Chart.js-将鼠标悬停在图例上时显示工具提示

问题描述：

我最近将我的Chart.js版本从 v2.3 升级到了 v2.7.1 ，现有功能，当用户将鼠标悬停在相应的图例项目上时，甜甜圈图中的指定段将处于活动状态（悬停颜色，显示工具提示）。该代码如下所示：

I recently upgraded my version of Chart.js from v2.3 to v2.7.1, which broke an existing functionality where the specified segment in a doughnut chart would be active (hover color, tooltip shown) when the user hovered over the corresponding legend item. That code looked like this:

 var " + ClientID + @" = new Chart(" + ClientID + @"CTX, {
    data: { ... },
    options: {
        legend: {
            onHover: function(evt, legendItem) {
                var index = " + ClientID + @".data.labels.indexOf(legendItem.text);
                if (" + ClientID + @".data.datasets[0].data[index] > 0) {
                    var metaData = " + ClientID + @".getDatasetMeta(0);
                    var activeSegment = metaData.data[index];
                    " + ClientID + @".tooltipActive = [activeSegment];
                    " + ClientID + @".active = [activeSegment];
                }                                   
            },
        }
    }
});

浏览Chart.js文件和文档，看起来像 tooltipActive 属性已被完全删除，从而打破了图例悬停功能。我在 Chart.js git 上浏览了发行说明和PR。找出该标记为重大更改的地方，或任何提及的地方。我必须升级Chart.js的版本才能进行单独的更改，因此无法恢复到 v2.3 。

Looking through the Chart.js file and documentation, it looks like the tooltipActive property has been completely removed, thus breaking the legend hover functionality. I looked through the release notes and PRs on the Chart.js git but couldn't find where this was noted as a breaking change, or any mention of it whatsoever. I have to upgrade versions of Chart.js for a separate change I'm making, so reverting back to v2.3 is not an option. Has anyone else run into this?

答

这是基于 timclutton 中的a / 53781749/2358409>此答案，它与Chart.js的当前版本（ 2.9.3）。

Here's a solution based on this anwser from timclutton that works with the current version of Chart.js (2.9.3).

const chart = new Chart('chart', {
  type: 'doughnut',
  data: {
    labels: ['One', 'Two', 'Three'],
    datasets: [{
      data: [4, 5, 3],
      backgroundColor: ['rgba(255, 99, 132, 0.2)', 'rgba(255, 159, 64, 0.2)', 'rgba(54, 162, 235, 0.2)'],
      borderColor: ['rgb(255, 99, 132)', 'rgb(255, 159, 64)', 'rgb(54, 162, 235)'],
      hoverBackgroundColor: ['rgba(255, 99, 132, 0.4)', 'rgba(255, 159, 64, 0.4)', 'rgba(54, 162, 235, 0.4)'],
      borderWidth: 1,
      hoverBorderWidth: 3
    }]
  },
  options: {
    legend: {
      onHover: (evt, legendItem) => {
        const index = chart.data.labels.indexOf(legendItem.text);
        const rect = chart.canvas.getBoundingClientRect();
        const point = chart.getDatasetMeta(0).data[index].getCenterPoint();
        const e = new MouseEvent('mousemove', {
          clientX: rect.left + point.x,
          clientY: rect.top + point.y
        });
        chart.canvas.dispatchEvent(e);
      }
    }
  }
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.3/Chart.min.js"></script>
<canvas id="chart" height="80"></canvas>

Chart.js-将鼠标悬停在图例上时显示工具提示

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