MagneticPlotMap.h

/******************************************************************************
 * $Id: MagneticPlotMap.h,v 1.0 2011/02/26 01:54:37 nohal Exp $
 *
 * Project:  OpenCPN
 * Purpose:  WMM Plugin
 * Author:   Sean D'Epagnier
 *
 ***************************************************************************
 *   Copyright (C) 2013 by Sean D'Epagnier   *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,  USA.         *
 ***************************************************************************
 */
 
#include <list>
#include "pi_TexFont.h"
#include "GeomagnetismHeader.h"
 
enum MagneticPlotType {
  DECLINATION_PLOT,
  INCLINATION_PLOT,
  FIELD_STRENGTH_PLOT
};
 
class pi_ocpnDC;
 
/* must be a power of 2, and also divide 360 and 176;
   really only 8 works without more modifications */
#define ZONE_SIZE 8
 
/* divisible by 8 and any closer to the pole than this plots
   horribly anyway on a flattened earth. */
#define MAX_LAT 88
#define LATITUDE_ZONES (2 * MAX_LAT / ZONE_SIZE) /* perfectly divisible */
#define LONGITUDE_ZONES (360 / ZONE_SIZE)
 
/* a single line segment in the plot */
class PlotLineSeg {
public:
  PlotLineSeg(double _lat1, double _lon1, double _lat2, double _lon2,
              double _contour)
      : lat1(_lat1), lon1(_lon1), lat2(_lat2), lon2(_lon2), contour(_contour) {}
  double lat1, lon1, lat2, lon2;
  double contour;
};
 
/* cache values computed from wmm to improve speed */
class ParamCache {
public:
  ParamCache() : values(NULL), m_step(0), m_lat(0.0) {}
  ~ParamCache() { delete[] values; }
  void Initialize(double step);
  bool Read(double lat, double lon, double &value);
 
  double *values;
  double m_step;
  double m_lat;
};
 
/* main model map suitable for a single plot type */
class MagneticPlotMap {
public:
  MagneticPlotMap(MagneticPlotType type, MAGtype_MagneticModel *&mm,
                  MAGtype_MagneticModel *&tmm, MAGtype_Ellipsoid *ellip)
      : m_type(type),
        m_bEnabled(false),
        m_Spacing(0.0),
        m_Step(0.0),
        m_PoleAccuracy(0.0),
        MagneticModel(mm),
        TimedMagneticModel(tmm),
        Ellip(ellip),
        lastx(0),
        lasty(0) {
    UserDate.Year = 2015;
    UserDate.Month = 1;
    UserDate.Day = 1;
    UserDate.DecimalYear = 2015.0;
  }
 
  ~MagneticPlotMap() { ClearMap(); }
 
  void ConfigureAccuracy(int stepsize, int poleaccuracy);
  double CalcParameter(double lat, double lon);
  void BuildParamCache(ParamCache &cache, double lat);
  double CachedCalcParameter(double lat, double lon);
  bool Interpolate(double x1, double x2, double y1, double y2, bool lat,
                   double lonval, double &rx, double &ry);
  void PlotRegion(std::list<PlotLineSeg *> &region, double lat1, double lon1,
                  double lat2, double lon2);
  bool Recompute(wxDateTime date);
  void Plot(pi_ocpnDC *dc, PlugIn_ViewPort *vp, wxColour color);
 
  void ClearMap();
  void DrawContour(pi_ocpnDC *dc, PlugIn_ViewPort &VP, double contour,
                   double lat, double lon);
 
  MagneticPlotType m_type;
  bool m_bEnabled;
  double m_Spacing;
  double m_Step;
  double m_PoleAccuracy;
 
  /* two caches for all longitudes alternate
     places (step over each other) to cover the two latitudes
     currently being built */
  ParamCache m_Cache[2];
 
  MAGtype_MagneticModel *&MagneticModel;
  MAGtype_MagneticModel *&TimedMagneticModel;
  MAGtype_Ellipsoid *Ellip;
  MAGtype_Date UserDate;
 
  /* the line segments for the entire globe split into zones */
  std::list<PlotLineSeg *> m_map[LATITUDE_ZONES][LONGITUDE_ZONES];
 
  TexFont m_TexFont;
  int lastx, lasty; /* when rendering to prevent overcluttering */
};