Click events on Pie Charts in Chart.js
JavascriptJqueryChartschart.jsJavascript Problem Overview
I've got a question regard Chart.js.
I've drawn multiple piecharts using the documentation provided. I was wondering if on click of a certain slice of one of the charts, I can make an ajax call depending on the value of that slice?
For example, if this is my data
var data = [ { value: 300, color:"#F7464A", highlight: "#FF5A5E", label: "Red" }, { value: 50, color: "#46BFBD", highlight: "#5AD3D1", label: "Green" }, { value: 100, color: "#FDB45C", highlight: "#FFC870", label: "Yellow" }],
is it possible for me to click on the Red labelled slice and call a url of the following form:
example.com?label=red&value=300? If yes, how do I go about this?
Javascript Solutions
Solution 1 - Javascript
Update: As @Soham Shetty comments, getSegmentsAtEvent(event) only works for 1.x and for 2.x getElementsAtEvent should be used.
> .getElementsAtEvent(e)
>
> Looks for the element under the event point, then returns all elements
> at the same data index. This is used internally for 'label' mode
> highlighting.
>
> Calling getElementsAtEvent(event) on your Chart instance passing an
> argument of an event, or jQuery event, will return the point elements
> that are at that the same position of that event.
>
> canvas.onclick = function(evt){
> var activePoints = myLineChart.getElementsAtEvent(evt);
> // => activePoints is an array of points on the canvas that are at the same position as the click event.
> };
Example: https://jsfiddle.net/u1szh96g/208/
Original answer (valid for Chart.js 1.x version):
You can achieve this using getSegmentsAtEvent(event)
> Calling getSegmentsAtEvent(event) on your Chart instance passing an
> argument of an event, or jQuery event, will return the segment
> elements that are at that the same position of that event.
From: Prototype Methods
So you can do:
$("#myChart").click(
function(evt){
var activePoints = myNewChart.getSegmentsAtEvent(evt);
/* do something */
}
);
Here is a full working example:
<html>
<head>
<script type="text/javascript" src="http://code.jquery.com/jquery-2.0.2.js"></script>
<script type="text/javascript" src="Chart.js"></script>
<script type="text/javascript">
var data = [
{
value: 300,
color:"#F7464A",
highlight: "#FF5A5E",
label: "Red"
},
{
value: 50,
color: "#46BFBD",
highlight: "#5AD3D1",
label: "Green"
},
{
value: 100,
color: "#FDB45C",
highlight: "#FFC870",
label: "Yellow"
}
];
$(document).ready(
function () {
var ctx = document.getElementById("myChart").getContext("2d");
var myNewChart = new Chart(ctx).Pie(data);
$("#myChart").click(
function(evt){
var activePoints = myNewChart.getSegmentsAtEvent(evt);
var url = "http://example.com/?label=" + activePoints[0].label + "&value=" + activePoints[0].value;
alert(url);
}
);
}
);
</script>
</head>
<body>
<canvas id="myChart" width="400" height="400"></canvas>
</body>
</html>
Solution 2 - Javascript
Using Chart.JS version 2.1.3, answers older than this one aren't valid anymore. Using getSegmentsAtEvent(event) method will output on console this message:
> getSegmentsAtEvent is not a function
So i think it must be removed. I didn't read any changelog to be honest. To resolve that, just use getElementsAtEvent(event) method, as it can be found [on the Docs][1].
Below it can be found the script to obtain effectively clicked slice label and value. Note that also retrieving label and value is slightly different.
var ctx = document.getElementById("chart-area").getContext("2d");
var chart = new Chart(ctx, config);
document.getElementById("chart-area").onclick = function(evt)
{
var activePoints = chart.getElementsAtEvent(evt);
if(activePoints.length > 0)
{
//get the internal index of slice in pie chart
var clickedElementindex = activePoints[0]["_index"];
//get specific label by index
var label = chart.data.labels[clickedElementindex];
//get value by index
var value = chart.data.datasets[0].data[clickedElementindex];
/* other stuff that requires slice's label and value */
}
}
Hope it helps. [1]: http://www.chartjs.org/docs/#advanced-usage-prototype-methods
Solution 3 - Javascript
Chart.js 2.0 has made this even easier.
You can find it under common chart configuration in the documentation. Should work on more then pie graphs.
options:{
onClick: graphClickEvent
}
function graphClickEvent(event, array){
if(array[0]){
foo.bar;
}
}
It triggers on the entire chart, but if you click on a pie the model of that pie including index which can be used to get the value.
Solution 4 - Javascript
Working fine chartJs sector onclick
ChartJS : pie Chart - Add options "onclick"
options: {
legend: {
display: false
},
'onClick' : function (evt, item) {
console.log ('legend onClick', evt);
console.log('legd item', item);
}
}
Solution 5 - Javascript
I was facing the same issues since several days, Today i have found the solution. I have shown the complete file which is ready to execute.
<html>
<head><script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.2/Chart.js">
</script>
</head>
<body>
<canvas id="myChart" width="200" height="200"></canvas>
<script>
var ctx = document.getElementById("myChart").getContext('2d');
var myChart = new Chart(ctx, {
type: 'bar',
data: {
labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
datasets: [{
label: '# of Votes',
data: [12, 19, 3, 5, 2, 3],
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
}]
},
options: {
scales: {
yAxes: [{
ticks: {
beginAtZero:true
}
}]
},
onClick:function(e){
var activePoints = myChart.getElementsAtEvent(e);
var selectedIndex = activePoints[0]._index;
alert(this.data.datasets[0].data[selectedIndex]);
}
}
});
</script>
</body>
</html>
Solution 6 - Javascript
If using a Donught Chart, and you want to prevent user to trigger your event on click inside the empty space around your chart circles, you can use the following alternative :
var myDoughnutChart = new Chart(ctx).Doughnut(data);
document.getElementById("myChart").onclick = function(evt){
var activePoints = myDoughnutChart.getSegmentsAtEvent(evt);
/* this is where we check if event has keys which means is not empty space */
if(Object.keys(activePoints).length > 0)
{
var label = activePoints[0]["label"];
var value = activePoints[0]["value"];
var url = "http://example.com/?label=" + label + "&value=" + value
/* process your url ... */
}
};
Solution 7 - Javascript
If you are using TypeScript, the code is a little funky because there is no type inference, but this works to get the index of the data that has been supplied to the chart: // events public chartClicked(e:any):void { //console.log(e);
try {
console.log('DS ' + e.active['0']._datasetIndex);
console.log('ID ' + e.active['0']._index);
console.log('Label: ' + this.doughnutChartLabels[e.active['0']._index]);
console.log('Value: ' + this.doughnutChartData[e.active['0']._index]);
} catch (error) {
console.log("Error In LoadTopGraph", error);
}
try {
console.log(e[0].active);
} catch (error) {
//console.log("Error In LoadTopGraph", error);
}
}
Solution 8 - Javascript
To successfully track click events and on what graph element the user clicked, I did the following in my .js file I set up the following variables:
vm.chartOptions = {
onClick: function(event, array) {
let element = this.getElementAtEvent(event);
if (element.length > 0) {
var series= element[0]._model.datasetLabel;
var label = element[0]._model.label;
var value = this.data.datasets[element[0]._datasetIndex].data[element[0]._index];
}
}
};
vm.graphSeries = ["Series 1", "Serries 2"];
vm.chartLabels = ["07:00", "08:00", "09:00", "10:00"];
vm.chartData = [ [ 20, 30, 25, 15 ], [ 5, 10, 100, 20 ] ];
Then in my .html file I setup the graph as follows:
<canvas id="releaseByHourBar"
class="chart chart-bar"
chart-data="vm.graphData"
chart-labels="vm.graphLabels"
chart-series="vm.graphSeries"
chart-options="vm.chartOptions">
</canvas>
Solution 9 - Javascript
var ctx = document.getElementById('pie-chart').getContext('2d');
var myPieChart = new Chart(ctx, {
// The type of chart we want to create
type: 'pie',
});
//define click event
$("#pie-chart").click(
function (evt) {
var activePoints = myPieChart.getElementsAtEvent(evt);
var labeltag = activePoints[0]._view.label;
});
Solution 10 - Javascript
You can add in the options section an onClick function, like this:
options : {
cutoutPercentage: 50, //for donuts pie
onClick: function(event, chartElements){
if(chartElements){
console.log(chartElements[0].label);
}
},
},
the chartElements[0] is the clicked section of your chart, no need to use getElementsAtEvent anymore.
It works on Chart v2.9.4
Solution 11 - Javascript
I have an elegant solution to this problem. If you have multiple dataset, identifying which dataset was clicked gets tricky. The _datasetIndex always returns zero. But this should do the trick. It will get you the label and the dataset label as well. Please note ** this.getElementAtEvent** is without the s in getElement
options: {
onClick: function (e, items) {
var firstPoint = this.getElementAtEvent(e)[0];
if (firstPoint) {
var label = firstPoint._model.label;
var val = firstPoint._model.datasetLabel;
console.log(label+" - "+val);
}
}
}
Solution 12 - Javascript
Within options place your onclick and call the function you need as an example the ajax you need, I'll leave the example so that every click on a point tells you the value and you can use it in your new function.
options: {
plugins: {
// Change options for ALL labels of THIS CHART
datalabels: {
color: 'white',
//backgroundColor:'#ffce00',
align: 'start'
}
},
scales: {
yAxes: [{
ticks: {
beginAtZero:true,
fontColor: "white"
},gridLines: {
color: 'rgba(255,255,255,0.1)',
display: true
}
}],
xAxes: [{
ticks: {
fontColor: "white"
},gridLines: {
display: false
}
}]
},
legend: {
display: false
},
//onClick: abre
onClick:function(e){
var activePoints = myChart.getElementsAtEvent(e);
var selectedIndex = activePoints[0]._index;
alert(this.data.datasets[0].data[selectedIndex]);
}
}