Plot_setupRealtimeDataDemo

void MainWindow::setupRealtimeDataDemo(QCustomPlot *customPlot) { demoName = "Real Time Data Demo"; // 实时数据示例 // include this section to fully disable antialiasing for higher performance: // 开启 完全禁用抗锯齿以获得更高的性能 /* customPlot->setNotAntialiasedElements(QCP::aeAll); QFont font; font.setStyleStrategy(QFont::NoAntialias); customPlot->xAxis->setTickLabelFont(font); customPlot->yAxis->setTickLabelFont(font); customPlot->legend->setFont(font); */ customPlot->addGraph(); // blue line customPlot->graph(0)->setPen(QPen(QColor(40, 110, 255))); customPlot->addGraph(); // red line customPlot->graph(1)->setPen(QPen(QColor(255, 110, 40))); QSharedPointer<QCPAxisTickerTime> timeTicker(new QCPAxisTickerTime); // 时间刻度 timeTicker->setTimeFormat("%h:%m:%s"); customPlot->xAxis->setTicker(timeTicker); customPlot->axisRect()->setupFullAxesBox(); customPlot->yAxis->setRange(-1.2, 1.2); // make left and bottom axes transfer their ranges to right and top axes: connect(customPlot->xAxis, SIGNAL(rangeChanged(QCPRange)), customPlot->xAxis2, SLOT(setRange(QCPRange))); connect(customPlot->yAxis, SIGNAL(rangeChanged(QCPRange)), customPlot->yAxis2, SLOT(setRange(QCPRange))); QTimer dataTimer; // setup a timer that repeatedly calls MainWindow::realtimeDataSlot: connect(&dataTimer, SIGNAL(timeout()), this, SLOT(realtimeDataSlot())); // F2快捷键 跳转定义 // 全速、实时、连续刷新画面 dataTimer.start(0); // Interval 0 means to refresh as fast as possible }

void MainWindow::realtimeDataSlot() { static QTime timeStart = QTime::currentTime(); // calculate two new data points: double key = timeStart.msecsTo(QTime::currentTime())/1000.0; // time elapsed since start of demo, in seconds 毫秒 - 秒 static double lastPointKey = 0; if (key - lastPointKey > 0.002) // at most add point every 2 ms { // add data to lines: ui->customPlot->graph(0)->addData(key, qSin(key) + std::rand() / (double)RAND_MAX * 1 * qSin(key / 0.3843)); ui->customPlot->graph(1)->addData(key, qCos(key) + std::rand() / (double)RAND_MAX * 0.5 * qSin(key / 0.4364)); // rescale value (vertical) axis to fit the current data: // 自动缩放 数值轴，让数据刚好充满整个图表，不超出屏幕 // ui->customPlot->graph(0)->rescaleValueAxis(); // rescaleValueAxis(bool onlyVisible = false); true根据所有显示曲线调整范围 // ui->customPlot->graph(1)->rescaleValueAxis(true); lastPointKey = key; } // make key axis range scroll with the data (at a constant range size of 8): ui->customPlot->xAxis->setRange(key, 8, Qt::AlignRight); ui->customPlot->replot(); // calculate frames per second: // static 变量未初始化 默认值为0 static double lastFpsKey; static int frameCount; ++frameCount; if (key - lastFpsKey > 2) // average fps over 2 seconds { ui->statusBar->showMessage( QString("%1 FPS, Total Data points: %2") .arg(frameCount / (key - lastFpsKey), 0, 'f', 0) .arg(ui->customPlot->graph(0)->data()->size() + ui->customPlot->graph(1)->data()->size()) , 0); lastFpsKey = key; frameCount = 0; } }