文章目录

大致效果如下：

相关代码如下：

    centerWidgetLayout->addLayout(hboxLayout,1);

    customplot = new QCustomPlot(centerWidget);
    centerWidgetLayout->addWidget(customplot,100);


    int  xPointNum = 1300 ;
    customplot->plotLayout()->clear(); //删除默认的

    //多个Y轴
    axisRect1 =  new QCPAxisRect(customplot);
    customplot->plotLayout()->addElement(0,0, axisRect1 );
    axisRect1->axis(QCPAxis::atLeft)->setLabel("s");
    axisRect1->axis(QCPAxis::atBottom)->setRange(0, xPointNum);
    axisRect1->axis(QCPAxis::atLeft)->setRange(0, 55);
    //axisRect1->axis(QCPAxis::atRight)->setVisible(true);

    //一个X 多个平行的Y轴
    axisRect1->addAxis(QCPAxis::atRight);
    axisRect1->axis(QCPAxis::atRight , 0)->setPadding(0);
    axisRect1->axis(QCPAxis::atRight , 1)->setPadding(10);
    axisRect1->axis(QCPAxis::atBottom, 0)->setPadding(20);

    axisRect1->axis(QCPAxis::atLeft)->setRange(0, 100);
    axisRect1->axis(QCPAxis::atRight, 0)->setRange(0, 50);
    axisRect1->axis(QCPAxis::atRight, 0)->setLabel("v");
    axisRect1->axis(QCPAxis::atRight, 1)->setRange(0, 200);
    axisRect1->axis(QCPAxis::atRight, 1)->setLabel("a");
    axisRect1->setupFullAxesBox(true);
    axisRect1->axis(QCPAxis::atRight, 0)->setTickLabels(true);


    //绘图
    graph1 = customplot->addGraph(axisRect1->axis(QCPAxis::atBottom), axisRect1->axis(QCPAxis::atLeft , 0));
    graph2 = customplot->addGraph(axisRect1->axis(QCPAxis::atBottom), axisRect1->axis(QCPAxis::atRight, 0));
    graph3 = customplot->addGraph(axisRect1->axis(QCPAxis::atBottom), axisRect1->axis(QCPAxis::atRight, 1));

    graph1->setPen(QPen(Qt::red));
    graph2->setPen(QPen(Qt::black));
    graph3->setPen(QPen(Qt::blue));


    m_pHorReffer = new QCPItemStraightLine(customplot);
    m_pHorReffer->setPen(QPen(Qt::red, 2, Qt::DotLine));
    //绑定坐标
    m_pHorReffer->setClipAxisRect(axisRect1);
    m_pHorReffer->point1->setCoords( 30,  750);//设置点1的坐标
    m_pHorReffer->point2->setCoords( 30,  0)  ;//设置点2的坐标
    connect(customplot, SIGNAL(mousePress(QMouseEvent*)),  this, SLOT(MymousePressEvent(QMouseEvent*)));

    //mTag1 = new AxisTag(graph1->valueAxis());
    mTag1 = new AxisTag(graph1->valueAxis());
    mTag1->setPen(graph1->pen());

    mTag1->updatePosition(0.0);
    mTag1->setText(QString::number(  0, 'f', 2));

    //customplot->setInteractions(QCP::iRangeDrag|QCP::iRangeZoom| QCP::iSelectAxes |
    //               QCP::iSelectLegend | QCP::iSelectPlottables);

    //生成游标
    tracer = new QCPItemTracer(customplot); 
    tracer->setPen(QPen(Qt::red));
    tracer->setBrush(QBrush(Qt::red));
    tracer->setStyle(QCPItemTracer::tsCircle);
    tracer->position->setTypeX(QCPItemPosition::ptPlotCoords);
    tracer->position->setTypeY(QCPItemPosition::ptAxisRectRatio);
    tracer->position->setCoords(0.5, 0);
    tracer->setSize(4);//设置大小

    mArrow = new QCPItemLine(customplot);
    mArrow->setLayer("overlay");
    mArrow->setClipToAxisRect(false);
    mArrow->setHead(QCPLineEnding::esSpikeArrow);
    mArrow->end->setParentAnchor(tracer->position);
    mArrow->start->setParentAnchor(mArrow->end);
    mArrow->start->setCoords(0, 10);

    tracerLabel = new QCPItemText(customplot); 
    tracerLabel->setLayer("overlay");  
    tracerLabel->setClipToAxisRect(false); 
    tracerLabel->setPadding(QMargins(3, 0, 3, 0)); 
    tracerLabel->setPen(QPen(Qt::black));
    tracerLabel->setBrush(QBrush(Qt::green));
    tracerLabel->setPositionAlignment(Qt::AlignTop | Qt::AlignHCenter);//上中间
    tracerLabel->position->setParentAnchor(mArrow->start); //将游标说明锚固在tracer位置处，实现自动跟随

    tracer->position->setCoords(4, 1);
	//tracerLabel->position->setCoords(0, 15);
	mArrow->start->setCoords(0, 15);
	mArrow->end->setCoords(0, 0);
	tracerLabel->setText("###");