給echarts 的圖例改變形狀

legend: {
                            
    data:[
            {    
                name:'手機',
                           icon : 'force',    //變成你想要的圖例的類型
                        textStyle:{fontWeight:'bold', color:'green'}
                                    
            },
            {    
                name:'ipad',
                           icon : 'force',
                        textStyle:{fontWeight:'bold', color:'green'}
                                    
            },
            {    
                name:'電腦',
                           icon : 'force',   
                        textStyle:{fontWeight:'bold', color:'green'}
                                    
            },
        ]
                            
},