javascript - 添加阴影 Chart.js

Question

我正在使用最新版本的 chart.js，我想为每个条形图添加一个阴影

代码示例

<canvas id="myChart" width="400" height="400"></canvas> 

<script> 
var ctx = document.getElementById("myChart").getContext('2d');
var myChart = new Chart(ctx, {
    type: 'bar',
    data: {
        labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
        datasets: [{
            label: '# of Votes',
            data: [12, 19, 3, 5, 2, 3],
            backgroundColor: ['rgba(255, 99, 132, 0.2)', 'rgba(54, 162, 235, 0.2)', 'rgba(255, 206, 86, 0.2)', 'rgba(75, 192, 192, 0.2)', 'rgba(153, 102, 255, 0.2)', 'rgba(255, 159, 64, 0.2)'],
            borderColor: ['rgba(255,99,132,1)', 'rgba(54, 162, 235, 1)', 'rgba(255, 206, 86, 1)', 'rgba(75, 192, 192, 1)', 'rgba(153, 102, 255, 1)', 'rgba(255, 159, 64, 1)'],
            borderWidth: 1
        }]
    },
    options: {
        scales: {
            yAxes: [{
                ticks: {
                    beginAtZero: true
                }
            }]
        }
    }
});
</script>

Answer 1

这适用于折线图。

[编辑...]

Chart.types.Line.extend({
  name: "LineAlt",
  initialize: function () {
    Chart.types.Line.prototype.initialize.apply(this, arguments);

    var ctx = this.chart.ctx;
    var originalStroke = ctx.stroke;
    ctx.stroke = function () {
      ctx.save();
      ctx.shadowColor = '#000';
      ctx.shadowBlur = 10;
      ctx.shadowOffsetX = 8;
      ctx.shadowOffsetY = 8;
      originalStroke.apply(this, arguments)
      ctx.restore();
    }
  }
});

var data = {
  labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
  datasets: [
    {
      fillColor: "rgba(255, 99, 132, 0.2)",
      strokeColor: "rgba(54, 162, 235, 0.2)",
      pointColor: "rgba(255, 206, 86, 0.2)",
      pointStrokeColor: "#fff",
      pointHighlightFill: "#fff",
      pointHighlightStroke: "rgba(75, 192, 192, 0.2)",
      data: [12, 19, 3, 5, 2, 3]
    }
  ]
};

var ctx = document.getElementById("myChart").getContext("2d");
var canvas = new Chart(ctx).LineAlt(data, {
  datasetFill: false
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/1.0.2/Chart.min.js"></script>
<canvas id="myChart" width="600" height="300"></canvas>

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