Version 2.4.1 released, 7/2000.  [Includes libplot 4.1, interface age=2.]

graph,plot,tek2plot,plotfont,pic2plot: `--page-size' option and PAGESIZE
	 environment variable now allow precise specification of viewport
	 size and location on the printed page.  For example,
	 `--page-size=letter,xsize=5in,ysize=3in,xorigin=1in,yorigin=2in'
	 is now a possible command-line option.  The traditional `xoffset'
	 and `yoffset' fields are still supported.
libplot: PAGESIZE parameter extended, to allow precise specification of
	 viewport size and location on the printed page (see item above).
libplot: bug dealing with filling of paths formed from segments of multiple
	 types now fixed.  It affected CGM and possibly other output
	 formats.  (CGM version number was affected: it could be too high.)
pic2plot: pic parser extended to support a new command, srand(), which sets
	 the seed for the random number generator that rand() invokes.
	 This is for compatibility for GNU pic, which (as distributed in
	 the recently released groff-1.16) now supports srand().
libplot: a bug in xfig is now worked around.  When producing Fig output,
	 any text string consisting of a single space, which is rotated at
	 a nonzero angle, is no longer written to the output file.  As of
	 xfig-3.2.2, xfig crashes when it sees such strings.
installation: `configure' now supports `--with-athena=DIR' and
	 `--with-motif=DIR' options, to allow specification of location of
	 Athena and Motif files.  Also, `--with-xpm=DIR' is now supported,
	 since some versions of Motif require linking with libXpm, and the
	 libXpm may be located in an odd place.  (Thanks, Albert Chin.)
pic2plot: distributed `gram.c' file is now prepared with bison-1.28, so it
	 should compile under Solaris 2.7.  (Thanks, Albert Chin.)
	 
Version 2.4 released, 6/2000.  [Includes libplot 4.0, interface age=2.]

libplot: libxmi rendering module (used by GIF/PNM/PNG drivers) has been
	 upgraded from version 1.1.1 to 1.2.  This fixed an obscure bug
	 that appeared when regions of one color were completely covered by
	 regions of another color.  The bug caused both memory allocation
	 failures and segfaulting.
libplot: library now contains a version string, `pl_libplot_ver'.  The
         plot.h and plotter.h header files now contain both the version
	 string and a numeric variant of it, as macros.  Cf. libpng.
libplot: rendering of color on truecolor X displays has been speeded up.
	 Pixel value computations are now performed in libplot, not in the
	 X display.  Useful Plotter parameter XDRAWABLE_VISUAL added.
graph,plot,tek2plot,plotfont,pic2plot: `-T svg --bg-color none' and `-T cgm
	 --bg-color none' now supported (see below).
libplot: SVG and CGM Plotters now support a background color of "none", to
	 turn off the background.  This is useful when generated graphics
	 files that will be placed in Web pages, especially.
graph,plot,tek2plot,plotfont,pic2plot: `-T svg' now allowed.
libplot: SVG driver added, which outputs the new XML-based SVG (scalable
	 vector graphics) format.
graph,plot,tek2plot,plotfont,pic2plot: all color names, when supplied as
	 command-line arguments, may now be specified as 24-bit RGB
	 strings, e.g., '#ffffff'.
libplot: pencolorname(), fillcolorname(), and bgcolorname() now allow
	 colors to be specified as 24-bit RGB strings, e.g., '#ffffff'.
libplot: space() operation, or equivalent, no longer needs to be invoked at
	 the beginning of each page of graphics to set the user coordinate
	 system.  Default coordinate system assigns coordinates (0,0),
	 (1,0), (1,1), (0,1) to the corners of the graphics display.
libplot: fontsize() operation now accepts an argument of zero, though the
	 meaning of `font size 0' is Plotter-dependent.  Few Plotters can
	 draw strings with zero font size; in non-Hershey fonts, anyway.
libplot: Tektronix driver now analyses the environment variable TERM more
	 carefully.  Any string beginning with "xterm", "nxterm", or
	 "kterm" is treated as as equivalent to "xterm", for example.
documentation: man page for plotfont added.
libplot: completely new metafile export driver, written from scratch.
libplot: filled marker symbols were sometimes drawn incorrectly.  Fixed.
ode: distributed `gram.c' file is now prepared with bison-1.28, so it
	 should now compile under Solaris 2.7.  (Thanks, Albert Chin.)
libplot: alabel() function now accepts a `C' positioning option, which
	 aligns a label's cap line with the current vertical position.
libplot: escape sequences "\r^" and "\l^" in labels, which shift right and
	 left by 1/12 em, respectively, weren't working if the current font
	 was a Hershey font.  Fixed.
libplot: new function, fsetmatrix(), added to the API.  It sets the
	 transformation matrix from user coordinates to normalized device
	 coordinates.  In NDC coordinates, the graphics display,
	 i.e. viewport, has corners (0,0), (1,0), (1,1), (0,1).
libplot: bug in drawing of rectangles by X driver, when ROTATION parameter
	 is set, now fixed.  (It affected `graph -TX --rotation=90'.)
graph,plot,tek2plot,plotfont,pic2plot: `-T regis' now allowed.
libplot: ReGIS driver added, which outputs ReGIS (DEC's remote graphics
	 instruction set, understood by DEC's VT340 and earlier terminals,
	 and also emulators like DEC's decterm).  No support yet for filling
	 paths that extend beyond the boundaries of a ReGIS display, due to
	 a need for clipping code.
libplot: flattening of Beziers into polylines, in output formats that don't
	 provide native support for Beziers, now much improved.  An
	 adaptive scheme now handles unusually `bent' sections of a Bezier.
libplot: when producing PCL 5 output, ellipses and elliptic arcs are now
	 approximated by cubic Beziers.  When producing Illustrator output,
	 circular arcs are now approximated by them, too.
libplot: bugs in rendering of elliptic arcs, ellipses, and circles, in
	 Illustrator output format, now fixed.  The bugs were due to an
	 incorrect approximation of these primitives by cubic Beziers.
libplot: in GIF, PNM, and PNG output, arcs (circular and elliptic), circles
	 and ellipses are now drawn using libxmi scan-conversion, rather
	 than being polygonalized, and drawn by libxmi as polylines.
libplot: PCL5 driver now uses the HP-GL/2 `SV' and `CF' instructions to do
	 a better job of matching user-specified pen colors.  It can now
	 employ shaded (desaturated) versions of the defined pen colors, as
	 well as the defined colors themselves.  Of course, only PCL5
	 printers that support dynamic pen color assignment (which you must
	 request via the `PCL_ASSIGN_COLORS' option) do a perfect job of
	 matching user-specified pen colors.  Many monochrome PCL5 printers
	 map all 7 standard PCL5 (i.e. HP-GL/2) pen colors to `black'.
graph,plot,tek2plot,plotfont,pic2plot: `-T png' now allowed if libplot
	 contains a PNG driver.
libplot: PNG driver added, which outputs PNG (portable network graphics)
	 format.  Included only if libpng (version number >= 0.95) and libz
	 are found at package installation time.  `configure' now supports
	 a `--without-libpng' option to disable PNG support.
pic2plot: if the `-d' option is used to request precision dotting or
	 dashing, filled rounded boxes with a dotted or dashed boundary are
	 no longer displayed with an unwanted solid edge.
libplot: marker symbols are now always drawn with pentype `1', fixing
	 a bug that appeared when pentype was manually set to `0'.
graph,plot,tek2plot,plotfont,pic2plot: `--emulate-color yes' option now
	 supported, to replace each color in the output by a grayscale
	 approximation.  Particularly useful when preparing PCL 5 output
	 with `-T pcl', to be printed on a monochrome PCL 5 printer.  Most
	 such printers map HP-GL/2's seven standard pen colors (even
	 yellow!) to black.
libplot: EMULATE_COLOR Plotter parameter added.  If "yes", grayscale
	 emulation of colors results, in accord with the CIE luminance
	 computation standardized by Rec. 790.
libplot: PS driver now maps the output of each call to box() to idraw's
	 `Rect' primitive, rather than to idraw's `Poly' primitive.
libplot: some obscure bugs involving the edging of rectangles with
	 user-defined dashing patterns have been corrected.  If the
	 rectangle is generated by calling box(), the dash pattern now
	 starts at the first-specified vertex, in all output formats.
libplot: zero-length dash arrays [specified with linedash()] were causing a
	 segfault in HPGL Plotters when HPGL_VERSION="1.5" or "1".  Fixed.
libplot and applications: when producing HP-GL/2 output, e.g., via the
	 default `-T hpgl' option, the kerning of non-fixed width device
	 resident fonts such as "Arc" has been much improved.  Also, such
	 half-Japanese fonts as "StickANK" and "ArcANK" can now be used.
libplot and applications: when producing generic HP-GL output, via the
	 option `-T hpgl' with HPGL_VERSION=1, basic device-resident vector
	 fonts such as "Stick" and "Arc" can now be used, if present.
libplot: when HPGL_VERSION is 1.5 or 1, the filling of regions has been
	 improved.  Solid filling with a single pen was used, but this has
	 been changed to cross-hatching, to match better the filling color.
	 The algorithm for choosing the inter-line distance in the
	 cross-hatch is from the HP7550B (HP's first HP-GL/2 pen plotter).
libplot: HP-GL and PCL Plotters, in their output files, now round the miter
	 limit to the nearest integer, downwards.  That's because there's
	 at least one HP-GL/2 interpreter (the firmware in the HP7550B pen
	 plotter) that insists that it be an integer.  In early
	 documentation, HP itself seems to have been unclear on that point.
libplot: due to renaming of external symbols, it is now possible to link
	 both libplot/libplotter and libxmi simultaneously with an
	 application, if desired.
libplot: as previously promised in libplot documentation, calling the API
	 function pentype() with a value argument of `0' now turns off the
	 drawing of markers and `points' (i.e., pixels), besides turning
	 off the edging of paths, which is all that it formerly did.
libplot: bug in drawing of rectangles by X and XDrawable Plotters, when
	 user coordinate system has been rotated relative to the default
	 coordinate system, now fixed.
libplot: invoking closepl() on an XPlotter or XDrawablePlotter when the
	 stack of drawing states is nonempty, without first calling
	 restorestate() repeatedly to pop the stack, formerly yielded
	 erratic behavior.  Now fixed.
libplot: X driver, very rarely, would sometimes block, waiting for user
	 input such as mouse motion.  This was due to blocking behavior of
	 select(), invoked by XtAppPending() in our hand-crafted event
	 loop.  Now fixed; previously, the bug had almost (but not
	 completely!)  been fixed in plotutils-2.2.  Thanks to Massimo
	 Santini for providing a system call trace, as a useful diagnostic.
libplot: X driver now checks the coordinates of each polyline, before
	 drawing it, to determine whether they can be represented as 2-byte
	 integers in accordance with the X11 wire protocol.  If not,
	 polyline is truncated and a warning message is emitted.
libplot: PCL driver, when generating PCL 5 output containing Postscript
	 fonts, was specifying the wrong font number for Bookman.  Fixed.
	 (This bug was significant only if `--enable-ps-fonts-in-pcl' was
	 specified at installation time.)
libplot: the point() operation, when invoked on a CGM Plotter, was not
	 updating the graphics cursor position.  Fixed.
libplot: font descriptions included in WebCGM output files, to facilitate
	 font substitution, incorrectly identified italic Postscript fonts
	 as `oblique' rather than italic, and contained incorrect
	 classifications for AvantGarde and NewCenturySchlbk.  This
	 affected `-T cgm' output from all graphics utilities.  Fixed.
libplot: `offset' parameter of linedash() function, if nonzero, did not
	 produce correct effect in WebCGM output.  Fixed.
libplot: when producing WebCGM output, libplot's `triangular' line cap
	 style is now mapped to CGM's round line cap style, rather than
	 CGM's triangular line cap style, since the latter disagrees with
	 libplot's convention (taken from HP-GL/2) that the cap should be a
	 stubby triangle, not an equilateral one.
libplot: when a FigPlotter runs out of user-defined colors (511 appears to
	 be the maximum), it now quantizes to the nearest standard or
	 user-defined color.  Previously, exceeding the maximum number of
	 user-defined colors triggered a bug.
installation: CFLAGS and CXXFLAGS may now be set at build time, i.e., if
	 set, will not be ignored.

Version 2.3 released, 10/1999.  [Includes libplot 3.0, interface age=1.]

graph,plot,tek2plot,plotfont,pic2plot: `-T cgm' option now allowed.  The
	 CGM version number and encoding scheme may be selected by setting
	 the CGM_MAX_VERSION, CGM_ENCODING environment variables.
libplot: CGM support added.  By default, a CGM Plotter produces
	 binary-encoded version-3 CGM format, which conforms to the WebCGM
	 profile.  Parameters CGM_MAX_VERSION, CGM_ENCODING are supported.
libplot: X Plotters now support an X_AUTO_FLUSH parameter, with default
	 value "yes".  Set it to "no" to turn off the invocation of
	 XFlush() after each drawing operation, which slows down some
	 applications that use libplot's X Plotter support.
libplot: when producing X11 output, box() and fbox() were drawing
	 rectangles clockwise, beginning at the upper left corner,
	 disagreeing with libplot's convention of drawing rectangles
	 counterclockwise, beginning at the first-specified vertex.  Fixed.
libplot: new function pentype() added to the API.  If its argument is 0,
	 stroking of paths (as opposed to filling) is turned off.  So,
	 e.g., `edgeless polygons' can now be drawn.
libplot: fixed the `zombie children' problem with the X driver.  With each
	 invocation of closepl(), a child process is forked off to manage a
	 popped-up X window.  Previously, if `q' was typed in a previously
	 popped-up window, that window would close, but its process would
	 turn into a zombie (still appearing in the process table).
libplot: flinedash() was not acting correctly on Metafile Plotters unless
	 the META_PORTABLE parameter was set to "yes".  Fixed.
libplot: width tables for the AlbertusMedium font, available when producing
	 PCL5 and HP-GL/2 output, contained errors, giving incorrect
	 positioning of text strings, e.g., by `graph -T pcl'.  Now fixed.
libplot: label() and alabel() operations, when applied to a MetaPlotter,
	 now check that the argument string contains only characters in the
	 printable ISO-Latin range.  Other Plotters already did this.
libplot: fixed problem with Illustrator Plotters sometimes changing line
	 styles and other drawing attributes when erase() was invoked.
graph,plot: `--max-line-length' option was incorrectly ignored; now fixed.
libplot: MAX_LINE_LENGTH Plotter parameter variable was usually ignored;
	 this has been fixed.
tests: regression tests performed by `make check' now include tests on PCL5
	 output.
graph: new `-H' option added.  `graph -H' will draw a copy of the graph
	 frame (including grid lines) on top of the data, as well as
	 beneath it.  This is useful if the plotted dataset(s) project
	 slightly beyond the frame, due to large symbols or a large line
	 thickness being used.
libplot: for X, X Drawable, PNM, GIF, and PCL/HP-GL Plotters, introduced a
	 convention for how to draw polylines all of whose vertices are
	 mapped to the same pixel in integer device coordinates.  Now drawn
	 as a filled circle of diameter equal to line width, provided that
	 either (1) the points in user space weren't all the same, or (2)
	 they were all the same, but the cap mode is "round".  (Line width
	 0 is treated as line width 1 here.)  If neither (1) nor (2) holds,
	 draw nothing.  Tektronix Plotters now follow a similar policy on
	 whether or not to display such polylines visibly.
libplot: PCL and HP-GL Plotters no longer segfault (due to a stack blowout)
	 when trying to render very small line segments or marker symbols.
libplot: PNM and GIF Plotters were incorrectly displaying paths with line
	 mode "disconnected" as a sequence of single pixels, rather than a
	 sequence of filled circles of diameter equal to linewidth.  Fixed.
libplot: incorrect PCL font names Univers-Italic and Univers-BoldItalic
	 changed to Univers-Oblique and Univers-BoldOblique.  Similarly,
	 UniversCondensed-{Italic,BoldItalic} renamed.
libplot: new ROTATION parameter added, to provide support at the libplot
	 level for the `--rotation' option of the command-line utilities.
	 It rotates the viewport on the display device, without changing its
	 position.  The rotation maps vertices to vertices.
libplot: default font when producing PCL5 output is now Univers rather than
	 HersheySerif.
libplot: on their output pages, PCL, Fig, PS, and HP-GL Plotters will now
	 shift their viewports as specified in the PAGESIZE
	 parameter/environment variable.  E.g., its value could be
	 "letter,xoffset=1in,yoffset=-2cm" or "a4,yoffset=+12mm", as well
	 as just "letter" or "a4".  Default viewport locations documented.
libplot: PCL Plotters and Fig Plotters now position their viewports
	 (i.e. "graphics displays") in the center of their pages, like PS
	 Plotters.  So support for the PCL_XOFFSET and PCL_YOFFSET
	 parameters has been dropped.  Support for HPGL_XOFFSET and
	 HPGL_YOFFSET also removed for consistency, even though the default
	 HP-GL viewport position has not changed.
libplot: PS fonts Courier-Oblique, Courier-BoldOblique can now be requested
	 under the names Courier-Italic, Courier-BoldItalic.  Also, PCL
	 fonts Courier-Italic, Courier-BoldItalic can now be requested
	 under the names Courier-Oblique, Courier-BoldOblique.
libplotter: fixed a very bad bug in the MetaPlotter output routine that was
	 garbling output in non-portable mode.
libplotter: fixed a very bad bug in warning-message and error-message
	 handlers.  Messages were being written to output stream, not error
	 stream.
libplot and graph: substantial changes to the code that plots marker
	 symbols.  The marker symbols that `graph' produces when `-TX',
	 `-Tgif', or `-Tpnm' is specified are now much better-looking.
graph: data files in the `table' format produced by recent versions of
	 gnuplot can now be read, if the `-I g' option is specified.
libplot: support for "triangular" join mode added to PNM and GIF Plotters.
	 Partial support for triangular cap mode too (for single arcs, but
	 not for polylines or arbitrary paths).  Triangular joins and caps
	 have the same meaning as in HP-GL/2.
libplot and installation: libpthread, and support for pthreads (Posix
	 threads) in libc, are now checked for at build time.  If they're
	 found, special support for multithreading is added to libplot.
libplot: new thread-safe C++ API added (via PlotterParams object, passed to
	 Plotter ctors).  Old non-thread-safe C++ API still supported.
libplot: new thread-safe C API added, with function names like pl_newpl_r()
	 and pl_openpl_r().  Much hacking of libplot source code to make it
	 thread-safe, but the old C API (non-thread-safe) is still
	 supported.
graph: improved the computation of the x and y ranges, if only partially
	 specified by user.  Now expanded to show, in full, truncated line
	 segments between data points (if any).
spline: some numerical instability problems fixed (tension parameter may
	 now be taken extremely large without ill effects).
libxmi: new low-level scan conversion library, containing the X11
	 rasterization code used by PNM and GIF Plotters.  Installed as a
	 standalone library, along with header file xmi.h, if `./configure
	 --enable-libxmi' is done.  Separate texinfo documentation
	 installed too.  libxmi will be distributed as a separate GNU
	 package, also.
installation: if gcc is employed, optimization option "-O2" is now used.
	 Well-known strength-reduction bug in "gcc -O2" is checked for.
tek2plot: each `point' in a Tektronix-type input file is now mapped to
	 libplot marker symbol #1 (a dot).  This improves visibility.
libplot: marker symbol #1 (a dot) is now drawn in many output formats as a
	 small filled circle, of diameter equal to one-fifth of the
	 diameter of marker symbol #4 (an open circle).  This improves
	 visibility for the output of `graph -m 0 -S 1' (previously, in
	 many output formats marker symbol #1 was too small to see).  If
	 this is too large, specify a second argument to the `-S' option.
installation: --enable-lj-fonts-in-ps option now works (no more compilation
	 problems).
graph,plot,tek2plot,plotfont,pic2plot: fixed the output of `-T hpgl
	 --list-fonts', which unlike `-T hpgl --help-fonts', was listing
	 the names of some Stick fonts (i.e. HP vector fonts) that are
	 inaccessible unless HPGL_VERSION is "1.5".
installation: bizarre installation problem on powerpc-apple-machten4
	 systems (involving presence of .xcoff files) now worked around.
	 (Configure script now ignores *.xcoff files.)

Version 2.2 released, 3/1999.  [Includes libplot 2.0, interface age=0.]

libplotter: added support for iostreams.
libplot: X Drawable Plotters can now use double buffering (a fatal
	 error was identified and fixed, thanks to Georgy Salnikov).
graph: increased number of orders of magnitude that a logarithmic axis may
	 span, before ticks not at powers of ten are omitted.  Was 4.0; now
	 5.0.  Suggested by Martin Ward.
graph: -R option sometimes caused crashing on logarithmic axes, since it
	 could change the lower endpoint of the axis to zero.  Fixed.
libplot: values "yes" and "fast" for USE_DOUBLE_BUFFERING are now
	 equivalent.  If double buffering, X driver now automatically uses
	 the DBE protocol extension (or the MBX extension) if available.
libplot: X driver, very rarely, would sometimes block, waiting for user
	 input such as mouse motion.  Traced to blocking behavior of
	 select(), invoked by XEventsQueued(), invoked by XtAppPending().
	 Problem now fixed (thanks, Nathan Salwen).
libplot: Tektronix driver, when driving a kermit Tektronix emulator, can
	 now set the background to any ansi.sys color.  So commands like
	 "TERM=kermit graph -Ttek --bg-color=green" now work.
libplot: outfile() operation declared obsolescent.  Now undocumented,
	 and will eventually be dropped.	 
libplot: fixed a bug in PCL and HP-GL Plotters that sometimes resulted in
	 an infinite loop when drawing very short paths, or rendering text
	 in very small font sizes.  Thanks, Stefan Wagner.
libplot: PCL and HP-GL Plotters now support "triangular" caps and joins,
	 in addition to the three standard cap types and join types.
pic2plot: new utility, which can translate the pic language to any
	 supported graphics format, including X11.  Based on James Clark's
	 gpic.
libplot: functions linedash()/flinedash() added to API, supporting
	 arbitrary PS-style dashing styles.  Most Plotter types support them.
	 (Old, unused, Unix libplot `d' opcode now represents linedash.)
libplot: fixed bug that was occasionally causing paths to be broken after
	 circular arc segments, in some output formats.
libplot: Appearance of HersheyEUC font improved by shrinking the stroke
	 width.  Also, row 1, character 1 of the font is now a full-width
	 space, of the same width as any other Japanese character.
plotfont: title of any character map for the HersheyEUC font now refers to
	 `row' of font, not `page', and character numbering changed too.
	 --jis-row option added, and --jis-page option declared
	 obsolescent.
libplot: non-solid line types ("dotted", "dotdashed", etc.)
	 redesigned, and are now as device-independent as possible.
libplot: new "dotdotdashed" line style added, supported by all Plotters
	 except Tektronix Plotters.  "dotdotdotdashed" added too.
graph: font size, tick size, and symbol size are now specified as fraction
	 of size of plotting box, where size means minimum dimension (width
	 or height).  Documentation clarified.
graph: no more bogus error messages when `-N x' or `-N y' is specified.	 
graph: --toggle-switch-axis-end option renamed --toggle-axis-end, and `-E'
	 is made an alias for it.  Also, conventions reversed: `-E x' and
	 `-E y' now do what `-E y' and `-E x' would have done.
graph: any of the three arguments to each of the -x and -y options (the
	 min, max, and spacing values for an axis) may now be supplied as
	 "-" (a single hyphen), to indicate that it should be computed from
	 the dataset.  E.g. "echo 0 0 1 1 2 0 | graph -x - 3 -" will work.
libplot: paths may now contain segments that are quadratic and cubic Bezier
	 curves.  bezier2(), bezier3() etc. operations now included in API.
	 Illustrator Plotters now draw each ellipse, elliptic arc, and
	 circular arc using cubic Beziers, like Illustrator itself.
libplot: fixed bugs dealing with multi-page HP-GL or PCL output files
	 (e.g., pages were incorrectly merged into a single page).
plot: parsing of portable metafile format is now more flexible.  Arbitrary
	 white space can be included in file.
libplot: fixed bug in x_endpath.c that would occasionally cause X errors
	 related to a bad drawable in an X_DrawPoints request.
libplot: support for Adobe Illustrator version 3 format now obsolescent.
	 Format still supported, but no longer mentioned in documentation.
libplot,graph: fixed bug in drawing marker symbols 14,21,28 (fancy
	 squares), and decreased sizes of symbols 30,31 (octagons).
graph,plot: arguments of --font-size and --title-font-size arguments no
	 longer allowed to be >=1.0.  (By passing bogus values, lusers or
	 nefarious users could crash X servers).
libplot: fixed bug dealing with retrieval of X fonts rotated 180 degrees.
graph,tek2plot,plotfont: new --rotation option (can rotate plots
	 counterclockwise within the graphics display by 90, 180, or 270
	 degrees).
libplot: new fillmod() operation.  For self-intersecting paths, can now
	 specify nonzero-winding-rule filling rather than even-odd filling.
libplotter: new C++ library.  Provides base Plotter class, subclasses for
	 the different sorts of Plotter.  Massive restructuring of code.
libplot: if line width is zero, the X driver now draws each line in a
	 polyline immediately (it doesn't wait until endpath() is invoked).
	 So if you do `graph -TX -W 0', and type in the coordinates of a
	 series of points manually, you'll now see the polyline drawn in
	 real time, as long as you also use the `-x' and `-y' options.
libplot: text string format now supports "\fP" macro for switching to
	 previous font (cf. troff; "\fR", "\fI", "\fB" supported too).
libplot: fmiterlimit() operation added to API.
documentation: man pages for ode, spline, plot, tek2plot added.
graph,plot,tek2plot,plotfont: `-T pnm' and `-T gif' now allowed.
libplot: PNM driver added, which outputs PBM/PGM/PPM format.
libplot: pseudo-GIF driver added, using miGIF run-length encoding routines
	 (thanks, Maus and ivo).  Incorporates X11 polygon filling and wide
	 line code, as a more or less independent module.
libplot: selectpl() now returns the handle of the previously selected
	 Plotter.
libplot: X Drawable and X Plotters now fill `rotated' ellipses (those whose
	 axes are not aligned with the coordinate axes) more speedily,
	 using the special X rendering algorithm for filling convex
	 polygons.  This speeds up the the `drifting eye' example in the
	 manual.
libplot: fixed bugs in handling of "disconnected" line type.  Our
	 convention: no Plotter should draw anything when circle() or
	 ellipse() is invoked, if the current line type is "disconnected".

Version 2.1.6 released, 10/1998.  [Includes libplot 1.6, interface age=1.]

plot: new `-s' option, which merges together all displayed pages. This is
	 to assist people who are accustomed to concatenating Unix plot
	 files together (GNU metafiles can also be concatenated together,
	 but the resulting metafile does not merge pages).
libplot: PS driver now correctly updates list of used PS fonts when erase()
	 is invoked.  This was causing ISO-Latin-1 fonts in multipage
	 documents not to be reencoded correctly.
libplot: Fig driver now places each drawn object at its own depth level.
	 This is because fig2dev seems not to use xfig's own conventions
	 for layering objects within a single depth level.
libplot: Japanese page size "B5" now supported.  So the `--page-size'
	 option to graph,plot,tek2plot,plotfont now supports "B5" too.
libplot: Fig driver now properly supports "dotdashed" line type, since it
	 is supported in Fig 3.2 format.  So `graph -m 3 -T fig' now works
	 as it should.
libplot: Fig driver now produces Fig 3.2 format, so xfig 3.2 is required to
	 view and edit it.  This affects output obtained with `-T fig'.
plot.h: marker symbols and metafile op codes are now defined as enum's,
	 rather than via #define's.
graph,plot,tek2plot,plotfont: `-T ai' option added, for Illustrator output.
libplot: Adobe Illustrator driver added, outputting either Illustrator
	 file format version 3 or version 5 (latter is default).
plot.h: old workarounds for change in 2.1 from `endpoly' to `endpath'
	 and from `fill' to `filltype' finally removed (they were
	 conflicting with a Debian package).
libplot: in each Hershey font, stroke width increased by about 20%,
	 to remove white (i.e. unfilled) space in some characters.
libplot: when space() is invoked, X Plotters no longer attempt immediately
	 to retrieve a font from the X server (they wait until
	 fontname/fontsize/textangle is next invoked, or failing that, until
	 alabel/labelwidth is).  This reduces the chance of failing to
	 retrieve a too-small or too-large X font.
libplot: in metafiles, separate op codes for frotate, fscale, ftranslate
	 operations now obsolete (they are mapped into fconcat, internally).
libplot: fixed bug in Metafile Plotter support for convenience operations
	 frotate, fscale, franslate.
libplot: fixed inelegance in Metafile Plotter portable output (a couple of 
	 op codes needed only for binary-format were being emitted).
libplot: HP-GL and PCL Plotters now emit more compact code for any path
	 that contains more than a single circular arc (the HP-GL `AA'
	 instruction, rather than a polygonal approximation, is now used).
libplot: new internal `path' structure now used (a linked list of elements).
libplot: invocations of space() on a Plotter, after the first mandatory
	 invocation for each page, no longer affect the line width or font
	 size in terms of user coordinates.  This is for consistency with
	 fconcat() and for consistency with Postscript.  Postscript does not
	 change user-frame line widths or user-frame font sizes when the
	 affine map from user coordinates to device coordinates is updated.
libplot: No more bogus warnings issued by Metafile Plotters if they're
	 asked to render a label in a non-builtin font, e.g. a non-PS X
	 font.  (This removes some bogus warning messages from raw `graph'.)
graph/plot/tek2plot/plotfont and libplot: in code, exit(1) replaced by
	 exit(EXIT_FAILURE) to improve portability beyond Unix.

Version 2.1.5 released, 8/1998.  [Includes libplot 1.5, interface age=1.]

texinfo documentation: full explanation given of the 18 supported
	 Hewlett-Packard vector fonts, also known as `stick fonts'.
libplot: escape sequences added for the 12 signs of the zodiac; they are
	 recognized in labels whenever the current font is a Hershey font.
libplot: new escape sequences "\r^" and "\l^" added, for use in labels;
	 they shift right and left by 1/12 em, respectively.  (Cf. troff.)
libplot: 3 missing Japanese Katakana added to the HersheyEUC font (they
	 are the 3 that have no Hiragana counterpart).
graph,plot,tek2plot,plotfont: `-T pcl' option added, for PCL 5 output.
libplot: PCL 5 driver added; it essentially outputs HP-GL/2, with 
	 a preceding control sequence to switch the printer or plotter 
	 from PCL 5 mode to HP-GL/2 mode, and a following control sequence 
	 to switch back.
plot: parsing bug fixed; files may now be listed on command line.
configure: options now include `--enable-ps-fonts-in-pcl', 
	 `--enable-lj-fonts-in-ps', and `enable-lj-fonts-in-x'.  Previous
	 option `--enable-lj-fonts' was split into final two.
libplot: HP-GL/2 driver now supports the 35 PS fonts.  So e.g. in principle
	 `plotfont -Thpgl Helvetica > map.plt' will work, allowing a PS
	 character map to be displayed on a PCL device.  But PS fonts are
	 available only on high-end PCL devices, e.g., 4000-series
	 LaserJets.
libplot: when drawing labels in any of the 43 ISO-Latin-1 PCL fonts,
	 HP-GL/2 driver previously displayed five characters (-, `, ', ^, ~)
	 incorrectly.  Final four of these were displayed as accents.
	 Problem was traced to HP's idiosyncratic definition of ISO-Latin-1
	 ("ECMA-96 Latin-1").  Now fixed.

Version 2.1.4 released, 7/1998.  [Includes libplot 1.4, interface age=1.]

libplot: HP-GL driver now supports 8 Stick fonts (device-resident vector
	 fonts) when producing HP-GL/2 output, and 18 Stick fonts when
	 producing output for an HP7550A plotter (HPGL_VERSION="1.5").  Not
	 yet documented because kerning is being worked on, but they show
	 up when `--help-fonts' or `--list-fonts' is used.
libplot: HP-GL driver, if HPGL_VERSION is "1.5", will no longer attempt to
	 use pen #0 as a white pen, when filling polygons that are meant to
	 be filled with white.
graph, plot, tek2plot, plotfont: no more segmentation faults when using the
	 `--help-fonts' or `--list-fonts' options.

Version 2.1.3 released, 7/1998.  [Includes libplot 1.3, interface age=1.]

plotfont: new `--numbering-font-name' option.
libplot: color was not being updated (if necessary) before rendering labels 
	 in HP-GL[/2] output. Now fixed.
libplot: default value for HPGL_PENS parameter/environment variable is now
	 "1=black:2=red:3=green:4=yellow:5=blue:6=magenta:7=cyan" when
	 HPGL_VERSION is "1.5", as well as when it is "2".
tests: validation tests may now be run even if the build directory is
	 different from the source directory (thanks Thomas Walter).
tests: bug in test for HP-GL/2 output fixed (thanks Thomas Walter).

Version 2.1.2 released, 7/1998.  [Includes libplot 1.2, interface age=1.]

libplot: any polyline with "disconnected" line type is now drawn as a set
	 of filled circles, one centered on each defining point.  Circle
	 diameter is chosen to be the nominal line width.
libplot: PS driver previously did not quite close large filled circles
	 and ellipses, leading to an `inverse pie-wedge' effect.  Now fixed.
libplot: previously the HP-GL driver required that HPGL_VERSION be "1" 
	 to produce paths, arcs, etc. that would be positioned correctly on
	 generic HP-GL (as opposed to HP-GL/2) devices.  No longer
	 absolutely necessary: HP-GL/2 line graphics produced by the driver
	 should be positioned correctly even when erroneously sent to an
	 HP-GL device.  Fonts do not work, however.
libplot: HP-GL driver now visibly displays zero-length line segments,
	 if cap mode is `round' or `projecting'.
libplot: dot/dash spacing in the "dotted", "dotdashed", "shortdashed" and
	 "longdashed" line types, as produced by the PS, Fig, HP-GL/2, and
	 X11 drivers, now scales with line width.  This affects the lines
	 produced by the `-m' option to `graph', when used with `-W'.
spline, double: now permit comment lines in ascii input files, like `graph'.
double: default is now to print all fields, i.e., `-f' option is not
	 needed in order for the program to function.  Instructions on using
	 `double' added to double.c, but not yet to texinfo documentation.
libplot: when producing HP-GL/2 output, can now use 8 builtin HP-GL/2
	 vector typefaces (Arc as well as Stick; usual 4 variants for each).
libplot and utilities based on it: installation-time option
	 "--enable-lj-fonts" allows use of PCL fonts when using `-T X' or
	 `-T ps' options.  For this to be meaningful, installer must obtain
	 the 45 PCL (i.e. LaserJet) fonts from Hewlett-Packard and install
	 them.  They are available for free via the net (see instructions in
	 ./INSTALL.fonts).
libplot: small errors in positioning text strings, when producing PS
	 output, now fixed.  The bug only appeared when rendering
	 non-Courier text strings with nonzero angle of inclination.
libplot: X Windows names of several of the 35 supported PS fonts to agree
	 with current conventions.  (Old names continue to work.)
	 "avantgarde-medium-r-normal" is now "itc avant garde
	 gothic-book-r-normal", "zapfchancery-medium-i-normal" is now 
	 "itc zapf chancery-medium-i-normal", etc.
libplot: In HP-GL/2 driver code, fixed slight errors in positioning text
	 strings, when rendered in the PCL and Stick fonts.  Errors were due
	 to an unusual HP-GL/2 `leftward shift' label positioning convention
	 dating back to pen plotter days.
texinfo documentation: Fixed incorrect statement that for `plot' and
	 `tek2plot', the relative order of filenames and command-line
	 options matters.
graph,plot,tek2plot,plotfont: --rotate option dropped, and ROTATE
	 environment variable renamed to HPGL_ROTATE.  `Rotation' only
	 occurs if `-T hpgl' is specified, and HP-GL[/2] output is produced.
	 So by our coding standards, it doesn't deserve a command-line option.
libplot: ROTATE Plotter parameter, which affected only HPGL Plotters,
	 renamed to HPGL_ROTATE.  (It doesn't provide a pure rotation; in
	 HP-GL, `rotation' includes a coordinate shift as well.)
plotfont: new utility, displays either half of any recognized font.  Which
	 fonts are recognized depends on the output device (set with -T
	 option).  `plotfont -T X' will also display any X font specified by
	 [truncated] XLFD name, e.g. "utopia-medium-r-normal".  By doing
	 e.g. `--bitmap-size 300x450' you can scale fonts anisotropically.
libplot: HP-GL driver had two characters out of place in the upper half of
	 the Stick font.  Fixed.
libplot: all substitutions of fonts (due to lack of availability) and
	 colors (due to color names not being recognized) now yield a
	 warning message.  However, only the first font warning message
	 and the first color warning message of each sort (pen color,
	 fill color, background color) is actually emitted.
graph,plot,tek2plot: new --list-fonts option.	 
libplot: On X11R6 displays, X driver now rasterizes and retrieves only the
	 characters in any scalable font that will actually be used in
	 drawing a text string.  This _enormously_ speeds up the drawing of
	 text strings and the animation of text.
libplot: default value of Plotter parameter HPGL_OPAQUE_MODE is now "yes"
	 rather than "no", for consistency with libplot's imaging model.
	 Some rather old HP-GL/2 devices (large pen plotters?) are reported
	 to malfunction if asked to switch from transparent mode to opaque
	 mode.  Set the parameter to "no" for such devices.
configuration: now checks for -lXp if --with-motif is used (for Motif 2.x).
libplot: X driver now treats absurdly small numbers passed back from some
	 X11R6 servers when requesting fonts rotated by 0 or 90 degrees
	 (e.g., 4e-311) as zero.  Such numbers are too small to be
	 manipulated arithmetically on DEC Alphas, and caused floating point
	 exceptions in `graph -T X' when the `-Y' option was used.
all utilities: output of --help option now includes an email address
	 for reporting bugs.
package: several small changes made to ensure it will compile under DOS
	 with DJGPP (thanks Michel de Ruiter).
libplot: X Plotters now support hardware (i.e. server-supported) double
	 buffering, if available.  Set USE_DOUBLE_BUFFERING to "fast" to
	 obtain it.  Both DBE and MBX, of the standard X11 double buffering 
	 extensions, are tried.
libplot: output of PS driver now fully conforms to the PS DSC (Document
	 Structuring Conventions).  If output is only a single page of
	 graphics, it is in EPS format.
libplot: Plotters that do not do output in real time (i.e. Fig, HP-GL, and
	 PS Plotters) must now, in general, be deleted in order for an
	 output file to be written.  That is, _in general_ each page is not
	 emitted when closepl() is called.  In practice, pages are still
	 emitted when closepl() is seen, for Fig and HP-GL Plotters.  But PS
	 Plotters now do not emit anything until deletepl() is called.
libplot: fixed bugs dealing with Greek and mathematical symbol escapes in
	 text strings, when the current font is a user-specified X Windows
	 font (e.g. "utopia-medium-r-normal" or "vtsingle").  When the
	 user-specified font is an ISO-Latin-1 font, the usual ISO-Latin-1
	 escape sequences (e.g. "\sc" for the section symbol) now work also.
	 This fixed problems with `graph' labels.
libplot: Fig Plotters now produce only a single page of output,
	 irrespective of how many times openpl..closepl are invoked.  Only
	 the first page of graphics is written to the file, since Fig format
	 currently supports only a single page of graphics.
libplot: Tektronix driver now visibly displays zero-length line segments,
	 if cap mode is `round' or `projecting'.
libplot: HersheyGothic-German font renamed HersheyGothicGerman, etc.
	 (Former font names continue to work.)  Similarly,
	 HersheySerif-Symbol and HersheySans-Symbol fonts renamed
	 HersheySerifSymbol and HersheySansSymbol.  Oblique, Bold,
	 BoldOblique variants added to former; Oblique variant added to
	 latter.  Similarly, HersheyCyrillic-Oblique added.
	 HersheySerifSymbol-Bold is based on Allen Hershey's Triplex Greek
	 alphabet.  There are now 22 Hershey fonts in all.
libplot: Hershey glyph database updated.  Now incorporates Allen Hershey's
	 final revisions, and his Triplex Greek alphabet.  That alphabet
	 does not appear in most releases of the Hershey glyphs, since it
	 was developed c. 1990.  See ./doc/h-fonts.doc, ./doc/h-glyphs.doc.

Version 2.1.1 released, 5/1998.  [Includes libplot 1.1, interface age=1.]

libplot: to permit smooth animations, double buffering is now implemented
	 for X and X Drawable Plotters.  Double buffering is turned on if a
	 new device parameter, USE_DOUBLE_BUFFERING, is set to "yes" at
	 Plotter creation time.  Successive frames of graphics are separated
	 by invocations of erase().
libplot: X and X Drawable Plotters now maintain a local cache of X color
	 cells, and no longer automatically allocate new one(s) for each
	 plotted object.  This speeds up rendering, and avoids a memory leak
	 in the X server.  If color cells in the standard colormap are
	 exhausted, an X Plotter (but not an X Drawable Plotter) will switch
	 to a private colormap.
libplot: new device driver parameters, BG_COLOR and XDRAWABLE_COLORMAP.
	 Former allows background color of an X or X Drawable Plotter to be
	 specified at creation time; latter adds support for non-default
	 colormaps.
libplot: setting unrecognized parameters with parampl()	 no longer yields
	 a warning message.
libplot: bug in point() that affected X Drawable Plotters now fixed.
libplot: erase() now acts correctly on X and X Drawable Plotters: any
	 path under construction is flushed out before erasure.
libplot: nearly all internal read-only tables now defined as `const', so
	 that on	 most systems the linker will place them in a sharable 
	 read-only data section.
libplot: X driver now visibly displays zero-length line segments, if cap
	 mode is `round' or `projecting'.  This fixes a problem with
	 `tek2plot -TX', since Tektronix files use zero-length lines as
	 points.
tek2plot: now uses rounded cap mode for line segments obtained from vectors,
	 to improve visibility of zero-length lines.  Rounded join mode 
	 now used too, to smooth out curves.
texinfo documentation: now processed correctly by texi2html.

Version 2.1 released, 4/1998.  [Includes libplot 1.0, interface age=1.]

graph:  may access the new Euro currency symbol by using the '\eu' escape 
	 sequence.  This may be used when labelling the axes of graphs, etc.
	 Accessible whenever the current font is a Postscript or PCL
	 font.  Be sure to install the Postscript fonts accompanying the 
	 plotutils distribution on your X server, if you want to see it.
	 Whether or not you see the new symbol when you send a plot to
	 a Postscript or a PCL printer, depends on whether or the printer
	 has up-to-date firmware.  (E.g. HP LaserJet 5's don't.)
libplot: may access the new Euro symbol, when drawing text strings in
	 a Postscript or PCL font, by using the '\eu' escape sequence.  
fonts: included Type1 Symbol font, from URW++, now includes the
	 Euro glyph (the new European currency symbol).
libplot: a bug in handling of an empty plot, i.e. openpl() immediately
	 followed by closepl(), now fixed.  (This situation caused garbage 
	 output from several drivers.)
libplot: X driver no longer prints a warning message when substituting
	 a Hershey font for an unavailable PS font.  (Substitution often
	 occurs when the X server doesn't support anamorphically transformed
	 fonts, e.g. if it's a pre-X11R6 server.)  Warning message was
	 confusing `graph' end-users.
libplot: fixed a bug in X driver that was selecting fonts based on point
	 size rather than pixel size, leading to different-sized labels
	 on X displays of different resolution.  This affected 
	 graph,plot,tek2plot.
libplot: fixed a sign error in x_erase.c that prevented erase() 
	 from working on Sun's OpenWindows 3.0 X server, and other 
	 early X11 displays; this affected graph,plot,tek2plot.
graph,plot,tek2plot: --bitmap-size option added, affecting output 
	 on X displays only.
libplot: added BITMAPSIZE device driver parameter, which currently 
	 affects only X Plotters (sets size of popped-up window).
plot: new --page-number option, cf. tek2plot.
graph,plot,tek2plot: on X11R6 systems, now linked with -lSM -lICE in
	 the correct way (-lSM -lICE -lXext -lX11 follows -lXt on command
	 line).  This previously caused problems on cygwin32 systems.
libplot: X Drawable Plotters now use parameters XDRAWABLE_DISPLAY etc.,
	 in accordance with documentation, rather than X_DRAWABLE_DISPLAY etc.
tek2plot: when parsing multipage Tektronix files, now calls
	 openpl()..closepl() on each page.  So `tek2plot -TX' now yields
	 multiple X windows, unless the --page-number option is used.
libplot: PS driver hacked so that output, when openpl..closepl is invoked
	 more than once, is closer to conforming to the PS DSC (document
	 structuring conventions).  You may modify the PS file so that it is
	 fully conformant (remove extraneous %%EOF's, i.e., all but the
	 final one, and correct the pagecount on the %%Pages line).  When
	 openpl..closepl is invoked only once, it is fully conformant.
graph,plot,tek2plot: --bg-color option added, for use on X displays only.
libplot: new bgcolor() and bgcolorname() functions added to API.
	 They affect only X and X Drawable Plotters.  Libplot API version
	 bumped to 1:0:1 (i.e. version 1.0, supporting 0.x interface also).
graph: new --pen-colors option, allowing the specification of the color
	 of each of the five pens used for drawing colored plots.  The
	 default choice is the usual "1=red:2=green:3=blue:4=magenta:5=cyan".
spline: some numerical instability problems fixed (tension parameter may
	 now be taken arbitrarily close to zero without ill effects).
spline: support for multidimensional splines added (-d, -s, -A options)
spline: now tests for monotonicity of abscissa variable in each dataset
graph,spline,double: now test for NaN's (not-a-number's) when reading
	 floating point numbers from an input file.  plot already did this.
plot:   When reading input files in plot(5) format, negative integers
	 (i.e. negative integer coordinates) now parsed correctly.
plot: 	 Multiple '\n' separator characters now ignored in
	 portable GNU metafiles, and in input files in `-A' format too.
plot: -A option (replacing -I, which disappeared with 1.x) added and
	 documented.  It enables metafiles in the ascii version of plot(5)
	 format (e.g., obtained with Unix plottoa(1)) to be plotted; also it
	 will handle portable GNU metafiles generated by plotutils-1.x.

Version 2.0 released, 1/1998.  [Includes libplot 0.0, interface age=0.]

Installation process now installs (by default in subdirectories of
	 /usr/local/share) documentation files for ode, tek2plot, and libplot.
libplot: a new type of Plotter added.  An `X Drawable Plotter' will draw
	 graphics to one or two drawables (e.g. a window and a pixmap).	 
spline, tek2plot: "-" on command line now means standard input.
libplot: function declarations in plot.h header file now use `const char *'
	 as appropriate.  parampl() now takes a void * as value argument.
libplot: semantics of "disconnected" linetype clarified.  For ellipses,
	 circles, and boxes it's the same as "solid".  For paths, it means
	 the defining points are plotted, and nothing else (it's irrelevant
	 whether they were joined by line segments or arcs).
libplot: invoking deletepl() on an XPlotter now sends a SIGKILL to the
	 forked-off processes maintaining each of the X windows generated by a
	 openpl()..closepl() pair, causing said X windows to vanish.
libplot: metafile driver now has access to metrics for Hershey, PS, and PCL
	 fonts.  So it can compute string widths with the labelwidth() method.
libplot and plot: graphics metafile format now supports `open device' 
	 and `close device' directives, as in Plan 9.
spline: -x option (--x-limits) replaced by -t (--t-limits), in preparation
	 for a move to multidimensional splining.  --tension option moved
	 accordingly from -t to -T.  Yes, this smacks of overloading.
libplot: box() now moves graphics cursor to midpoint of the box, not
	 the second-specified vertex.
graph, spline, double: support for two additional binary input/output formats,
	 namely single-precision floating point and integer.
libplot: new user-settable error handlers added as global variables
	 (libplot_error and libplot_warning; former is fatal).
plotutils: package converted to use automake and libtool.
libplot: falabel() dropped from the API, and alabel() no longer returns a
	 value related to the width of the label.  This is in preparation
	 for a more object-oriented version of the library.  If you need to
	 get the width of a label, use flabelwidth() or labelwidth().
libplot: undocumented dot() function dropped from the API.  Seems last
	 to have been used in Unix libplot on a Bell Labs PDP-11 in the 
	 mid-'70s, driving a Tektronix 611 ("Versitek") storage scope.
	 (Thanks Lorinda Cherry <llc@research.att.com> for background info!)
graph,plot,tek2plot: --ascii-output option renamed --portable-output.
libplot: all 45 fonts resident in PCL 5 devices such as recent HP LaserJets 
	 are now supported by the HP-GL/2 driver.  Traditional Stick and 
	 Stick-Bold fonts supported too.
libplot: font size can now be set to zero without unexpected consequences.
libplot: improper affine transformations from user to device coordinates,
	 i.e., those that involve a reflection, now fully supported.  Many
	 bugs dealing with them, in all device drivers, were fixed.
libplot: fallback font for nonexistent or inaccessible X fonts is now a
	 Hershey font.  (No more problems with old X servers not being able
	 to retrieve rotated or sheared fonts!)  Similarly, retrieving an
	 anamorphically transformed PS font from the xfig driver will now
	 yield a Hershey font, since xfig does not support anamorphic
	 transformations (only rotations).
graph,plot,tek2plot: display device type now specified with `-T' option.
libplot: support now added for multiple display devices.  The libplot
	 family of libraries is merged into a single library.  The C binding
	 supports multiple display devices through new functions newpl(),
	 selectpl(), and deletepl().
libplot: code completely reconfigured, internally, in preparation for a C++
	 binding.  Now quite object-oriented, including a form of dynamic
	 binding.  `Plotter objects' introduced, each with private data and
	 public methods.
libplot: all external variables now begin with an underscore, to
	 avoid namespace collisions.
libplot, all versions: new havecap() function, which checks a version
	 of libplot for capabilities (0/1/2=yes/no/maybe).  Replaces
	 the undocumented external capability variables.
raw libplot: binary metafile format now uses ints rather than short ints to
	 represent integers.  Plot filters changed to compensate.  Plot
	 filters should still parse traditional plot(5) input format,
	 however; if there are any problems, be sure to use the -h or -l
	 option, whichever is appropriate for your architecture.
plot: undocumented --guess-byte-order option dropped as obsolete.
graph: line width used in drawing marker symbols is now properly
	 device-independent, and a fixed fraction of the marker size.
graph: --help-fonts option now yields nicely formatted 2-column lists of 
	 fonts.
libplotps: BoundingBox computations now take line widths into account,
	 cap styles and join styles too.
libplotps and graph-ps: line widths are no longer quantized, as seen by
	 a Postscript interpreter (they continue to be quantized when the
	 output file is edited with idraw, since idraw supports only line
	 widths that are integer multiples of 1 point).
libplotX: setting join mode for polylines no longer core dumps.
libplot, all versions: "mitre" is now a synonym for "miter" 
	 (i.e. as an argument to the joinmod() function).
libplotX (and graph-X etc.): previously, xplot.geometry resource needed to
	 be set, to adjust window size.  Now, Xplot.geometry suffices, in
	 agreement with documentation.
tek2plot: new -p option, to select frame in Tek file by number.
tek2plot: Tek parser completely rewritten (now uses essentially the same
	 parse tables as the Tek emulator in xterm(1), developed by Edward Moy
	 at Berkeley in the mid-'80s).  tek2plot documented.
graph: bug in plots with a user-specified reversed (min > max) axis fixed 
	 (axis range on other axis no longer incorrectly set).
ode/specfun.c: gamma support now always works (no more compilation problems).
New libplot function, parampl(), for setting device-specific driver
	 parameters.  Can also set them via environment variables 
	 (parampl() wins).
All user-writable external variables removed from libplot (they were
	 undocumented, in fact anything undocumented is subject to change).
libplottek: `graphics display' (a square) is now central 3/4 of Tek display
	 rather than left 3/4.  This affects graph-tek and plot2tek.
tek2plot command-line parsing improved.  --pen-color initialization 
	 and --help-fonts command-line options added.
graph: Partial workaround of problem with xfig 3.1: text strings
	 containing a printable 8-bit (non-ascii) char, followed by a digit,
	 are incorrectly displayed by xfig.  Fixed in xfig 3.2.
Output from libplotps now uses idraw `Circ' primitive instead of `Elli'
	 to draw circles.
Plot filter options --{high|low}-byte-order renamed to 
	 --{high|low}-byte-order-input.
	 Also, -I option dropped as unnecessary (due to magic string).
	 Continues to exist, but is now undocumented and flagged for deletion.
Each graphics metafile produced by raw libplot (or raw graph, or plot2plot)
	 now begins with a magic string, currently "#PLOT" followed by the
	 metafile format number.
libplotps: capmod() and joinmod() now take effect (non-default cap style
	 and join style are not recognized by idraw, however).
graph:  --{high|low}-byte-order options now dropped as obsolete.
Plot filter parser overhauled.  plot filters should no longer crash on
	 garbage input (keep fingers crossed here).  If input file named on
	 command line is nonexistent, plot filter no longer opens stdin
	 instead.
Improved parsing of graph command-line options.  Bad syntax now recognized
	 immediately, without data files or stdin being read.
libplothpgl: new libplot library, by default emitting HP-GL/2.
	 plot2hpgl and graph-hpgl are linked with it.  Many options specified
	 via environment variables (HP-GL and HP7550A format also supported).
In raw libplot, space2() produced wrong plot(5) op code.  Now fixed.
Bad problems with fill color in libplotps now fixed (quantization for idraw
	 was interfering with fill color as seen by a PS interpreter).	 
New convention on quantization of pen colors in versions of libplot which
	 quantize them (libplothpgl unless HPGL_HAVE_LOGICAL_PENS is set and
	 HPGL_VERSION is 2, libplotps when producing colors for idraw,
	 libplottek when producing kermit output).  Non-white pen colors are
	 no longer quantized to white, to avoid confusion.
In several versions of libplot, calling endpoly() on polylines with linemode 
	 "disconnected" was incorrectly moving the graphics cursor.  Now fixed.
libplot: New `plotter-like' semantics for arc() and ellarc().  After drawing,
	 position of graphics cursor now moves to endpoint of arc.  
libplot: arc() now draws an arc with sweep angle no greater than 180
	 degrees, which may be clockwise as well as counterclockwise.  Also,
	 ellarc() now always draws a quarter-ellipse, never a three-quarter
	 ellipse.
Remaining positioning problems in graph-fig and libplotfig fixed: 
	 later-plotted objects now never placed `behind' previously 
	 plotted ones.
libplotps and graph-ps: PS_ANY_LINE_WIDTH environment variable now supported.
	 If set to "yes", no quantization of line widths; arbitrarily thin lines
	 may be drawn, but support for editing the PS output with idraw is lost.
libplotps,libplotfig,libplothpgl: PAGESIZE environment variable now
	 supported, can be any ISO or ANSI size such as "a4", "a3", "a2",
	 "a1", "a0", "letter" (i.e. "usletter" or "a" ), "legal"
	 (i.e. "uslegal"), "ledger" (i.e. "usledger"), "tabloid" (i.e. "b"),
	 "c", "d", or "e".
libplot: calling closepl() to end a plot, when there is one or more
	 drawing states on the stack, no longer generates a warning message.
libplottek: exiting from kermit Tektronix emulation mode no longer
	 incorrectly affects text color.
libplotX: in Motif, drag-and-drop via middle mouse button should now work.

Version 1.3 released, 9/1997.

Major improvements to process of configuration and building (thanks to
	 Nelson Beebe <beebe@math.utah.edu>, many new configs now work).
Validation test of plot2fig no longer fails on some systems due to
	 innocuous causes (sign differences).  This does not include
	 NeXT's, which format floating point numbers in a genuinely
	 nonstandard way.
Output of libplotfig and graph-fig now indicates (via comment lines) which
	 ellipse objects are circles.
Bugs in support for MS-DOS kermit's Tektronix emulation fixed: initial
	 drawing color now is white, background black.  TERM="kermit",
	 "kterm" now recognized.  Linemodes 3, 4 no longer incorrectly
	 swapped.
Library linking (if Athena widgets used) is now -lXmu -lXt, not the reverse.
ode: improvements to arithemetic exception handling (error or warning
	 message now always printed).
ode/specfun.c: `signgam' variable declared and used properly.
Problems with pointers to signed vs. unsigned chars, which gave problems on
	 overly strict ANSI or pseudo-ANSI compilers, fixed.

Version 1.2 released, 9/1997.

Problems with 8-bit characters (`8-bit uncleanliness') fixed in libplot.
	 In `graph', they affected the drawing of axis labels containing
	 8-bit characters.
graph: buggy --reposition option fixed.
--with-motif configuration option added, for systems (e.g. HP/UX) with
	 Motif widgets but not Athena widgets.
libplotps (and e.g. graph-ps) output is now conformant EPS, version 3.0.
	 No more spare dictionary left on the PS stack, which interfered
	 with inclusion as an EPS file and importing into xfig.
Escape sequences which allow access to Greek characters and mathematical
	 symbols (e.g. "\*a", which means `alpha') now work in graph-X and
	 in general in libplotX even if the current font is a non-builtin
	 (user-specified) X font.
libplotX: switching among builtin PS fonts in a single label was causing
	 slightly incorrect estimates for the label width, with not-so-good
	 horizontal justification as a result (visible e.g. in graph-X
	 labels).  Fixed.
raw libplot: functions that take a string argument no longer try to write
	 into the string.
graph: when labelling ticks along an axis with large or small numbers
	 (printed in exponent form, i.e. FOOx10^BAR), zero is now printed
	 just as `0', not as 0.0x10^0.
graph: FOOx10^BAR form for tick labels now works even when current font is
	 a symbol font.
graph: identical upper and lower limits on an axis no longer cause an error
	 message and an abort. Instead each limit is displaced by 1 unit,
	 with a warning message.
graph: -s option (--save-screen) now works.  (Meaningful only for
	 graph-tek and raw graph.)
libplotfig: later-drawn objects, of whatever kind, now appear in front of
	 (rather than behind) earlier-drawn objects.  This has implications
	 for graph-fig (it fixes a bug previously mentioned in the PROBLEMS
	 file).
graph: new --frame-color option (sets name of color of frame, and plotted
	 curves too if -C option is not used)
New libplot functions: pencolorname(), fillcolorname(), colorname(), which
	 search a database of color names (orig. from X11R6 rgb.txt).
New libplot function: pencolor().  color() now just calls it and fillcolor().
plot filters: bug in parsing of fmarkerrel() op code fixed.
plot filters (plot2X etc.) now abort instead of just printing a warning, if
	 an unrecognized directive is seen in the input stream.  This is to
	 avoid confusing ascii-format input streams with binary-format
	 input streams (which can cause X servers to crash).
Regression tests in ./test reworked; different options now used
	 on `graph', in the tests.  Output is more visually pleasing.
ode-examples directory reworked; examples are documented and some
	 are renamed.
ode arithmetic exception handling improved.
Separate ascii-format doc on ode (originally nroff) merged into texinfo
	 doc, heavily edited.
In ./ode, gram.c, gram.tab.h and lex.c are no longer removed during a `make
	 distclean'.  This is for the benefit of people who may not have
	 bison or yacc.  If you want to re-make them, you should do a `make
	 realclean'.  The info/plotutils.info documentation file and
	 test/*.xout are similarly not removed except in a `make
	 realclean'.
No more annoying flicker in graph-X after plot is drawn (libplotX
	 no longer clears window before redrawing, when closepl() is called).
alloca.c now supplied in ./ode directory for machines that don't have alloca.
Repeated calls to openpl..closepl in libplotps were producing
	 incorrect %%DocumentFonts lines in the PS output; now fixed.
Closed polylines (final vertex = initial vertex) drawn with libplotps now
	 close correctly, as seen by a PS interpreter.
Widths of lines drawn with libplotps, as displayed by idraw, now agree with
	 the widths seen by a PS interpreter such as Ghostscript.  If lines
	 now look too thick, use the zero-linewidth (`-W 0') option.
Octagonal markers added (markers #30 and #31), as in UGS marker set.
Bug in special function code (used by ode), for machines that don't have
	 them, now fixed (compilation of ode/specfun.c no longer bombs).
Hershey fonts now include Russian HersheyCyrillic, and HersheyEUC (for Japanese
	 support; Hiragana, Katakana, and 603 Kanji are supported).
HersheyScript is now located in its own typeface; HersheySans-Oblique
	 and HersheySans-BoldOblique created.
Ligature support added to certain Hershey fonts.
ISO-Latin-1 characters in Hershey fonts now include most accented
	 characters.
Characters missing from Hershey fonts now print as an
	 `undefined character' symbol (seven horizontal strokes).
Hershey astronomical and misc. symbols added.
Many miscellaneous cleanups to Hershey fonts 
	 (inverted questionmark and exclamation point now supported, 
	 for example; `asteriskmath' vertical height fixed, etc.).
plot.h now works with C++ as well as C

Version 1.1 released, 7/1997.  See ONEWS for earlier changes.