Function DrawMapLine

xcharts0.cpp:1695–1736

// between them.

void DrawMapLine(real lon1, real lat1, real lon2, real lat2,
  flag fGlobe, int nScl, CIRC *pcr, real deg)
{
  int x1, y1, x2, y2;
  real lon3, lat3;
#ifdef WIRE
  int z1, z2;
#endif

  // Recursive case: Draw each half of the line separately.
  if (SphDistance(lon1, lat1, lon2, lat2) > 10.0) {
    SphRatio(lon1, lat1, lon2, lat2, 0.5, &lon3, &lat3);
    DrawMapLine(lon1, lat1, lon3, lat3, fGlobe, nScl, pcr, deg);
    DrawMapLine(lon3, lat3, lon2, lat2, fGlobe, nScl, pcr, deg);
    return;
  }

  // Base case: Draw a single line segment.
  lat1 = rDegQuad - lat1;
  lat2 = rDegQuad - lat2;
#ifdef WIRE
  if (gs.ft == ftWire) {
    WireGlobeCalc(lon1, lat1, &x1, &y1, &z1, nScl, deg);
    WireGlobeCalc(lon2, lat2, &x2, &y2, &z2, nScl, deg);
    WireLine(x1, y1, z1, x2, y2, z2);
    return;
  }
#endif
  if (!FMapCalc(lon1, lat1, &x1, &y1, fGlobe, -1, 0.0, nScl, pcr, deg) &&
    !FMapCalc(lon2, lat2, &x2, &y2, fGlobe, -1, 0.0, nScl, pcr, deg)) {
    if (gi.nMode != gWorldMap || gs.fMollweide) {
      if (NAbs(x2-x1) < (pcr->xr >> 2))
        DrawLine(x1, y1, x2, y2);
    } else {
      if (lat1 <= 0.0 || lat1 >= rDegHalf)
        x1 = x2;
      else if (lat2 <= 0.0 || lat2 >= rDegHalf)
        x2 = x1;
      DrawWrap(x1, Min(y1, gs.yWin-1), x2, Min(y2, gs.yWin-1), 0, gs.xWin-1);
    }
  }
}


// Draw a triangle between three coordinates on the globe, in which other