- Qt 6.9
- Qt Charts
- Customizing Charts
- Qt Charts | Commercial or GPLv3

# Customizing Charts

Note: This is part of the Charts with Widgets Gallery example.

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

     auto series = new QLineSeries;
     *series << QPointF(0, 6) << QPointF(9, 4) << QPointF(15, 20) << QPointF(25, 12) << QPointF(29, 26);
     auto 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("Custom Chart");

     // 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.

     auto axisX = new QCategoryAxis;
     auto 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.

     createDefaultChartView(chart);

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