3、QtCharts 动态曲线图

效果

声明变量

构建静态图表

   //构建曲线系列m_splineSerise=new QSplineSeries(this);//为折线添加数据qreal x=0.f;for (size_t i=0;i<c_MaxSize;i++){x=qreal(i+1)/c_MaxSize;m_splineSerise->append(i,getData(x));}//构建图标对象m_chart=new QChart();//注意：先添加到图表再创建坐标轴,否则无效//1.将折线系列添加到图表m_chart->addSeries(m_splineSerise);//构建坐标轴m_axisX = new QValueAxis();m_axisX->setRange(0,c_MaxSize);m_axisX->setTitleText(QStringLiteral("X"));//设置标题m_axisX->setLabelFormat("%g");//设置格式m_axisX->setTickCount(5);//设置刻度数m_axisY= new QValueAxis();m_axisY->setRange(-10,10);m_axisY->setTitleText(QStringLiteral("Y"));//将坐标轴绑定m_chart->setAxisX(m_axisX,m_splineSerise);m_chart->setAxisY(m_axisY,m_splineSerise);//隐藏图例m_chart->legend()->hide();//设置图标主题m_chart->setTheme(QtCharts::QChart::ChartThemeBlueCerulean);//设置标题m_chart->setTitle(QString("图表1"));//设置尺寸m_chart->setGeometry(0,0,500,300);//构建场景m_pScene =new QGraphicsScene(this);//为视图构建场景ui->graphicsView->setScene(m_pScene);//将图表添加到场景m_pScene->addItem(m_chart);//设置抗锯齿ui->graphicsView->setRenderHint(QPainter::Antialiasing,true);

创建计时器连接信号与槽

  	//构造定时器m_timer=new QTimer(this);m_timer->setInterval(100);//设置定时器间隔//绑定定时器connect(m_timer,&QTimer::timeout,this,&Dialog::slot_timer);m_timer->start();

槽函数核心代码

qreal Dialog::getData(qreal x)
{return qSin(x*2*M_PI)*7;
}void Dialog::slot_timer()
{//首先用一个静态对象存储启动时间static QTime tmBegin=QTime::currentTime();//将tmBegin流失的时间存到变量quint64 tmEllapsed=tmBegin.elapsed();quint64 nSkip=tmEllapsed-m_tmLast;//计时器两次定时中断（超时）之间的时间差QVector<QPointF> ptsOld = m_splineSerise->pointsVector();QVector<QPointF> ptsNew;//跟新后的数据//将后面的数据向前平移qint64 i=0;for(i=0;i<(ptsOld.count()-nSkip);i++){//将后面的数据平移到开头ptsNew.append(QPointF(i,ptsOld[nSkip+i].y()));}qreal x=0.f;//补充新数据for(i=ptsOld.count()-nSkip;i<ptsOld.count();i++){x=qreal(m_tmLast+i+1)/c_MaxSize;//将后面的数据平移到开头ptsNew.append(QPointF(i,getData(x)));}//更新系列m_splineSerise->replace(ptsNew);//更新上次进入定时器的时间m_tmLast=tmEllapsed;
}