angular - ng2-图表 : How to show percentage values inside the chart?

Question

我已经用谷歌搜索了几个小时，但还没有找到答案。我正在使用 ng2-chart 在我的仪表板中生成图表。它运行良好，问题是我想在圆环图中显示百分比值，但我不知道该怎么做。

这是我的代码:

<canvas baseChart [data]="dashboard.graficoDespesaMensal.valorTotalDespesa"
                [labels]="dashboard.graficoDespesaMensal.descricaoCategoria" [options]="optionsGraficoDespesa"
                [chartType]="'doughnut'">
              </canvas>

  optionsGraficoDespesa: ChartOptions = {
    responsive: true,
    tooltips: {
      enabled: true,
      callbacks: {
        label: function (tooltipItem, data) {
          let label = data.labels[tooltipItem.index];
          let count: any = data
            .datasets[tooltipItem.datasetIndex]
            .data[tooltipItem.index];
          return label + ": " + new Intl.NumberFormat('pt-BR', { style: 'currency', currency: 'BRL' }).format(count);
        },
      },
    },
    plugins: {
      datalabels: {
        formatter: (value, ctx) => {
          let sum = 0;
          let dataArr = ctx.chart.data.datasets[0].data;
          dataArr.map(data => {
            sum += data;
          });
          let percentage = (value * 100 / sum).toFixed(2) + "%";
          return percentage;
        },
        color: '#fff',
      }
    }
  };

结果是:

不幸的是，我在 [options] 输入中使用的插件无法正常工作。我该如何解决这个问题？

Answer 1

我通过执行以下操作解决了这个问题:

npm i chartjs-plugin-datalabels

组件:

import * as pluginDataLabels from 'chartjs-plugin-datalabels';

public chartPlugins = [pluginDataLabels];

  optionsGraficoDespesa: ChartOptions = {
    responsive: true,
    tooltips: {
      enabled: true,
      callbacks: {
        label: function (tooltipItem, data) {
          let label = data.labels[tooltipItem.index];
          let count: any = data
            .datasets[tooltipItem.datasetIndex]
            .data[tooltipItem.index];
          return label + ": " + new Intl.NumberFormat('pt-BR', { style: 'currency', currency: 'BRL' }).format(count);
        },
      },
    },
    plugins: {
      datalabels: {
        formatter: (value, ctx) => {
          let sum = 0;
          let dataArr: any[] = ctx.chart.data.datasets[0].data;
          dataArr.map((data: number) => {
            sum += data;
          });
          let percentage = (value * 100 / sum).toFixed(2) + "%";
          return percentage;
        },
        color: '#fff',
      }
    }
  };

HTML

<canvas baseChart data]="dashboard.graficoDespesaMensal.valorTotalDespesa"
[labels]="dashboard.graficoDespesaMensal.descricaoCategoria" [options]="optionsGraficoDespesa" [plugins]="chartPlugins"[chartType]="'doughnut'">

结果: