plotutils

esp32: This library will use PSRAM if you have it. Otherwise, you will probably not be able to work with images larger than ~140x140

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 bug-plotutils@gnu.org, and suggestions for longer-range improvements to both bug-plotutils@gnu.org and the principal author and current maintainer, Robert Maier rsm@math.arizona.edu.

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.

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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.