#include <QApplication>
#include <QtWidgets>

int main(int argc, char *argv[])
{
  QApplication app(argc, argv);

  QWidget w;
  w.setLayout(new QVBoxLayout());

  QLabel *ttl = new QLabel("Hover me", &w);
  ttl->setToolTip("This is a test.");
  w.layout()->addWidget(ttl);

  QLabel *l = new QLabel("L", &w);
  l->setAlignment(Qt::AlignCenter);
  l->resize(100, 100);
  QFont fnt;
  fnt.setPointSize(24);
  l->setFont(fnt);
  w.layout()->addWidget(l);

  QPropertyAnimation *a = new QPropertyAnimation(l, "size");
  a->setDuration(10000);
  a->setStartValue(QSize(100, 30));
  a->setEndValue(QSize(30, 100));
  a->setLoopCount(-1);

  w.resize(150, 150);
  w.show();
  a->start();

  return app.exec();
}