_hover_point(-1, -1)
{
connect(horizontalScrollBar(), SIGNAL(valueChanged(int)),
this, SLOT(h_scroll_value_changed(int)));
connect(verticalScrollBar(), SIGNAL(valueChanged(int)),
this, SLOT(v_scroll_value_changed(int)));
_hover_point(-1, -1)
{
connect(horizontalScrollBar(), SIGNAL(valueChanged(int)),
this, SLOT(h_scroll_value_changed(int)));
connect(verticalScrollBar(), SIGNAL(valueChanged(int)),
this, SLOT(v_scroll_value_changed(int)));