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I'm making a pie chart and I'm struggling to show the pie chart data value of each slices. As my application is written in React.js, I use react-chartjs-2.

I found this solution for chart.js and tried to implement, but it didn't work for react-chartjs-2.

How to display pie chart data values of each slice in chart.js

How can I add value to each slices? Any help is appreciated.

This is a current view of pie chart.

enter image description here

According to the advice, I implemented chart.piecelabel.js. It does not work yet..

My code

import {Pie} from 'react-chartjs-2';
import {pieceLabel} from 'chart.piecelabel.js';

export default class Categories extends React.Component{
constructor(props){
    super(props);
    this.state = {
        slideOpen : false,
        piData : piData
      }

this.handleClick = this.handleClick.bind(this);
this.update = this.update.bind(this);
this.doParentToggle = this.doParentToggle.bind(this);
}

doParentToggle(){


this.setState({
    piData : piData
  })
  console.log('-------')
  console.log('parentToggle' + piData )
  console.log('parentToggle' + piData2 )
  console.log('parentToggle' + piData3 )
  console.log('-------')
  this.update();
 }

handleClick(){
    this.setState({
        slideOpen : !this.state.slideOpen
    })
}

update() {
  var piData;
  this.setState({
    piData : piData
  })
  console.log('-------')
  console.log('parentToggle' + piData )
  console.log('parentToggle' + piData2 )
  console.log('parentToggle' + piData3 )
  console.log('-------')
  }    

render(){
 const CategoriesPanel = this.state.slideOpen? "slideOpen" : "";
 const { length } = this.props


  var totalData = piData + piData2 + piData3 + piData4 + piData5;

   let newpiData =  function() {
   return parseFloat((piData /  totalData ) * 100 ).toFixed(2) };

   let newpiData2 =  function() {
   return parseFloat((piData2 /  totalData ) * 100).toFixed(2) };

   let newpiData3 =  function() {
   return  parseFloat((piData3 /  totalData ) * 100).toFixed(2) };

   let newpiData4 =  function() {
   return parseFloat((piData4 /  totalData ) * 100).toFixed(2) };

   let newpiData5 =  function() {
   return parseFloat((piData5 /  totalData ) * 100).toFixed(2) };

  const data = {
  datasets: [{
    data: [ newpiData() , newpiData2(), newpiData3(), newpiData4(), newpiData5()],
    backgroundColor: [
    'orange',
    'blue',
    'red',
    'purple',
    'green'
    ],
    hoverBackgroundColor: [
    'orange',
    'blue',
    'red',
    'purple',
    'green'
    ],
    borderColor: [ 'orange',
    'blue',
    'red',
    'purple',
    'green'
    ]
  }],
  options : [{
    pieceLabel: { render: 'value' }
  }]};

   var pieOptions = {
   events: false,
   animation: {
   duration: 500,
   easing: "easeOutQuart",
   onComplete: function () {
   var ctx = this.chart.ctx;
   ctx.font = Chart.helpers.fontString(Chart.defaults.global.defaultFontFamily, 'normal', Chart.defaults.global.defaultFontFamily);
   ctx.textAlign = 'center';
   ctx.textBaseline = 'bottom';

   this.data.datasets.forEach(function (dataset) {

    for (var i = 0; i < dataset.data.length; i++) {
      var model = dataset._meta[Object.keys(dataset._meta)[0]].data[i]._model,
          total = dataset._meta[Object.keys(dataset._meta)[0]].total,
          mid_radius = model.innerRadius + (model.outerRadius - model.innerRadius)/2,
          start_angle = model.startAngle,
          end_angle = model.endAngle,
          mid_angle = start_angle + (end_angle - start_angle)/2;

      var x = mid_radius * Math.cos(mid_angle);
      var y = mid_radius * Math.sin(mid_angle);

      ctx.fillStyle = '#fff';
      if (i == 3){ // Darker text color for lighter background
        ctx.fillStyle = '#444';
      }
      var percent = String(Math.round(dataset.data[i]/total*100)) + "%";
      ctx.fillText(dataset.data[i], model.x + x, model.y + y);
      // Display percent in another line, line break doesn't work for fillText
      ctx.fillText(percent, model.x + x, model.y + y + 15);
    }
   });               
   }
   }
 };
return(
<div>
<div id="chart" className={CategoriesPanel}>
<Pie style={{"fontSize" : "20px" }}data={data}/>
<div className="categoriesSlide" onClick={this.handleClick}>{this.state.slideOpen? <img src={Arrowup} alt="arrowup" className="arrowup" /> : <img src={Arrowdown} alt="arrowdown" className="arrowdown"/>}</div>
<button onClick={this.update} className="chartButton">Update Information</button></div>

 <div className="clear">
 <List parentToggle={this.doParentToggle} />
 <ListSecond parentToggle={this.doParentToggle} />
 <ListThird parentToggle={this.doParentToggle} />
 <ListFourth parentToggle={this.doParentToggle} />
 <ListFifth parentToggle={this.doParentToggle} />
 </div>
 </div>
    )
}
}

1 Answer 1

7

You can use this ChartJS Plugin - Chart.PieceLabel.js

first, install it via npm :

npm install chart.piecelabel.js --save

then, import it in your component :

import 'chart.piecelabel.js';

and finally, add the following in your chart options :

pieceLabel: {
   render: 'value'
}

note: this is the minimum option needed to be set to display the value and you can find more options here.

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9 Comments

Hi, thank you so much for the suggestion. Actually I tried this before trying the above solution. Unfortunately it didn't work. Do you have a working demo?
Your import statement should be import 'chart.piecelabel.js'; not import {pieceLabel} from 'chart.piecelabel.js';
um.. that shouldn't occur. you've also added the option in wrong place. add pieceLabel: { render: 'value' } inside pieOptions
Tried it long ago, no longer have that repo. Anyway, just noticed you've set options inside dataset which is incorrect, You need to add options separately. Try with this code - kopy.io/Waaxo
Sorry I didn't understand what you mean before. Your code clarified it. Thank you so much for your kind help!!!
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