Returns the X, Y value for the given point.
        
        :param      point | <QPoint>
        
        :return     (<variant> x, <variant> y)

def valueAt( self, point ):
        """
        Returns the X, Y value for the given point.
        
        :param      point | <QPoint>
        
        :return     (<variant> x, <variant> y)
        """
        x = point.x()
        y = point.y()
        
        hruler = self.horizontalRuler()
        vruler = self.verticalRuler()
        
        grid   = self._buildData.get('grid_rect')
        if ( not grid ):
            return (None, None)
        
        x_perc = 1 - ((grid.right() - x) / grid.width())
        y_perc = ((grid.bottom() - y) / grid.height())
        
        return (hruler.valueAt(x_perc), vruler.valueAt(y_perc))