Qt 5.8 | Qt Data Visualization | Custom Proxy Example | rainfallgraph.cpp Example File

Qt 5.8.0 Reference Documentation

# rainfallgraph.cpp Example File

customproxy/rainfallgraph.cpp

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      ** Contact: https://www.qt.io/licensing/
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      #include "rainfallgraph.h"
      #include <QtDataVisualization/qcategory3daxis.h>
      #include <QtDataVisualization/qvalue3daxis.h>
      #include <QtDataVisualization/q3dscene.h>
      #include <QtDataVisualization/q3dcamera.h>
      #include <QtDataVisualization/qbar3dseries.h>
      #include <QtDataVisualization/q3dtheme.h>
      #include <QtGui/QGuiApplication>
      #include <QtGui/QFont>
      #include <QtCore/QDebug>
      #include <QtCore/QTextStream>
      #include <QtCore/QFile>

      using namespace QtDataVisualization;

      RainfallGraph::RainfallGraph(Q3DBars *rainfall)
          : m_graph(rainfall)
      {
          // In data file the months are in numeric format, so create custom list
          for (int i = 1; i <= 12; i++)
              m_numericMonths << QString::number(i);

          m_columnCount = m_numericMonths.size();

          m_proxy = new VariantBarDataProxy;
          QBar3DSeries *series = new QBar3DSeries(m_proxy);
          m_graph->addSeries(series);

          updateYearsList(2000, 2012);

          // Set up bar specifications; make the bars as wide as they are deep,
          // and add a small space between the bars
          m_graph->setBarThickness(1.0f);
          m_graph->setBarSpacing(QSizeF(1.1, 1.1));

          // Set axis labels and titles
          QStringList months;
          months << "January" << "February" << "March" << "April" << "May" << "June" << "July" << "August" << "September" << "October" << "November" << "December";
          m_graph->rowAxis()->setTitle("Year");
          m_graph->columnAxis()->setTitle("Month");
          m_graph->valueAxis()->setTitle("rainfall");
          m_graph->valueAxis()->setLabelFormat("%d mm");
          m_graph->valueAxis()->setSegmentCount(5);
          m_graph->rowAxis()->setLabels(m_years);
          m_graph->columnAxis()->setLabels(months);

          // Set bar type to cylinder
          series->setMesh(QAbstract3DSeries::MeshCylinder);

          // Set shadows to medium
          m_graph->setShadowQuality(QAbstract3DGraph::ShadowQualityMedium);

          // Set selection mode to bar and column
          m_graph->setSelectionMode(QAbstract3DGraph::SelectionItemAndColumn | QAbstract3DGraph::SelectionSlice);

          // Set theme
          m_graph->activeTheme()->setType(Q3DTheme::ThemeArmyBlue);

          // Override font in theme
          m_graph->activeTheme()->setFont(QFont("Century Gothic", 30));

          // Override label background for theme
          m_graph->activeTheme()->setLabelBackgroundEnabled(false);

          // Set camera position and zoom
          m_graph->scene()->activeCamera()->setCameraPreset(Q3DCamera::CameraPresetIsometricRightHigh);

          // Set window title
          m_graph->setTitle(QStringLiteral("Monthly rainfall in Northern Finland"));

          // Set reflections on
          m_graph->setReflection(true);
      }

      RainfallGraph::~RainfallGraph()
      {
          delete m_mapping;
          delete m_dataSet;
          delete m_graph;
      }

      void RainfallGraph::start()
      {
          addDataSet();
      }

      void RainfallGraph::updateYearsList(int start, int end)
      {
          m_years.clear();
          for (int i = start; i <= end; i++)
              m_years << QString::number(i);

          m_rowCount = m_years.size();
      }

      void RainfallGraph::addDataSet()
      {
          // Create a new variant data set and data item list
          m_dataSet =  new VariantDataSet;
          VariantDataItemList *itemList = new VariantDataItemList;

          // Read data from a data file into the data item list
          QTextStream stream;
          QFile dataFile(":/data/raindata.txt");
          if (dataFile.open(QIODevice::ReadOnly | QIODevice::Text)) {
              stream.setDevice(&dataFile);
              while (!stream.atEnd()) {
                  QString line = stream.readLine();
                  if (line.startsWith("#")) // Ignore comments
                      continue;
                  QStringList strList = line.split(",", QString::SkipEmptyParts);
                  // Each line has three data items: Year, month, and rainfall value
                  if (strList.size() < 3) {
                      qWarning() << "Invalid row read from data:" << line;
                      continue;
                  }
                  // Store year and month as strings, and rainfall value as double
                  // into a variant data item and add the item to the item list.
                  VariantDataItem *newItem = new VariantDataItem;
                  for (int i = 0; i < 2; i++)
                      newItem->append(strList.at(i).trimmed());
                  newItem->append(strList.at(2).trimmed().toDouble());
                  itemList->append(newItem);
              }
          } else {
              qWarning() << "Unable to open data file:" << dataFile.fileName();
          }

          // Add items to the data set and set it to the proxy
          m_dataSet->addItems(itemList);
          m_proxy->setDataSet(m_dataSet);

          // Create new mapping for the data and set it to the proxy
          m_mapping =  new VariantBarDataMapping(0, 1, 2, m_years, m_numericMonths);
          m_proxy->setMapping(m_mapping);
      }