C++ ChartRenderer::GetCanvas方法代码示例

void 
TraceHistoryRenderer::render_filled_posneg(ChartRenderer &chart,
                                           const TraceVariableHistory& var) const
{
  fixed x_last(fixed(0)), y_last(fixed(0));
  unsigned i=0;
  for (auto it = var.begin(); it != var.end(); ++it, ++i) {
    fixed x= fixed(i);
    fixed y= *it;
    if (i) {
      if (sgn(y)*sgn(y_last)<0) {
        if (positive(y_last))
          chart.DrawFilledLine(x_last, y_last, x_last+fixed(0.5), fixed(0),
                               vario_look.lift_brush);
        else if (negative(y_last))
          chart.DrawFilledLine(x_last, y_last, x_last+fixed(0.5), fixed(0),
                               vario_look.sink_brush);

        x_last = x-fixed(0.5);
        y_last = fixed(0);

      }
      if (positive(y) || positive(y_last))
        chart.DrawFilledLine(x_last, y_last, x, y, vario_look.lift_brush);
      else if (negative(y) || negative(y_last))
        chart.DrawFilledLine(x_last, y_last, x, y, vario_look.sink_brush);
    }
    x_last = x;
    y_last = y;
  }
  if (look.inverse)
    chart.GetCanvas().SelectWhiteBrush();
  else
    chart.GetCanvas().SelectBlackBrush();
  chart.DrawDot(x_last, y_last, Layout::Scale(2));
}

//.........这里部分代码省略.........
  const ThermalBandInfo &thermal_band = calculated.thermal_band;

  // calculate height above safety height
  fixed hoffset = task_props.route_planner.safety_height_terrain +
    calculated.GetTerrainBaseFallback();

  fixed h = fixed(0);
  if (basic.NavAltitudeAvailable()) {
    h = basic.nav_altitude - hoffset;
    chart.ScaleYFromValue(h);
  }

  bool draw_start_height = false;
  fixed hstart = fixed(0);

  draw_start_height = ordered_props
    && calculated.ordered_task_stats.task_valid
    && ordered_props->start_constraints.max_height != 0
    && calculated.terrain_valid;
  if (draw_start_height) {
    hstart = fixed(ordered_props->start_constraints.max_height);
    if (ordered_props->start_constraints.max_height_ref == AltitudeReference::AGL &&
        calculated.terrain_valid)
      hstart += calculated.terrain_altitude;

    hstart -= hoffset;
    chart.ScaleYFromValue(hstart);
  }

  // no thermalling has been done above safety height
  if (!positive(calculated.thermal_band.max_thermal_height))
    return;

  // calculate averages
  int numtherm = 0;

  fixed Wmax = fixed(0);
  fixed Wav = fixed(0);
  fixed Wt[ThermalBandInfo::NUMTHERMALBUCKETS];
  fixed ht[ThermalBandInfo::NUMTHERMALBUCKETS];

  for (unsigned i = 0; i < ThermalBandInfo::NUMTHERMALBUCKETS; ++i) {
    if (thermal_band.thermal_profile_n[i] < 6) 
      continue;

    if (positive(thermal_band.thermal_profile_w[i])) {
      // height of this thermal point [0,mth]
      // requires 5 items in bucket before displaying, to eliminate kinks
      fixed wthis = thermal_band.thermal_profile_w[i] / thermal_band.thermal_profile_n[i];
      ht[numtherm] = i * calculated.thermal_band.max_thermal_height 
        / ThermalBandInfo::NUMTHERMALBUCKETS;
      Wt[numtherm] = wthis;
      Wmax = std::max(Wmax, wthis);
      Wav+= wthis;
      numtherm++;
    }
  }
  chart.ScaleXFromValue(Wmax);
  if (!numtherm)
    return;
  chart.ScaleXFromValue(fixed(1.5)*Wav/numtherm);

  if ((!draw_start_height) && (numtherm<=1))
    // don't display if insufficient statistics
    // but do draw if start height needs to be drawn
    return;

  const Pen *fpen = is_infobox ? NULL : &look.pen;

  // position of thermal band
  if (numtherm > 1) {
    std::vector< std::pair<fixed, fixed> > thermal_profile;
    thermal_profile.reserve(numtherm);
    for (int i = 0; i < numtherm; ++i)
      thermal_profile.emplace_back(Wt[i], ht[i]);

    if (!is_infobox) {
#ifdef ENABLE_OPENGL
      const GLEnable blend(GL_BLEND);
#endif
      chart.DrawFilledY(thermal_profile, look.brush, fpen);
    } else
      chart.DrawFilledY(thermal_profile, look.brush, fpen);
  }

  // position of thermal band
  if (basic.NavAltitudeAvailable()) {
    const Pen &pen = is_infobox && look.inverse
      ? look.white_pen : look.black_pen;
    chart.DrawLine(fixed(0), h,
                   settings_computer.polar.glide_polar_task.GetMC(), h, pen);

    if (is_infobox && look.inverse)
      chart.GetCanvas().SelectWhiteBrush();
    else
      chart.GetCanvas().SelectBlackBrush();
    chart.DrawDot(settings_computer.polar.glide_polar_task.GetMC(),
                  h, Layout::Scale(2));
  }
}