What's new in 3.6 ?

Still to do
  Many terminals to be converted to new layout
  someone has contributed a new hidden-line-removal
  '-' as load filename / command-line param
  terminals are no longer allowed to do their own scaling

Plus quite a few contributed patches that I haven't yet installed (sorry)

in latest
  allow negative ticslevel
  geometric series tics for logscale
  enhanced sprintf format for tics
  take plot size and driver into account when choosing tics
  accept x1y2 etc in place of first/second
  extra line in boxed key
  x2 label
  fonts for label
  strftime format for 'set time'
  more timeseries patches
  set locale
  try to fix postscript bounding box

in 224
  set clabel ['format']
  pstexdriver
  set encoding
  enhpost moved into post.trm
  index a:b:c for splot

in 194
  multiplot for splot

in 188
  os9 port
  set xrange [] reverse writeback
  allow mix of co-ordinate systems within an arrow/label posn
  initial multiplot support
  - doesn't yet check that terminal is capable, but there is a
    flags field added to the terminal entry to tell gnuplot about this.
    also, suspend() / resume() entry points which are to be called
    between plots of a multiplot.

in 178
   arbitrary length/number of columns in datafile
   accept double/quad-precision fortran numbers (1.23{dDqQ}4)
   - but not in scanf format string
   undefined fit parameters start at 1 rather than 1e-30
   - more chance of convergence / less change of unitary matrix
   WIN32 / Win-NT support
   table output can be read back in for data splot
   - hence gnuplot can be used to dgrid a datafile and write it out
   set missing 'string'
   - nominate a token as standing for missing values in datafile
   - not yet added to documentation
   updates to time-series stuff (so it doesn't break at 2000)
   - except it has become horribly non-portable :-(
   split graph3d.c into util3d.c and hidden3d.c

in 166
   set bar <size>
   - a number rather than just small or large
   allow different linetypes for grid at major and minor tics
   a few more set no* commands for consistency.
   initial go at implementing tic mirrors and axes for splot
   - no ztic axis yet (or no zzeroaxis)
   - tics on axes are not hidden by surface
   attempt to make sin(x) behave as expected when set angle degrees
   - gives answers if x is complex, but I dont know if they are correct
     - acos(cos(x)) seems to give x, so at least its consistent
   - fix a bug which made acos(cos({0,1})) undefined
   new grass.trm

in release 162/164
   set size [{no}square] x,y  - tries to plot with aspect ratio 1
   - seems to work great for postscript
   - please check with your favourite driver
   - uses relative sizes of tics to determine required size.
   posn for key, labels and arrows can be in one of 4 co-ordinate systems
   - first_axes (default)
   - second_axes (for plot..second)
   - graph  (0,0 -> 1,1 = plotting area)
   - screen (0,0 -> 1,1 = whole screen)
   - arrows needn't have endpoints in same co-ords. see help set label
   via is now a required keyword for fit
   - fit f(x) 'file' ... via { 'file' | a,b,... }
   - this is to avoid confusing 'file' with 'using-format-string'
   win32 and 16-bit dos fixes
   - I can compile with tc++, but get an overlay error at runtime.
   new set of documentation programs (I haven't tried them)
   various tweaks to makefile
   changes to pslatex
   - substitute .ps at _last_ . in filename 
   - accept font size of enclosing document as an option.
   - dont forget to close aux file

in release 151

  linux security patch
  can specify font for labels, etc (postscript only ? - I haven't tried this)
  can specify linetype to draw grid / zeroaxes / arrows
  emx terminal driver
  first attempt at pipes for VMS and vector style - needs more work
  l/b/r/t-margin  in place of xmargin - more control over size of margins
  incompatible changes to polar mode:
  - t is now the dummy variable, so x is width of plot as expected
  - tics are not automatically on axes -   set {xy}tics axis nomirror
  - grid is not automatically polar - set grid x [mx] polar [angle]
  - no numbers on grid - they were always in degrees
  second axes
  - x2 and y2 are an independent pair of axes, but they inherit
    ranges from x and y if no second data
    - there can be problems with this, actually - if x2tics are not
      shown, x2range is not autoextended to whole number of tics, so
      same data might not have same range.
  - set x2tics/y2tics/x2label/y2label
  - set [no]log x2 / y2
  - plot [first,] f(x), 'file', ..., second, g(x), ...
  - get specify grid at any/all of x,y,x2,y2
  - see electron.dem
  set border <mask> - 12 bit binary number selects 12 sides of cube around splot
  can specify grid z, to get a grid on back wall of splot
  set mxtics [<interval>|default] | set nomxtics
  - set mxtics  gives auto for logscale, fixed for linear 
  binary, index and every keywords to datafiles.
  - every also works with binary files
  can use '-' as datafile for inline data (ends at line with e)
  can use '' to mean reuse previous file
  splot and fit now use datafile module
  - FIT_SKIP no longer supported - use fit f(x) 'file' every n
  can limit fit range using   fit [variable=min:max] f(variable) ...
  set ticscale <major> [<minor>]
  surface is clipped with no hidden line removal
  - still to do contour and hidden-line surface
  set {x|y|x2|y2} [axis|border] [no]mirror
  - can put tics on border or axes
  - mirror controls mirroring of tics on opposite axis
    - no longer coupled to  set tics out  setiing.
  No longer need to specify parametric mode for 3-column data files.
  ranges automatically extended to whole number of tic intervals
  - doesn't always manage to drop vertical from surface to corner of base
    - workaround is either specify range or use  set border

patchlevel 140
--------------
I've probably missed a lot of features since I'm so used to them.
Plus I never bothered with 3.5 so some of these may have been there.
some of these may have made it into the documentation
Here goes:

  fit f(x) 'file' via ...
  read and plot time data  (timedat.dem)
  set key [top|bottom|under] [left|right|out] [reverse] [box [<linetype>]]
  set key title 'text'
  Processing of escape sequences in "strings" but not 'strings'
  - TeX users in particular advised to use ''
  Multiline labels, etc, using "first\nsecond"
  enhpost driver
  call command (load with parameters)
  x error bars. splines. boxes. [some may have been in 3.5]
  pipes for amiga
  the using patch   plot 'file' using spec:spec:...
  - spec is either column number or (expression in $1, $2, ...)
  new pslatex driver with postscript to aux file.
  set pointsize <scale factor> on some terminals
  doubles in  plot...using  format string - %lf
  unlimited input line length and expression (action) table
  minor tic-marks (like logscale but also for linear)
  - also set grid [mx|my]



that's all I can think of for the moment...
