Custom Chart Example

Running the Example

To run the example from Qt Creator, open the Welcome mode and select the example from Examples. For more information, visit Building and Running an Example.

Customizing Charts

We begin by creating a simple line series and a chart object.

      QLineSeries *series = new QLineSeries();
      *series << QPointF(0, 6) << QPointF(9, 4) << QPointF(15, 20) << QPointF(25, 12) << QPointF(29, 26);
      QChart *chart = new QChart();
      chart->legend()->hide();
      chart->addSeries(series);

First we customize the series and the chart's title and background.

      // Customize series
      QPen pen(QRgb(0xfdb157));
      pen.setWidth(5);
      series->setPen(pen);

      // Customize chart title
      QFont font;
      font.setPixelSize(18);
      chart->setTitleFont(font);
      chart->setTitleBrush(QBrush(Qt::white));
      chart->setTitle("Customchart example");

      // Customize chart background
      QLinearGradient backgroundGradient;
      backgroundGradient.setStart(QPointF(0, 0));
      backgroundGradient.setFinalStop(QPointF(0, 1));
      backgroundGradient.setColorAt(0.0, QRgb(0xd2d0d1));
      backgroundGradient.setColorAt(1.0, QRgb(0x4c4547));
      backgroundGradient.setCoordinateMode(QGradient::ObjectBoundingMode);
      chart->setBackgroundBrush(backgroundGradient);

      // Customize plot area background
      QLinearGradient plotAreaGradient;
      plotAreaGradient.setStart(QPointF(0, 1));
      plotAreaGradient.setFinalStop(QPointF(1, 0));
      plotAreaGradient.setColorAt(0.0, QRgb(0x555555));
      plotAreaGradient.setColorAt(1.0, QRgb(0x55aa55));
      plotAreaGradient.setCoordinateMode(QGradient::ObjectBoundingMode);
      chart->setPlotAreaBackgroundBrush(plotAreaGradient);
      chart->setPlotAreaBackgroundVisible(true);

Then we customize the axes.

      QCategoryAxis *axisX = new QCategoryAxis();
      QCategoryAxis *axisY = new QCategoryAxis();

      // Customize axis label font
      QFont labelsFont;
      labelsFont.setPixelSize(12);
      axisX->setLabelsFont(labelsFont);
      axisY->setLabelsFont(labelsFont);

      // Customize axis colors
      QPen axisPen(QRgb(0xd18952));
      axisPen.setWidth(2);
      axisX->setLinePen(axisPen);
      axisY->setLinePen(axisPen);

      // Customize axis label colors
      QBrush axisBrush(Qt::white);
      axisX->setLabelsBrush(axisBrush);
      axisY->setLabelsBrush(axisBrush);

      // Customize grid lines and shades
      axisX->setGridLineVisible(false);
      axisY->setGridLineVisible(false);
      axisY->setShadesPen(Qt::NoPen);
      axisY->setShadesBrush(QBrush(QColor(0x99, 0xcc, 0xcc, 0x55)));
      axisY->setShadesVisible(true);

Then the axis label values and ranges. Once the axes are ready, we set them to be used by the chart.

      axisX->append("low", 10);
      axisX->append("optimal", 20);
      axisX->append("high", 30);
      axisX->setRange(0, 30);

      axisY->append("slow", 10);
      axisY->append("med", 20);
      axisY->append("fast", 30);
      axisY->setRange(0, 30);

      chart->addAxis(axisX, Qt::AlignBottom);
      chart->addAxis(axisY, Qt::AlignLeft);
      series->attachAxis(axisX);
      series->attachAxis(axisY);

Finally, we create a view containing the chart.

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

Now we are ready to show the chart on a main window.

      QMainWindow window;
      window.setCentralWidget(chartView);
      window.resize(400, 300);
      window.show();

Files:

• customchart/customchart.pro
• customchart/main.cpp