I am using chart.js to develop a TreeMap. It works great but the issue is each rectangle only shows the value of the data. I want to add some custom text next to the value. How do I achieve this?
var topTags = [
{tag:'python',num:133269},{tag:'javascript',num:109742},{tag:'java',num:65490},{tag:'c#',num:45445},{tag:'html',num:43767},{tag:'android',num:42657},{tag:'reactjs',num:38844},{tag:'php',num:34381},{tag:'sql',num:29996},{tag:'python',num:29942},{tag:'css',num:29654},{tag:'r',num:28319},{tag:'c++',num:27389},{tag:'node.js',num:25415},{tag:'angular',num:24093},{tag:'pandas',num:23826},{tag:'arrays',num:23075},{tag:'jquery',num:18968},{tag:'mysql',num:18863},{tag:'swift',num:17971},{tag:'ios',num:17600},{tag:'json',num:15589},{tag:'laravel',num:15537},{tag:'flutter',num:15201},{tag:'c',num:15195},{tag:'django',num:14748},{tag:'sql',num:12752},{tag:'reactjs',num:10974},{tag:'excel',num:10962},{tag:'list',num:10726},{tag:'regex',num:10676}
];
var canvas = document.getElementById("treemap");
var ctx = canvas.getContext("2d");
var chart = window.chart = new Chart(ctx, {
type: "treemap",
data: {
datasets: [{
tree: topTags,
key: "num",
groups: ['num'],
spacing: 0.5,
borderWidth: 1.5,
fontColor: "black",
borderColor: "grey"
}]
},
options: {
maintainAspectRatio: false,
legend: { display: false },
tooltips: { enabled: false }
}
});
When running this code, I get the numbers in each rectangle but I need some text to be appended next to the numbers for each rectangle. How do I achieve this?
You can use the formatter options in the labels section:
const options = {
type: 'treemap',
data: {
datasets: [{
label: '# of Votes',
tree: [12, 19, 3, 5, 2, 3],
backgroundColor: 'pink',
labels: {
display: true,
formatter(ctx) {
const data = ctx.chart.data;
return `Custom Text: ${data.datasets[ctx.datasetIndex].tree[ctx.dataIndex]}`;
}
},
}]
},
options: {}
}
const ctx = document.getElementById('chartJSContainer').getContext('2d');
new Chart(ctx, options);
<body>
<canvas id="chartJSContainer" width="600" height="400"></canvas>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.7.0/chart.js"></script>
<script src="https://cdn.jsdelivr.net/npm/chartjs-chart-treemap#2.0.1/dist/chartjs-chart-treemap.js"></script>
</body>
Related
I have been struggling to make a chart.js line chart start at 0 when all of the values are 0. If all of the data of a dataset is 0 the y axis will always show values below 0 which I don't want there.
Here is the example:
<div class="container">
<canvas id="lineChart"></canvas>
<script>
var ctx = document.getElementById('lineChart');
var lineChart = new Chart(ctx, {
type: 'line',
data: {
labels: [1,2,3],
datasets: [{
data: [0, 0, 0]
}]
},
options: {
responsive: true,
scales: {
y: {
ticks: {
beginAtZero:true
}
}
}
}
});
</script>
<div>
As you can see I am changing the options the scales as suggested in the documentation here (apparently there has been migration and this is the way to go in v3, which is what I am using). But the graph still won't start at 0:
Any axis options other than the ticks work correctly.
Any ideas of what I might be doing wrong?
You tried to place the beginAtZero in the V2 place, in V3 you have to put it in the root of the scale object like so:
const options = {
type: 'line',
data: {
labels: [1, 2, 3],
datasets: [{
label: '# of Votes',
data: [0, 0, 0],
borderColor: 'pink'
}]
},
options: {
scales: {
y: {
beginAtZero: true
}
}
}
}
const ctx = document.getElementById('chartJSContainer').getContext('2d');
new Chart(ctx, options);
<body>
<canvas id="chartJSContainer" width="600" height="400"></canvas>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.7.0/chart.js"></script>
</body>
For all changes between V2 and V3 you can read the migration guide
I'm using Chart JS version 3.5.1, and I can't get the onHover function to work. My goal is to have the user hover or a data point, and then have the dataset values available to me inside the onHover.
Here's my setup:
var context = document.getElementById('canvas').getContext('2d')
var options = {
onHover: function(evt) {
console.log(evt)
var item = myChart.getElementAtEvent(evt)
console.log(item)
},
interaction: {
mode: 'index',
intersect: false,
},
plugins: {
legend: {
display: false,
}
},
responsive: true,
maintainAspectRatio: false
}
var myChart = new Chart(context, {
type: 'line',
data: {
labels: obj.labels,
datasets: [...]
},
options: options
})
I'm getting and error on this line:
var item = myChart.getElementAtEvent(evt)
The error says:
myChart.getElementAtEvent is not a function
I have confirmed that myChart is an object, but there doesn't appear to be a getElementAtEvent function.
I also tried the example in the docs here:
const canvasPosition = Chart.helpers.getRelativePosition(e, chart);
// Substitute the appropriate scale IDs
const dataX = chart.scales.x.getValueForPixel(canvasPosition.x);
const dataY = chart.scales.y.getValueForPixel(canvasPosition.y);
But it says:
Cannot read property 'getValueForPixel' of undefined
Does anyone know how I can successfully use onHover with version 3.5.1 of Chart JS?
You are using chart.js v3, in v3 there is no getElementAtEvent, it has been replaced with getElementsAtEventForMode. You can use this to get the active elements but you can also use the second argument the onHover function recieves which is an array with all the active elements:
var options = {
type: 'line',
data: {
labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
datasets: [{
label: '# of Votes',
data: [12, 19, 3, 5, 2, 3],
borderColor: 'pink'
},
{
label: '# of Points',
data: [7, 11, 5, 8, 3, 7],
borderColor: 'orange'
}
]
},
options: {
onHover: (evt, activeEls, chart) => {
if (activeEls.length === 0 || chart.getElementsAtEventForMode(evt, 'nearest', {
intersect: true
}, true).length === 0) {
return;
}
console.log('Function param: ', activeEls[0].index);
console.log('lookup with the event: ', chart.getElementsAtEventForMode(evt, 'nearest', {
intersect: true
}, true)[0].index);
activeEls.forEach(point => {
console.log('val: ', chart.data.datasets[point.datasetIndex].data[point.index])
})
}
}
}
var ctx = document.getElementById('chartJSContainer').getContext('2d');
new Chart(ctx, options);
<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>
I am trying to personalize a chart.js. But I can not find how to remove (or hide) the X and Y axes.
I am also interested in not showing data on hover and I would like not to show the reference on the top. I am just starting with chart.js and I only need to do a few graphs.
Thank you :)
This is the graph I currently have
datasets: {
label: "I need help plz",
backgroundColor: gradient,
fill: true,
borderColor: "rgb(0, 50, 100)",
borderWidth: 0.001,
tension: 0.4,
radius: 0,
data: dataset,
},
For removing the references on the top this post was useful Chart.js v2 hide dataset labels
As described in the documentation (https://www.chartjs.org/docs/master/axes/#common-options-to-all-axes) you can set in the options of the scale the display to true or false or 'auto' where auto hides the scale if no dataset is visable that is linked to that axis.
For not showing data on hover you can set the tooltip to enabled: false
Example (y auto display and no x axis):
var options = {
type: 'bar',
data: {
labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
datasets: [{
label: '# of Votes',
data: [12, 19, 3, 5, 2, 3],
borderWidth: 1,
backgroundColor: 'red'
}, ]
},
options: {
plugins: {
tooltip: {
enabled: false
}
},
scales: {
y: {
display: 'auto'
},
x: {
display: false
}
}
}
}
var ctx = document.getElementById('chartJSContainer').getContext('2d');
new Chart(ctx, options);
<body>
<canvas id="chartJSContainer" width="600" height="400"></canvas>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.3.2/chart.js"></script>
</body>
Just wondering if there is any way to set the horizontal bar labels for y-axis using chart.js. Here is how I set up the chart:
<div class="box-body">
<canvas id="chart" style="position: relative; height: 300px;"></canvas>
</div>
Javascript:
var ctx = document.getElementById('chart').getContext("2d");
var options = {
layout: {
padding: {
top: 5,
}
},
responsive: true,
animation: {
animateScale: true,
animateRotate: true
},
};
var opt = {
type: "horizontalBar",
data: {
labels: label,
datasets: [{
data: price,
}]
},
options: options
};
if (chart) chart.destroy();
chart= new Chart(ctx, opt);
chart.update();
As you all can see, the first and third labels are too long and cut off. Is there a way to make the label multi-line?
If you want to have full control over how long labels are broken down across lines you can specify the breaking point by providing labels in a nested array. For example:
var chart = new Chart(ctx, {
...
data: {
labels: [["Label1 Line1:","Label1 Line2"],["Label2 Line1","Label2 Line2"]],
datasets: [{
...
});
You can use the following chart plugin :
plugins: [{
beforeInit: function(chart) {
chart.data.labels.forEach(function(e, i, a) {
if (/\n/.test(e)) {
a[i] = e.split(/\n/);
}
});
}
}]
add this followed by your chart options
ᴜꜱᴀɢᴇ :
add a new line character (\n) to your label, wherever you wish to add a line break.
ᴅᴇᴍᴏ
var chart = new Chart(ctx, {
type: 'horizontalBar',
data: {
labels: ['Jan\n2017', 'Feb', 'Mar', 'Apr'],
datasets: [{
label: 'BAR',
data: [1, 2, 3, 4],
backgroundColor: 'rgba(0, 119, 290, 0.7)'
}]
},
options: {
scales: {
xAxes: [{
ticks: {
beginAtZero: true
}
}]
}
},
plugins: [{
beforeInit: function(chart) {
chart.data.labels.forEach(function(e, i, a) {
if (/\n/.test(e)) {
a[i] = e.split(/\n/);
}
});
}
}]
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.6.0/Chart.min.js"></script>
<canvas id="ctx"></canvas>
My problem is similar to How to show bar labels in legend in Chart.js 2.1.6?
I want to have to same output a pie chart give, but I do not want to create multiple datasets. I managed to do this, but now I can't find how.
Here is my code sample :
var myChart = new Chart(ctx, {
type: type_p,
data: {
labels: ['Lundi','Mardi'],
datasets: [{
data: [50,20],
backgroundColor: color,
borderColor: color,
borderWidth: 1
}]
}
I want the same legend as a pie chart, but with a bar chart:
Is this a way to do this?
To accomplish this, you would have to generate custom labels (using generateLabels() function) based on the labels array of your dataset.
legend: {
labels: {
generateLabels: function(chart) {
var labels = chart.data.labels;
var dataset = chart.data.datasets[0];
var legend = labels.map(function(label, index) {
return {
datasetIndex: 0,
fillStyle: dataset.backgroundColor && dataset.backgroundColor[index],
strokeStyle: dataset.borderColor && dataset.borderColor[index],
lineWidth: dataset.borderWidth,
text: label
}
});
return legend;
}
}
}
add this in your chart options
ᴡᴏʀᴋɪɴɢ ᴇxᴀᴍᴘʟᴇ ⧩
var ctx = canvas.getContext('2d');
var chart = new Chart(ctx, {
type: 'bar',
data: {
labels: ['Lundi', 'Mardi', 'Mercredi', 'Jeudi', 'Vendredi'],
datasets: [{
data: [1, 2, 3, 4, 5],
backgroundColor: ['#ff6384', '#36a2eb', '#ffce56', '#4bc0c0', '#9966ff'],
borderColor: ['#ff6384', '#36a2eb', '#ffce56', '#4bc0c0', '#9966ff'],
borderWidth: 1
}]
},
options: {
scales: {
yAxes: [{
ticks: {
beginAtZero: true
}
}]
},
legend: {
labels: {
generateLabels: function(chart) {
var labels = chart.data.labels;
var dataset = chart.data.datasets[0];
var legend = labels.map(function(label, index) {
return {
datasetIndex: 0,
fillStyle: dataset.backgroundColor && dataset.backgroundColor[index],
strokeStyle: dataset.borderColor && dataset.borderColor[index],
lineWidth: dataset.borderWidth,
text: label
}
});
return legend;
}
}
}
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.6.0/Chart.min.js"></script>
<canvas id="canvas"></canvas>