X N E C V I E W
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A program for visualizing NEC2 input and output data (Unix/X-windows).

Copyright (C) 1998-2001, Pieter-Tjerk de Boer

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HISTORY:
--------

Version 0.1, 1998-06-06:
- first public release
- only few input card types supported

Version 0.2, 1998-12-13:
- almost all input card types supported
- added plotting of gain pattern
- colour added
- made front and back of surfaces distinguishable (by colour)

Version 0.3, 1999-1-15
- added PostScript output
- added third gain scale, "log"
- added buttons in the window
- added plotting of gain as slices in coordinate planes
- very small mouse dragging is treated as clicking
- corrected handling of output files which sweep over only one angle
- man page added, thanks to Joop Stakenborg, PA3ABA.

Version 0.4, 1999-5-30
- fixed bug in PostScript output
- added handling of GS cards
- "long" options now need -- instead of -
- fixed colours on 1bpp screen

Version 0.5, 1999-6-13
- added double buffering support: this reduces flickering by drawing in
  a separate 'Pixmap' instead of on the screen
- postscript now uses a private dictionary
- more general NEC output reading routine
- uses hinted motion events to speed up dragging
- motion+first button now rotates entire gain pattern, motion + second
  button rotates simplified gain pattern (quicker)
- fixed bug in linear gain scale
- removed -q/--quick option
- added a (too?) simple icon to appear when xnecview is iconified
The first 5 of these changes were essentially contributed by
Alan Bain, M1BXV; thanks!

Version 0.6, 1999-7-4
- added display of wire numbers
- added display of location of excitations and loads
- added display of 'X', 'Y' and 'Z' at axes
- configuration is now separate .h file
- corrected "ARRL style" gain scale (now 0.89 per 2 dB, as per the "ARRL
  Antenna Book"; tnx Don, VE3HUR)
- added handling of GM cards with non-zero ITS
- xnecview no longer exits when supplied with incorrect input
- an error message is printed when writing postscript fails (tnx Alan Bain)
- standard X command line options like -geometry now work

Version 1.0, 1999-7-25
- GW cards lacking the wire radius are now accepted
- GC cards now produce a warning
- added a bit of text to the postscript output
(tnx to Don VE3HUR for testing and remarks resulting in the above changes)
- iconifying now uses own icon again (didn't in 0.6)

Version 1.01, 2000-01-21
- card types of structure input ("GW" etc.) now also accepted in lower case

Version 1.02, 2000-03-25
- print not only maximum gain, but also direction of maximum gain and
  front-to-back-ratio.
- plot radial lines every 10 degrees when looking along the X/Y/Z axis
  (essentially contributed by Marco Menchise, IZ8AEB; tnx!)

Version 1.10, 2000-04-25
- added a window with plots of SWR, gain, etc. as a function of frequency
  (inspired by a preliminary implementation by Marco Menchise, IZ8AEB; tnx!)
- added support for radiation diagrams at multiple frequencies
- added plotting multiple sets of radiation data (= results from RP cards)
  for a frequency.
- added reading of multiple output files.
- removed unbuffered option.
- minor rewrites of some parts of the code.
- revised the documentation, creating new files USAGE and HISTORY, thus
  shortening README.

Version 1.11, 2000-07-15
- added "support" for GC cards (i.e., they are ignored since xnecview
  does not display the wire thickness).
- added calculation and plotting of gain and f/b in direction toward observer.
- added a line of text showing frequency and gain in bottom of 3D plot.
- added centered titles to the 2D plots.
- mostly rewrote the man page on the basis of the USAGE file.
- some optimizations by caching often calculated data; however, the Xserver's
  speed seems to be the limiting factor on my system, so this doesn't bring
  much.
- bugfix: clicking on the gainscale button if no radiation pattern data was
  available produced a segmentation fault.
- bugfix: reading multiple sets of radiation data sometimes gave an empty
  radiation pattern plot, depending on the order of the data.
- bugfix: GW cards with NRPT=0 or ITS>0 were not handled correctly.
Note: this version is a snapshot taken just before the GTK version started
to diverge too far to keep developing both versions in parallel.

Version 1.20, 2000-08-07
- user interface code converted to use the GTK library instead of Xaw/Xmu/Xt.
- added display of phase and magnitude of currents in wires (based on original
  suggestions by Marco Menchise IZ8AEB and Francesco Messineo IW8QPI; tnx!).
- changed mouse bindings for dragging and zooming
- added support for TL and NT cards
- dynamic memory allocation for radiation pattern data, resulting in much
  smaller memory usage.
- dropped the USAGE file, the man page is now the only file with detailed
  usage information.

Version 1.30, 2000-11-05
- added linear-in-voltage scale; the original linear scale was (and
  still is) linear in power.
- animated display of currents, charges, electric and magnetic (near) field
  vector, Poynting vector.
- command-line options; xnecview options in comment line of NEC input
- fix some compiler warnings
- limit display of Z to 20*Z0
- add display of phi(Z)/abs(Z)
- don't draw a square at each data point if there are many (window 2)
  (latter four changes essentially contributed by Joerg Wunsch DL8DTL; tnx!)
- number of grid lines in freqplots adapts to size of graph
- output files without currents information no longer cause a segfault
- some other minor fixes

Version 1.31, 2001-06-24
- changed axes of frequency plots: number of subdivisions can now be
  variable, resulting in a more readable axis (stepsizes are now always
  multiples of 1, 2, 2.5, or 5; no longer 4 or 7.5).
- if f/b is unknown, '-' is printed (instead of -1e-308) in table
- hide 'nan' on axes (window 2) if no relevant data available
- impedance (Z0) can now have up to 4 digits (instead of 2)
- new option: -aupdate to set the update interval of animation
- bugfix: extremely large values of Zi could hang xnecview
- some small fixes in choosing which frequency is used for radiation
  pattern display after reloading

Version 1.32, 2002-08-25
- the radiation pattern can now be displayed as a "wire grid" (like in
  earlier versions) or as an "opaque" surface (i.e., with hidden lines
  removed). The latter view is usually much easier to interpret, especially
  when there are many sidelobes.
- the gain display can now be limited to one polarization component, or
  the 3D pattern can be coloured according to the dominant polarization.
- changed some of the default colors, which did not contrast enough with
  the white background. But you can of course change them again, by
  editing config.h .
- keypress 'z' now suspends/resumes the animation
- typo & corrections in manpage
- fixed bug that could cause segfault if NEC output file initially
  contained data at one frequency, and at more frequencies upon reread.
- reduced memory usage by changing arrays from double to float
- bugfix: missing lines in eps-export of freqplot
- bugfix: GS card vs. currents data
- if only a NEC output file is given and no input file, the structure view
  now defaults to 'none' rather than 'currents'.

Version 1.33, 2002-12-27
- now all memory allocation is dynamic, so no limitations on model size
  anymore.
- output is now also correctly interpreted if numerical Green's function 
  is used (GF card).
- added commandline option --pol .
- changed rotation "speed": this is now independent of zoom factor
- bugfix: if surfaces were present, GS cards were not interpreted properly
- bugfix: segfault sometimes when selecting 'opaque' while no radiation data
  was available
- elaborate bugfix of opaque drawing; in practice, this mostly affects drawing
  of points on the Z axis, when a polarization different from 'total' is
  selected.
- fixes to the Imakefile (tnx Alan Bain)

Version 1.34, 2003-09-10
- yet another opaque drawing bugfix.
- bugfix: when zooming in very far, coordinates became too large for X11,
  causing incorrect lines to appear.
- converted the last bits of Xlib code to GTK.
- changed line ending style from "butt" to "round".
- bugfix in parsing xnecview options embedded in NEC input file
- minor fixes in handling of window (re)sizing