QT QChart使用基本常识

1. 效果图

1. 准备工作

ui添加QGraphicsView，提升为QChartView，命名graphicsView。

1. 接口和变量声明

QChart *chart;
QXYSeries *series1;
QXYSeries *series2;
QXYSeries *series3;
QXYSeries *series4;
QXYSeries *series5;
QXYSeries *series6;

void initChart();
QDateTimeAxis* ceateXAxis(QString name);
QValueAxis* ceateYAxis(QString name);
QXYSeries* ceateSeries(QString name, QColor color);

1. 接口定义

void MainWindow::initChart()
{
    chart = new QChart();
    chart->setTheme(QChart::ChartThemeDark);

    QDateTimeAxis *axisX = ceateXAxis("时间坐标系");
    QValueAxis *axisYLeft = ceateYAxis("Y轴-左");
    QValueAxis *axisYRight = ceateYAxis("Y轴-右");

    series1 = ceateSeries("数据1", Qt::red);
    series2 = ceateSeries("数据2", Qt::green);
    series3 = ceateSeries("数据3", Qt::blue);
    series4 = ceateSeries("数据4", Qt::darkRed);
    series5 = ceateSeries("数据5", Qt::darkGreen);
    series6 = ceateSeries("数据6", Qt::darkBlue);

    chart->addSeries(series1);
    chart->addSeries(series2);
    chart->addSeries(series3);
    chart->addSeries(series4);
    chart->addSeries(series5);
    chart->addSeries(series6);

    axisYLeft->setMin(-30);
    axisYLeft->setMax(30);
    axisYRight->setMin(-20);
    axisYRight->setMax(20);

    axisYLeft->setTickCount(10);
    axisYRight->setTickCount(10);

    chart->addAxis(axisX, Qt::AlignBottom);
    chart->addAxis(axisYLeft, Qt::AlignLeft);
    chart->addAxis(axisYRight, Qt::AlignRight);

    series1->attachAxis(axisX);
    series1->attachAxis(axisYLeft);
    series2->attachAxis(axisX);
    series2->attachAxis(axisYLeft);
    series3->attachAxis(axisX);
    series3->attachAxis(axisYLeft);

    series4->attachAxis(axisX);
    series4->attachAxis(axisYRight);
    series5->attachAxis(axisX);
    series5->attachAxis(axisYRight);
    series6->attachAxis(axisX);
    series6->attachAxis(axisYRight);

    ui->graphicsView->setChart(chart);
    ui->graphicsView->setRenderHint(QPainter::Antialiasing, true);//平滑曲线
    ui->graphicsView->setRubberBand(QChartView::RectangleRubberBand);//缩放
}

QDateTimeAxis* MainWindow::ceateXAxis(QString name)
{
    QDateTimeAxis *axisX = new QDateTimeAxis();
    axisX->setTitleText(name);
    axisX->setFormat("mm:ss");
    axisX->setTickCount(10);
    axisX->setLabelsAngle(-45);
    return axisX;
}

QValueAxis* MainWindow::ceateYAxis(QString name)
{
    QValueAxis *axisY = new QValueAxis();
    axisY->setTitleText(name);
    return axisY;
}

QXYSeries* MainWindow::ceateSeries(QString name, QColor color)
{
    QSplineSeries *series = new QSplineSeries();
    series->setName(name);
    series->setColor(color);
    return series;
}

1. 测试代码

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    initChart();

    timer = new QTimer();
    timer->setInterval(1000);
    connect(timer,SIGNAL(timeout()),this,SLOT(slotTimer()));
    timer->start();
}

void MainWindow::slotTimer()
{
    QDateTime time = QDateTime::currentDateTime();
    QRandomGenerator rand(QTime(0,0,0).secsTo(QTime::currentTime()));

    QList<QAbstractAxis*> axes = chart->axes(Qt::Horizontal);
    axes[0]->setMin(QDateTime::currentDateTime().addSecs(-5*1));
    axes[0]->setMax(QDateTime::currentDateTime().addSecs(0));

    QXYSeries *series[] = {series1, series2, series3, series4, series5, series6};
    for ( int i=0; i<=2; i++){
        if(series[i]->count()>150) {
            series[i]->removePoints(0, series[i]->count() - 150);
            series[i+3]->removePoints(0, series[i+3]->count() - 150);
        }

        int Y1 = rand.generate() % 60 - 30;
        int Y2 = Y1 - 10;
        series[i]->append(time.toMSecsSinceEpoch(), Y1);
        series[i+3]->append(time.toMSecsSinceEpoch(), Y2);
    }
}