legend: {
    
    
     data: this.legend
     orient: "horizontal", //垂直显示还是水平显示
     right: 60, //legend相对位置
     top: 0, //legend相对位置
     textStyle: {
    
     
         fontSize: "14", 
         color:'#fff'
     }, //legend字体大小
     selected: {
    
    }
},

// 设置selected默认第一个为true
var selected_item = {
    
    };
for (var k = 0; k < this.legend.length; k++) {
    
    
     var key_name = this.legend[k];
     if (k >= 1){
    
    
         selected_item[key_name] = false;
     } else {
    
    
         selected_item[key_name] = true;
     }
}
 option.legend.selected = selected_item