		   GNUPLOT VERSION 4.6.6
	    ===================================

This is an incremental update of gnuplot version 4.6 containing bug fixes
and some minor additions that increase forward compatibility with the
next major gnuplot release (5.0).

This is the last incremental update planned for gnuplot 4.6, as initial
release candidates for gnuplot 5.0 are already available.  Version 5 will
offer significant improvements over version 4, but some of these are not
100% backwards compatible with scripts written for version 4.  Therefore
anyone interested in long-term 100% compatibility with existing gnuplot
scripts may want to install and continue to provide version 4.6.6 even
after release of gnuplot version 5.

A short list of changes since the previous patchlevel (version 4.6.5)
is given below and in the NEWS file.  Detailed information is in ChangeLog.

New features, changes and fixes since gnuplot version 4.6.5
===========================================================

* NEW linetype keyword "nodraw" can be used to draw only the points in "with lp"
* NEW plot option to "skip N" lines at start of an ascii data file
* NEW 'set fit prescale' normalized fit parameters before M-L refinement
* NEW update svg terminal to grey out the key entry when a plot is toggled off
* NEW allow keywords "comma" and "tab" for "set datafile separator"
* CHANGE Accept "with image pixels" as a synonym for "with image failsafe"
* CHANGE return NaN if a requested numerical data value finds a string instead
* CHANGE Consume only one space following the font name in an enhanced test string
* CHANGE respond to left mouse click on press rather than on release
* FIX Faster recovery from outboard server gnuplot_qt being killed
* FIX get rid of O(N^2) memory allocation for string data in long input lines
* FIX large integers in iteration spec could cause overflow in end condition check
* FIX object fillcolors should be consistent with the color of current linetypes
* FIX LFS support on 64bit platforms (not backported for 32bit platforms)
* FIX timecolumn() applied to non-axis data reports an error rather than faulting
* FIX clipping could fail on integer overflow
* FIX segfault resulting from strcol(N) applied to empty field in a *.csv file
* FIX adjustment of key size to accommodate long key title
* FIX treat data value read as "NaN" the same as we would "1/0"
* FIX handling of events triggered by closing the qt plot window
* FIX iteration failure due to integer overflow
* FIX clip r axis tics to current plot boundary
* FIX logscale cb axis with volatile data
* FIX qt terminal timing problem with mouse click+release
* FIX qt terminal handle window close events
* FIX incorrect processing of certain loop [start:end:incr] combinations
* FIX Fix y extent and clipping of rectangles with y coord < 0 or inverted axes
* FIX handle columnheaders in input to fit
* FIX add sanity check in pdf.trm to avoid strcpy(fontname,fontname)


		 NOTES TO PACKAGERS AND TESTERS 
		===============================

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

The 4.6 source code supports three primary cross-platform output modes
in addition to several platform-specific modes.

1) Cairo/pango/wxWidgets
   These terminals were introduced in version 4.4 and are now the most
   stable and full-featured option.  This set of terminals includes
   - pngcairo, pdfcairo, epscairo, and cairolatex for output to a file
   - wxt for interactive display
   This is the default configuration, but requires prior installation of
   libcairo, libpango, libcairo, libwxgtk, and related support libraries
   The wxt terminal (but not the others) requires wxWidgets.  Note that
   wxWidgets 3.0 is not yet supported.

   To disable all of these terminals:
       ./configure --without-cairo --disable-wxt

   To disable only wxt:
       ./configure --with-cairo --disable-wxt

2) Qt
   The qt terminal supports interactive display with menu-driven
   output to png, svg or pdf.
   The gnuplot 4.6 autoconfigure and build system handles only Qt4.
       ./configure --enable-qt

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
- Many flavors of TeX/LaTeX output, including TikZ and ConTeXt (new)
- Bitmapped output to support many older devices (e.g. HP deskjet, epson,
  seiko printers, pbm bitmapped graphics files) is available if needed
  but is no longer configured in by default.
      ./configure --with-bitmap-terminals

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.

Online demo plots
-----------------

Demo plots illustrating new and old features are online at

	http://gnuplot.sourceforge.net/demo/


		          OTHER NOTES
		===============================

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

You can download a source tarball for gnuplot version 4.6.6 from the 
gnuplot development site on SourceForge.

	http://sourceforge.net/project/showfiles.php?group_id=2055

Installation instructions are available in the source itself; the short
version for linux/unix-like systems is to unpack the tarball and then
build it:
		cd gnuplot-4.6.6 ; ./configure ; make
test it:
		make check
install it:
		make install

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. 


Known issues
------------

- Mac OSX ships with a terminal input library that appears to be GNU
libreadline, but isn't really.  The program tries to cope with this, but
you may get better results by configuring gnuplot to use either its own
built-in readline routines or the real GNU libreadline.

- The gnuplot build system is not very good at figuring out where to find
or install LaTeX-related files.  This can affect use of the new lua/tikz
and ConTeXt terminals.

- You can configure support for both wxt and qt into the same gnuplot
executable, but only one of these two output modes can be used in any
given gnuplot session.


Support
-------
Please report all bugs and installation problems to the bug tracker
on SourceForge:

	http://sourceforge.net/tracker/?group_id=2055&atid=102055

There is also an gnuplot discussion forum on usenet group

	comp.graphics.apps.gnuplot


Development
-----------
Gnuplot development is quite active. The development branch on SourceForge
contains many new features.  The current development branch is labeled 5.1.
Feedback and contributions of code are very welcome.
