给echarts 的图例改变形状

legend: {
                            
    data:[
            {    
                name:'手机',
                           icon : 'force',    //变成你想要的图例的类型
                        textStyle:{fontWeight:'bold', color:'green'}
                                    
            },
            {    
                name:'ipad',
                           icon : 'force',
                        textStyle:{fontWeight:'bold', color:'green'}
                                    
            },
            {    
                name:'电脑',
                           icon : 'force',   
                        textStyle:{fontWeight:'bold', color:'green'}
                                    
            },
        ]
                            
},