Comparatively minor things, for Versions 2.x
--------------------------------------------

graph: need better clipping for filled regions (present gnuplot-style
clipping scheme is right for unfilled regions but wrong for filled ones)

graph parsing: allow all command-line options in data files, on comment lines

graph: add legend support (need new --legend :string1:string2: option),
i.e. gnuplot-style `key'.  Maybe arbitrarily positioned arrows, text
strings also

old HP-GL plotters can't handle full range of coordinates (AutoCAD values
for range may not be good)

libplot: report failure-to-retrieve font (e.g. anamorphic problem) better.
Maybe print anamorphic message only when alabel() is called?

Also improve libplot error reporting: change libplot error handler to use
name of executable

libplot: redo X driver, to support window reuse (`persistence') by any
X Plotter.  Will require forking off an outboard process.

graph: new option to put frame on top of plot, not vice versa
maybe automatic, if `plotting is real time' capability is set?

spline, double: should ignore comment lines in ascii input (cf. graph)

graph: fix positioning of top labels, especially at large sizes

HP-GL/2 stick font size should be reduced?

Add comment() function, takes printable string as arg (no control chars)

PCL fonts for libplot: keep trying to track down slight differences between
HP-GL/2's font sizes and font sizes as specifed in the .AFM files
accompanying the Microsoft HP Font Set.

alabel, labelwidth: should not use clean_iso_string for Wingdings?

libplot: In X driver, need sanity check on font size: should switch to a
Hershey font if requested font is larger than display size.

ode: need no stack blowout

libplot: make meaning of "dotted", "dotdashed" etc. line types fully
device-independent

Internationalization: think about removing strcasecmp (what if user called
setlocale i.e. set LOCALE env var)?  Similarly worry about . vs ,
everywhere, e.g. in PS files.

libplot: add a command to set miter limit for line joins, to the API

Hershey fonts:
1. add cedilla; also embolden `times', > , < , etc.
2. Add support for Hershey indexical positioning on baseline?
3. Invert `glaze' glyph for EUC, also `therefore'

polyline hatching as well as filling

check into test/plot2tek.test (not currently run, seems to give
system-dependent behavior depending on rounding mode?)

======================================================================

Major Enhancements (Possible, Probable, or Certain)
---------------------------------------------------

C++ binding for libplot

graph: librarify the plotting routines, and incorporate them in libplot.

libplot: Incorporate all functionality of VOGLE, PGPLOT, and PLPLOT
libraries.  Think about Guile, and Tcl/Tk, and Python.

libplot: Support Adobe Illustrator format (-T ai).

graph: Write alternative parser for interactive version (gnuplot replacement).

libplot: add support for compound objects, spline objects, raster objects

libplot: Clipping and the setting of a viewport, double buffering to support animation.

Need interactivity (e.g. getloc()), during openpl()...closepl().  For
libplot Tektronix, implement GIN mode (need stty twiddling?).  Also need
char input (cf. starbase).

libplot: write a version producing a bitmap format (e.g. PBM); use new
freeware rasterizer for type 1 fonts

libplot: add the display list concept (would facilitate addition of
compound objects).  Once display list is there, support zooming in libplot
X driver [PS output via buttons?].  Add a `close window' button instead of
closing by a single mouse click.

libplot text string format: \mk..\rt etc. should be stack machine; include
overline, underline, radical etc.  Cf. Alan Hershey's typesetting.

Break out spline() as subroutine(s), cf. fitpack?  Similarly with plot
frame / axis drawing.  For this, check into NCAR Graphics package,
`autograph' routines; need contouring routines or app also (use plplot for
this)

libplot: spline the Hershey fonts

ode: extend parser to plot functions as well as solve differential equations

ode: need popen() for output; cf. gnuplot

graph: add `boxes', `steps', `impulses', `bars' plot types (as in gnuplot).
Boxes, bars should properly support --fill-fraction option.

Write a sort of pic2plot.c, which could be linked with libplot to yield
pic2fig, pic2ps, pic2X, etc.

Private colormap for libplot X driver?

graph: add support for polar/spherical plots, 3-D (surface) plotting

spline: add support for smoothing splines as well as interpolatory splines?

Other needed math software:

	fitting capability
	contour plotting via level curves; also compute enclosed area
	surface plotting	(cf. IDL for plotting and contouring)
