Paints this item as the group look.
        
        :param      painter | <QPainter>

def paintGroup( self, painter ):
        """
        Paints this item as the group look.
        
        :param      painter | <QPainter>
        """
        # generate the rect
        rect    = self.rect()
        
        padding = self.padding()
        gantt   = self.scene().ganttWidget()
        cell_w  = gantt.cellWidth()
        cell_h  = gantt.cellHeight()
        
        x       = 0
        y       = self.padding()
        w       = rect.width()
        h       = rect.height() - (padding + 1)
        
        # grab the color options
        color       = self.color()
        alt_color   = self.alternateColor()
        
        if ( self.isSelected() ):
            color       = self.highlightColor()
            alt_color   = self.alternateHighlightColor()
        
        # create the background brush
        gradient = QLinearGradient()
        gradient.setStart(0, 0)
        gradient.setFinalStop(0, h)
        
        gradient.setColorAt(0,   color)
        gradient.setColorAt(0.8, alt_color)
        gradient.setColorAt(1,   color)
        
        painter.setPen(self.borderColor())
        painter.setBrush(QBrush(gradient))
        
        pen = painter.pen()
        pen.setWidthF(0.5)
        painter.setPen(pen)
        painter.setRenderHint( painter.Antialiasing )
        
        path = QPainterPath()
        path.moveTo(x - cell_w / 4.0, y)
        path.lineTo(w + cell_w / 4.0, y)
        path.lineTo(w + cell_w / 4.0, y + h / 2.0)
        path.lineTo(w, h)
        path.lineTo(w - cell_w / 4.0, y + h / 2.0)
        path.lineTo(x + cell_w / 4.0, y + h / 2.0)
        path.lineTo(x, h)
        path.lineTo(x - cell_w / 4.0, y + h / 2.0)
        path.lineTo(x - cell_w / 4.0, y)
        
        painter.drawPath(path)
        
        # create the progress brush
        if ( self.showProgress() ):
            gradient = QLinearGradient()
            gradient.setStart(0, 0)
            gradient.setFinalStop(0, h)
            gradient.setColorAt(0, self.progressColor())
            gradient.setColorAt(0.8, self.alternateProgressColor())
            gradient.setColorAt(1, self.progressColor())
            
            prog_w = (w - 4) * (self._percentComplete/100.0)
            
            painter.setPen(Qt.NoPen)
            painter.setBrush(QBrush(gradient))
            painter.drawRect(x, y, prog_w, y + h / 2.0)
        
        # draw the text on this item
        if ( self.text() ):
            painter.setPen(self.textColor())
            painter.drawText(x, y, w, h, Qt.AlignCenter, self.text())