Develop Reference

Custom tooltip React ChartJs

I'm having an issue while creating a custom tooltip using react-chartjs-2 library where my chart rerenders whenever I hover the chart and change the state of the tooltip's future data. (currently tooltip doesn't exist I'm simply logging some data which Ill use later)
I referenced this question while trying to create a tooltip however they are using a class component and I use functional component but it shouldn't really change anything but anyway. I'd be really grateful of someone could provide a working example of a custom tooltip with react-chartjs-2 because I'm still not sure whether tooltip should be a separate jsx component or what is the proper way to create a custom tooltip in React. Thanks in advance
My code
const GraphTooltip = ({ data }) => {
return (
<div
style={{
padding: 20,
position: 'absolute',
border: '1px solid',
borderColor: '#fff8f9',
backgroundColor: 'rgba(53,53,53,0.81)',
borderRadius: 4,
top: data.top,
left: data.left,
}}
></div>
);
};
const LineChart = ({ values, labels }) => {
const isSSR = useIsSSR();
const [tooltipData, setTooltipData] = useState(null);
console.log(tooltipData);
const chartRef = useRef(null);
const customTooltip = useCallback(tooltipModel => {
if (tooltipModel.tooltip.opacity == 0) {
setTooltipData(null);
console.log('Hide tooltip');
return;
}
console.log(tooltipModel);
const chart = chartRef.current;
const canvas = chart.canvas;
console.log(canvas);
if (canvas) {
const position = canvas.getBoundingClientRect();
// set position of tooltip
const left = tooltipModel.tooltip.x;
console.log(position.left);
console.log(tooltipModel.tooltip);
const top = tooltipModel.tooltip.y;
tooltipData?.top != top && setTooltipData({ top: top, left: left });
}
});
const options = useMemo(() => ({
scales: {
x: {
ticks: {
beginAtZero: true,
},
grid: {
color: '#EEF5FF',
},
},
y: {
grid: {
color: '#EEF5FF',
},
},
},
plugins: {
legend: {
display: false,
position: 'right',
},
tooltip: {
enabled: false,
external: customTooltip,
},
},
}));
const data = {
labels: labels,
datasets: [
{
data: values,
fill: false,
backgroundColor: '#88B1DD',
borderColor: '#88B1DD',
pointRadius: 6,
tension: 0.5,
},
],
};
if (isSSR) return null;
return (
<>
<div className="header"></div>
<div className="relative">
<Line data={data} options={options} ref={chartRef} />
{tooltipData ? <GraphTooltip data={tooltipData} /> : <div />}
</div>
</>
);
};

Using https://www.npmjs.com/package/test-react-chartjs-2 actually fixed this. Some problems in the package itself.

How to add custom text inside the bar and how to reduce the step size in y axis in chart js( Bar chart )

I am trying to insert the custom text inside the bar, I have searched lot of threads still i didn't get any solution. Then i want to reduce the step size in y axis. I have attached my code.
jQuery( document ).ready(function() {
var ctx = document.getElementById('myChart');
if(ctx){
var ctxn = ctx.getContext('2d');
var myChart = new Chart(ctxn, {
type: 'bar',
data: {
labels: ['Sale Estimate'],
datasets: [{
label: 'Original Sale Estimate',
data: [4200000],
backgroundColor: '#bcbec0'
}, {
label: 'Final Sale Price',
data: [5000000],
backgroundColor: '#5a00fe'
}]
},
options: {
scales: {
yAxes: [{
ticks: {
beginAtZero: true,
stacked: true,
// Abbreviate the millions
callback: function(value, index, values) {
return '$' +value / 1e6 + 'M';
}
}
}],
xAxes: [{
// Change here
gridLines : {
display : false
},
barPercentage: 0.8,
barThickness: 84,
stacked: true
}]
}, legend: {
display: false
},
tooltips: {
callbacks: {
label: function(tooltipItems, data) {
var roundoffLabel = Math.round(tooltipItems.yLabel);
var millionAft = convertNum(roundoffLabel);
return data.datasets[tooltipItems.datasetIndex].label +': ' + '$' + millionAft;
},labelTextColor: function(tooltipItem, chart) {
return '#000';
}
},
titleSpacing: 5,
backgroundColor: '#ffffff',
titleFontColor : '#000000',
cornerRadius : 0,
xPadding : 10,
yPadding : 10,
mode: 'index'
}
}
});
}
});
My current code giving this output. I need exact design attached above. I have tried to reduce the stepsize in y-axis i am not able to find the correct solution.
Please anyone help me to fix this.

You can add labels using
afterDatasetsDraw
and change the steps using
stepSize
jQuery( document ).ready(function() {
var maxValue = 5200000;
var ctx = document.getElementById('myChart');
if(ctx){
var ctxn = ctx.getContext('2d');
var myChart = new Chart(ctxn, {
type: 'bar',
data: {
labels: ['Sale Estimate'],
datasets: [{
label: 'Original Sale Estimate',
data: [3950000],
backgroundColor: '#bcbec0'
}, {
label: 'Final Sale Price',
data: [maxValue],
backgroundColor: '#5a00fe'
}]
},
options: {
scales: {
yAxes: [{
ticks: {
beginAtZero: true,
stacked: true,
// Abbreviate the millions
callback: function(value, index, values) {
return '$ ' + value / 1e6 + 'M';
},
stepSize: 1000000, // <----- This prop sets the stepSize,
max: 6000000
}
}],
xAxes: [{
// Change here
gridLines : {
display : false
},
barPercentage: 0.8,
barThickness: 84,
stacked: true
}]
}, legend: {
display: false
},
tooltips: {
callbacks: {
label: function(tooltipItems, data) {
var roundoffLabel = Math.round(tooltipItems.yLabel);
var millionAft = parseFloat(roundoffLabel);
return data.datasets[tooltipItems.datasetIndex].label +': ' + '$' + millionAft;
},labelTextColor: function(tooltipItem, chart) {
return '#000';
}
},
titleSpacing: 5,
backgroundColor: '#ffffff',
titleFontColor : '#000000',
cornerRadius : 0,
xPadding : 10,
yPadding : 10,
mode: 'index'
}
}
});
Chart.plugins.register({
afterDatasetsDraw: function(chart, easing) {
// To only draw at the end of animation, check for easing === 1
var ctx = chart.ctx;
chart.data.datasets.forEach(function (dataset, i) {
var meta = chart.getDatasetMeta(i);
if (!meta.hidden) {
meta.data.forEach(function(element, index) {
if (dataset.data[index] == 5000000) return;
// Draw the text in white, with the specified font
ctx.fillStyle = 'rgb(255, 255, 255)';
var fontSize = 16;
var fontStyle = 'bold';
var fontFamily = 'Arial';
ctx.font = Chart.helpers.fontString(fontSize, fontStyle, fontFamily);
// Just naively convert to string for now
var dataString = dataset.data[index].toString();
// Make sure alignment settings are correct
ctx.textAlign = 'center';
ctx.textBaseline = 'text-top';
var padding = 30;
var position = element.tooltipPosition();
ctx.fillText((maxValue - dataset.data[index])/1000000, position.x, position.y - (fontSize / 2) - padding);
//ctx.fillText(dataset.data[index], position.x, position.y - (fontSize / 2) - padding);
padding = 12;
fontStyle = 'normal';
ctx.font = Chart.helpers.fontString(fontSize, fontStyle, fontFamily);
ctx.fillText("million", position.x, position.y - (fontSize / 2) - padding);
});
}
});
}
});
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.8.0/Chart.min.js" type="text/javascript"></script>
<canvas id="myChart"></canvas>

ChartJS Doughnout Chart Pie Offset on Hover

I have this:
Is it possible to animate one section of this chart, a Pie, on hover to make it grow, as in offset by either giving it padding or a different height?
I think this should be possible because on their site it says " Animate everything!", but haven't had any luck yet. Tried using events but not working.
// Doughnut chart
var myDoughnutChart = new Chart(ctx, {
type: 'doughnut',
data: {
datasets: [{
data: [11, 47, 53],
backgroundColor: ['rgb(137, 207, 191)', 'rgb(140, 187, 206)', 'rgb(144, 156, 209)']
}],
labels: [
'Elementary',
'Middle School',
'High School'
],
},
options: {
cutoutPercentage: 60,
title: {
display: true,
text: 'Grade',
position: 'top',
fontFamily: 'sans-serif',
fontSize: 18,
fontColor: 'rgb(97, 98, 116)',
padding: '20'
},
layout: {
padding: {
top: 20,
}
},
legend: {
display: true,
},
onHover: stuff,
slices: {
1: {
offset: .5
}
}
}
});
function stuff(e) {
var activePoints = myDoughnutChart.getElementsAtEvent(e);
console.log(activePoints);
}
Thanks for any help.

Add this code in update function of doughnut
var innerRadius = reset && animationOpts.animateScale ? 0 : me.innerRadius;
if (index == doughnutIndex) {
innerRadius = innerRadius + 10;
}
And add a new function setHoverStyle
setHoverStyle: function(arc) {
doughnutIndex = arc._index;
this.update();
},

If what you are wanting is for the section to move outward on hover, that is done with simply setting hoverOffset with a number. See this example and documentation here.

How Align the Legend Items in Chart.js 2?

I just need to align the Chart Legend so it don't look too messy as the default shows, here is an example what I'm trying to achieve:
Please give some code suggestions: https://jsfiddle.net/holp/68wf75r8/
new Chart(document.getElementById("field-0"), {
type: 'pie',
data: {
labels: ["Chat", "Prospeção", "Whatsapp", "Trial", "Site", "Telefone", "E-mail", "Evento"],
datasets: [{
data: [700, 400, 200, 150, 80, 50, 20, 10],
borderWidth: 2,
hoverBorderWidth: 10,
backgroundColor: pieColors,
hoverBackgroundColor: pieColors,
hoverBorderColor: pieColors,
borderColor: pieColors
}]
},
options: {
legend: {
labels: {
padding: 20
}
}
}
});

There is legend.labels.generateLabels hook you generally can use to customise your legend labels.
I found out, that you can put something like below to adjust Chart.js calculations.
generateLabels: function (chart) {
chart.legend.afterFit = function () {
var width = this.width; // guess you can play with this value to achieve needed layout
this.lineWidths = this.lineWidths.map(function(){return width;});
};
// here goes original or customized code of your generateLabels callback
}
Weird thing that there is no actual configuration option to achieve this.

Chartjs v2 creates an overhead to handle the legends. Basically what you are looking for is to leverage the usage of generateLabels.
The key point to bare in mind is that you need to return an valid array of legend objects.
This plunker describes the solution.
Main focus on this part:
generateLabels: (chart) => {
chart.legend.afterFit = function () {
var width = this.width;
console.log(this);
this.lineWidths = this.lineWidths.map( () => this.width-12 );
this.options.labels.padding = 30;
this.options.labels.boxWidth = 15;
};
var data = chart.data;
//https://github.com/chartjs/Chart.js/blob/1ef9fbf7a65763c13fa4bdf42bf4c68da852b1db/src/controllers/controller.doughnut.js
if (data.labels.length && data.datasets.length) {
return data.labels.map((label, i) => {
var meta = chart.getDatasetMeta(0);
var ds = data.datasets[0];
var arc = meta.data[i];
var custom = arc && arc.custom || {};
var getValueAtIndexOrDefault = this.getValueAtIndexOrDefault;
var arcOpts = chart.options.elements.arc;
var fill = custom.backgroundColor ? custom.backgroundColor : getValueAtIndexOrDefault(ds.backgroundColor, i, arcOpts.backgroundColor);
var stroke = custom.borderColor ? custom.borderColor : getValueAtIndexOrDefault(ds.borderColor, i, arcOpts.borderColor);
var bw = custom.borderWidth ? custom.borderWidth : getValueAtIndexOrDefault(ds.borderWidth, i, arcOpts.borderWidth);
return {
text: label,
fillStyle: fill,
strokeStyle: stroke,
lineWidth: bw,
hidden: isNaN(ds.data[i]) || meta.data[i].hidden,
// Extra data used for toggling the correct item
index: i
};
});
}
return [];
}

I tried to do as advised by the comments above. But to see that it is really difficult. It’s better and easier for me to set:
legend: {display: FALSE, ..} `, and then render the legend using html (angular, react, view .. another render template):
// part of angualr model class
public dataSets = [{
label: "New Deals",
backgroundColor: "#88B2FF",
data: [26, 15, 5],
},
{
label: "Active Deals",
backgroundColor: "#397FFF",
data: [7, 13, 22],
},
....
this.chart = new Chart(ctx, {
type: "roundedBar",
data: {
labels: this.xLabels,
datasets: this.dataSets,
},
<div style="width: 380px;height: 200px; display: inline-block;">
<canvas id="chart" aria-label="Hello ARIA World" role="img"></canvas>
</div>
<!-- This is angular template -->
<ul class="legend">
<li *ngFor="let set of dataSets">
<i [style.backgroundColor]="set.backgroundColor" class="icon"></i>
<label>
{{ set.label }}
</label>
</li>
</ul>
<style>
.legend {
display: flex;
text-align: center;
justify-content: space-between;
font-size: 10px;
line-height: 12px;
}
.icon {
width: 10px;
height: 10px;
border-radius: 50%;
display: inline-block;
}
</style>

ChartJS New Lines '\n' in X axis Labels or Displaying More Information Around Chart or Tooltip with ChartJS V2

I'm using chart.js (V2) to try to build a bar chart that has more information available to user without having to hover over or click anywhere. I've provided two examples of how I hope to edit my chart.
Two edited versions of what I hope to achieve
As can be seen, I hope to place (somewhere), some extra information outside of the labels. I had hope that by adding '\n' to the labels I might have been able to get what I was looking for similar to option A.
Some edited code is provided blow:
var barChartData = {
labels: playerNames,
datasets: [{
label: 'Actual Score/Hour',
backgroundColor: "rgba(0, 128, 0,0.5)",
data: playerScores
}, {
label: 'Expected Score/Hour',
backgroundColor: "rgba(255,0,0,0.5)",
data: playerExpected
}]
};
function open_win(linktosite) {
window.open(linktosite)
}
canvas.onclick = function(evt){
var activePoints = myBar.getElementsAtEvent(evt);
console.log(activePoints);
linktosite = 'https://www.mytestsite.com/' + activePoints[1]['_model']['label'];
open_win(linktosite);
};
window.onload = function() {
var ctx = document.getElementById("canvas").getContext("2d");
window.myBar = new Chart(ctx, {
type: 'bar',
data: barChartData,
options: {
title:{
display:true,
text:"Player Expected and Actual Score per Hour"
},
tooltips: {
mode: 'label'
},
responsive: true,
scales: {
xAxes: [{
stacked: false,
}],
yAxes: [{
stacked: false
}]
},
animation: {
onComplete: function () {
var ctx = this.chart.ctx;
ctx.textAlign = "center";
Chart.helpers.each(this.data.datasets.forEach(function (dataset) {
Chart.helpers.each(dataset.metaData.forEach(function (bar, index) {
// console.log("printing bar" + bar);
ctx.fillText(dataset.data[index], bar._model.x, bar._model.y - 10);
}),this)
}),this);
}
}
}
});
// Chart.helpers.each(myBar.getDatasetMeta(0).data, function(rectangle, index) {
// rectangle.draw = function() {
// myBar.chart.ctx.setLineDash([5, 5]);
// Chart.elements.Rectangle.prototype.draw.apply(this, arguments);
// }
// }, null);
};
At this point I'd be satisfied with having the extradata anywhere on the bar. Any help would be appreciated. Thanks~

Chart.js v2.1.5 allows for multi-line labels using nested arrays (v2.5.0 fixes it for radar graphs):
...
data: {
labels: [["Jake", "Active: 2 hrs", "Score: 1", "Expected: 127", "Attempts: 4"],
["Matt", "Active: 2 hrs", "Score: 4", "Expected: 36", "Attempts: 4"]],
...
However, this does mean that you will have to pre-calculate the label values.

var config = {
type: 'line',
data: {
labels: [["January","First Month","Jellyfish","30 of them"], ["February","Second Month","Foxes","20 of them"], ["March","Third Month","Mosquitoes","None of them"], "April", "May", "June", "July"],
datasets: [{
label: "My First dataset",
data: [65, 40, 80, 81, 56, 85, 45],
backgroundColor: "rgba(255,99,132,0.2)",
}, {
label: "My Second dataset",
data: [40, 80, 21, 56, 85, 45, 65],
backgroundColor: "rgba(99,255,132,0.2)",
}]
},
scales : {
xAxes : [{
gridLines : {
display : false,
lineWidth: 1,
zeroLineWidth: 1,
zeroLineColor: '#666666',
drawTicks: false
},
ticks: {
display:true,
stepSize: 0,
min: 0,
autoSkip: false,
fontSize: 11,
padding: 12
}
}],
yAxes: [{
ticks: {
padding: 5
},
gridLines : {
display : true,
lineWidth: 1,
zeroLineWidth: 2,
zeroLineColor: '#666666'
}
}]
},
spanGaps: true,
responsive: true,
maintainAspectRatio: true
};
var ctx = document.getElementById("myChart").getContext("2d");
new Chart(ctx, config);
<div class="myChart">
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.2/Chart.bundle.js"></script>
<canvas id="myChart"></canvas>
</div>
If a label is an array as opposed to a string i.e. [["June","2015"], "July"] then each element is treated as a separate line. The appropriate calculations are made to determine the correct height and width, and rotation is still supported.
charJS version 2.7.2 used
this also works in https://github.com/jtblin/angular-chart.js

If you are using Chart.js v2.7.1, the above solution might not work.
The solution that actually worked for us was adding a small plugin right in the data and options level:
const config = {
type: 'bar',
data: {
// ...
},
options: {
// ...
},
plugins: [{
beforeInit: function (chart) {
chart.data.labels.forEach(function (label, index, labelsArr) {
if (/\n/.test(label)) {
labelsArr[index] = label.split(/\n/)
}
})
}
}]
};
A full description of how to fix this issue can be found here.

With Chart.js v2.1, you can write a chart plugin to do this
Preview
Script
Chart.pluginService.register({
beforeInit: function (chart) {
var hasWrappedTicks = chart.config.data.labels.some(function (label) {
return label.indexOf('\n') !== -1;
});
if (hasWrappedTicks) {
// figure out how many lines we need - use fontsize as the height of one line
var tickFontSize = Chart.helpers.getValueOrDefault(chart.options.scales.xAxes[0].ticks.fontSize, Chart.defaults.global.defaultFontSize);
var maxLines = chart.config.data.labels.reduce(function (maxLines, label) {
return Math.max(maxLines, label.split('\n').length);
}, 0);
var height = (tickFontSize + 2) * maxLines + (chart.options.scales.xAxes[0].ticks.padding || 0);
// insert a dummy box at the bottom - to reserve space for the labels
Chart.layoutService.addBox(chart, {
draw: Chart.helpers.noop,
isHorizontal: function () {
return true;
},
update: function () {
return {
height: this.height
};
},
height: height,
options: {
position: 'bottom',
fullWidth: 1,
}
});
// turn off x axis ticks since we are managing it ourselves
chart.options = Chart.helpers.configMerge(chart.options, {
scales: {
xAxes: [{
ticks: {
display: false,
// set the fontSize to 0 so that extra labels are not forced on the right side
fontSize: 0
}
}]
}
});
chart.hasWrappedTicks = {
tickFontSize: tickFontSize
};
}
},
afterDraw: function (chart) {
if (chart.hasWrappedTicks) {
// draw the labels and we are done!
chart.chart.ctx.save();
var tickFontSize = chart.hasWrappedTicks.tickFontSize;
var tickFontStyle = Chart.helpers.getValueOrDefault(chart.options.scales.xAxes[0].ticks.fontStyle, Chart.defaults.global.defaultFontStyle);
var tickFontFamily = Chart.helpers.getValueOrDefault(chart.options.scales.xAxes[0].ticks.fontFamily, Chart.defaults.global.defaultFontFamily);
var tickLabelFont = Chart.helpers.fontString(tickFontSize, tickFontStyle, tickFontFamily);
chart.chart.ctx.font = tickLabelFont;
chart.chart.ctx.textAlign = 'center';
var tickFontColor = Chart.helpers.getValueOrDefault(chart.options.scales.xAxes[0].fontColor, Chart.defaults.global.defaultFontColor);
chart.chart.ctx.fillStyle = tickFontColor;
var meta = chart.getDatasetMeta(0);
var xScale = chart.scales[meta.xAxisID];
var yScale = chart.scales[meta.yAxisID];
chart.config.data.labels.forEach(function (label, i) {
label.split('\n').forEach(function (line, j) {
chart.chart.ctx.fillText(line, xScale.getPixelForTick(i + 0.5), (chart.options.scales.xAxes[0].ticks.padding || 0) + yScale.getPixelForValue(yScale.min) +
// move j lines down
j * (chart.hasWrappedTicks.tickFontSize + 2));
});
});
chart.chart.ctx.restore();
}
}
});
and then
...
data: {
labels: ["January\nFirst Month\nJellyfish\n30 of them", "February\nSecond Month\nFoxes\n20 of them", "March\nThird Month\nMosquitoes\nNone of them", "April", "May", "June", "July"],
...
Note - we assume that the maximum content of one line will fit between the ticks (i.e. that no rotation logic is needed. I'm sure it's possible to incorporate rotation logic too, but it would be a tad more complicated)
You should format the tooltips to not show the x axis label, or format it to show a shorter version of the label.
Fiddle - http://jsfiddle.net/m0q03wpy/