Chart.js and long labels

Question

I use Chart.js to display a Radar Chart. My problem is that some labels are very long : the chart can\'t be display or it appears very small.

So, is there a way to b

Answer 1

You can write a javascript function to customize the label: // Interpolated JS string - can access value scaleLabel: "<%=value%>",

See http://www.chartjs.org/docs/#getting-started-global-chart-configuration

Answer 2

For Chart.js 2.0+ you can use an array as label:

Quoting the DOCs:

"Usage: If a label is an array as opposed to a string i.e. [["June","2015"], "July"] then each element is treated as a seperate line."

var data = {
   labels: [["My", "long", "long", "long", "label"], "another label",...],
   ...
}

Answer 3

Unfortunately there is no solution for this until now (April 5th 2016). There are multiple issues on Chart.js to deal with this:

• https://github.com/nnnick/Chart.js/issues/358 (the main one)
• https://github.com/nnnick/Chart.js/issues/608 (closed with no fix)
• https://github.com/nnnick/Chart.js/issues/358 (closed with no fix)
• https://github.com/nnnick/Chart.js/issues/780 (closed with no fix)
• https://github.com/nnnick/Chart.js/issues/752 (closed with no fix)

This is a workaround: Remove x-axis label/text in chart.js

Answer 4

It seems you might be actually be talking about data labels and not the scale labels. In this case you'd want to use the pointLabelFontSize option. See below example:

var ctx = $("#myChart").get(0).getContext("2d");

var data = {
  labels: ["Eating", "Sleeping", "Coding"],
  datasets: [
    {
        label: "First",
        strokeColor: "#f00",
        pointColor: "#f00",
        pointStrokeColor: "#fff",
        pointHighlightFill: "#fff",
        pointHighlightStroke: "#ccc",
        data: [45, 59, 90]
    },
    {
        label: "Second",
        strokeColor: "#00f",
        pointColor: "#00f",
        pointStrokeColor: "#fff",
        pointHighlightFill: "#fff",
        pointHighlightStroke: "#ccc",
        data: [68, 48, 40]
    }
  ]
};

// This is the important part
var options = {
  pointLabelFontSize : 20
};

var myRadarChart = new Chart(ctx).Radar(data, options);

Finally you may want to play with the dimensions of your < canvas > element as I've found sometimes giving the Radar chart more height helps the auto scaling of everything.

Answer 5

With ChartJS 2.1.6 and using @ArivanBastos answer

Just pass your long label to the following function, it will return your label in an array form, each element respecting your assigned maxWidth.

/* takes a string phrase and breaks it into separate phrases 
   no bigger than 'maxwidth', breaks are made at complete words.*/

function formatLabel(str, maxwidth){
    var sections = [];
    var words = str.split(" ");
    var temp = "";

    words.forEach(function(item, index){
        if(temp.length > 0)
        {
            var concat = temp + ' ' + item;

            if(concat.length > maxwidth){
                sections.push(temp);
                temp = "";
            }
            else{
                if(index == (words.length-1))
                {
                    sections.push(concat);
                    return;
                }
                else{
                    temp = concat;
                    return;
                }
            }
        }

        if(index == (words.length-1))
        {
            sections.push(item);
            return;
        }

        if(item.length < maxwidth) {
            temp = item;
        }
        else {
            sections.push(item);
        }

    });

    return sections;
}

Answer 6

To wrap the xAxes label, put the following code into optoins. (this will split from white space and wrap into multiple lines)

scales: {         
  xAxes: [
    {
      ticks: {
        callback: function(label) {
          if (/\s/.test(label)) {
            return label.split(" ");
          }else{
            return label;
          }              
        }
      }
    }
  ]
}