Method paint

src/openms_gui/source/VISUAL/Painter2DBase.cpp:124–227

  }

  void Painter2DPeak::paint(QPainter* painter, Plot2DCanvas* canvas, int layer_index)
  {
    // renaming some values for readability
    const auto& peak_map = *layer_->getPeakData();

    // skip empty peak maps
    if (peak_map.empty())
    {
      return;
    }

    const auto [rt_min, rt_max] = canvas->visible_area_.getAreaUnit().RangeRT::getNonEmptyRange();
    const auto [mz_min, mz_max] = canvas->visible_area_.getAreaUnit().RangeMZ::getNonEmptyRange();
    const auto [im_min, im_max] = canvas->visible_area_.getAreaUnit().RangeMobility::getNonEmptyRange();

    //-----------------------------------------------------------------------------------------------
    // Determine number of shown scans (MS1)
    std::vector<Size> scan_indices; // list of visible RT/IM scans in MS1 with at least 2 points
    const auto rt_end = peak_map.RTEnd(rt_max);
    for (auto it = peak_map.RTBegin(rt_min); it != rt_end; ++it)
    {
      if (it->getMSLevel() == 1 && it->size() > 1 && Math::contains(it->getDriftTime(), im_min, im_max))
      {
        scan_indices.push_back(std::distance(peak_map.begin(), it));
      }
    }
    Size n_ms1_scans = scan_indices.size();

    if (n_ms1_scans > 0)
    {
      // sample #of points at 3 scan locations (25%, 50%, 75%)
      // and take the median value
      Size n_peaks_in_scan(0);
      {
        static constexpr std::array<double, 3> quantiles = {0.25, 0.50, 0.75};
        std::array<Size, quantiles.size()> n_s;
        for (Size i = 0; i < quantiles.size(); ++i)
        {
          const auto& spec = peak_map[scan_indices[n_ms1_scans * quantiles[i]]];
          if (!spec.isSorted())
            throw Exception::BaseException();
          n_s[i] = std::distance(spec.MZBegin(mz_min), spec.MZEnd(mz_max));
        }
        std::sort(n_s.begin(), n_s.end());
        n_peaks_in_scan = n_s[1]; // median
      }

      Size rt_pixel_count, mz_pixel_count;
      { // obtain number of pixels in RT/IM and MZ dimension
        auto tmp = canvas->getPixelRange().getAreaUnit();
        rt_pixel_count = tmp.RangeRT::isEmpty() ? tmp.getMaxMobility() : tmp.getMaxRT();
        mz_pixel_count = tmp.getMaxMZ();
      }
      double ratio_data2pixel_rt = n_ms1_scans / (double)rt_pixel_count;
      double ratio_data2pixel_mz = n_peaks_in_scan / (double)mz_pixel_count;

      // minimum fraction of image expected to be filled with data
      // if not reached, we upscale point size