Echart 饼图背景颜色设置

option = {  
        title : {  
        text: '颜色范围选择',  
               x:'left',  
               y:'top'  
        },  
        tooltip : {  
               show: true,  
               formatter: "{a} 
{b} : {c} ({d}%)"  
        },  
        color:['red', 'green','yellow','blueviolet']  
}