下面是一个工作示例的代码段。https://codepen.io/stockinail/pen/OJENbwM
需要一个额外的插件来为画布的背景着色，如CHARt.JS doc https://www.chartjs.org/docs/latest/configuration/canvas-background.html中所报告的：

const plugin = {
  id: 'custom_canvas_background_color',
  beforeDraw: (chart) => {
    const {ctx} = chart;
    ctx.save();
    ctx.globalCompositeOperation = 'destination-over';
    ctx.fillStyle = 'white';
    ctx.fillRect(0, 0, chart.width, chart.height);
    ctx.restore();
  }
};

必须将插件添加到图表配置中，如下所示：

const myChart = new Chart(ctx, {
  type: 'bar',
  plugins: [plugin], // <<--- adds plugin to color the background of the canvas
  data: chartData
});