求大神解答！！关于QCustomplot多坐标轴的QCPItemTracer的游标问题！

月色伤地满霜 2021-01-29 02:47:00

最近在做一个仿真波形的模块，用到了QCustomplot。其中有个功能是模仿matlab的subplot。我的思路是创建多个坐标轴QCPAxisRect，然后往坐标轴添加Graph。最后用QCPItemTracer跟Graph绑定。布局方面就用plotLayout()->addElement()往下添加行。我现在遇到的问题是不管这个游标tracer绑定哪个Graph，他只显示在第0行0列的坐标轴里。其他坐标轴不显示。我不清楚这个新建的QCPAxisRect这个矩形区域能否实现这个显示游标，我也不知道我是不是思路出了问题。求各位大神能够解答！！下面是测试的代码跟效果图。



MainWindow::MainWindow(QWidget *parent)

    : QMainWindow(parent)

    , ui(new Ui::MainWindow)

{

    ui->setupUi(this);

    test();

    for ( int i = 0; i < 3; i++) {

        tracer[i] = new QCPItemTracer(ui->customPlot);

        tracer[i]->setPen(QPen(Qt::DashLine));

        tracer[i]->setStyle(QCPItemTracer::tsPlus);//游标样式：十字星、圆圈、方框等



        tracerLabel[i] = new QCPItemText(ui->customPlot); //生成游标说明

        //下面的代码就是设置游标说明的外观和对齐方式等状态

        tracerLabel[i]->setLayer("overlay");

        tracerLabel[i]->position->setCoords(0.5, 0);

        tracerLabel[i]->setFont(QFont(font().family(), 10));

        tracerLabel[i]->setPen(QPen(Qt::black));

        tracerLabel[i]->setPositionAlignment(Qt::AlignLeft | Qt::AlignTop);

        tracerLabel[i]->setBrush(Qt::green);

        //下面这个语句很重要，它将游标说明锚固在tracer位置处，实现自动跟随

        tracerLabel[i]->position->setParentAnchor(tracer[i]->position);



        m_lineV[i] = new QCPItemStraightLine(ui->customPlot);

        QPen linesPen(Qt::red, 1, Qt::SolidLine);

        m_lineV[i]->setLayer("overlay");

        m_lineV[i]->setPen(linesPen);

        m_lineV[i]->setClipToAxisRect(true);

        m_lineV[i]->point1->setCoords(0, 0);

        m_lineV[i]->point2->setCoords(0, 0);

    }

    connect(ui->customPlot, &QCustomPlot::mouseMove, this, &MainWindow::myMoveEvent);

}



MainWindow::~MainWindow()

{

    delete ui;

}



void MainWindow::myMoveEvent(QMouseEvent *event)

{

            double xValue;

            double yValue;



            qDebug() << "aaaa";

            double yy = wideAxisRect->axis(QCPAxis::atBottom)->pixelToCoord(event->pos().x());

            m_lineV[0]->point1->setCoords(yy, 1);

            m_lineV[0]->point2->setCoords(yy, 0);

                tracer[0]->setGraph(mainGraphCos);//将游标和该曲线图层想连接

                tracer[0]->position->setAxes(wideAxisRect->axis(QCPAxis::atBottom), wideAxisRect->axis(QCPAxis::atLeft));

                tracer[0]->setGraphKey(yy); //将游标横坐标（key）设置成刚获得的横坐标数据

                tracer[0]->setInterpolating(true); //游标的纵坐标可以通过曲线数据线性插值自动获得（这就不用手动去计算了）

                tracer[0]->updatePosition(); //使得刚设置游标的横纵坐标位置生效

                //以下代码用于更新游标说明的内容

                xValue = tracer[0]->position->key();

                yValue = tracer[0]->position->value();

                //设置游标说明（tracerLabel）的内容

                tracerLabel[0]->setText(QString("x = %1, y = %2").arg(xValue).arg(yValue));



            double xx = subRectLeft->axis(QCPAxis::atBottom)->pixelToCoord(event->pos().x());

            m_lineV[1]->point1->setCoords(xx, 1);

            m_lineV[1]->point2->setCoords(xx, 0);

            tracer[1]->setGraph(subGraphRandom);//将游标和该曲线图层想连接

            tracer[1]->position->setAxes(subRectLeft->axis(QCPAxis::atBottom), subRectLeft->axis(QCPAxis::atLeft));

            tracer[1]->setGraphKey(xx); //将游标横坐标（key）设置成刚获得的横坐标数据x

            tracer[1]->setInterpolating(true); //游标的纵坐标可以通过曲线数据线性插值自动获得（这就不用手动去计算了）

            tracer[1]->updatePosition(); //使得刚设置游标的横纵坐标位置生效

            //以下代码用于更新游标说明的内容

            xValue = tracer[1]->position->key();

            yValue = tracer[1]->position->value();

            //设置游标说明（tracerLabel）的内容

            tracerLabel[1]->setText(QString("x = %1, y = %2").arg(xValue).arg(yValue));





            double x = subRectRight->axis(QCPAxis::atBottom)->pixelToCoord(event->pos().x());

            m_lineV[2]->point1->setCoords(x, 1);

            m_lineV[2]->point2->setCoords(x, 0);

            tracer[2]->setGraph(subBars);//将游标和该曲线图层想连接

            tracer[2]->position->setAxes(subRectRight->axis(QCPAxis::atBottom), subRectRight->axis(QCPAxis::atLeft));

            tracer[2]->setGraphKey(x); //将游标横坐标（key）设置成刚获得的横坐标数据x

            tracer[2]->setInterpolating(true); //游标的纵坐标可以通过曲线数据线性插值自动获得（这就不用手动去计算了）

            tracer[2]->updatePosition(); //使得刚设置游标的横纵坐标位置生效

            //以下代码用于更新游标说明的内容

            xValue = tracer[2]->position->key();

            yValue = tracer[2]->position->value();

            //设置游标说明（tracerLabel）的内容

            tracerLabel[2]->setText(QString("x = %1, y = %2").arg(xValue).arg(yValue));



            ui->customPlot->replot();

}



void MainWindow::test()

{

    ui->customPlot->plotLayout()->clear();   // 首先清空默认的轴矩形，让我们从头开始



    ui->customPlot->setInteractions(QCP::iRangeDrag | QCP::iRangeZoom | QCP::iSelectPlottables | QCP::iSelectLegend);

    wideAxisRect = new QCPAxisRect(ui->customPlot);   // 还记得setupDefaultAxes为true时的作用吗，忘了的话翻上去看吧

    wideAxisRect->setupFullAxesBox(true);    // 让四个轴关联，并全部显示出来

    wideAxisRect->addAxis(QCPAxis::atLeft)->setTickLabelColor(QColor("#6050F8"));  // 在左边多添加一个轴并且设置它的颜色





    ui->customPlot->plotLayout()->addElement(2, 0, wideAxisRect);     // 在第一行添加轴矩形       // 在第二行添加一个子布局，后面会添加两个轴矩形在里面



    subRectLeft = new QCPAxisRect(ui->customPlot);   // 不配置轴

    subRectRight = new QCPAxisRect(ui->customPlot);





    ui->customPlot->plotLayout()->addElement(0, 0, subRectLeft);                      // 在第一列添加轴矩形

    ui->customPlot->plotLayout()->addElement(1, 0, subRectRight);                     // 在第二列添加轴矩形





    subRectLeft->axis(QCPAxis::atLeft)->ticker()->setTickCount(2); // 设置轴的刻度为一个固定的步进值

    subRectRight->axis(QCPAxis::atLeft)->ticker()->setTickCount(2);





    // 准备数据

    QVector<QCPGraphData> dataCos(21), dataGauss(50), dataRandom(100);

    QVector<double> x3, y3;

    qsrand(3);

    for (int i=0; i<dataCos.size(); ++i) {

        dataCos[i].key = i/(double)(dataCos.size()-1)*10-5.0;

        dataCos[i].value = qCos(dataCos[i].key);

    }

    for (int i=0; i<dataGauss.size(); ++i) {

        dataGauss[i].key = i/(double)dataGauss.size()*10-5.0;

        dataGauss[i].value = qExp(-dataGauss[i].key*dataGauss[i].key*0.2)*1000;

    }

    for (int i=0; i<dataRandom.size(); ++i) {

        dataRandom[i].key = i/(double)dataRandom.size()*10;

        dataRandom[i].value = qrand()/(double)RAND_MAX-0.5+dataRandom[qMax(0, i-1)].value;

    }

    x3 << 1 << 2 << 3 << 4;

    y3 << 2 << 2.5 << 4 << 1.5;



    // mainGraphCos和 mainGraphGauss 共享下轴，但是它们的左轴不同

    mainGraphCos = ui->customPlot->addGraph(wideAxisRect->axis(QCPAxis::atBottom), wideAxisRect->axis(QCPAxis::atLeft));

    mainGraphCos->data()->set(dataCos);

    mainGraphCos->valueAxis()->setRange(-1, 1);

    mainGraphCos->rescaleKeyAxis();

    mainGraphCos->setScatterStyle(QCPScatterStyle(QCPScatterStyle::ssCircle, QPen(Qt::black), QBrush(Qt::white), 6));

    mainGraphCos->setPen(QPen(QColor(120, 120, 120), 2));





    subGraphRandom = ui->customPlot->addGraph(subRectLeft->axis(QCPAxis::atBottom), subRectLeft->axis(QCPAxis::atLeft));

    subGraphRandom->data()->set(dataCos);

    subGraphRandom->valueAxis()->setRange(-1,5);





    subBars = ui->customPlot->addGraph(subRectRight->axis(QCPAxis::atBottom), subRectRight->axis(QCPAxis::atLeft));

    subBars->data()->set(dataGauss);

    subBars->valueAxis()->setRange(0,1000);



    qDebug() << ui->customPlot->axisRectCount();

    qDebug() << ui->customPlot->graphCount();

    QCPMarginGroup *marginGroup = new QCPMarginGroup(ui->customPlot);



    for (int j = 0; j < ui->customPlot->axisRectCount(); j++) {

        ui->customPlot->axisRect(j)->setMarginGroup(QCP::msLeft|QCP::msRight, marginGroup);

    }

}