate package,
is based on the scan-conversion code in the sample X Window
System server.
Visit the Free Software Directory's Science section for more utilities and related software.
Return to the GNU Project home page.
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Updated: $Date: 2004/07/28 13:19:39 $ $Author: derekgnu $