Function UpdatePlotCache

Charts/Core/vtkChartXY.cxx:71–114

  }

  void UpdatePlotCache()
  {
    if (!this->PlotCacheUpdated)
    {
      this->PlotCache.clear();

      // build map to find array index from its pointer to speed up access
      // the table should be shared between all plots
      std::unordered_map<vtkTable*, std::unordered_map<vtkAbstractArray*, vtkIdType>> colMap;
      for (vtkPlot* plot : this->plots)
      {
        vtkTable* table = plot->GetInput();
        if (table)
        {
          auto it = colMap.find(table);
          if (it == colMap.end())
          {
            std::unordered_map<vtkAbstractArray*, vtkIdType> tableColMap;

            vtkIdType nbCols = table->GetNumberOfColumns();
            for (vtkIdType i = 0; i < nbCols; i++)
            {
              tableColMap[table->GetColumn(i)] = i;
            }

            colMap[table] = std::move(tableColMap);
          }
        }
      }

      // build map to find plot from column index
      for (vtkPlot* plot : this->plots)
      {
        vtkTable* table = plot->GetInput();

        constexpr int idx = 1; // column
        vtkAbstractArray* array = plot->GetData()->GetInputAbstractArrayToProcess(idx, table);

        this->PlotCache[colMap[table][array]] = plot;
      }

      this->PlotCacheUpdated = true;
    }
  }

  std::vector<vtkPlot*> plots;                   // Charts can contain multiple plots of data
  std::vector<vtkContextTransform*> PlotCorners; // Stored by corner...