QCharts 后面可能不会再用了,但是记录下绘历史曲线图

// 划了两条曲线
// 类似于QGraphicsView组件，用来显示曲线
QChartView *chartView = new QChartView(ui->graphicsView);
QChart *chart = new QChart();
//    chart->setTitle("简单函数曲线");
chartView->setChart(chart);//设置新chart，会自动清除之前的chart
chartView->setGeometry(0,0,this->width()-240,this->height()-25);
// 创建曲线序列
QLineSeries *series0 = new QLineSeries();
QLineSeries *series1 = new QLineSeries();
series0->setName("3A6B");
series1->setName("3A7B");
chart->addSeries(series0);
chart->addSeries(series1);
// chartView->setGeometry(QRect(0,0,500,500));
// 序列添加数值
qreal t = 0, y1, y2, intv = 0.1;
int cnt = 200;
for(int i = 0; i < cnt; ++i){
y1 = qSin(t);//真好，连头文件都不用添加了，嘻嘻嘻
series0->append(t, y1);

y2=qCos(t);
series1->append(t,y2);

t+=intv;  //每次角度增加
}
chartView->setRenderHint(QPainter::Antialiasing);

// 创建坐标
QValueAxis *axisX = new QValueAxis;
axisX->setRange(0, 10);//设置坐标轴范围
axisX->setTitleText("时间");//标题
axisX->setLabelFormat("%.1f"); //标签格式：每个单位保留1位小数
axisX->setTickCount(1); //主分隔个数：0到10分成20个单位
axisX->setMinorTickCount(1); //每个单位之间绘制了多少虚网线

QValueAxis *axisY = new QValueAxis; //Y 轴
axisY->setRange(-10,70);
axisY->setTitleText("温度");
axisY->setLabelFormat("%.1f"); //标签格式
axisY->setTickCount(10);
axisY->setMinorTickCount(4);

//为序列设置坐标轴
chart->setAxisX(axisX, series0);
chart->setAxisY(axisY, series0);

chart->setAxisX(axisX, series1);
chart->setAxisY(axisY, series1);

• 注意,将数据(时间戳(秒级))放到QLineSeries直线容器里,需要把时间戳转成毫秒级

//类似于QGraphicsView组件，用来显示曲线
QChartView *chartView = new QChartView(ui->graphicsView);  
// 支持鼠标缩放
chartView->setRubberBand(QChartView::RectangleRubberBand);

QChart *chart = new QChart();

// 支持缩放  
chart->scroll(-10, 5);//整体平移(-10, 5)，两个参数分别为Δx和Δy
chart->zoom(0.9);  //整体缩放，参数为放缩系数，<1代表缩小，>1代表放大  

chartView->setChart(chart);//设置新chart，会自动清除之前的chart
chartView->setGeometry(0, 0, this->width() - 240, this->height() - 25);
//创建曲线序列
QLineSeries *series0 = new QLineSeries();
series0->setName("3A6B");
chart->addSeries(series0);
// 序列添加数值
qreal t = 0, y1, y2, intv = 0.1;
int cnt = 200;
QMessageBox::information(nullptr, "info", QString::fromStdString(std::to_string(items.size())));

// 老老实实从容器中取出数据  
for (uint64_t i = 0; i < items.size(); ++i)
{
        series0->append(items.at(i).timestamp*1000, items.at(i).temperature);
}
chartView->setRenderHint(QPainter::Antialiasing);

// x 轴为时间轴
QDateTimeAxis* axisX = new QDateTimeAxis();
// axisX->setFormat("yyyy-M-d HH:mm s");// 145°时："yyyy-M-d HH:mm s\""  
axisX->setFormat("M-d HH:mm s");// 145°时："yyyy-M-d HH:mm s\""  
const uint64_t how_long_for_show = 60 * 60 * 2; /*60 * 60 * 24 * 30 */;	// default 30 days	
axisX->setMin(QDateTime::fromSecsSinceEpoch(time(0) - how_long_for_show));
axisX->setMax(QDateTime::fromSecsSinceEpoch(time(0)));
axisX->setTickCount(1); //主分隔个数：0到10分成20个单位
axisX->setLabelsAngle(1);

QValueAxis *axisY = new QValueAxis; //Y 轴
axisY->setRange(-10, 70);  	
axisY->setTitleText("Temperature");
axisY->setLabelFormat("%.1f"); //标签格式
axisY->setTickCount(10);
axisY->setMinorTickCount(4);

//为序列设置坐标轴
chart->addAxis(axisX, Qt::AlignBottom);
chart->addAxis(axisY, Qt::AlignLeft);
series0->attachAxis(axisX);
series0->attachAxis(axisY);  
series0->show();