#include <QtWidgets>
class FontSwitcher : public QWidget {
public:
    FontSwitcher(QWidget *parent = nullptr) : QWidget(parent) {
        fooBar();
    }
private:
    QLabel *label_QtVersion;
    QLabel *label_TimesNewRoman;
    QLabel *label_TimesNewRomanDB;
    QLabel *label_NotoSans;
    QLabel *label_NotoSansDB;
    QLabel *label_NotoSansDisplay;
    QLabel *label_NotoSansDisplayDB;

    void fooBar() {
        QVBoxLayout *layout = new QVBoxLayout(this);

        label_QtVersion = new QLabel(QString("Running with Qt %1.%2.%3").arg(QString::number(QT_VERSION_MAJOR), QString::number(QT_VERSION_MINOR), QString::number(QT_VERSION_PATCH)));
        QFont font_Times("Times", 16);
        label_QtVersion->setFont(font_Times);
        layout->addWidget(label_QtVersion);

        label_TimesNewRoman = new QLabel(" Hello World in Times New Roman.");
        QFont font_TimesNewRoman("Times New Roman", 16);
        label_TimesNewRoman->setFont(font_TimesNewRoman);
        layout->addWidget(label_TimesNewRoman);

        label_TimesNewRomanDB = new QLabel(" Hello World in Times New Roman DemiBold.");
        QFont font_TimesNewRomanDB("Times New Roman", 16);
        font_TimesNewRomanDB.setWeight(QFont::DemiBold);
        label_TimesNewRomanDB->setFont(font_TimesNewRomanDB);
        layout->addWidget(label_TimesNewRomanDB);

        label_NotoSans = new QLabel(" Hello World in Noto Sans.");
        QFont font_NotoSans("Noto Sans", 16);
        label_NotoSans->setFont(font_NotoSans);
        layout->addWidget(label_NotoSans);

        label_NotoSansDB = new QLabel(" Hello world in Noto Sans DemiBold.");
        QFont font_NotoSansDB("Noto Sans", 16);
        font_NotoSansDB.setWeight(QFont::DemiBold);
        label_NotoSansDB->setFont(font_NotoSansDB);
        layout->addWidget(label_NotoSansDB);

        label_NotoSansDisplay = new QLabel(" Hello World in Noto Sans Display.");
        QFont font_NotoSansDisplay("Noto Sans Display", 16);
        label_NotoSansDisplay->setFont(font_NotoSansDisplay);
        layout->addWidget(label_NotoSansDisplay);

        label_NotoSansDisplayDB = new QLabel(" Hello world in Noto Sans Display DemiBold.");
        QFont font_NotoSansDisplayDB("Noto Sans Display", 16);
        font_NotoSansDisplayDB.setWeight(QFont::DemiBold);
        label_NotoSansDisplayDB->setFont(font_NotoSansDisplayDB);
        layout->addWidget(label_NotoSansDisplayDB);
    }
};

int main(int argc, char *argv[]) {
    QApplication app(argc, argv);
    FontSwitcher window;
    window.setWindowTitle("Qt Font Example");
    window.show();
    return app.exec();
}