		Gnuplot Version 5.4.2 Release Notes
		===================================

This release contains bug fixes and a few new features back-ported from the
development version.  Gnuplot development is tracked in a git repository on
SourceForge.  You can generate a complete history of changes using "git log"
after downloading:

	git clone -b branch-5-4-stable git://git.code.sf.net/p/gnuplot/gnuplot-main

Known issue:
    When run on Windows 10, gnuplot 5.4 does not work reliably with piped input
Work-around:
    Stick with version 5.2.8 on Windows 10.

Release Notes date: 28-May-2021

Changes in 5.4.2
================
* NEW in "using" context, $# means "number of columns in current data line"
* NEW define on program entry:   I = sqrt(-1) = {0.,1.}
* NEW support input data that uses epidemiological date-week formats
* NEW optional fillcolor for "set key opaque"
* NEW provide and document use of a plugin to provide uigamma function
* CHANGE much improved domain and precision for igamma function
* CHANGE generate only one key entry per multi-dataset input file Bug #2380
* CHANGE (Windows): attempt to convert unicode on command line to UTF-8
* CHANGE clip `with image` to plot boundary in 2D plots
* CHANGE In gprintf format "%c", add no space for a null prefix Bug #2266
* CHANGE Make auto-placement of left border less sensitive to plot size Bug #2415
* FIX time formats %U %W Bug #2390
* FIX left-justification of titles in splot with user-specified key position
* FIX clipping of filled polygons that have only 1 or 2 vertices Bug #2400
* FIX "set tics front" unexpectedly made all grid lines invisible
* FIX more terminals support requested linewidth for textbox borders
* FIX indexing of multiple matrix data sets in a single input file
* FIX do not inject extra '\n' into input stream after 'set term' Bug #2292
* FIX cairo terminals: Do not lose font info during multi-line enhanced text
* FIX cairo terminals (Windows): ignore "text scaling" from user screen settings
* FIX pm: better mousing and font handling
* FIX win: instabilities associated with changing window size Bug #2301 #2304
* FIX wxt: use of multiple plot windows from single-threaded wxt terminal
* FIX qt: prevent creation of zombie gnuplot_qt process Bug #2188


Features introduced in 5.4.1
============================
* NEW "with rgbimage" and "with rgbalpha" accept single column ARGB input
* NEW keyword "smooth kdensity period <val>"
* NEW time format %tD encodes days relative to time 0
* NEW pm3d quadrangles in 2D projection are clipped smoothly to x and y

Features introduced in version 5.4
==================================

* Support for 64-bit integer arithmetic
	o All evaluation of expressions and functions uses 64-bit arithmetic
	  if supported by the hardware platform.
	o Integer overflow is detected and handled according to user preference.

* Voxel grids
	o Gnuplot now supports operations based on 3D grids of voxel data.
	o The current content of one or more voxel grids can be referenced by
	  splot commands to assign colors or other properties to plot elements.
	o Data in a voxel grids can be plotted by splot styles dots, points,
	  or isosurface.

* Pixmaps as objects
	o "set pixmap" allows import of a png/jpeg/gif image as a pixmap that
	  can be positioned anywhere in a plot or on the page.  Unlike plotting
	  "with image", pixmap objects retain their original aspect ratio and
	  size independent of axis scaling or rotation.
	  Example: http://gnuplot.info/demo_5.4/pixmap.html

* New plot styles and plot options
	o 3D plot style "with polygons" reads polygon faces from a data file.
	  These can be used to create a surface or to describe a solid object.
	  Example: http://gnuplot.info/demo_5.4/polygons.html
	o "splot $voxelgrid with isosurface" creates a tessellated 3D surface
	  enclosing voxels above a requested threshold level.
	  Example: http://gnuplot.info/demo_5.4/isosurface.html
	o "set spiderplot" selects a new plotting mode for creating spider
	  plots, also known as radar charts. These are essentially parallel
	  axis plots in which the axes are arranged radially rather than
	  vertically.
	  Example: http://gnuplot.info/demo_5.4/spiderplot.html
	o Plot styles "with circles" and "with boxes" can be used in 3D plots.
	  Example: http://gnuplot.info/demo_5.4/3Dboxes.html
	o 2D plot style "with arrows" is a variant of "with vectors" in which
	  each arrow is specified by x:y:length:angle rather than x:y:dx:dy.
	o pm3d surfaces can have individual fill styles and separate top/bottom
	  fill colors.
	  Example: http://gnuplot.info/demo_5.4/hidden_compare.html
	o pm3d option "noclipcb" causes quadrangles with palette color outside
	  cbrange to be omitted from the plot rather than being assigned a
	  color clipped to cbmin or cbmax.
	o Contour line types can be customized.
	  Example: http://gnuplot.info/demo_5.4/custom_contours.html

* New data pre-processing filters
	o "smooth zsort" sorts 2D points on values in a 3rd column to determine
	  their drawing order.  In combination with using palette colors, this
	  facilitates highlighting outliers in a crowded scatter plot.

* New commands and command options
	o Voxel grid commands "set vgrid", "set vxrange", "vclear", "vfill"
	  and voxel().
	o New options "set walls" and "set grid vertical" for showing the
	  xy, xz, and yz planes in 3D plots.
	o "set table separator {tab|comma|"char"}" and "plot with table"
	  can be used to create csv files.
	o Array size can be implicit if an initializer is present, e.g.
	  Array A = [1,2,3]
	o Extra lines of text or symbols in the key can be added by
	  substituting "keyentry" in place of a filename or function in
	  plot and splot commands.
	o User-specified interpretation of mouse coordinates.
	  See map-projection demos.
	o The "load" command can input commands from a data block as an
	  alternative to reading them from a file.
	o "set datafile columnheaders" causes the first line of input to be
	  read as strings rather than as data values. This is equivalent to
	  "set key autotitle columnheader" but does not affect generation of
	  key entries.  Column headers are collected into an array of strings
	  by any subsequent "stats" commands.
	o "set view projection {xz|yz}"

* New terminals and terminal options
	o New latex terminal "pict2e" supersedes older terminals "latex",
	  "emtex", "eepic", and "tpic", which are no longer built by default.
	o The "pstricks" terminal now supports current gnuplot features
	  including RGB colors, transparency, filled polygons, and boxes.
	o The "pcl5" terminal now supports current gnuplot features.
	o The "texdraw" terminal has been updated.
	o The "windows" terminal now uses Direct2D rather than GDI/GDI+.
	o The "dospc" and "svga" DOS terminals now support interactive
	  terminal and mouse input.

* Other new features
	o Enhanced text mode accepts the escape sequence \U+xxxx (where xxxx
	  is a 4 or 5 character hexadecimal) to represent a Unicode code point
	  that is converted to the corresponding UTF-8 byte sequence on output.
	o Plot titles are evaluated _after_ plotting, rather than before.
	  This allows the title to reference values generated while plotting.
	o Hypertext from "set label ... hypertext" is sent to the clipboard
	  on left mouse-click.
	o Time/date input recognizes format %p to handle am/pm field
	o Support for multiple textbox styles
	o Built-in modified Bessel functions (besi0 besi1 besin)
	o Built-in order N Bessel functions of the 1st and 2nd kind (besjn besyn)

* Changes/Differences to previous gnuplot versions
	o Plot style "with parallelaxes" has revised syntax to match
	  histogram and spiderplot commands.  There is no longer a limit
	  on the number of axes in a plot, and iteration is possible:
	  E.g.: "plot for [column=1:N] DATA using column with parallelaxes"
	o pm3d filled area quadrangles are clipped smoothly to the current
	  zrange. This affects pm3d surfaces and the faces of 3D boxes,
	  polygons, etc.
	  Example: http://gnuplot.info/demo_5.4/pm3d_clip.html
	o Imaginary values returned by the "using" specifier of a 2D plot
	  are treated as undefined values (NaN).  This was already true for
	  function plots and for 3D data plots.
	o The "set fontpath" command is deprecated (only affects PostScript).
	o Since the "latex" and "eepic" terminals are deprecated, the
	  tutorial for using them is no longer included with the distribution.


		 Notes for packagers and testers
		================================

Obsolete or deprecated components
---------------------------------

The "gnuplot mode" elisp and TeX files for use with emacs are now
maintained as a separate project: https://github.com/bruceravel/gnuplot-mode
so there is no longer a configuration option --with-lisp-files.

LaTeX-related terminal drivers latex, emtex, eepic, and tpic are no longer
built by default.  Their closest equivalent is the new pict2e terminal, but
LaTeX users who want support for the full range of gnuplot plot styles are
recommended to use the cairolatex or tikz terminals.

The Japanese man page is provided both in eucJP and UTF-8 encodings.
Installation into appropriate directories is left to packagers.

Configuration options for interactive use
-----------------------------------------

The 5.4 source code supports three primary cross-platform interactive
modes in addition to several platform-specific modes.

1) Qt

   The qt terminal supports interactive display with menu-driven
   output to png, svg or pdf.  If either Qt4 or Qt5 is detected by the
   configure script, this will be the default terminal.  It is now the
   fastest and most full-featured interactive terminal option.

   To disable this terminal:
      ./configure --without-qt

   To force use of Qt4 even if Qt5 is present:
      ./configure --with-qt=qt4

2) Cairo/pango/wxWidgets

   This set of terminals includes pngcairo, pdfcairo, epscairo, and cairolatex
   for output to a file. The wxt terminal provides interactive display
   All of these will be built by default if the configuration script finds
   the required libcairo, libpango, libcairo, libwxgtk, and related
   support libraries

   To disable these terminals:
       ./configure --without-cairo
       ./configure --with-cairo --disable-wxwidgets

3) X11 (the "classic" interactive interface)
   This used to be the preferred interactive interface, but the newer
   wxt and qt terminals offer nicer output and a wider range of features.


Options for output to files
---------------------------

Of course the terminals (output modes) present in previous gnuplot versions
are also still available. These include, among many more obscure options:

- png/jpeg/gif output via libgd
- PostScript (*.ps or *.eps)
- Many flavors of TeX/LaTeX output, including TikZ and ConTeXt
- Bitmapped output to support older devices (e.g. HP deskjet, epson, and
  seiko printers, pbm bitmapped graphics files) is available if needed
  but is no longer configured in by default.
      ./configure --with-bitmap-terminals

Output of inline graphics to xterm or linux console terminal emulator
---------------------------------------------------------------------

The sixel or sixelgd terminals display graphics in-line with the commands
typed on a suitable terminal emulator.  For example "xterm -ti 340"
emulates a vt340 with sixel color graphics.  The yaft terminal emulator
can be run at linux console level with no x11 or other windowing system
active.

Options for generating interactive plots for web display
--------------------------------------------------------

- Mouseable output for display on the web can be created using either
  the canvas terminal (HTML5 2D canvas element) or the svg terminal.
  Both allow zooming, toggling plot elements on/off, and user-scriptable
  hot keys.

			Other Notes
			===========

Installation
------------

You can download a source tarball for the current gnuplot version
from the gnuplot development site on SourceForge.
	http://sourceforge.net/projects/gnuplot

Installation instructions are available in the source itself; the short
version for linux/unix-like systems is to unpack the tarball and then
<PRE>
build it:
      cd gnuplot-5.4.2 ; ./configure ; make
test it:
      make check
install it:
      make install
</PRE>

Pay careful attention to the output of the ./configure script.
It may indicate that some output drivers have been omitted because the
necessary support libraries were not found.  In general you need to have
previously installed the "*-devel-*" versions of these libraries.


Support
-------
Please report all bugs and installation problems to the bug tracker
on SourceForge:
	https://sourceforge.net/p/gnuplot/bugs/

Development
-----------
Gnuplot development is ongoing. The development branch contains preliminary
implementations of new features.  The current development version is 5.5
(odd minor number) and will eventually be released as version 5.6 or 6.0
(even minor number).  Bugfixes to version 5.4 will appear in patchlevel
releases 5.4.1, 5.4.2, etc., approximately twice a year or as needed
to correct a serious problem.
