我可以抵消chart.js堆叠条形图中的条形吗？

Question

我可以像这样抵消一下chart.js堆叠条形图中的条形：

Answer 1

基于此answer，我创建了一个可运行的代码段，说明了如何完成此操作。我不使用堆叠式条形图，因为用例对我来说并不清晰，问题中的图像看起来像是带有阴影的条形图。

const dataset = [40, 80, 50, 60, 70];
const offset = 8;

Chart.pluginService.register({
    afterUpdate: function(chart) {
        var dataset = chart.config.data.datasets[1];
        for (var i = 0; i < dataset._meta[0].data.length; i++) {
            var model = dataset._meta[0].data[i]._model;
            model.x += offset;
            model.controlPointNextX += offset;
            model.controlPointPreviousX += offset;
        }
    }
});

var data = {
    labels: ["A", "B", "C", "D", "E"],
    datasets: [{
            backgroundColor: [
              'rgba(255, 99, 132)',
              'rgba(255, 206, 86)',
              'rgba(54, 162, 235)',              
              'rgba(75, 192, 192)',
              'rgba(153, 102, 255)'
              ],
            borderWidth: 1,
            data: dataset,
            xAxisID: "bar-x-axis1",
            categoryPercentage: 0.5,
            barPercentage: 0.5,
        },
        {
            backgroundColor: 'rgba(0, 0, 0, 0.2)',
            data: dataset.map(v => v + offset),
            xAxisID: "bar-x-axis2",
            categoryPercentage: 0.5,
            barPercentage: 0.5
        }
    ]
};

var options = {  
    legend: {
        display: false
    },
    tooltips: {
        enabled: false
    },
    scales: {        
        xAxes: [
            {
                id: "bar-x-axis2"
            },
            {
                id: "bar-x-axis1",              
                offset: true,
                ticks: {
                   display: false
                }
           }
        ],
        yAxes: [{
            id: "bar-y-axis1",
            ticks: {
                beginAtZero: true,
                stepSize: 50
            }
        }]
    }
};

var ctx = document.getElementById("myChart").getContext("2d");
var myBarChart = new Chart(ctx, {
    type: 'bar',
    data: data,
    options: options
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.3/Chart.min.js"></script>
<canvas id="myChart" height="60"></canvas>