52.Qt-Charts动态显示多条折线电压值(实现示波器效果)-白红宇的个人博客

发布日期：2021-05-09 04:34:33 浏览次数：15 分类：博客文章

本文共 5518 字，大约阅读时间需要 18 分钟。

Qt 5.7过后Qt添加了官方的Chart库,之前就用的比较习惯,这次把源码发出来,给入门的同学们参考参考.

效果如下所示:

1.chartsView.h如下所示:

#ifndef VIEW_H#define VIEW_H#include 
    
     #include 
     
      #include 
      
       #include 
       
        #include 
        
         #include 
         
          QT_BEGIN_NAMESPACEclass QGraphicsScene;class QMouseEvent;class QResizeEvent;QT_END_NAMESPACEQT_CHARTS_BEGIN_NAMESPACEclass QChart;QT_CHARTS_END_NAMESPACEclass Callout;QT_CHARTS_USE_NAMESPACEclass ChartsView: public QGraphicsView{ Q_OBJECT qint64 MSecBase; public: ChartsView(int YRange, QWidget *parent = 0); QLineSeries series[3]; void initLineSeries(int YRange); void initMSecBase(int YRange); //初始化MSecBase,以MSecBase为开头 void clearMSecBase(); //清0,从头开始 void addLineSeries(int i,float value); //添加value值到第几个线上面 void addLineSeries(int i,float s,float value); //添加s时间和value值到第几个线上面 void setShowLine(int flag); //0~2:显示某个曲线 否则的话显示所有曲线protected: void resizeEvent(QResizeEvent *event); void mouseMoveEvent(QMouseEvent *event);public slots:private: QGraphicsSimpleTextItem *m_Line[3]; QGraphicsSimpleTextItem *m_coordX; QGraphicsSimpleTextItem *m_coordY; QChart *m_chart; QValueAxis *axisX; QValueAxis *axisY;signals: void mouseMoveisChange(QPointF point);};#endif

2.chartsView.cpp如下所示:

#include 
    
     #include "ChartsView.h"#include 
     
      #include 
      
       #include 
       
        #include 
        
         #include 
         
          #include 
          
           #include 
           
            #include 
            
              #define X_Width 5 //宽度5S ChartsView::ChartsView(int YRange, QWidget *parent) : QGraphicsView(new QGraphicsScene, parent), m_coordX(0), m_coordY(0), m_chart(0){ setDragMode(QGraphicsView::NoDrag); setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff); setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff); m_chart = new QChart; initLineSeries( YRange); m_chart->setAcceptHoverEvents(true); setRenderHint(QPainter::Antialiasing); scene()->addItem(m_chart); m_coordX = new QGraphicsSimpleTextItem(m_chart); m_coordX->setPos(m_chart->size().width()/2 + 100, m_chart->size().height()); m_coordX->setText(""); m_coordX->setPen(QColor(20,164,226)); m_coordY = new QGraphicsSimpleTextItem(m_chart); m_coordY->setPos(m_chart->size().width()/2 - 50, m_chart->size().height()); m_coordY->setText(""); m_coordY->setPen(QColor(226,20,216)); this->setMouseTracking(true); MSecBase = QDateTime::currentDateTime().toMSecsSinceEpoch();} void ChartsView::initLineSeries(int YRange){ QColor colors[3] = {QColor(20,164,226),QColor(36,20,226),QColor(226,20,216)}; //创建X轴和Y轴 axisX = new QValueAxis; axisX->setLabelFormat("%ds"); axisX->setTickCount(X_Width); //定义X有多少个表格 axisX->setRange(0,X_Width); axisY = new QValueAxis; axisY->setRange(-YRange,YRange); axisY->setTitleText("纹波值"); axisY->setTickCount(9); //定义Y有多少个表格 for(int i =0; i<3;i++) { series[i].setColor(colors[i]); series[i].setName(QString("测值%1").arg(i)); series[i].setVisible(true); m_chart->addSeries(&series[i]); m_chart->setAxisX(axisX,&series[i]); m_chart->setAxisY(axisY,&series[i]); m_Line[i] = new QGraphicsSimpleTextItem(m_chart); m_Line[i]->setPos(34+i*40, m_chart->size().height()- 20); m_Line[i]->setText(QString("测值%1").arg(i)); m_Line[i]->setPen(colors[i]); } //设置底部 m_chart->legend()->setVisible(false); }void ChartsView::initMSecBase(int YRange) //初始化MSecBase,以MSecBase为开头{ axisX->setMin(0); axisX->setMax(X_Width); axisY->setMin(-YRange); axisY->setMax(YRange); for(int i=0;i<3;i++) { series[i].clear(); series[i].clear(); series[i].append(QPointF(0,0)); } MSecBase = QDateTime::currentDateTime().toMSecsSinceEpoch();} void ChartsView::clearMSecBase(){ MSecBase = QDateTime::currentDateTime().toMSecsSinceEpoch();} void ChartsView::setShowLine(int flag) //0~2:显示某个曲线 否则的话显示所有曲线{ for(int i=0;i<3;i++) { if(flag>=0&&flag<=2) { if(flag==i) series[i].show(); else series[i].hide(); } else series[i].show(); } } void ChartsView::addLineSeries(int i,float value){ float currentS =(QDateTime::currentDateTime().toMSecsSinceEpoch() - MSecBase)/1000.0; //1s=1000MS if(i>=3) return; if(currentS>=axisX->max()) { axisX->setMin(currentS-X_Width); axisX->setMax(currentS); } if(value>=qMax(qAbs(axisY->max()),qAbs(axisY->min()))) { axisY->setMin(-value*1.1); axisY->setMax(value*1.1); } //定时清除以前不要的曲线数据 if(series[i].count()>600) { series[i].removePoints(0,series[i].count()/2); } series[i].append(QPointF(currentS,value));} void ChartsView::addLineSeries(int i,float s,float value){ if(s>=axisX->max()) { axisX->setMin(s-X_Width); axisX->setMax(s); } if(value>=qMax(qAbs(axisY->max()),qAbs(axisY->min()))) { axisY->setMin(-value*1.1); axisY->setMax(value*1.1); } series[i].append(QPointF(s,value)) ;} void ChartsView::resizeEvent(QResizeEvent *event){ if (scene()) { scene()->setSceneRect(QRect(QPoint(0, 0), event->size())); m_chart->resize(event->size()); m_coordX->setPos(m_chart->size().width()/2 + 100, m_chart->size().height() - 20); m_coordY->setPos(m_chart->size().width()/2 - 50, m_chart->size().height() - 20); for(int i=0;i<3;i++) { m_Line[i]->setPos(34+i*40, m_chart->size().height()- 20); m_Line[i]->setText(QString("测值%1").arg(i)); } } QGraphicsView::resizeEvent(event);} void ChartsView::mouseMoveEvent(QMouseEvent *event){ m_coordX->setText(QString("值:%1mV").arg(QString::asprintf("%.2f",m_chart->mapToValue(event->pos()).y()))); m_coordY->setText(QString("时间:%1S").arg(QString::asprintf("%.2f",m_chart->mapToValue(event->pos()).x()))); emit mouseMoveisChange(QPointF(m_chart->mapToValue(event->pos()).x(),m_chart->mapToValue(event->pos()).y())); QGraphicsView::mouseMoveEvent(event);}

具体项目下载地址:

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