Google 图表 - 在柱形图上绘制趋势线

Google charts - Plot trendlines on column chart

我正在尝试在柱形图上绘制趋势线。但是线条不显示。 请参考 jsfiddle https://jsfiddle.net/sashant9/m04py64w/

我根据 google 图表文档使用了 'trendlines: { 1:{},2:{}}'。

请检查下面的代码。

    function drawVisitorGraph() {


        var data = new google.visualization.DataTable();
        data.addColumn('string', 'Date');
        data.addColumn('number', 'Search Visitors');
        data.addColumn('number', 'Unique Visitors');

        data.addRow(["2015-07-01",1774,3266]);
        data.addRow(["2015-07-02",1891,3017]);
        data.addRow(["2015-07-03",1572,2730]);
        data.addRow(["2015-07-04",979,1604]);
        data.addRow(["2015-07-05",1024,1702]);
        data.addRow(["2015-07-06",2163,4097]);

        var chart = new google.visualization.ColumnChart(document.querySelector('#visitor_graph'));

        var options = {
                bars: 'vertical',
                vAxis: {format: 'decimal'},
                trendlines: { 1:{},2:{}}, 
                width: '100%',
                height: '100%',
                colors: ['#070979', '#EC0F13']
            }
            chart.draw(data,options);

    }

    //google.setOnLoadCallback(drawChart);

    google.load('visualization', '1.1', {packages: ['corechart'], callback: drawVisitorGraph});

请尝试下面的代码,检查工作 fiddle here.

function drawVisitorGraph() {


    var data = new google.visualization.DataTable();
    data.addColumn('date', 'Date');
    data.addColumn('number', 'Search Visitors');
    data.addColumn('number', 'Unique Visitors');

    data.addRow([new Date(2015,07,01),1774,3266]);
    data.addRow([new Date(2015,07,02),1891,3017]);
    data.addRow([new Date(2015,07,03),1572,2730]);
    data.addRow([new Date(2015,07,04),979,1604]);
    data.addRow([new Date(2015,07,05),1024,1702]);
    data.addRow([new Date(2015,07,06),2163,4097]);

    var chart = new google.visualization.ColumnChart(document.querySelector('#visitor_graph'));

    var options = {
            bars: 'vertical',
            vAxis: {format: 'decimal'},
            trendlines: { 0:{},1:{}}, 
            width: '100%',
            height: '100%',
            colors: ['#070979', '#EC0F13']
        }
        chart.draw(data,options);

}

//google.setOnLoadCallback(drawChart);

google.load('visualization', '1.1', {packages: ['corechart'], callback: drawVisitorGraph});