#include <QApplication>
#include <QFont>
#include <QPushButton>
#include <QElapsedTimer>
#include <QDebug>
#include <QLibraryInfo>
#include <QFile>
#include <QHBoxLayout>

class MyPushButton : public QPushButton
{
public:
    MyPushButton( const QString & p_text, QWidget *p) : QPushButton( p_text,p ) {}

protected:
    void paintEvent(QPaintEvent * p_event )
    {
        QElapsedTimer timer;
        timer.start();
		QPushButton::paintEvent( p_event );
        qDebug() << "paint event time: " << timer.elapsed();
	}
};

int main(int argc, char *argv[])
{
    QElapsedTimer timer;
    timer.start();

    QApplication a(argc,argv);

    QString t = QLatin1String(QT_VERSION_STR);
#if QT_VERSION >= 0x050000
    t += QLatin1Char(' ') + a.platformName();
#endif

    qDebug() << t << "clock type: " << QElapsedTimer::clockType() << '\n'
#if QT_VERSION >= 0x050400
     <<  QLibraryInfo::build() << '\n'
#endif
     << "\napp constructor time: " << timer.elapsed();

	timer.restart();

    QWidget top;
    auto lt = new QHBoxLayout(&top);
    top.setWindowTitle(t);
    MyPushButton *quit = new MyPushButton("🙋‍♂тоуеひらがな", &top);
    quit->resize(175,30);
    QObject::connect(quit,SIGNAL(clicked()),&a,SLOT(quit()));
    lt->addWidget(quit);

    MyPushButton *quit2 = new MyPushButton("🙋‍♂тоуеひらがな", &top);
    quit2->resize(175,30);
    quit2->setFont(QFont("Courier",18,QFont::Bold));
    QObject::connect(quit2,SIGNAL(clicked()),&a,SLOT(quit()));
    lt->addWidget(quit2);

    MyPushButton *quit3 = new MyPushButton("🙋‍♂тоуеひらがな", &top);
    quit3->resize(175,30);
    quit3->setFont(QFont("Segoe UI Emoji",18,QFont::Bold));
    QObject::connect(quit3,SIGNAL(clicked()),&a,SLOT(quit()));
    lt->addWidget(quit3);

    MyPushButton *quit4 = new MyPushButton("🙋‍♂тоуеひらがな", &top);
    quit4->resize(175,30);
    quit4->setFont(QFont("Invalid font name",18,QFont::Bold));
    QObject::connect(quit4,SIGNAL(clicked()),&a,SLOT(quit()));
    lt->addWidget(quit4);    
    top.show();
    qDebug() << "button creation time: " << timer.elapsed();

    return a.exec();
}