图例换行

描述:当前是关于Echarts图表中的 柱状图 示例。
 
            /* 图例换行  特殊字符串 ''(空字符串)或者 '\n'(换行字符串)用于图例的换行 */
option = {
    legend: {
        data: ['Matcha Latte', 'Milk Tea', 'Cheese Cocoa', '','2012', '2013', '2014', '2015']
    },
    tooltip: {},
    dataset: {
        source: [
            ['product', '2012', '2013', '2014', '2015'],
            ['Matcha Latte', 41.1, 30.4, 65.1, 53.3],
            ['Milk Tea', 86.5, 92.1, 85.7, 83.1],
            ['Cheese Cocoa', 24.1, 67.2, 79.5, 86.4]
        ]
    },
    xAxis: [
        {type: 'category', gridIndex: 0},
        {type: 'category', gridIndex: 1}
    ],
    yAxis: [
        {gridIndex: 0},
        {gridIndex: 1}
    ],
    grid: [
        {bottom: '55%'},
        {top: '55%'}
    ],
    series: [
        // 第一个柱状图
        {type: 'bar', seriesLayoutBy: 'row'},
        {type: 'bar', seriesLayoutBy: 'row'},
        {type: 'bar', seriesLayoutBy: 'row'},
        // 第二个柱状图
        {type: 'bar', xAxisIndex: 1, yAxisIndex: 1},
        {type: 'bar', xAxisIndex: 1, yAxisIndex: 1},
        {type: 'bar', xAxisIndex: 1, yAxisIndex: 1},
        {type: 'bar', xAxisIndex: 1, yAxisIndex: 1}
    ]
};