connect(rowsSB, SIGNAL(valueChanged(int)),
this, SLOT(rowsChanged(int)));
connect(columnsSB, SIGNAL(valueChanged(int)),
this, SLOT(columnsChanged(int)));
connect(rowsSB, SIGNAL(valueChanged(int)),
this, SLOT(rowsChanged(int)));
connect(columnsSB, SIGNAL(valueChanged(int)),
this, SLOT(columnsChanged(int)));