Plot Screenshots: Realtime Data Demo
Setup function:
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);
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)));
// setup a timer that repeatedly calls MainWindow::realtimeDataSlot:
connect(&dataTimer, SIGNAL(timeout()), this, SLOT(realtimeDataSlot()));
dataTimer.start(0); // Interval 0 means to refresh as fast as possible
realtimeDataSlot, called by timer:
static QTime time(QTime::currentTime());
// calculate two new data points:
double key = time.elapsed()/1000.0; // time elapsed since start of demo, in seconds
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)+qrand()/(double)RAND_MAX*1*qSin(key/0.3843));
ui->customPlot->graph(1)->addData(key, qCos(key)+qrand()/(double)RAND_MAX*0.5*qSin(key/0.4364));
// rescale value (vertical) axis to fit the current data:
//ui->customPlot->graph(0)->rescaleValueAxis();
//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 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;
}