Qt 5.9 | Qt Charts | Nested Donuts Example | widget.cpp Example File

Qt 5.9.3 Reference Documentation

# widget.cpp Example File

nesteddonuts/widget.cpp

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      ** Contact: https://www.qt.io/licensing/
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      ** This file is part of the Qt Charts module of the Qt Toolkit.
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      #include "widget.h"
      #include <QtCharts/QChartView>
      #include <QtCharts/QChart>
      #include <QtCharts/QLegend>
      #include <QtCharts/QPieSeries>
      #include <QtCharts/QPieSlice>
      #include <QtCore/QTime>
      #include <QtWidgets/QGridLayout>
      #include <QtCore/QTimer>

      QT_CHARTS_USE_NAMESPACE

      Widget::Widget(QWidget *parent)
          : QWidget(parent)
      {
          setMinimumSize(800, 600);
          qsrand(QTime(0, 0, 0).secsTo(QTime::currentTime()));

          QChartView *chartView = new QChartView;
          chartView->setRenderHint(QPainter::Antialiasing);
          QChart *chart = chartView->chart();
          chart->legend()->setVisible(false);
          chart->setTitle("Nested donuts demo");
          chart->setAnimationOptions(QChart::AllAnimations);

          qreal minSize = 0.1;
          qreal maxSize = 0.9;
          int donutCount = 5;

          for (int i = 0; i < donutCount; i++) {
              QPieSeries *donut = new QPieSeries;
              int sliceCount =  3 + qrand() % 3;
              for (int j = 0; j < sliceCount; j++) {
                  qreal value = 100 + qrand() % 100;
                  QPieSlice *slice = new QPieSlice(QString("%1").arg(value), value);
                  slice->setLabelVisible(true);
                  slice->setLabelColor(Qt::white);
                  slice->setLabelPosition(QPieSlice::LabelInsideTangential);
                  connect(slice, &QPieSlice::hovered, this, &Widget::explodeSlice);
                  donut->append(slice);
                  donut->setHoleSize(minSize + i * (maxSize - minSize) / donutCount);
                  donut->setPieSize(minSize + (i + 1) * (maxSize - minSize) / donutCount);
              }
              m_donuts.append(donut);
              chartView->chart()->addSeries(donut);
          }

          // create main layout
          QGridLayout *mainLayout = new QGridLayout;
          mainLayout->addWidget(chartView, 1, 1);
          setLayout(mainLayout);

          updateTimer = new QTimer(this);
          connect(updateTimer, &QTimer::timeout, this, &Widget::updateRotation);
          updateTimer->start(1250);
      }

      Widget::~Widget()
      {

      }

      void Widget::updateRotation()
      {
          for (int i = 0; i < m_donuts.count(); i++) {
              QPieSeries *donut = m_donuts.at(i);
              qreal phaseShift =  -50 + qrand() % 100;
              donut->setPieStartAngle(donut->pieStartAngle() + phaseShift);
              donut->setPieEndAngle(donut->pieEndAngle() + phaseShift);
          }
      }

      void Widget::explodeSlice(bool exploded)
      {
          QPieSlice *slice = qobject_cast<QPieSlice *>(sender());
          if (exploded) {
              updateTimer->stop();
              qreal sliceStartAngle = slice->startAngle();
              qreal sliceEndAngle = slice->startAngle() + slice->angleSpan();

              QPieSeries *donut = slice->series();
              qreal seriesIndex = m_donuts.indexOf(donut);
              for (int i = seriesIndex + 1; i < m_donuts.count(); i++) {
                  m_donuts.at(i)->setPieStartAngle(sliceEndAngle);
                  m_donuts.at(i)->setPieEndAngle(360 + sliceStartAngle);
              }
          } else {
              for (int i = 0; i < m_donuts.count(); i++) {
                  m_donuts.at(i)->setPieStartAngle(0);
                  m_donuts.at(i)->setPieEndAngle(360);
              }
              updateTimer->start();
          }
          slice->setExploded(exploded);
      }