Recalculates the chart information when the widget resizes.
        
        :param      event | <QResizeEvent>

def resizeEvent(self, event):
        """
        Recalculates the chart information when the widget resizes.
        
        :param      event | <QResizeEvent>
        """
        super(XChart, self).resizeEvent(event)
        
        if self.isVisible():
            self.recalculate()