Chart.js Data Decimation 示例

HTML

CSS

JavaScript

HTML

<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no" />
<title>Chart.js Data Decimation</title>
<meta name="keywords" content="LightYear,光年,后台模板,后台管理系统,光年HTML模板">
<meta name="description" content="LightYear是一个基于Bootstrap的后台管理系统的HTML模板。">
<meta name="author" content="yinqi">
<link rel="stylesheet" type="text/css" href="http://lyear.itshubao.com/v4/css/bootstrap.min.css">
<link rel="stylesheet" type="text/css" href="http://lyear.itshubao.com/v4/css/style.min.css">
</head>
  
<body>
<div class="chart-example">
  <div class="tab-content">
    <div class="chart-view"><canvas id="myChart"></canvas></div>
    <div class="chart-actions mt-3"></div>
    <ul class="nav nav-tabs mt-3">
      <li class="nav-item">
        <a class="nav-link active" data-toggle="tab" href="#myChart-decimation" aria-selected="true">Decimation</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" data-toggle="tab" href="#myChart-data" aria-selected="true">Data</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" data-toggle="tab" href="#myChart-setup" aria-selected="false">Setup</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" data-toggle="tab" href="#myChart-actions" aria-selected="false">Actions</a>
      </li>
    </ul>
    <div class="tab-content">
      <div class="tab-pane fade show active tab-pane-code" id="myChart-decimation">
        <pre>
const decimation = {
  enabled: false,
  algorithm: 'min-max',
};
        </pre>
      </div>
      <div class="tab-pane fade show tab-pane-code" id="myChart-data">
        <pre>
const NUM_POINTS = 100000;
Utils.srand(10);

// parseISODate returns a luxon date object to work with in the samples
// We will create points every 30s starting from this point in time
const start = Utils.parseISODate('2021-04-01T00:00:00Z').toMillis();
const pointData = [];

for (let i = 0; i < NUM_POINTS; ++i) {
  // Most data will be in the range [0, 20) but some rare data will be in the range [0, 100)
  const max = Math.random() < 0.001 ? 100 : 20;
  pointData.push({x: start + (i * 30000), y: Utils.rand(0, max)});
}

const data = {
  datasets: [{
    borderColor: Utils.CHART_COLORS.red,
    borderWidth: 1,
    data: pointData,
    label: 'Large Dataset',
    radius: 0,
  }]
};
        </pre>
      </div>
      <div class="tab-pane fade tab-pane-code" id="myChart-setup">
        <pre>
const config = {
  type: 'line',
  data: data,
  options: {
    // Turn off animations and data parsing for performance
    animation: false,
    parsing: false,

    interaction: {
      mode: 'nearest',
      axis: 'x',
      intersect: false
    },
    plugins: {
      decimation: decimation,
    },
    scales: {
      x: {
        type: 'time',
        ticks: {
          source: 'auto',
          // Disabled rotation for performance
          maxRotation: 0,
          autoSkip: true,
        }
      }
    }
  }
};
        </pre>
      </div>
      <div class="tab-pane fade tab-pane-code" id="myChart-actions">
        <pre>
const actions = [
  {
    name: 'No decimation (default)',
    handler(chart) {
      chart.options.plugins.decimation.enabled = false;
      chart.update();
    }
  },
  {
    name: 'min-max decimation',
    handler(chart) {
      chart.options.plugins.decimation.algorithm = 'min-max';
      chart.options.plugins.decimation.enabled = true;
      chart.update();
    },
  },
  {
    name: 'LTTB decimation (50 samples)',
    handler(chart) {
      chart.options.plugins.decimation.algorithm = 'lttb';
      chart.options.plugins.decimation.enabled = true;
      chart.options.plugins.decimation.samples = 50;
      chart.update();
    }
  },
  {
    name: 'LTTB decimation (500 samples)',
    handler(chart) {
      chart.options.plugins.decimation.algorithm = 'lttb';
      chart.options.plugins.decimation.enabled = true;
      chart.options.plugins.decimation.samples = 500;
      chart.update();
    }
  }
];
        </pre>
      </div>
    </div>
  </div>
</div>

<script type="text/javascript" src="http://lyear.itshubao.com/v4/js/jquery.min.js"></script>
<script type="text/javascript" src="http://lyear.itshubao.com/v4/js/popper.min.js"></script>
<script type="text/javascript" src="http://lyear.itshubao.com/v4/js/bootstrap.min.js"></script>
<script type="text/javascript" src="https://cdn.bootcdn.net/ajax/libs/Chart.js/4.1.1/chart.umd.min.js"></script>
<script type="text/javascript" src="https://cdn.bootcdn.net/ajax/libs/luxon/3.2.0/luxon.min.js"></script>
<script type="text/javascript" src="http://libs.itshubao.com/chartjs/utils.js"></script>
<script type="text/javascript" src="https://cdn.bootcdn.net/ajax/libs/moment.js/2.29.4/moment.min.js"></script>
<script type="text/javascript" src="https://cdn.bootcdn.net/ajax/libs/moment.js/2.29.4/locale/zh-cn.min.js"></script>
<script type="text/javascript" src="https://cdn.jsdelivr.net/npm/chartjs-adapter-moment@1.0.1"></script>
</body>
</html>

CSS

body{
  background: #fff;
}
.tab-content .chart-view {
  max-width: 800px;
}
.tab-content .tab-pane-code {
  height: 360px;
  overflow: auto;
}
.tab-content .tab-pane-code pre {
  height: 100%;
  margin: 0px;
}
.chart-example {
  width: calc(100% - 2px);
  border: 1px solid #ececec;
  padding: 10px;
}

JavaScript

const actions = [
  {
    name: 'No decimation (default)',
    handler(chart) {
      chart.options.plugins.decimation.enabled = false;
      chart.update();
    }
  },
  {
    name: 'min-max decimation',
    handler(chart) {
      chart.options.plugins.decimation.algorithm = 'min-max';
      chart.options.plugins.decimation.enabled = true;
      chart.update();
    },
  },
  {
    name: 'LTTB decimation (50 samples)',
    handler(chart) {
      chart.options.plugins.decimation.algorithm = 'lttb';
      chart.options.plugins.decimation.enabled = true;
      chart.options.plugins.decimation.samples = 50;
      chart.update();
    }
  },
  {
    name: 'LTTB decimation (500 samples)',
    handler(chart) {
      chart.options.plugins.decimation.algorithm = 'lttb';
      chart.options.plugins.decimation.enabled = true;
      chart.options.plugins.decimation.samples = 500;
      chart.update();
    }
  }
];

const NUM_POINTS = 100000;
Utils.srand(10);

// parseISODate returns a luxon date object to work with in the samples
// We will create points every 30s starting from this point in time
const start = Utils.parseISODate('2021-04-01T00:00:00Z').toMillis();
const pointData = [];

for (let i = 0; i < NUM_POINTS; ++i) {
  // Most data will be in the range [0, 20) but some rare data will be in the range [0, 100)
  const max = Math.random() < 0.001 ? 100 : 20;
  pointData.push({x: start + (i * 30000), y: Utils.rand(0, max)});
}

const data = {
  datasets: [{
    borderColor: Utils.CHART_COLORS.red,
    borderWidth: 1,
    data: pointData,
    label: 'Large Dataset',
    radius: 0,
  }]
};

const decimation = {
  enabled: false,
  algorithm: 'min-max',
};

const config = {
  type: 'line',
  data: data,
  options: {
    // Turn off animations and data parsing for performance
    animation: false,
    parsing: false,

    interaction: {
      mode: 'nearest',
      axis: 'x',
      intersect: false
    },
    plugins: {
      decimation: decimation,
    },
    scales: {
      x: {
        type: 'time',
        ticks: {
          source: 'auto',
          // Disabled rotation for performance
          maxRotation: 0,
          autoSkip: true,
        }
      }
    }
  }
};

const ctx = document.getElementById('myChart');

const chart = new Chart(ctx, config);

$.each(actions, function(index, value) {
    let aHtml = $('<a></a>').addClass('btn btn-default m-r-5').html(value.name);
    $('.chart-actions').append(aHtml);
    aHtml.on('click', function () {
        value.handler(chart);
    });
});