ChartJS 仅显示特定刻度的大字体大小

我试图强调 X 轴上的特定值（如果它满足特定条件）。

例如，在我的codepen https://codepen.io/nuclearslug/pen/NJGmmy我只想更改“蓝色”栏的字体大小。这对于 Chart.js 来说是可能的吗？

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
                }
            }],
            xAxes: [{
                ticks: {
                    //only show large font size for 'Blue'
                    fontSize: 16
                }
            }]
        }
    }
});

Chartjs 没有公共 api 来执行此操作，但您可以修改内部_ticks on beforeDraw https://www.chartjs.org/docs/latest/developers/plugins.html#plugin-core-api并将标签“蓝色”设置为major: true那么该标签将使用major https://www.chartjs.org/docs/latest/axes/styling.html#tick-configuration勾选配置选项中的样式。

也要谨慎使用它，因为它依赖于内部实现，因此可能会在未来的版本中中断（不太可能发生，但只是说一下）。

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
                }
            }],
            xAxes: [{
                ticks: {
                    fontSize: 16,
                    major: {
                      fontSize: 20
                    }
                }
            }]
        }
    }, 
    plugins: [{
        beforeDraw: function({ chart }, options) {
            chart.boxes
            .find(box => box.id === "x-axis-0")
            ._ticks
            .find(tick => tick.label === "Blue")
            .major = true;
        }
    }]
});

<canvas id="myChart"></canvas>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.3/Chart.min.js"></script>

PS：以防万一有人想知道我如何知道我搜索的这个内部实现fillText在 ChartJS github 源代码中和console.log(myChart) xD