how change color of labels of legends of chart.js-CodePudding

i use of chart.js package for create a chart.

my problem: how change the color of label of each legends?

for example:

color of "legend1" be: red.
color of "legend2" be: blue.

my codes:

const ctx = document.getElementById('myChart').getContext('2d');
const myChart = new Chart(ctx, {
  data: {
    labels: ['۱۴۰۰/۰۱/۰۱', '۱۴۰۰/۰۱/۰۲', '۱۴۰۰/۰۱/۰۳', '۱۴۰۰/۰۱/۰۴', '۱۴۰۰/۰۱/۰۵', '۱۴۰۰/۰۱/۰۶'],
    datasets: [{
        type: 'line',
        label: 'legend1',
        backgroundColor: 'rgb(14, 156, 255)',
        data: [6, 5.5, 4, 7, 5.4, 5.8],
        fill: false,
        borderColor: 'rgb(14, 156, 255)',
        tension: 0
      },
      {
        type: 'line',
        label: 'legend2',
        backgroundColor: 'rgb(22, 185, 156)',
        data: [6.2, 5.7, 3.8, 7.2, 5.2, 5.9],
        fill: false,
        borderColor: 'rgb(22, 185, 156)',
        tension: 0
      }
    ] //end : datasets
  }, // end: data
  options: {
    plugins: {
      legend: {
        labels: {
          font: {
            size: 18
          } // end: font
        } // end: labels
        ,
        position: 'bottom',
        rtl: true,
        align: "start"
      } // end: legend
    }, // end: plugins
    scales: {
      y: {
        beginAtZero: true,
        display: false
      } // end: y 
      ,
      x: {
        grid: {
          borderDash: [6, 5],
          lineWidth: 1,
          color: '#CCCCCC'
        } // end: grid
      } //end:x
    } // end: scales
  } //end: options
});

<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/chart.min.js"></script>
<canvas id="myChart" width="778" height="433"></canvas>

my problem is just that: how change the color of each legend's text? color of "legend1" text and color of "legend2" text.

my codes result:

CodePudding user response：

To achieve what you want you will need to use a custom generateLabels function like so:

const legendColors = ['red', 'blue']
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'
      },
      {
        label: '# of Points',
        data: [7, 11, 5, 8, 3, 7],
        borderColor: 'orange'
      }
    ]
  },
  options: {
    plugins: {
      legend: {
        labels: {
          generateLabels: (chart) => {
            const datasets = chart.data.datasets;
            const {
              labels: {
                usePointStyle,
                pointStyle,
                textAlign,
                color
              }
            } = chart.legend.options;

            return chart._getSortedDatasetMetas().map((meta, i) => {
              const style = meta.controller.getStyle(usePointStyle ? 0 : undefined);
              const borderWidth = Chart.helpers.toPadding(style.borderWidth);

              return {
                text: datasets[meta.index].label,
                fillStyle: style.backgroundColor,
                fontColor: legendColors[i],
                hidden: !meta.visible,
                lineCap: style.borderCapStyle,
                lineDash: style.borderDash,
                lineDashOffset: style.borderDashOffset,
                lineJoin: style.borderJoinStyle,
                lineWidth: (borderWidth.width   borderWidth.height) / 4,
                strokeStyle: style.borderColor,
                pointStyle: pointStyle || style.pointStyle,
                rotation: style.rotation,
                textAlign: textAlign || style.textAlign,
                borderRadius: 0, // TODO: v4, default to style.borderRadius

                // Below is extra data used for toggling the datasets
                datasetIndex: meta.index
              };
            }, this);
          }
        }
      }
    }
  }
}

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

<body>
  <canvas id="chartJSContainer" width="600" height="400"></canvas>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.7.1/chart.js"></script>
</body>

CodePudding user response：

Did you try the hex format ? For example, you could try replacing "rgb(14, 156, 255)" by "#0e9cff"

More info here : https://devsheet.com/code-snippet/change-color-of-the-line-in-chartjs-line-chart/