Qt 5.7 | Qt Charts | AreaChart Example

Qt 5.7.1 Reference Documentation

# AreaChart Example

To create area charts, we need two QLineSeries instances. They are going to define the upper and lower boundary of the area.

          QLineSeries *series0 = new QLineSeries();
          QLineSeries *series1 = new QLineSeries();

We add data to both series and use the stream operator.

          *series0 << QPointF(1, 5) << QPointF(3, 7) << QPointF(7, 6) << QPointF(9, 7) << QPointF(12, 6)
                   << QPointF(16, 7) << QPointF(18, 5);
          *series1 << QPointF(1, 3) << QPointF(3, 4) << QPointF(7, 3) << QPointF(8, 2) << QPointF(12, 3)
                   << QPointF(16, 4) << QPointF(18, 3);

Now we create a QAreaSeries instance using two line series objects. We set the custom gradient fill and width of the outline.

          QAreaSeries *series = new QAreaSeries(series0, series1);
          series->setName("Batman");
          QPen pen(0x059605);
          pen.setWidth(3);
          series->setPen(pen);

          QLinearGradient gradient(QPointF(0, 0), QPointF(0, 1));
          gradient.setColorAt(0.0, 0x3cc63c);
          gradient.setColorAt(1.0, 0x26f626);
          gradient.setCoordinateMode(QGradient::ObjectBoundingMode);
          series->setBrush(gradient);

Last we create the QChartView instance, set the title, set anti-aliasing, and add the area series. We also create the default axes and specify the ranges on them.

          QChart *chart = new QChart();
          chart->addSeries(series);
          chart->setTitle("Simple areachart example");
          chart->createDefaultAxes();
          chart->axisX()->setRange(0, 20);
          chart->axisY()->setRange(0, 10);

The chart is ready to be shown.

          QChartView *chartView = new QChartView(chart);
          chartView->setRenderHint(QPainter::Antialiasing);

Files:

- areachart/main.cpp
- areachart/areachart.pro