Legends in Chart Js don't appears - javascript

The legend is not shown in Chart JS, I have read documentation and others but nothing...
Only the label in which you typed a phrase is displayed. I know it's something very simple but it's making me waste my time.
my chart
Code:
type: 'bar',
data: {
labels: [{% for elemento1 in mesesEvolucion %}'{{ elemento1 }}',{% endfor %} ],
datasets: [{
label: 'Evolucion de el último año',
data: [{% for elemento1 in elemento.datosGraficaEvolucion %}{{ elemento1.mesX }},{% endfor %} ],
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: {
y: {
beginAtZero: true,
ticks: {color: 'white'}
},
x: {
beginAtZero: true,
ticks: {color: 'white'}
}
},
plugins: {
legend: {
display: true,
labels: {
color: 'rgb(255, 255, 255)'
}
},
title: {
display: true,
text: 'Evolución anual',
color: '#FFFFFF',
font: {
size: '14'
}
}
}
}


Try this:
plugins: {
legend: {
position: "top",
display: true,
labels: {
color: "#0d6dfdb0",
font: {
family: "IRANSansWeb"
}
},
tooltip: {
bodyFont: {
family: "IRANSansWeb"
},
titleFont: {
family: "IRANSansWeb"
}
}
},
title: {
display: true,
text: "some title",
color: "rgb(16, 97, 219)",
font: {
family: "IRANSansWeb",
},
},
},

Related

How to pass my array of objects into a graph with Chart.js

Hello I am trying to present my array of objects in a graph with Chart.js here is the code
let timers = {neutral: 0, happy: 0, sad: 0, angry: 0, surprised: 0, disgust: 0};
var detection = new Chart(c, {
type: 'bar',
data: {
labels: ["Neutral", "Happy", "Sad", "Angry", "Surprised", "Disgust"],
datasets: [{
fill: false,
backgroundColor: [
'rgba(255, 99, 132, 0.2)', // neutral
'rgba(54, 162, 235, 0.2)', // happy
'rgba(255, 206, 86, 0.2)', // sad
'rgba(75, 192, 192, 0.2)', // angry
'rgba(153, 102, 255, 0.2)', // surprised
'rgba(255, 159, 64, 0.2)' // disgust
],
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: 2,
data: timers,
}]
},
options: {
indexAxis: 'x',
responsive: true,
plugins: {
legend: {
display: false,
labels: {
font: {
size: 50
}
}
},
title: {
display: true,
text: "Emotion timers"
}
}
}
});
The problem is that the graph does not take as labels the one that I am giving to it but instead it takes as labels the names from the object array and due to that I cannot resize the x labels to be bigger. Thanks in advance for any tips.

As per the chart js documentation, when you give a map (key,value) to data field like timers in your case, chart js automatically takes keys as labels and values as data points to be plotted.
So, if you want to give your own labels in spite of this, you can add following snippet to your existing code.
var keys = Object.keys(timers);
var values = keys.map(function(v) { return timers[v]; });
and pass values instead of timers.
Full code -
let timers = {neutral: 0, happy: 0, sad: 0, angry: 0, surprised: 0, disgust: 0};
var keys = Object.keys(timers);
var values = keys.map(function(v) { return timers[v]; });
var detection = new Chart(c, {
type: 'bar',
data: {
labels: ["Neutral", "Happy", "Sad", "Angry", "Surprised", "Disgust"],
datasets: [{
fill: false,
backgroundColor: [
'rgba(255, 99, 132, 0.2)', // neutral
'rgba(54, 162, 235, 0.2)', // happy
'rgba(255, 206, 86, 0.2)', // sad
'rgba(75, 192, 192, 0.2)', // angry
'rgba(153, 102, 255, 0.2)', // surprised
'rgba(255, 159, 64, 0.2)' // disgust
],
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: 2,
data: values,
}]
},
options: {
indexAxis: 'x',
responsive: true,
plugins: {
legend: {
display: false,
labels: {
font: {
size: 50
}
}
},
title: {
display: true,
text: "Emotion timers"
}
}
}
});
Update:
As you want to update charts as timers are getting updated in setInterval, you have to put chart creation code also in setInterval function.
For example, you can refer to the following full html file
<head>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.5.1/chart.min.js" integrity="sha512-Wt1bJGtlnMtGP0dqNFH1xlkLBNpEodaiQ8ZN5JLA5wpc1sUlk/O5uuOMNgvzddzkpvZ9GLyYNa8w2s7rqiTk5Q==" crossorigin="anonymous" referrerpolicy="no-referrer">
</script>
<script>
var i = 0;
setInterval(updateChart,3000);
function updateChart(){
var c = document.getElementById("myChart");
let chartStatus = Chart.getChart("myChart"); // <canvas> id
if (chartStatus != undefined) {
chartStatus.destroy();
}
i = i+1;
let timers;
if(i%2==0){
timers = {neutral: 20, happy: 0, sad: 0, angry: 0, surprised: 0, disgust: 0};
}
else{
timers = {neutral: 0, happy: 20, sad: 0, angry: 0, surprised: 0, disgust: 0};
}
var keys = Object.keys(timers);
var values = keys.map(function(v) { return timers[v]; });
var detection = new Chart(c, {
type: 'bar',
data: {
labels: ["Neutral", "Happy", "Sad", "Angry", "Surprised", "Disgust"],
datasets: [{
fill: false,
backgroundColor: [
'rgba(255, 99, 132, 0.2)', // neutral
'rgba(54, 162, 235, 0.2)', // happy
'rgba(255, 206, 86, 0.2)', // sad
'rgba(75, 192, 192, 0.2)', // angry
'rgba(153, 102, 255, 0.2)', // surprised
'rgba(255, 159, 64, 0.2)' // disgust
],
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: 2,
data: keys.map(function(v) { return timers[v]; }),
}]
},
options: {
indexAxis: 'x',
responsive: true,
plugins: {
legend: {
display: false,
labels: {
font: {
size: 50
}
}
},
title: {
display: true,
text: "Emotion timers"
}
}
}
});
}
</script>
</head>
<button onclick="updateChart()">Update Chart</button>
<canvas id="myChart" width="100" height="100"></canvas>
You can run this html code for better understanding.

You just need to let the labels array out of the chart like so:
const ctx = document.getElementById('chartJSContainer').getContext('2d');
const timers = {
neutral: 10,
happy: 0,
sad: 0,
angry: 0,
surprised: 0,
disgust: 20
};
const detection = new Chart(ctx, {
type: 'bar',
data: {
datasets: [{
fill: false,
backgroundColor: [
'rgba(255, 99, 132, 0.2)', // neutral
'rgba(54, 162, 235, 0.2)', // happy
'rgba(255, 206, 86, 0.2)', // sad
'rgba(75, 192, 192, 0.2)', // angry
'rgba(153, 102, 255, 0.2)', // surprised
'rgba(255, 159, 64, 0.2)' // disgust
],
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: 2,
data: timers,
}]
},
options: {
indexAxis: 'x',
responsive: true,
plugins: {
legend: {
display: false,
labels: {
font: {
size: 50
}
}
},
title: {
display: true,
text: "Emotion timers"
}
}
}
});
<body>
<canvas id="chartJSContainer" width="600" height="400"></canvas>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.5.1/chart.js"></script>
</body>

charts js grid line not removing

I am trying to remove gridlines from my chart that i have created using chrts.js but it is not working and verything seems right but i dont understand what is wrong, here's the code, i'll be grateful if someone could help me
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: [{
gridLines: {
display: false,
drawOnChartArea: false,
drawTicks: false
},
}]
}
}
});

If you want to remove all gridlines from the chart area, you should define the option gridLines.drawOnChartArea: false for the y-axis and the x-axis.
Please have a look at your amended code below.
var myChart = new Chart('myChart', {
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: [{
gridLines: {
drawOnChartArea: false
},
ticks: {
beginAtZero: true,
stepSize: 5
}
}],
xAxes: [{
gridLines: {
drawOnChartArea: false
},
}]
}
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.3/Chart.min.js"></script>
<canvas id="myChart" height="80"></canvas>

ChartJS Only Show Large Font Size for a Specific Tick

I am attempting to emphasize a specific value on the X-Axis if it meets a specific condition.
For example, in my codepen I want to only change the font size of the 'blue' bar. Is this even possible with Chart.js?
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
}
}],
xAxes: [{
ticks: {
//only show large font size for 'Blue'
fontSize: 16
}
}]
}
}
});

Chartjs doesn't have a public api to do this but you can modify internal _ticks on beforeDraw and make the label "Blue" as major: true then that label will be drawn using the major styling in tick configuration options.
Also use this with caution since it relies on internal implementation and thus might break in future releases (very unlikely to happen but just saying).
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
}
}],
xAxes: [{
ticks: {
fontSize: 16,
major: {
fontSize: 20
}
}
}]
}
},
plugins: [{
beforeDraw: function({ chart }, options) {
chart.boxes
.find(box => box.id === "x-axis-0")
._ticks
.find(tick => tick.label === "Blue")
.major = true;
}
}]
});
<canvas id="myChart"></canvas>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.3/Chart.min.js"></script>
PS: Just in case someone is wondering how I know this internal implementation I searched fillText in chartjs github source code and console.log(myChart) xD

Looks like it's not possible according to their docs. You can only do something like uppercase needed label with callback function
xAxes: [{
ticks: {
fontSize: 16,
callback: v => v === 'Blue' ? v.toUpperCase() : v
}
}]

For chartjs 3.0 and higher, it can be done by using scriptable-options. Include it like this into your options for ticks:
options: {
scales: {
x: {
ticks: {
font: {
size: (c) => {
if (c.index==1){
return 20 // at tick label with idx one set fontsize 20
}
else {
return 12 // for all other tick labels set fontsize 12
}
},
},
},
},
},
},

Chartjs - Add backgroundColor for labels radar chart

>>> Radar chart labels with background color
Hi there, I just want to ask for an option to add the background color (a rounded rect with bg color) for labels (individually) in Chartjs. Is there any callback that I can apply for changing this, any help is appreciated with best regards!
This is the current code:
let chart = new Chart('chart-0', {
type: 'radar',
data: radarChartData,
options: {
responsive: true,
legend: {
position: 'top',
},
title: {
display: true,
text: 'Radar Chart | Chart.js',
fontSize: 16
},
scale: {
ticks: {
beginAtZero: true
},
pointLabels: {
fontSize: 14, // fontSize is ok
fontColor: presets.blue, // fontColor is accessible
backgroundColor: presets.yellow //This is not working for sure!
}
},
animation: {
animateScale: true,
animateRotate: true
}
}
});

You can do using backgroundColor.
data: {
labels: chart_label,
datasets: [{
label: '# of Votes',
data: chart_data,
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
}]
},

In case someone needs the answer, I did posted in in chartjs and Tim has done it so well: https://github.com/chartjs/Chart.js/issues/5085
Rgrds,

Chart.js with dual axis incorrect starting points (if negative values)

I have a chart.js chart in my app. This is how it looks without negative values:
With negative values:
As you can see I have dual axisY. They work as needed if there are no negative values. But if there are some, right AxisY starts in the incorrect position.
How to make it starts in the same place as left AxisY?
Here is my code:
private buildOptions(): any {
return {
responsive: true,
title: {
display: false,
text: ''
},
tooltips: {
mode: 'index',
intersect: true
},
scales: {
yAxes: [{
position: "left",
id: "y-axis-0",
fontColor: '#fff'
}, {
position: "right",
id: "y-axis-1",
fontColor: '#fff'
}]
},
legend: {
display: true,
labels: {
fontColor: '#fff'
}
}
};
}
Thank you.

Have you tried setting the same min value for both axes?
You can use ticks for specifying it:
ticks: {
min: -5
}
Here's an example snippet I made for you:
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, -5, 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: [{
position: "left",
id: "y-axis-0",
fontColor: '#fff',
ticks: {
min: -5
}
}, {
position: "right",
id: "y-axis-1",
fontColor: '#fff',
ticks: {
min: -5
}
}]
}
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.4.0/Chart.bundle.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div style="width:50%;">
<canvas id="myChart" width="400" height="400"></canvas>
</div>

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