qt_demoe/third/qcustomplotdemo/frmexample/frmdate.cpp

#include "frmdate.h"
#include "ui_frmdate.h"
#include "qdebug.h"

frmDate::frmDate(QWidget *parent) : QWidget(parent), ui(new Ui::frmDate)
{
    ui->setupUi(this);
    this->initForm();
}

frmDate::~frmDate()
{
    delete ui;
}

void frmDate::initForm()
{
    // set locale to english, so we get english month names:
    ui->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().toMSecsSinceEpoch() / 1000.0;
    srand(8); // set the random seed, so we always get the same random data
    // create multiple graphs:
    for (int gi = 0; gi < 5; ++gi) {
        ui->customPlot->addGraph();
        QColor color(20 + 200 / 4.0 * gi, 70 * (1.6 - gi / 4.0), 150, 150);
        ui->customPlot->graph()->setLineStyle(QCPGraph::lsLine);
        ui->customPlot->graph()->setPen(QPen(color.lighter(200)));
        ui->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);
            }
        }
        ui->customPlot->graph()->data()->set(timeData);
    }

    // configure bottom axis to show date instead of number:
    QSharedPointer<QCPAxisTickerDateTime> dateTicker(new QCPAxisTickerDateTime);
    dateTicker->setDateTimeFormat("d. MMMM\nyyyy");
    ui->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");
    ui->customPlot->yAxis->setTicker(textTicker);

    // set a more compact font size for bottom and left axis tick labels:
    ui->customPlot->xAxis->setTickLabelFont(QFont(QFont().family(), 8));
    ui->customPlot->yAxis->setTickLabelFont(QFont(QFont().family(), 8));

    // set axis labels:
    ui->customPlot->xAxis->setLabel("Date");
    ui->customPlot->yAxis->setLabel("Random wobbly lines value");

    // make top and right axes visible but without ticks and labels:
    ui->customPlot->xAxis2->setVisible(true);
    ui->customPlot->yAxis2->setVisible(true);
    ui->customPlot->xAxis2->setTicks(false);
    ui->customPlot->yAxis2->setTicks(false);
    ui->customPlot->xAxis2->setTickLabels(false);
    ui->customPlot->yAxis2->setTickLabels(false);

    // set axis ranges to show all data:
    ui->customPlot->xAxis->setRange(now, now + 24 * 3600 * 249);
    ui->customPlot->yAxis->setRange(0, 60);

    // show legend with slightly transparent background brush:
    ui->customPlot->legend->setVisible(true);
    ui->customPlot->legend->setBrush(QColor(255, 255, 255, 150));
    ui->customPlot->setInteractions(QCP::iRangeDrag | QCP::iRangeZoom);
}