Qt QCustomPlot 绘制子轴

抄大神杰作：QCustomplot（五）QCPAxisRect进行子绘图-CSDN博客文章浏览阅读5.9k次，点赞7次，收藏60次。文中介绍了QCustomPlot 子绘图需要掌握的类，也就是Matlab中的subplot，最后给出了一个完整的例子。_qcpaxisrecthttps://blog.csdn.net/weixin_39258979/article/details/122008568

需求来源：试验数据需要多轴对比。之前有过初步尝试​​​​​​​还是大佬们写的好。

实现多Y轴、单X轴、X轴是时间轴、X轴range联动、rect之间的间距是0，每个图上有legend(这里有个疑问，每添加个rect在这个rect上添加graph，再添加legend,第一个rect上就有多个legend，其他rect上就只有一个。)；

实现多Y轴、多X轴，x轴不联动。

频谱图，多Y轴，单X轴

关键代码如下，请大佬们多多指正：文章来源地址https://www.toymoban.com/news/detail-808551.html

//时域图
void MultiAxisWidget::recvRawData(int iRow, QString oStrLabel, QVector<double> adX, QVector<double> adY)
{
    QCPAxisRect* poAxisRect = new QCPAxisRect(ui->plot);
    poAxisRect->setAutoMargins(QCP::msNone);
    poAxisRect->setMargins(QMargins(100, 0, 0, 0));

    ui->plot->plotLayout()->addElement(iCntIndex, 0, poAxisRect);

    QCPAxis* poAxisX = poAxisRect->axis(QCPAxis::atBottom);
    QCPAxis* poAxisY = poAxisRect->axis(QCPAxis::atLeft);

    poAxisX->setVisible(false);

    poAxisY->grid()->setZeroLinePen(QPen(Qt::red));

    poAxisX->grid()->setSubGridVisible(true);
    poAxisY->grid()->setSubGridVisible(true);

    QList<QCPAxis*> aaxisField;
    aaxisField << poAxisX;
    poAxisRect->setRangeZoomAxes(aaxisField);

    poAxisY->setVisible(true);
    poAxisY->setLabel("振幅(mV)");

    auto poGraph = ui->plot->addGraph(poAxisX, poAxisY);

    poGraph->setName(oStrLabel);
    poGraph->setData(adX, adY);
    poGraph->setLineStyle(QCPGraph::lsLine);
    poGraph->setPen(QPen(Qt::blue, 2));

    poGraph->rescaleKeyAxis(true);
    poGraph->rescaleValueAxis(true, true);
    poGraph->rescaleAxes();

    auto poThread = new QThread;
    poGraph->setParent(nullptr);
    poGraph->moveToThread(poThread);
    poGraph->setVisible(true);

    QPair<QCPAxisRect*, QCPGraph*> pairContent(poAxisRect, poGraph) ;

    aopContent.append(pairContent);

    ++iCntIndex;

    QSharedPointer<QCPAxisTickerDateTime> dateTicker(new QCPAxisTickerDateTime);//日期做X轴
    dateTicker->setDateTimeFormat("HH:mm:ss");//日期格式(可参考QDateTime::fromString()函数)
    dateTicker->setTickCount(12);

    switch(eAxisType)
    {
        case AXIS_X_M:
            poAxisRect->setAutoMargins(QCP::msBottom);
            poAxisX->setVisible(true);
            poAxisX->setTicker(dateTicker);//设置X轴为时间轴

            break;

        case AXIS_X_S:

            if(iCntIndex == iCnt)
            {
                poAxisRect->setAutoMargins(QCP::msBottom);
                poAxisX->setVisible(true);
                poAxisX->setTicker(dateTicker);//设置X轴为时间轴

                QTimer::singleShot(1000, this, [ = ]()
                {
                    this->linkage();
                });
            }
            break;
    }

    if(iCntIndex == iCnt)
    {
        for(QPair<QCPAxisRect*, QCPGraph*> pairContent : aopContent)
        {
            QCPLegend* poLegend = new QCPLegend;
            pairContent.first->insetLayout()->addElement(poLegend, Qt::AlignTop | Qt::AlignRight);
            poLegend->setLayer("legend");
            poLegend->addItem(new QCPPlottableLegendItem(poLegend, pairContent.second));
        }
    }

    ui->plot->replot();
}

//频谱图
void MultiAxisWidget::recvSpectrum(QString oStrLabel, QVector<double> x, QVector<double> y, QList<double> adTargetF)
{
    QCPAxisRect* poAxisRect = new QCPAxisRect(ui->plot);
    poAxisRect->setAutoMargins(QCP::msNone);
    poAxisRect->setMargins(QMargins(100, 0, 0, 0));

    ui->plot->plotLayout()->addElement(iCntIndex, 0, poAxisRect);

    QCPAxis* poAxisX = poAxisRect->axis(QCPAxis::atBottom);
    QCPAxis* poAxisY = poAxisRect->axis(QCPAxis::atLeft);

    poAxisX->setVisible(false);

    QList<QCPAxis*> aaxisField;
    aaxisField << poAxisX;
    poAxisRect->setRangeZoomAxes(aaxisField);

    poAxisX->setLabel("频率(Hz)");          //X轴文字显示
    poAxisY->setLabel("振幅(mV)");          //Y轴文字显示

    poAxisY->grid()->setZeroLinePen(QPen(Qt::red));

    poAxisX->setRangeReversed(true);
    poAxisX->setScaleType(QCPAxis::stLogarithmic);
    poAxisY->setScaleType(QCPAxis::stLogarithmic);

    ui->plot->xAxis->grid()->setSubGridVisible(true);
    poAxisY->grid()->setSubGridVisible(true);

    auto poGraph = ui->plot->addGraph(poAxisX, poAxisY);

    poGraph->setName(oStrLabel);
    poGraph->setData(x, y);
    poGraph->setLineStyle(QCPGraph::lsLine);
    poGraph->setPen(QPen(Qt::blue, 2));

    poGraph->rescaleKeyAxis(true);
    poGraph->rescaleValueAxis(true, true);
    poGraph->rescaleAxes();

    auto poThread = new QThread;
    poGraph->setParent(nullptr);
    poGraph->moveToThread(poThread);
    poGraph->setVisible(true);

    for(int i = 0; i < adTargetF.count(); i++)
    {
        QCPItemTracer* poTracer = new QCPItemTracer(ui->plot);

        poTracer->setGraphKey(adTargetF.at(i));
        poTracer->setInterpolating(false);
        poTracer->setStyle(QCPItemTracer::tsCircle);
        poTracer->setPen(QPen(Qt::yellow));
        poTracer->setBrush(Qt::red);
        poTracer->position->setType(QCPItemPosition::ptPlotCoords);
        poTracer->setSize(8);

        poTracer->setClipAxisRect(poAxisRect);//设置裁剪的坐标轴
        poTracer->setGraph(poGraph);

        QCPItemStraightLine* poLine = new QCPItemStraightLine(ui->plot);

        poLine->setPen(QPen(Qt::red, 0.5, Qt::DotLine));
        //垂直参考线，就是两点一线
        //m_pHorReffer_DG->setClipToAxisRect(false);//裁剪，让外部也要看到
        poLine->setClipAxisRect(poAxisRect);//设置裁剪的坐标轴
        poLine->point1->setAxes(poAxisRect->axis(QCPAxis::atBottom), poAxisRect->axis(QCPAxis::atLeft)); //绑定坐标
        poLine->point2->setAxes(poAxisRect->axis(QCPAxis::atBottom), poAxisRect->axis(QCPAxis::atLeft));

        poLine->point1->setCoords(adTargetF.at(i), 1);
        poLine->point2->setCoords(adTargetF.at(i), 2);
    }

    QPair<QCPAxisRect*, QCPGraph*> pairContent(poAxisRect, poGraph) ;

    aopContent.append(pairContent);

    ++iCntIndex;

    if(iCntIndex == iCnt)
    {
        poAxisRect->setAutoMargins(QCP::msBottom);

        QSharedPointer<QCPAxisTickerText> textTicker = QSharedPointer<QCPAxisTickerText>(new QCPAxisTickerText);
        textTicker.data()->clear();

        foreach(double dF, adTargetF)
        {
            textTicker->addTick(dF, QString("%1").arg(dF));
        }

        poAxisX->setTicker(textTicker);

        poAxisX->setTickLabelRotation(34.38);

        poAxisX->setVisible(true);

        QTimer::singleShot(1000, this, [ = ]()
        {
            this->linkage();
        });

        for(QPair<QCPAxisRect*, QCPGraph*> pairContent : aopContent)
        {
            QCPLegend* poLegend = new QCPLegend;
            pairContent.first->insetLayout()->addElement(poLegend, Qt::AlignTop | Qt::AlignRight);
            poLegend->setLayer("legend");
            poLegend->addItem(new QCPPlottableLegendItem(poLegend, pairContent.second));
        }
    }

    ui->plot->replot();
}

//多  x轴联动
void MultiAxisWidget::linkage()
{
    for(QPair<QCPAxisRect*, QCPGraph*> pairContent : aopContent)
    {
        for(QPair<QCPAxisRect*, QCPGraph*> pairContentOther : aopContent)
        {
            if(pairContentOther.first == pairContent.first)
            {
                continue;
            }
            connect(pairContent.first->axis(QCPAxis::atBottom), QOverload<const QCPRange&>::of(&QCPAxis::rangeChanged),
                    pairContentOther.first->axis(QCPAxis::atBottom), QOverload<const QCPRange&>::of(&QCPAxis::setRange));
        }
    }

    //鼠标双击曲线，在颜色对话框中给被点击的曲线设置颜色
    connect(ui->plot, &QCustomPlot::plottableDoubleClick, this, [ = ](QCPAbstractPlottable * plottable, int dataIndex, QMouseEvent * event)
    {
        QColorDialog colorDialog;
        colorDialog.setCurrentColor(Qt::red);

        // 显示对话框
        int result = colorDialog.exec();

        // 检查用户是否选择了颜色
        if (result == QDialog::Accepted)
        {
            // 获取选择的颜色
            QColor selectedColor = colorDialog.selectedColor();

            plottable->setPen(QPen(selectedColor, 2));

            ui->plot->replot();
        }
    });

    ui->plot->replot();
}

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