采用Qt绘制多条曲线，跟随鼠标动态显示线上点的值（基于Qt的开源绘图控件QCustomPlot进行二次开发） |
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采用Qt绘制多条曲线，跟随鼠标动态显示线上点的值（基于Qt的开源绘图控件QCustomPlot进行二次开发）
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采用Qt绘制多条曲线，跟随鼠标动态显示线上点的值（基于Qt的开源绘图控件QCustomPlot进行二次开发）
QCustomPlot是一个开源的基于Qt的第三方绘图库，能够绘制漂亮的2D图形。 QCustomPlot的官方网址：https://www.qcustomplot.com/ 从官网下载QCustomPlot的源文件，包括qcustomplot.h和qcustomplot.cpp。 本程序的源码下载地址： https://github.com/xiongxw/XCustomPlot.git 1. 自定义鼠标显示跟随类XxwTracer和XxwTraceLine：XxwTracer用于在图表中显示鼠标所在位置的x,y值 XxwTraceLine用于在图中显示水平或垂直的虚线 头文件XxwTracer.h #ifndef MYTRACER_H #define MYTRACER_H #include #include "qcustomplot.h" /// /// \brief The XxwTracer class:在图表中显示鼠标所在位置的x,y值的追踪显示器 /// class XxwTracer : public QObject { Q_OBJECT public: enum TracerType { XAxisTracer,//依附在x轴上显示x值 YAxisTracer,//依附在y轴上显示y值 DataTracer//在图中显示x,y值 }; explicit XxwTracer(QCustomPlot *_plot, TracerType _type, QObject *parent = Q_NULLPTR); ~XxwTracer(); void setPen(const QPen &pen); void setBrush(const QBrush &brush); void setText(const QString &text); void setLabelPen(const QPen &pen); void updatePosition(double xValue, double yValue); void setVisible(bool m_visible); protected: bool m_visible;//是否可见 TracerType m_type;//类型 QCustomPlot *m_plot;//图表 QCPItemTracer *m_tracer;//跟踪的点 QCPItemText *m_label;//显示的数值 QCPItemLine *m_arrow;//箭头 }; /// /// \brief The XxwCrossLine class:用于显示鼠标移动过程中的鼠标位置的直线 /// class XxwTraceLine : public QObject { public: enum LineType { VerticalLine,//垂直线 HorizonLine, //水平线 Both//同时显示水平和垂直线 }; explicit XxwTraceLine(QCustomPlot *_plot, LineType _type = VerticalLine, QObject *parent = Q_NULLPTR); ~XxwTraceLine(); void initLine(); void updatePosition(double xValue, double yValue); void setVisible(bool vis) { if(m_lineV) m_lineV->setVisible(vis); if(m_lineH) m_lineH->setVisible(vis); } protected: bool m_visible;//是否可见 LineType m_type;//类型 QCustomPlot *m_plot;//图表 QCPItemStraightLine *m_lineV; //垂直线 QCPItemStraightLine *m_lineH; //水平线 }; #endif // MYTRACER_H源文件MyTracer.cpp #include "MyTracer.h" XxwTracer::XxwTracer(QCustomPlot *_plot, TracerType _type, QObject *parent) : QObject(parent), m_plot(_plot), m_type(_type) { m_visible = true; m_tracer = Q_NULLPTR;// 跟踪的点 m_label = Q_NULLPTR;// 显示的数值 m_arrow = Q_NULLPTR;// 箭头 if (m_plot) { QColor clrDefault(Qt::red); QBrush brushDefault(Qt::NoBrush); QPen penDefault(clrDefault); // penDefault.setBrush(brushDefault); penDefault.setWidthF(0.5); m_tracer = new QCPItemTracer(m_plot); m_tracer->setStyle(QCPItemTracer::tsCircle); m_tracer->setPen(penDefault); m_tracer->setBrush(brushDefault); m_label = new QCPItemText(m_plot); m_label->setLayer("overlay"); m_label->setClipToAxisRect(false); m_label->setPadding(QMargins(5, 5, 5, 5)); m_label->setBrush(brushDefault); m_label->setPen(penDefault); m_label->position->setParentAnchor(m_tracer->position); // m_label->setFont(QFont("宋体", 8)); m_label->setFont(QFont("Arial", 8)); m_label->setColor(clrDefault); m_label->setText(""); m_arrow = new QCPItemLine(m_plot); QPen arrowPen(clrDefault, 1); m_arrow->setPen(penDefault); m_arrow->setLayer("overlay"); m_arrow->setClipToAxisRect(false); m_arrow->setHead(QCPLineEnding::esSpikeArrow);//设置头部为箭头形状 switch (m_type) { case XAxisTracer: { m_tracer->position->setTypeX(QCPItemPosition::ptPlotCoords); m_tracer->position->setTypeY(QCPItemPosition::ptAxisRectRatio); m_tracer->setSize(7); m_label->setPositionAlignment(Qt::AlignTop | Qt::AlignHCenter); m_arrow->end->setParentAnchor(m_tracer->position); m_arrow->start->setParentAnchor(m_arrow->end); m_arrow->start->setCoords(0, 20);//偏移量 break; } case YAxisTracer: { m_tracer->position->setTypeX(QCPItemPosition::ptAxisRectRatio); m_tracer->position->setTypeY(QCPItemPosition::ptPlotCoords); m_tracer->setSize(7); m_label->setPositionAlignment(Qt::AlignRight | Qt::AlignHCenter); m_arrow->end->setParentAnchor(m_tracer->position); m_arrow->start->setParentAnchor(m_label->position); m_arrow->start->setCoords(-20, 0);//偏移量 break; } case DataTracer: { m_tracer->position->setTypeX(QCPItemPosition::ptPlotCoords); m_tracer->position->setTypeY(QCPItemPosition::ptPlotCoords); m_tracer->setSize(5); m_label->setPositionAlignment(Qt::AlignLeft | Qt::AlignVCenter); m_arrow->end->setParentAnchor(m_tracer->position); m_arrow->start->setParentAnchor(m_arrow->end); m_arrow->start->setCoords(20, 0); break; } default: break; } setVisible(false); } } XxwTracer::~XxwTracer() { if(m_plot) { if (m_tracer) m_plot->removeItem(m_tracer); if (m_label) m_plot->removeItem(m_label); if (m_arrow) m_plot->removeItem(m_arrow); } } void XxwTracer::setPen(const QPen &pen) { if(m_tracer) m_tracer->setPen(pen); if(m_arrow) m_arrow->setPen(pen); } void XxwTracer::setBrush(const QBrush &brush) { if(m_tracer) m_tracer->setBrush(brush); } void XxwTracer::setLabelPen(const QPen &pen) { if(m_label) { m_label->setPen(pen); m_label->setBrush(Qt::NoBrush); m_label->setColor(pen.color()); } } void XxwTracer::setText(const QString &text) { if(m_label) m_label->setText(text); } void XxwTracer::setVisible(bool vis) { m_visible = vis; if(m_tracer) m_tracer->setVisible(m_visible); if(m_label) m_label->setVisible(m_visible); if(m_arrow) m_arrow->setVisible(m_visible); } void XxwTracer::updatePosition(double xValue, double yValue) { if (!m_visible) { setVisible(true); m_visible = true; } if (yValue > m_plot->yAxis->range().upper) yValue = m_plot->yAxis->range().upper; switch (m_type) { case XAxisTracer: { m_tracer->position->setCoords(xValue, 1); m_label->position->setCoords(0, 15); m_arrow->start->setCoords(0, 15); m_arrow->end->setCoords(0, 0); setText(QString::number(xValue)); break; } case YAxisTracer: { m_tracer->position->setCoords(0, yValue); m_label->position->setCoords(-20, 0); // m_arrow->start->setCoords(20, 0); // m_arrow->end->setCoords(0, 0); setText(QString::number(yValue)); break; } case DataTracer: { m_tracer->position->setCoords(xValue, yValue); m_label->position->setCoords(20, 0); setText(QString("x:%1,y:%2").arg(xValue).arg(yValue)); break; } default: break; } } XxwTraceLine::XxwTraceLine(QCustomPlot *_plot, LineType _type, QObject *parent) : QObject(parent), m_type(_type), m_plot(_plot) { m_lineV = Q_NULLPTR; m_lineH = Q_NULLPTR; initLine(); } XxwTraceLine::~XxwTraceLine() { if(m_plot) { if (m_lineV) m_plot->removeItem(m_lineV); if (m_lineH) m_plot->removeItem(m_lineH); } } void XxwTraceLine::initLine() { if(m_plot) { QPen linesPen(Qt::red, 1, Qt::DashLine); if(VerticalLine == m_type || Both == m_type) { m_lineV = new QCPItemStraightLine(m_plot);//垂直线 m_lineV->setLayer("overlay"); m_lineV->setPen(linesPen); m_lineV->setClipToAxisRect(true); m_lineV->point1->setCoords(0, 0); m_lineV->point2->setCoords(0, 0); } if(HorizonLine == m_type || Both == m_type) { m_lineH = new QCPItemStraightLine(m_plot);//水平线 m_lineH->setLayer("overlay"); m_lineH->setPen(linesPen); m_lineH->setClipToAxisRect(true); m_lineH->point1->setCoords(0, 0); m_lineH->point2->setCoords(0, 0); } } } void XxwTraceLine::updatePosition(double xValue, double yValue) { if(VerticalLine == m_type || Both == m_type) { if(m_lineV) { m_lineV->point1->setCoords(xValue, m_plot->yAxis->range().lower); m_lineV->point2->setCoords(xValue, m_plot->yAxis->range().upper); } } if(HorizonLine == m_type || Both == m_type) { if(m_lineH) { m_lineH->point1->setCoords(m_plot->xAxis->range().lower, yValue); m_lineH->point2->setCoords(m_plot->xAxis->range().upper, yValue); } } } 2. 自定义的图表类XCustomPlotXCustomPlot是基于QCustomPlot二次开发的图表类，在鼠标移动过程中动态显示曲线上点的值。 头文件XCustomPlot.h #ifndef XCUSTOMPLOT_H #define XCUSTOMPLOT_H #include "XxwTracer.h" #include "qcustomplot.h" #include #include class XxwCustomPlot:public QCustomPlot { Q_OBJECT public: XxwCustomPlot(QWidget *parent = 0); protected: virtual void mouseMoveEvent(QMouseEvent *event); public: /// /// \brief 设置是否显示鼠标追踪器 /// \param show:是否显示 /// void showTracer(bool show) { m_isShowTracer = show; if(m_xTracer) m_xTracer->setVisible(m_isShowTracer); foreach (XxwTracer *tracer, m_dataTracers) { if(tracer) tracer->setVisible(m_isShowTracer); } if(m_lineTracer) m_lineTracer->setVisible(m_isShowTracer); } /// /// \brief 是否显示鼠标追踪器 /// \return /// bool isShowTracer(){return m_isShowTracer;}; private: bool m_isShowTracer;//是否显示追踪器（鼠标在图中移动，显示对应的值） XxwTracer *m_xTracer;//x轴 XxwTracer *m_yTracer;//y轴 QList m_dataTracers;// XxwTraceLine *m_lineTracer;//直线 }; #endif // XCUSTOMPLOT_H 源文件XCustomPlot.h #include "XxwCustomPlot.h" XxwCustomPlot::XxwCustomPlot(QWidget *parent) :QCustomPlot(parent) ,m_isShowTracer(false) ,m_xTracer(Q_NULLPTR) ,m_yTracer(Q_NULLPTR) ,m_dataTracers(QList()) ,m_lineTracer(Q_NULLPTR) { } void XxwCustomPlot::mouseMoveEvent(QMouseEvent *event) { QCustomPlot::mouseMoveEvent(event); if(m_isShowTracer) { //当前鼠标位置（像素坐标） int x_pos = event->pos().x(); int y_pos = event->pos().y(); //像素坐标转成实际的x,y轴的坐标 float x_val = this->xAxis->pixelToCoord(x_pos); float y_val = this->yAxis->pixelToCoord(y_pos); if(Q_NULLPTR == m_xTracer) m_xTracer = new XxwTracer(this, XxwTracer::XAxisTracer);//x轴 m_xTracer->updatePosition(x_val, y_val); if(Q_NULLPTR == m_yTracer) m_yTracer = new XxwTracer(this, XxwTracer::YAxisTracer);//y轴 m_yTracer->updatePosition(x_val, y_val); int nTracerCount = m_dataTracers.count(); int nGraphCount = graphCount(); if(nTracerCount < nGraphCount) { for(int i = nTracerCount; i < nGraphCount; ++i) { XxwTracer *tracer = new XxwTracer(this, XxwTracer::DataTracer); m_dataTracers.append(tracer); } } else if(nTracerCount > nGraphCount) { for(int i = nGraphCount; i < nTracerCount; ++i) { XxwTracer *tracer = m_dataTracers[i]; if(tracer) { tracer->setVisible(false); } } } for (int i = 0; i < nGraphCount; ++i) { XxwTracer *tracer = m_dataTracers[i]; if(!tracer) tracer = new XxwTracer(this, XxwTracer::DataTracer); tracer->setVisible(true); tracer->setPen(this->graph(i)->pen()); tracer->setBrush(Qt::NoBrush); tracer->setLabelPen(this->graph(i)->pen()); auto iter = this->graph(i)->data()->findBegin(x_val); double value = iter->mainValue(); // double value = this->graph(i)->data()->findBegin(x_val)->value; tracer->updatePosition(x_val, value); } if(Q_NULLPTR == m_lineTracer) m_lineTracer = new XxwTraceLine(this,XxwTraceLine::Both);//直线 m_lineTracer->updatePosition(x_val, y_val); this->replot();//曲线重绘 } } 3. 使用自定义图表类XCustomPlot在需要绘图的地方使用，代码如下： m_customPlot = new XxwCustomPlot(); m_customPlot->showTracer(true); // add title layout element: m_customPlot->plotLayout()->insertRow(0); m_customPlot->plotLayout()->addElement(0, 0, new QCPTextElement(m_customPlot, "标题", QFont("黑体", 12, QFont::Bold))); m_customPlot->legend->setVisible(true); QFont legendFont = font(); // start out with MainWindow's font.. legendFont.setPointSize(9); // and make a bit smaller for legend m_customPlot->legend->setFont(legendFont); m_customPlot->legend->setBrush(QBrush(QColor(255,255,255,230))); // by default, the legend is in the inset layout of the main axis rect. So this is how we access it to change legend placement: m_customPlot->axisRect()->insetLayout()->setInsetAlignment(0, Qt::AlignTop|Qt::AlignCenter); // make left and bottom axes always transfer their ranges to right and top axes: connect(m_customPlot->xAxis, SIGNAL(rangeChanged(QCPRange)), m_customPlot->xAxis2, SLOT(setRange(QCPRange))); connect(m_customPlot->yAxis, SIGNAL(rangeChanged(QCPRange)), m_customPlot->yAxis2, SLOT(setRange(QCPRange))); // Allow user to drag axis ranges with mouse, zoom with mouse wheel and select graphs by clicking: m_customPlot->setInteractions(QCP::iRangeDrag | QCP::iRangeZoom | QCP::iSelectPlottables); // generate some data: int nCount = 100; QVector x(nCount), y0(nCount), y1(nCount); // initialize with entries 0..100 for (int i = 0; i < nCount; ++i) { x[i] = i; // x goes from -1 to 1 y0[i] = qSin(i * 10.0f / nCount); //sin y1[i] = qCos(i * 10.0f / nCount); //cos } // create graph and assign data to it: QPen pen; int i = 1; QCPGraph *pGraph = m_customPlot->addGraph(); // m_customPlot->graph(0)->setData(x, y0); pGraph->setName("sin曲线"); pGraph->setData(x,y0); pGraph->setPen(QPen(Qt::blue)); pGraph = m_customPlot->addGraph(); // m_customPlot->graph(0)->setData(x, y0); pGraph->setName("cos曲线"); pGraph->setData(x,y1); pGraph->setPen(QPen(Qt::darkYellow)); // give the axes some labels: m_customPlot->xAxis->setLabel("x"); m_customPlot->yAxis->setLabel("y"); // set axes ranges, so we see all data: // m_customPlot->xAxis->setRange(-1, 1); // m_customPlot->yAxis->setRange(0, 1); m_customPlot->rescaleAxes(true); m_customPlot->replot(); 4. 效果图
效果图
本程序的源码下载地址： https://github.com/xiongxw/XCustomPlot.git 参考：https://blog.csdn.net/sunnyloves/article/details/82344815 |
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