Align doughnut/pie charts vertically in the container

Question

I have three doughnut charts side by side like so:

The problem is, the number of items is different between the charts, causing the legend have different height and in turn the charts are not in line. Is it possible to align the charts to the top of the container?

score 2 · Answer 1 · answered Jan 30 '22 at 14:50

You will need to use an custom plugin for this that makes an html legend:

const getOrCreateLegendList = (chart, id) => {
  const legendContainer = document.getElementById(id);
  let listContainer = legendContainer.querySelector('ul');

  if (!listContainer) {
    listContainer = document.createElement('ul');
    listContainer.style.display = 'flex';
    listContainer.style.flexDirection = 'row';
    listContainer.style.margin = 0;
    listContainer.style.padding = 0;

    legendContainer.appendChild(listContainer);
  }

  return listContainer;
};

const htmlLegendPlugin = {
  id: 'htmlLegend',
  afterUpdate(chart, args, options) {
    const ul = getOrCreateLegendList(chart, options.containerID);

    // Remove old legend items
    while (ul.firstChild) {
      ul.firstChild.remove();
    }

    // Reuse the built-in legendItems generator
    const items = chart.options.plugins.legend.labels.generateLabels(chart);

    items.forEach(item => {
      const li = document.createElement('li');
      li.style.alignItems = 'center';
      li.style.cursor = 'pointer';
      li.style.display = 'flex';
      li.style.flexDirection = 'row';
      li.style.marginLeft = '10px';

      li.onclick = () => {
        const {
          type
        } = chart.config;
        if (type === 'pie' || type === 'doughnut') {
          // Pie and doughnut charts only have a single dataset and visibility is per item
          chart.toggleDataVisibility(item.index);
        } else {
          chart.setDatasetVisibility(item.datasetIndex, !chart.isDatasetVisible(item.datasetIndex));
        }
        chart.update();
      };

      // Color box
      const boxSpan = document.createElement('span');
      boxSpan.style.background = item.fillStyle;
      boxSpan.style.borderColor = item.strokeStyle;
      boxSpan.style.borderWidth = item.lineWidth + 'px';
      boxSpan.style.display = 'inline-block';
      boxSpan.style.height = '20px';
      boxSpan.style.marginRight = '10px';
      boxSpan.style.width = '20px';

      // Text
      const textContainer = document.createElement('p');
      textContainer.style.color = item.fontColor;
      textContainer.style.margin = 0;
      textContainer.style.padding = 0;
      textContainer.style.textDecoration = item.hidden ? 'line-through' : '';

      const text = document.createTextNode(item.text);
      textContainer.appendChild(text);

      li.appendChild(boxSpan);
      li.appendChild(textContainer);
      ul.appendChild(li);
    });
  }
};

const options = {
  type: 'line',
  data: {
    labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
    datasets: [{
        label: '# of Votes',
        data: [12, 19, 3, 5, 2, 3],
        borderColor: 'pink',
        backgroundColor: 'pink'
      },
      {
        label: '# of Points',
        data: [7, 11, 5, 8, 3, 7],
        borderColor: 'orange',
        backgroundColor: 'orange'
      }
    ]
  },
  options: {
    plugins: {
      legend: {
        display: false,
      },
      htmlLegend: {
        // ID of the container to put the legend in
        containerID: 'legend-container',
      }
    }
  },
  plugins: [htmlLegendPlugin],
}

const ctx = document.getElementById('chartJSContainer').getContext('2d');
new Chart(ctx, options);

<body>
  <div id="legend-container"></div>
  <canvas id="chartJSContainer" width="600" height="400"></canvas>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.7.0/chart.js"></script>
</body>

Oh, I was hoping there's a built-in way of doing it I missed, but this does the trick! — suda, Jan 31 '22 at 16:11

Align doughnut/pie charts vertically in the container

1 Answers1