如何使用 ChartJS 在水平条形图上绘制垂直线?

2022-01-22 00:00:00 charts javascript html chart.js

有许多扩展图表以包含水平和垂直线的示例.但是，我还没有找到用水平条形图绘制垂直线的方法.

解决方案

ChartJS 支持自定义插件.创建一个插件，该插件将从图表选项中读取新属性并在指定索引处绘制线条.

在 Plunkr 上查看

//创建插件var originalLineDraw = Chart.controllers.horizontalBar.prototype.draw;Chart.helpers.extend(Chart.controllers.horizontalBar.prototype, {画:函数(){originalLineDraw.apply(this, arguments);var 图表 = this.chart;var ctx = 图表.chart.ctx;var index = chart.config.options.lineAtIndex;如果(索引){var xaxis = chart.scales['x-axis-0'];var yaxis = chart.scales['y-axis-0'];var x1 = xaxis.getPixelForValue(index);var y1 = yaxis.top;var x2 = xaxis.getPixelForValue(index);var y2 = yaxis.bottom;ctx.save();ctx.beginPath();ctx.moveTo(x1, y1);ctx.strokeStyle = '红色';ctx.lineTo(x2, y2);ctx.stroke();ctx.restore();}}});//设置图表数据变量数据 = {标签:[一月"，二月"，三月"，四月"，五月"，六月"，七月"]，数据集:[{标签:我的第一个数据集"，背景颜色: ['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)'],边框颜色: ['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)'],边框宽度:1，数据:[65、59、80、81、56、55、40]，}]};//加载图表var ctx = $("#myChart");var myBarChart = new Chart(ctx, {类型:'水平条'，数据:数据，选项: {//设置要画线的值的索引lineAtIndex:60，传奇: {显示:假}}});

 <canvas id="myChart"></canvas><script src="https://code.jquery.com/jquery-2.2.4.min.js" 完整性="sha256-BbhdlvQf/xTY9gja0Dq3HiwQF8LaCRTXxZKRutelT44=" crossorigin="anonymous"></script><script src='https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.2.2/Chart.min.js'></script><script src="horizontalBarPlugin.js"></script><script src="buildChart.js"></script>

There are many examples of extending a Chart to include a line, both horizontal and vertical. However, I have not found a way to draw a vertical line with a horizontal bar chart.

Horizontal line on horizontal line chart
Vertical line on horizontal line chart
Horizontal line on vertical bar chart

There is not a "vertical line chart" option like there is a "horizontal bar chart" option. How do I combine a horizontal bar chart with a vertical line?

Chart.js documentation

The result would have a bar dataset and a line dataset that can be used on the same chart using the same axis like below:

解决方案

ChartJS supports custom plugins. Create a plug in that will read a new property from the chart options and draw the line at the specified index.

See it on Plunkr

 //Create the plug in
  var originalLineDraw = Chart.controllers.horizontalBar.prototype.draw;
  Chart.helpers.extend(Chart.controllers.horizontalBar.prototype, {
  
      draw: function () {
          originalLineDraw.apply(this, arguments);
  
          var chart = this.chart;
          var ctx = chart.chart.ctx;
  
          var index = chart.config.options.lineAtIndex;
          if (index) {
  
              var xaxis = chart.scales['x-axis-0'];
              var yaxis = chart.scales['y-axis-0'];
  
              var x1 = xaxis.getPixelForValue(index);                       
              var y1 = yaxis.top;                                                   
  
              var x2 = xaxis.getPixelForValue(index);                       
              var y2 = yaxis.bottom;                                        
  
              ctx.save();
              ctx.beginPath();
              ctx.moveTo(x1, y1);
              ctx.strokeStyle = 'red';
              ctx.lineTo(x2, y2);
              ctx.stroke();
  
              ctx.restore();
          }
      }
  });

//Set up the chart data
  var data = {
      labels: ["January", "February", "March", "April", "May", "June", "July"],
      datasets: [
          {
              label: "My First dataset",
              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,
              data: [65, 59, 80, 81, 56, 55, 40],
          }
      ]
  };

  //Load Chart
  var ctx = $("#myChart");
  var myBarChart = new Chart(ctx, {
      type: 'horizontalBar',
      data: data,
      options: {
          //Set the index of the value where you want to draw the line
          lineAtIndex: 60,
          legend: {
            display: false
          }
      }
  });

    <canvas id="myChart"></canvas>

    <script   src="https://code.jquery.com/jquery-2.2.4.min.js" integrity="sha256-BbhdlvQf/xTY9gja0Dq3HiwQF8LaCRTXxZKRutelT44="   crossorigin="anonymous"></script>
    <script src='https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.2.2/Chart.min.js'></script>

    <script src="horizontalBarPlugin.js"></script>
    <script src="buildChart.js"></script>

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