How can i change text of legend in c3 pie chart

Question

How can I change the Text of legend of pie chart. I am using c3 charts in my php page. I have already read the documentation of c3 charts but no luck.

Currently i am using this code it show legend for true but I not able to change the text I have tried this.

var chart = c3.generate({
        bindto: '#container',
        padding: {
                  top: 10,
                  right: 0,
                  bottom: 10,
                  left: 0,
            },
        data: {
            columns: [<?php echo $pieChartDataString; ?>],
            type : 'pie',
            labels: true
        },
        legend: {
                show: true,
                position: 'upper-center'
                format: {
                        title: function () { return "Legend title"; },
                        name : function () { return "Legend name"; },
                        value: function () { return "Legend value";}
                        }
                }

   //But these legend values or not showing 

    });

It's not showing my legend values its always shows only columns as legend.

Is there any way that I can change the legend values.

Foreign

Answer 1

You haven't provided the data that gets outputted from your php, so it's hard to say.

But the first item in each of the columns array determines the name that goes in the legend. So:

columns: [
    ['this is legend 1', 30],
    ['put your value here', 120], 
]

would result in the legend labels being "this is legend 1" and "put your value here".

Here's a fiddle: http://jsfiddle.net/jrdsxvys/9/

Edit... Another option is to use the names property, as done here: http://jsfiddle.net/jrdsxvys/40/

data: {
    columns: [
      ['d1', 30],
      ['d2', 120]
    ],
    type: 'pie',
    labels: true,
    names: {
      d1: 'some name here',
      d2: 'another name'
    }
}

Mosera

I wish there were some more simple way . – Chronicle

Using names as above is a very easy method provided by the c3 library to modify legend labels. Here is another example provided by c3, which you can play around with and test to make it work: c3js.org/samples/data_name.html – Carrack

Answer 2

@agpt Yes. The names property is a good way to go generally because the first property of the columns data array eg 'd1' above is used when doing things like having multiple types on charts. eg for a bar and line combination using types instead of type: 'pie':

columns: [
   ['bar_1', 3, 8, 6],
   ['bar_2', 4, 0, 7],
   ['bar_3', 2, 3, 0] 
],

types: {
  bar_1: 'bar',
  bar_2: 'line',
  bar_3: 'bar'
},

names : {
      bar_1: 'Initial',
      bar_2: '3 month',
      bar_3: '6 month'                
}

So, using the names property allows you to use more 'dynamic' property names and be consistent throughout the config.

Tague

Is there a way to do this but put spaces in the name? For example instead of the legend showing bar_1 it would be bar 1? – Eureka

I am not working on that for now. Try eg names : { 'bar 1': 'Initial' etc } ie wrap all properties in quotes. Just a thought. – Tague