问如何设置较大的负值以在莫里斯条形图中显示较短的条形图？

EN

new Morris.Bar({
    // ID of the element in which to draw the chart.
    element: 'myfirstchart',
    // Chart data records -- each entry in this array corresponds to a point on
    // the chart.
    data: [
        { material: 'aaa', value: -20, vendor: 'aaa' },
        { material: 'bbb', value: -30, vendor: 'bbb' },
        { material: 'ccc', value: -40, vendor: 'ccc' },
        { material: 'ddd', value: -50, vendor: 'ddd' },
        { material: 'eee', value: -60, vendor: 'eee' }
        //,{ material: '', value: 0, vendor: '' }
    ],
    hoverCallback: function(index, options, content) {
        var row = options.data[index]; 
        return(row.value + "<br>" + row.vendor);
    },
    // The name of the data record attribute that contains x-values.
    xkey: 'material',
    // A list of names of data record attributes that contain y-values.
    ykeys: ['value'],
    // Labels for the ykeys -- will be displayed when you hover over the
    // chart.
    labels: ['not in use']
});