Chart.js not height responsive

Question

I have issues to get the chart.js line chart to be responsive on the height as well as the width.

See example what it should be working like:

• http://www.chartjs.org/samples/latest/charts/line/basic.html

Here is my code:

  var randomScalingFactor = function(){ return Math.round(Math.random()*100)};
  var lineChartData = {
    labels : ['January','February','March','April','May','June','July'],
    datasets : [
      {
        label: 'My First dataset',
        labelColor : '#fff',
        fontColor : '#fff' ,
        backgroundColor : 'rgba(220,220,220,0.2)',
        borderColor : 'rgba(220,220,220,1)',
        pointBackgroundColor : 'rgba(220,220,220,1)',
        pointBorderColor : '#fff',
        data : [randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor(),randomScalingFactor()]
      }
    ]
  }

  var options = {
    maintainAspectRatio: false,
    legend: {
      display: false,
    },
    scales: {
      xAxes: [{
        gridLines: {
         display: false,
         color: '#03A5C5',
         lineWidth: 8,
         },
        ticks: {
          fontColor: "white",
        },
      }],
      yAxes: [{
        gridLines: {
         display: false,
         color: '#03A5C5',
         lineWidth: 8,
         },
        ticks: {
          fontColor: "white",
          beginAtZero: true,
        }
      }]
    }
  };
  var ctx = document.getElementById('canvas-1');
  var chart = new Chart(ctx, {
    responsive: true,
    type: 'line',
    data: lineChartData,
    options: options
  });

Answer 1

1. Create Class

.chart-container {
    position: relative;
    margin: auto;
    height: 80vh;
    width: 80vw;
}

2. Create Div With class chart-container and place canvas tag inside it.

<div class="chart-container">
  <canvas id="canvas"></canvas>
</div>

3. Chart options, use property maintainAspectRatio set to false:

options: {
    maintainAspectRatio: false,
    responsive: true,  
    ...
}

Answer 2

As from Docs for Chart.js it's recommended to wrap canvas into container div and change width/height of the container. But basically it's changing either by given width or height.

Found a more flexible custom solution from lannymcnie that can be used for any canvas responsiveness:

 var stage = new createjs.Stage("canvas"); var c = new createjs.Shape(); c.graphics.f("#f00").dc(0,0,50); // Drawn a 100x100 circle from the center var t = new createjs.Text("Resize the browser/frame to redraw", "24px Arial bold", "#000"); tx = ty = 20; stage.addChild(c, t); window.addEventListener("resize", handleResize); function handleResize() { var w = window.innerWidth-2; // -2 accounts for the border var h = window.innerHeight-2; stage.canvas.width = w; stage.canvas.height = h; // var ratio = 100/100; // 100 is the width and height of the circle content. var windowRatio = w/h; var scale = w/100; if (windowRatio > ratio) { scale = h/100; } // Scale up to fit width or height c.scaleX= c.scaleY = scale; // Center the shape cx = w / 2; cy = h / 2; stage.update(); } handleResize(); // First draw

 html, body { padding: 0; margin: 0; overflow:hidden; } canvas { border: 1px solid #f00; }

 <script src="https://code.createjs.com/easeljs-0.8.2.min.js"></script> <canvas id="canvas" width="800" height="600"></canvas>

Answer 3

You can have it responsive and set a different aspect ratio. My issue was that the chart tend to be squeezed on mobile device taking barely no height.

To remedy, with chart.js 3.2.1, I am using the AspectRatio option:

options: {          
   aspectRatio: 1, 
}

This way the chart is square and stay square, you can play with this number usually between 0.5 to 2 to find a ratio that suits you on both displays.