plotutils-graph-patches-lloda

This is release 2.6 of the GNU plotutils (plotting utilities) package,
including release 4.4 of GNU libplot: a thread-safe function library for
exporting two-dimensional vector graphics files, and for displaying
animated vector graphics under the X Window System. The Web page for the
package is http://www.gnu.org/software/plotutils/plotutils.html .

In the top-level source directory, the file INSTALL contains generic
instructions for installing a GNU package, and the file INSTALL.pkg
contains package-specific instructions. Please read them _in full_,
as well as this file, before attempting to install the package.

Also in the top-level source directory, the file COMPAT contains release
notes, and comments on compatibility with previous versions. The file
PROBLEMS is worth looking at too.

Please send bug reports to , and suggestions for
longer-range improvements to both and the principal
author and current maintainer, Robert Maier .

NOTE: Neither the `pic2plot' program nor the `libplotter' C++ class library
is built by default, since they require a working C++ compiler. But it is
easy to request that they be built. For details, see INSTALL.pkg. Also, a
standalone version of the `libxmi' scan-conversion library isn't built by
default, since `libxmi' is distributed as a separate package.

----------------------------------------------------------------------

The contents of the plotutils package are:

1. libplot. This is the function library for device-independent
two-dimensional vector graphics that the sample
command-line programs `graph', `plot', `pic2plot',
`tek2plot', and `plotfont' (see below) are based on.
On platforms that support shared libraries, it is
installed as a shared library.

If you are a programmer, you may use this library yourself,
to export vector graphics in many different file formats.
You may also use it to create vector graphics animations
under the X Window System.

There are two versions of libplot: a conventional library
of C functions, which is also referred to as libplot, and
its C++ counterpart `libplotter', which is a class library.
The latter is more convenient to use if you are programming
in C++. You must request at installation time that
`libplotter' be built and installed, since it is not done
automatically. (See ./INSTALL.pkg.) When we refer to
`libplot', by default we mean both the C and the C++ versions.

libplot includes functions to draw objects of many types:
lines and polylines, circles and ellipses, circular and
elliptic arcs, quadratic and cubic Bezier curves, and
marker symbols. Postscript-style `paths', made up of many
segments, may be drawn. There is support for color (both
pen color and fill color for objects).

Output formats include X11, PNG, PNM (i.e. PBM/PGM/PPM),
pseudo-GIF, SVG, Adobe Illustrator, Postscript and
Encapsulated Postscript (editable with the idraw drawing
editor), CGM (by default, binary version-3 CGM output that
complies with the WebCGM profile for Web-based vector
graphics), Fig (editable with the xfig drawing editor), PCL
5, HP-GL and HP-GL/2, Regis, Tektronix, and GNU metafile
format. GNU metafile format may be translated into any of
the other formats with the `plot' utility (see below).

NOTE: pseudo-GIF format is not the same as GIF format,
since it does not use the LZW coding scheme. So it does
not transgress the well known Unisys LZW patent. However,
applications that can read GIF files should be able to read
pseudo-GIF files. libplot can also create animated
pseudo-GIFs.

libplot includes extensive support for accurate sizing and
positioning of text. This includes the placement of
subscripts and superscripts. Its X11, SVG, Illustrator,
Postscript, CGM, and Fig drivers all support the 35
standard Postscript fonts, and its PCL 5 and HP-GL/2
drivers support the 45 standard LaserJet fonts. In
addition, all of these, together with the other (bitmap)
drivers, support a set of 22 Hershey vector fonts. The
Hershey fonts include HersheyCyrillic and HersheyEUC (for
Japanese). Note that the Hershey fonts are not
anti-aliased, so they will look much better in vector
output, than in bitmap output.

All supported fonts may be arbitrarily rotated and scaled.
All fonts, except for symbol and dingbat fonts, and the
Hershey Cyrillic and Japanese fonts, use the ISO-Latin-1
encoding (a superset of ASCII; the ISO-Latin-1 support in
the 20 non-Cyrillic, non-Japanese Hershey fonts is
extensive but not quite complete).

(Clones of the 35 standard Postscript fonts, in Type 1
format, have been contributed by URW GmbH for distribution
under the GNU General Public License. They may well be
available on your system, already. If not, you may use the
versions distributed with this package. Installation
instructions are in the file ./INSTALL.fonts. Instructions
for obtaining and installing Type 1 versions of the 45
standard LaserJet fonts are included as well.)

Similarly to Postscript, libplot has the nice feature that
user coordinates (in terms of which you express the
location of graphical objects) may be transformed to device
coordinates by an arbitrary affine transformation. A stack
of drawing states (i.e., graphics contexts) is supported too.

2. libxmi. This is a function library for drawing X11-style vector
graphics (lines, polylines, polygons, circular and elliptic
arcs) on an in-memory bitmap. It is small, but powerful:
it contains a modernized version of the scan conversion
code contained in most X11 servers, which was written in
the mid-to-late 1980's by programmers associated with the
X Consortium. It is built and installed only if you specify
the `--enable-libxmi' option to ./configure. The public
header file for libxmi, xmi.h, will also be installed, as
will the documentation (in texinfo format).

The reason `libxmi' isn't built by default is that it's
also distributed as a separate package. Actually, what
isn't built by default is a standalone version of libxmi.
libplot/libplotter always contains an internal libxmi
module, which helps it produce output in bitmap formats.

3. Sample command-line programs based on libplot, including the following.

graph. A full-featured scientific plotting program for plotting
XY (i.e. 2-dimensional) data. It plots a stream of
datapoints, in real time if possible. There is a
well-chosen set of command-line options for adjusting the
visual appearance of the plot, labelling axes (with
expressions that may include subscripts and superscripts,
and mathematical symbols), choosing marker symbols from
various fonts, etc. Multiplotting is supported (a plot may
include sub-plots, side-by-side or inset). Filled regions
are also supported.

Unlike the well-known plotting program `gnuplot', `graph'
is device-independent in the sense that its options do not
depend on the display device the plot is destined for.
To the maximum degree feasible, the output of `graph' will
appear the same on all display devices.

Which display device is driven, or output format is
produced, is specified by the `-T' option. There are
effectively many different variants of `graph',
distinguished by the intended display device.

graph -T X A variant that pops up an X window on an X
display, and draws the plot in it. It is
most useful on modern (X11R6) displays,
which can rotate and scale text
arbitrarily. It uses the 35 standard
Postscript fonts.

graph -T png A variant that produces output in PNG
(Portable Network Graphics) format. Output
in this format can be viewed with the free
image display application `xv'.

graph -T pnm A variant that produces output in
`Portable Anymap' format (PBM/PGM/PPM,
whichever is appropriate). Output
in this format can be viewed with `xv',
or translated to other formats with the
`netpbm' package.

graph -T gif A variant that produces output in a
pseudo-GIF format that can be displayed
by many applications that understand
GIF format. The pseudo-GIF format uses
run-length encoding, so it does not
transgress the well known Unisys LZW
patent.

graph -T svg A variant that produces output in SVG
(scalable vector graphics) format. SVG is
the XML-based graphics format that
has been endorsed by the W3 Consortium
for Web use. See
http://www.w3.org/Graphics .
For comments on compatibility with other
software that can edit or display
SVG files, see the file ./COMPAT.

graph -T ai A variant that produces output in a
format that can be viewed or edited
with Adobe Illustrator.

graph -T ps A variant that produces EPS (encapsulated
Postscript) output, which can be printed,
displayed, or encapsulated in other
documents. Any standard page size is
supported (letter, legal, ANSI sizes, ISO
sizes such as a4 and a3, etc.) The EPS
output includes annotations that permit it
to be edited with the freeware `idraw'
drawing editor, or its successor
`drawtool'. See http://www.vectaport.com .

graph -T cgm A variant that produces CGM vector graphics
files (Computer Graphics Metafiles, as
defined by ISO 8632:1992). By default, its
output files are binary version-3 CGM files
that conform to the WebCGM profile for
Web-based vector graphics (for WebCGM info,
see http://www.cgmopen.org/ ).

graph -T fig A variant that produces a plot that
the freeware `xfig' drawing editor can
edit. xfig can export the plot in numerous
formats, such as GIF, X11 bitmap, and EPS.
See http://duke.usask.ca/~macphed/soft/fig .

graph -T pcl A variant that produces a plot in PCL 5
format, which is a sophisticated version of
Hewlett-Packard's Printer Control Language.
You may send the plot to a non-Postscript
LaserJet or a high-end inkjet. (Most
inkjets do not support PCL 5.) This
variant supports the 45 standard PCL 5
fonts that are built into many
non-Postscript printers, such as LaserJets.

graph -T hpgl A variant that produces HP-GL (or by
default, HP-GL/2) output. HP-GL is the
Hewlett-Packard Graphics Language, and may
be printed out or plotted on a
Hewlett-Packard LaserJet printer or
plotter. Also many applications, e.g. CAD
applications, can import HP-GL or HP-GL/2
figures. This variant supports the 45
standard PCL 5 fonts that are built into
many non-Postscript printers, such as
LaserJets.

graph -T regis A variant that produces ReGIS graphics
output, suitable for viewing on a
DECwindows dxterm or a DEC graphics
terminal, such as a VT340, VT330, VT241, or
VT240. (This variant lacks the Postscript
fonts of the other variants though, like
them, it has a complete set of vector
Hershey fonts.)

graph -T tek A variant that produces Tektronix output,
suitable for viewing, e.g., on an X Windows
xterm or an MS-DOS kermit doing Tektronix
emulation. (This variant lacks the
Postscript fonts of the other variants
though, like them, it has a complete set of
vector Hershey fonts. Also, it does not
support filling of regions.)

graph The `raw' variant, which produces output in
GNU graphics metafile format. This is an
enhanced version of the traditional plot(5)
format found on some operating systems.
The `plot' program (see below) must be used
to convert this to another format, or to
drive a display device.

Of these variants, `graph -T X', `graph -T tek', and raw
`graph' are real-time. That means that under some
circumstances, they act as filters: they read data points
from standard input, and plot them as they are read. For
this to happen, the abscissa and ordinate ranges of the
plot must be specified on the command line. (E.g., the
user would do

program | graph -T X -x xmin xmax -y ymin ymax

where `program' generates a stream of data points.)

All variants of `graph' will accept ASCII input (the
default), or unformatted binary input (i.e., a stream of
floating point numbers or integers), or input in the
`table' format produced by the program `gnuplot' (which you
may select by specifying the `-I g' option). Gnuplot will
produce table-format output if you do `set terminal table';
you can pipe gnuplot's output to any of the variants of
graph by using the gnuplot `set output' command. If you
are piping to `graph -T X', by repeatedly using the gnuplot
`set output' command you may easily produce an arbitrarily
large number of plots in different X windows, each in a
different style.

plot. This is a so-called plot filter, which takes a stream in GNU
graphics metafile format, and either translates it to
another format or uses it to drive a display device.

Since this distribution includes `graph -T X', `graph -T
png', `graph -T pnm', `graph -T gif', `graph -T svg',
`graph -T ai', `graph -T ps', `graph -T cgm', `graph -T
fig', `graph -T pcl', `graph -T hpgl', `graph -T regis',
and `graph -T tek', all of which can drive display devices
directly, `plot' is only occasionally useful. It may be
used, though, to produce graphical output in more than one
format at once. To do this, you would pipe the output of a
datapoint-generating program to the raw variant of `graph',
and then use the `tee' command to direct the output of raw
`graph', which is in metafile format, to two separate
invocations of `plot'.

`plot' may also be useful as a post-processor for older
programs that produce output in the traditional plot(5)
graphics format. GNU metafile format is an enhanced version
of plot(5) format.

pic2plot. This is a utility program that takes a file in the pic
language, and either translates it to another format or
displays it on an X display. The pic language, which was
developed at Bell Laboratories, is used for creating
box-and-arrow diagrams of the kind frequently found in
technical papers and textbooks. It was originally
introduced as a feature of the Bell Labs `troff'
text-processing software.

You must request at installation time that pic2plot be
built and installed, since it is not done automatically.
(See ./INSTALL.pkg.)

pic2plot is largely compatible with `gpic', the GNU
implementation of the pic-to-troff translator. However,
since it is built on top of libplot, it supports some new
features. It supports all the output formats that libplot
supports: X11, PNG, PNM, GIF, SVG, AI, PS, WebCGM, Fig,
PCL, HP-GL, Tek, and Metafile.

tek2plot. This is a utility program that emulates a Tektronix 4014
terminal in the sense that it reads a stream of Tektronix
commands, and either produces an output file in another
format or displays the corresponding graphics on an X
display. An output file in any of the graphics file
formats that libplot support can be produced.

tek2plot is useful if you have a legacy program that was
designed to drive a Tektronix terminal or emulator, or if
you have files in Tektronix format that need to be
translated to a modern format, or edited.

The directory ./tek2plot/teksamples includes a few files in
Tektronix format that you may experiment with. You may
also experiment by piping the output of `gnuplot', if you
have configured it to produce Tektronix-format plots, to
these filters (the gnuplot terminal types `kc_tek40xx',
`km_tek40xx', `tek40xx', and `vttek' all work). tek2plot
does an excellent job of emulating the non-interactive
features of a Tektronix 4014, and although it does not
support all the features supported by the Tektronix
emulator in the MS-DOS version of kermit, it can certainly
parse the output of the gnuplot Tektronix terminal drivers.

plotfont. This is a simple utility that prints out a character
chart for any font available to the above four utilities
(graph, plot, pic2plot, tek2plot) and the underlying
libplot library. All output formats are supported. Which
fonts are available depends on the `-T' option that is
specified, i.e., on the output format.

hersheydemo. This is a demo program for the Hershey vector fonts,
as implemented in the libplot library. It outputs a demo
page, designed by Dr. Hershey himself. The page is taken
from his 1972 article "A computer system for scientific
typography", published in Computer Graphics and Image
Processing (vol. 1, no. 4, pp. 373-385).

Note that the Hershey vector fonts look much better in
vector output formats, than they do in bitmap formats.
That is because libplot does not currently do anti-aliasing
of fonts (or more accurately the libxmi rasterization
library, which it relies on, does not). You would do
`hersheydemo -T ps > demo.ps' to produce PS output,
`hersheydemo -T svg > demo.svg' to produce SVG output, etc.

4. Command-line mathematical programs not based on libplot, including the
following.

spline. This program does spline interpolation of input data, which
may be of arbitrary dimensionality. That is, it takes a
file of datapoints, and interpolates between them to
produce an interpolated segment of the input data. It acts
as a filter, though usually not as a real-time one (in the
most common mode of operation, the entire input must be
read before any data points are output).

The output spline is normally a cubic spline, but if a
`tension' parameter is set to a nonzero value, the output
spline will be a so-called spline under tension. There is
also support for doing cubic Bessel interpolation. If this
option is selected, `spline' acts as a true real-time
filter, since cubic Bessel interpolation is local rather
than global.

ode. This interactive program supplements the computation engine
of `gnuplot', which will compute and plot functions, by
providing the ability to integrate systems of ordinary
differential equations (ODE's). ode will solve the initial
value problem for one or more first-order ODE's, when
provided with an explicit expression for each equation.
ode parses the set of equations and the set of initial
conditions, which may be typed in manually or read from a
file, and then produces a stream of data points that may be
piped to any of the variants of `graph'. If a real-time
variant of `graph' (e.g. `graph -T X' or `graph -T tek') is
used, the numerical solution will be displayed in real
time, as it is generated.

One application (certainly not the only one!) of ode is to
graph the indefinite integrals of the sorts of function
that gnuplot can graph. All the primitive real-valued
functions that are built into gnuplot are built into ode.

A directory of sample ode input files is installed (usually
as /usr/local/share/ode or /usr/share/ode) as part of the
package.

double. This is a filter for converting, scaling and cutting
unformatted (binary) or ASCII data streams. It is still
under development and is not yet documented.