Returns the minimum value for this ruler.  If the cached value is None,
        then a default value will be specified based on the ruler type.
        
        :return     <variant>

def minimum( self ):
        """
        Returns the minimum value for this ruler.  If the cached value is None,
        then a default value will be specified based on the ruler type.
        
        :return     <variant>
        """
        if ( self._minimum is not None ):
            return self._minimum
        
        rtype = self.rulerType()
        
        if ( rtype == XChartRuler.Type.Number ):
            self._minimum = 0
            
        elif ( rtype == XChartRuler.Type.Date ):
            self._minimum = QDate.currentDate()
        
        elif ( rtype == XChartRuler.Type.Datetime ):
            self._minimum = QDateTime.currentDateTime()
        
        elif ( rtype == XChartRuler.Type.Time ):
            self._minimum = QDateTime.currentDateTime().time()
        
        else:
            notches = self.notches()
            if ( notches ):
                self._minimum = notches[0]
        
        return self._minimum