Draws the inputed item as a bar graph.
        
        :param      item    | <XChartDatasetItem>
                    painter | <QPainter>
                    option  | <QStyleOptionGraphicsItem>

def drawItem(self, item, painter, option):
        """
        Draws the inputed item as a bar graph.
        
        :param      item    | <XChartDatasetItem>
                    painter | <QPainter>
                    option  | <QStyleOptionGraphicsItem>
        """
        dataset = item.dataset()
        
        painter.save()
        painter.setRenderHint(painter.Antialiasing)
        
        center = item.buildData('center')
        radius = item.buildData('radius')
        
        if int(option.state) & QStyle.State_MouseOver != 0:
            alpha = 20
            mouse_over = True
        else:
            alpha = 0
            mouse_over = False
        
        for value, subpath in item.buildData('subpaths', []):
            clr = dataset.color(value)
            
            bg = clr.lighter(110)
            bg.setAlpha(alpha + 100)
            painter.setBrush(bg)
            
            if mouse_over:
                scale = 1.08
                dx = (center.x() / scale) - center.x()
                dy = (center.y() / scale) - center.y()
                
                painter.save()
                painter.scale(scale, scale)
                painter.translate(dx, dy)
                painter.setPen(Qt.NoPen)
                painter.drawPath(subpath)
                painter.restore()
            
            pen = QPen(clr)
            pen.setWidth(0.5)
            painter.setPen(pen)
            
            painter.drawPath(subpath)
            
        painter.restore()