自定义图表

我们首先创建一个简单的线序列和一个图表对象。

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);

首先我们自定义序列和图表的标题和背景。

// 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);

然后我们自定义坐标轴。

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);

接着自定义坐标轴标签的值和范围。一旦坐标轴准备就绪，我们将它们设置为供图表使用。

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);

最后，我们创建一个包含图表的视图。

createDefaultChartView(chart);

现在我们准备在主窗口上显示图表。