code: func (v *TextView) GetLineAtY(y int) (*TextIter, int) {
  	var iter TextIter
  	var line_top C.gint
  	iiter := (C.GtkTextIter)(iter)
  	C.gtk_text_view_get_line_at_y(v.native(), &iiter, C.gint(y), &line_top)
  	return &iter, int(line_top)
  }
docs: // GetLineAtY is a wrapper around gtk_text_view_get_line_at_y().