Plot Screenshots: Date Axis Demo
// set locale to english, so we get english month names:
customPlot->setLocale(QLocale(QLocale::English, QLocale::UnitedKingdom));
// seconds of current time, we'll use it as starting point in time for data:
double now = QDateTime::currentDateTime().toTime_t();
srand(8); // set the random seed, so we always get the same random data
// create multiple graphs:
for (int gi=0; gi<5; ++gi)
{
customPlot->addGraph();
QColor color(20+200/4.0*gi,70*(1.6-gi/4.0), 150, 150);
customPlot->graph()->setLineStyle(QCPGraph::lsLine);
customPlot->graph()->setPen(QPen(color.lighter(200)));
customPlot->graph()->setBrush(QBrush(color));
// generate random walk data:
QVector<QCPGraphData> timeData(250);
for (int i=0; i<250; ++i)
{
timeData[i].key = now + 24*3600*i;
if (i == 0)
timeData[i].value = (i/50.0+1)*(rand()/(double)RAND_MAX-0.5);
else
timeData[i].value = qFabs(timeData[i-1].value)*(1+0.02/4.0*(4-gi)) + (i/50.0+1)*(rand()/(double)RAND_MAX-0.5);
}
customPlot->graph()->data()->set(timeData);
}
// configure bottom axis to show date instead of number:
QSharedPointer<QCPAxisTickerDateTime> dateTicker(new QCPAxisTickerDateTime);
dateTicker->setDateTimeFormat("d. MMMM\nyyyy");
customPlot->xAxis->setTicker(dateTicker);
// configure left axis text labels:
QSharedPointer<QCPAxisTickerText> textTicker(new QCPAxisTickerText);
textTicker->addTick(10, "a bit\nlow");
textTicker->addTick(50, "quite\nhigh");
customPlot->yAxis->setTicker(textTicker);
// set a more compact font size for bottom and left axis tick labels:
customPlot->xAxis->setTickLabelFont(QFont(QFont().family(), 8));
customPlot->yAxis->setTickLabelFont(QFont(QFont().family(), 8));
// set axis labels:
customPlot->xAxis->setLabel("Date");
customPlot->yAxis->setLabel("Random wobbly lines value");
// make top and right axes visible but without ticks and labels:
customPlot->xAxis2->setVisible(true);
customPlot->yAxis2->setVisible(true);
customPlot->xAxis2->setTicks(false);
customPlot->yAxis2->setTicks(false);
customPlot->xAxis2->setTickLabels(false);
customPlot->yAxis2->setTickLabels(false);
// set axis ranges to show all data:
customPlot->xAxis->setRange(now, now+24*3600*249);
customPlot->yAxis->setRange(0, 60);
// show legend with slightly transparent background brush:
customPlot->legend->setVisible(true);
customPlot->legend->setBrush(QColor(255, 255, 255, 150));