qt_demoe/third/qcustomplotdemo/frmexample/frmsincscatter.cpp

#include "frmsincscatter.h"
#include "ui_frmsincscatter.h"
#include "qdebug.h"

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

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

void frmSincScatter::initForm()
{
    ui->customPlot->legend->setVisible(true);
    ui->customPlot->legend->setFont(QFont("Helvetica", 9));
    // set locale to english, so we get english decimal separator:
    ui->customPlot->setLocale(QLocale(QLocale::English, QLocale::UnitedKingdom));
    // add confidence band graphs:
    ui->customPlot->addGraph();

    QPen pen;
    pen.setStyle(Qt::DotLine);
    pen.setWidth(1);
    pen.setColor(QColor(180, 180, 180));
    ui->customPlot->graph(0)->setName("Confidence Band 68%");
    ui->customPlot->graph(0)->setPen(pen);
    ui->customPlot->graph(0)->setBrush(QBrush(QColor(255, 50, 30, 20)));
    ui->customPlot->addGraph();
    ui->customPlot->legend->removeItem(ui->customPlot->legend->itemCount() - 1); // don't show two confidence band graphs in legend
    ui->customPlot->graph(1)->setPen(pen);
    ui->customPlot->graph(0)->setChannelFillGraph(ui->customPlot->graph(1));

    // add theory curve graph:
    ui->customPlot->addGraph();
    pen.setStyle(Qt::DashLine);
    pen.setWidth(2);
    pen.setColor(Qt::red);
    ui->customPlot->graph(2)->setPen(pen);
    ui->customPlot->graph(2)->setName("Theory Curve");

    // add data point graph:
    ui->customPlot->addGraph();
    ui->customPlot->graph(3)->setPen(QPen(Qt::blue));
    ui->customPlot->graph(3)->setName("Measurement");
    ui->customPlot->graph(3)->setLineStyle(QCPGraph::lsNone);
    ui->customPlot->graph(3)->setScatterStyle(QCPScatterStyle(QCPScatterStyle::ssCross, 4));

    // add error bars:
    QCPErrorBars *errorBars = new QCPErrorBars(ui->customPlot->xAxis, ui->customPlot->yAxis);
    errorBars->removeFromLegend();
    errorBars->setAntialiased(false);
    errorBars->setDataPlottable(ui->customPlot->graph(3));
    errorBars->setPen(QPen(QColor(180, 180, 180)));

    // generate ideal sinc curve data and some randomly perturbed data for scatter plot:
    QVector<double> x0(250), y0(250);
    QVector<double> yConfUpper(250), yConfLower(250);
    for (int i = 0; i < 250; ++i) {
        x0[i] = (i / 249.0 - 0.5) * 30 + 0.01; // by adding a small offset we make sure not do divide by zero in next code line
        y0[i] = qSin(x0[i]) / x0[i]; // sinc function
        yConfUpper[i] = y0[i] + 0.15;
        yConfLower[i] = y0[i] - 0.15;
        x0[i] *= 1000;
    }

    QVector<double> x1(50), y1(50), y1err(50);
    for (int i = 0; i < 50; ++i) {
        // generate a gaussian distributed random number:
        double tmp1 = rand() / (double)RAND_MAX;
        double tmp2 = rand() / (double)RAND_MAX;
        double r = qSqrt(-2 * qLn(tmp1)) * qCos(2 * M_PI * tmp2); // box-muller transform for gaussian distribution
        // set y1 to value of y0 plus a random gaussian pertubation:
        x1[i] = (i / 50.0 - 0.5) * 30 + 0.25;
        y1[i] = qSin(x1[i]) / x1[i] + r * 0.15;
        x1[i] *= 1000;
        y1err[i] = 0.15;
    }

    // pass data to graphs and let Qui->customPlot determine the axes ranges so the whole thing is visible:
    ui->customPlot->graph(0)->setData(x0, yConfUpper);
    ui->customPlot->graph(1)->setData(x0, yConfLower);
    ui->customPlot->graph(2)->setData(x0, y0);
    ui->customPlot->graph(3)->setData(x1, y1);
    errorBars->setData(y1err);
    ui->customPlot->graph(2)->rescaleAxes();
    ui->customPlot->graph(3)->rescaleAxes(true);

    // setup look of bottom tick labels:
    ui->customPlot->xAxis->setTickLabelRotation(30);
    ui->customPlot->xAxis->ticker()->setTickCount(9);
    ui->customPlot->xAxis->setNumberFormat("ebc");
    ui->customPlot->xAxis->setNumberPrecision(1);
    ui->customPlot->xAxis->moveRange(-10);

    // make top right axes clones of bottom left axes. Looks prettier:
    ui->customPlot->axisRect()->setupFullAxesBox();
    ui->customPlot->setInteractions(QCP::iRangeDrag | QCP::iRangeZoom);
}