TODO

* Implement the scales in OGL (a way to show the magnitudes of the radiation
patterns, I (Lisandro) have some ideas of how to do them, but I didn't have
time to ellaborate them).
* Change the color of the antennas
* have a touchstone file export for the impedance so users can use it
e.g. in qucs to create the matching and feeding network (Thanks Stefan)

I (Graham) also have a wish list.

* Now that Lisandro's ground plane radials display, to further
  modify them to display GD card additions, being zones of different
  ground plane parameters and heights (cliffs).
  This is maybe OK if RP specifies circular, but more awkward to generate
  the intersection line when it is linear.
  
* Add a "Recent Files" choose list to the File Menu.
  How many are in the list should be settable somehow, say by a value in
  a user "Preferences" file which overides a "defaults" version kept
  wherever qantenna puts its resources. Having an expansive "Preferences"
  feature is not high priority right now, but if somebody knows how to
  set up the basic method, that would be welcome.

* Have the "Help" open a help document file.
  HTML will do, because nearly everyone has a browser. OK - we are open
  to suggestions here.

* Have qantenna display ground plane and radial structures.
  Recent work by Lisandro now displays ground plane, radials, if present.
  Make the grid change to a darker, maybe brown colour if GN is present.
  The default maybe should be that they are a bit muted, so as not to be
  too competitive with the elements, and to leave room to highlight
  sources and loads, and other future stuff

*  Make the radials display colour configurable (Lisandro's idea)

* Display the radiation pattern computed for the Sommerfield/Norton
  ground result, even if the GN card comes *after* the RP card,
  essentially by moving GN to before any cards it might affect.
  Putting it right after GE might be best.

* Printable plots of RP projections horizontal and vertical. Also, plots
  of "slice" where the slice plane can be tilted and shifted. Slice
  outputs specified by card inputs have been a high-speed calculation
  feature of NEC2 since the beginning. Adding such features by using the
  handy dodge of artificially "adding in" a card line that was maybe not
  present in the original input is OK.

* Comparison plots in different colours for different conditions,
  e.g. one antenna compared to another, or same antenna at different
  frequencies.

* Frequency sweep, both as requested from file inputs, and interactive
  chosen by the user, again by artificially inserting card line inputs.
  The output set can then be displayed at spot frequencies using spinbox
  and/or animation. Related to this is cleanup of temporary files.

* Impedance, SWR and similar plots. Again, delivered if requested from
  card file content, or simply included anyway, regardless of card file
  input. These cursors on these should change in object-oriented fashion
  to match the current spinbox setting, and have cursors to aid getting
  numerical information from them. Multiple displays on the same graphs
  should have colours that match the colour of the corresponding antenna
  RP plot.

* Option for using density-gradient radiation pattern displays, so that
  3D displays of antenna can be compared, by using a different colour
  for each antenna. For single antennas, the present colour-spectrum
  display is very nice.

* Have the choice of gain displays Linear Power, Linear Voltage E-Field
  (to better show up side lobes), ARRL definition exp(0.05827*gain),
  and Logarithmic. these should be available for various polarization
  types, Near Field and Far Field. I have no idea yet what a nice
  user interface would be for these, nor what the defaults should be.

* Display of NEC warning outputs about file structures having geometric
  conditions that limit accuracy, such as unsuitable radius conductors,
  bad join angles, etc. These come free when necpp returns results.

* An editor aid, able to modify/fix existing input files, and to create
  new antenna files from the beginning, save/save-as with warning about
  overwriting existing files. We do not underestimate what a task this
  might be, but a box with the built-in Qt edit widget migh be a start.

* Scaling function, to be able to calculate the new antenna dimensions
  for an existing design, made for a new frequency. This feature has
  been available in programs even from the days of DOS only.

Much of this is beyond what I know how to do, but I am hoping some of
the skilled programmer folk out there may be able to help us get there.