I create charts for weather. I want to show automatically the tooltip on the last datapoint, when the chart is created. When the mouse is moved to another datapoint, the tootip should move to the new datapoint of the mouse or vanish if the mouse is outside.
https://www.chartjs.org/docs/3.8.0/samples/advanced/programmatic-events.html ist very close. Thanks!
function triggerTooltip(chart) {
const tooltip = chart.tooltip;
if (tooltip.getActiveElements().length > 0)
{ tooltip.setActiveElements([], {x: 0, y: 0}); }
else {
const chartArea = chart.chartArea;
tooltip.setActiveElements([
{
datasetIndex: 0,
index: 0,
}, {
datasetIndex: 1,
index: 0,
}],
{ x: (chartArea.left + chartArea.right) / 2,
y: (chartArea.top + chartArea.bottom) / 2, });
}
chart.update(); }
I did expect that the index controlls the bar, for the tooltip. But it makes no difference, whatever Index is set.
Also when I change x,y it is still on the same place (close to 3rd bar).
enter image description here
This can be done with the Plugin Core API in the afterDatasetUpdate hook as follows:
afterDatasetUpdate: chart => {
if (!chart.tooltip.getActiveElements().length) {
chart.tooltip.setActiveElements([{
datasetIndex: 0,
index: chart.data.datasets[0].data.length - 1
}]);
chart.update();
}
}
Please take a look at the runnable code snippet below and see how it works.
new Chart('myChart', {
type: 'line',
plugins: [{
afterDatasetUpdate: chart => {
if (!chart.tooltip.getActiveElements().length) {
chart.tooltip.setActiveElements([{
datasetIndex: 0,
index: chart.data.datasets[0].data.length - 1
}]);
chart.update();
}
}
}],
data: {
labels: ["January", "February", "March", "April", "May", "June", "July"],
datasets: [{
label: '# of Events',
data: [65, 59, 80, 81, 56, 55, 68],
borderColor: '#a00'
}]
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.7.1/chart.min.js"></script>
<canvas id="myChart" width="400" height="95"></canvas>
thanks - it is exactly, what I am looking for!
The snippet in your answer works with visible tooltip on the last data point.
When I try it in test.html in my browser (I tested firefox, edge,chrome) the tooltip is not visible.
Where is the mistake in my test.html?
<!DOCTYPE html>
<html>
<body>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.7.1/chart.min.js"></script>
<canvas id="myChart" width="400" height="95"></canvas>
<script type="text/javascript">
new Chart('myChart', {
type: 'line',
plugins: [{
afterDatasetUpdate: chart => {
if (!chart.tooltip.getActiveElements().length) {
chart.tooltip.setActiveElements([{
datasetIndex: 0,
index: chart.data.datasets[0].data.length - 1
}]);
chart.update();
}
}
}],
data: {
labels: ["January", "February", "March", "April", "May", "June", "July"],
datasets: [{
label: '# of Events',
data: [65, 59, 80, 20, 81, 56, 55, 68],
borderColor: '#a00'
}]
}
});
</script>
</body>
</html>
that is my test:
https://www.zebrafell.de/test.html
Related
I have chartjs v2.9.3 in my Django app and it works great. Now I need to add a box to one of my charts using chartjs-plugin-annotation, and I've followed all the steps, but I can't get it to work.
I've used chartjs-plugin-annotation v0.5.7 which is for v2.9.3. I get no errors in the console log.
First, scripts with chart.js and plugins:
<script src="https://cdn.jsdelivr.net/npm/chart.js#2.9.3/dist/Chart.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/chartjs-plugin-datalabels#0.7.0"></script>
<script src="https://cdn.jsdelivr.net/npm/chartjs-plugin-annotation#0.5.7/chartjs-plugin-annotation.min.js"></script>
My code for chart (chart works, I just can't get box to appear):
<canvas id="myChart" height="250"></canvas>
<script>
function setChart12(){
$('#myChart').remove();
$('#container_glavni').append('<canvas id="myChart" height="200"></canvas>');
var ctx = document.getElementById('myChart').getContext('2d');
var myChart = new Chart(ctx, {
type: 'bar',
data: {
labels: date,
datasets: [{
label: 'Number of reports',
data: data_nc
}, {
type: 'line',
label: 'Median',
data: [50],
fill: false,
borderColor: 'rgb(54, 162, 235)',
}],
},
options: {
layout: {
padding: {
top: 30
}
},
responsive: true,
legend: {
display: false
},
plugins: {
datalabels: {
anchor: 'end',
align: 'end',
offset: 5,
},
autocolors: false,
annotation: {
annotations: {
box1: {
type: 'box',
xMin: 0,
xMax: 1,
yMin: 0,
yMax: 30,
backgroundColor: 'rgba(255, 99, 132, 0.25)'}
}
}
},
scales: {
yAxes: [{
ticks: {
beginAtZero: true
}
}]
}
}
});}
</script>
I've tried:
Different values for min and max
Different colors
Different code formating
This is because you putted the options in the place where they belong in V1 of the annotation plugin and the syntax too. For V0.5.7 the annotation options have to be placed in the root of the options and also all the annotations are an array instead of seperate objects:
var options = {
type: 'line',
data: {
labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
datasets: [{
label: '# of Votes',
data: [12, 19, 3, 5, 2, 3],
borderWidth: 1
},
{
label: '# of Points',
data: [7, 11, 5, 8, 3, 7],
borderWidth: 1
}
]
},
options: {
annotation: {
annotations: [{
id: "hline",
type: "line",
mode: "horizontal",
scaleID: "y-axis-0",
value: 10,
borderColor: "red",
}]
},
}
}
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/2.9.4/Chart.js"></script>
<script src="https://cdn.jsdelivr.net/npm/chartjs-plugin-annotation#0.5.7/chartjs-plugin-annotation.min.js"></script>
</body>
I am setting the startAngle on my polar chart so the first category starts on the -180 degrees.
But I can't figure out why the data point labels don't correspondingly adjust and rotate. As a result, they show up incorrectly against the wrong data. As you can see in the image, Question 6 still appears where Question 1 should be. The tooltips on each section do appear correctly.
Note: When I use the datalabels plugin, it does show the label correctly. But I am not using it because it does not wrap the labels and also it cuts off the labels if they become too big. In addition I had responsiveness problems with it.
So please suggest a solution without that plugin if possible.
Thank you very much for helping me out.
const mydata = {
labels: [
'Question1',
'Question2',
'Question3',
'Question4',
'Question5',
'Question6'
],
datasets: [{
label: 'Data labels don't move',
data: [5, 8, 6, 6, 7, 8],
backgroundColor: [
'rgb(255, 99, 132)',
'rgb(75, 192, 192)',
'rgb(255, 205, 86)',
'rgb(201, 203, 207)',
'rgb(255, 99, 132)',
'rgb(201, 203, 207)'
]
}]
};
var myChart = new Chart('mychartId'),
{
type: "polarArea",
data: mydata,
options:
{
responsive: true,
cutoutPercentage: 20,
startAngle: -1 * Math.PI,
legend: {
display: false
},
layout: {
padding: 20
},
scale: {
ticks: {
max: 10,
beginAtZero: true,
min: 1,
stepSize: 1,
display: false
},
angleLines: {
display: false
},
pointLabels: {
display: true
}
}
}
}
sample image showing the problem
Update to V3, there they do turn with the chart if you adjust the startAngle
var options = {
type: 'polarArea',
data: {
labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
datasets: [{
label: '# of Votes',
data: [2, 9, 3, 5, 2, 3],
borderWidth: 1
}]
},
options: {
scales: {
r: {
startAngle: 180,
ticks: {
display: false
},
pointLabels: {
display: true
}
}
}
}
}
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/3.6.0/chart.js"></script>
</body>
V3 has some breaking changes over V2, for all of them you can read the migration guide
Good evening,
There's any way to alternate the chart's backgroud color for each dataSet of a result?
That's how I wish it.
enter image description here
Alternate background may be created with the use of chartjs-plugin-annotation.
Please have a look at the code snippet below that has been derived from the example code provided by the contributors of chartjs-plugin-annotation.
This code works with Chart.js 2.6.0 and it still produces a script error that may be ignored. Unfortunately I couldn't make it work with the newest version of Chart.js (currently 2.9.3) yet and I don't have time now to further investigate.
const labels = ["January", "February", "March", "April", "May", "June", "July"];
const annotations = [];
for (let i = 0; i < labels.length; i++) {
if (i % 2 == 0) {
annotations.push({
drawTime: "beforeDatasetsDraw",
type: "box",
xScaleID: "x-axis-0",
yScaleID: "y-axis-0",
xMin: labels[i],
xMax: labels[i + 1],
backgroundColor: "rgba(128, 128, 128, 0.5)",
borderColor: "rgb(128, 128, 128)",
borderWidth: 1
});
}
};
new Chart('chart', {
type: "bar",
data: {
labels: labels,
datasets: [{
label: "Dataset 1",
backgroundColor: 'red',
data: [95, 70, 55, -88, -64, 34, -55],
categoryPercentage: 1,
barPercentage: 0.8
},
{
label: "Dataset 2",
backgroundColor: 'green',
data: [81, 58, 30, -91, -74, 20, -40],
categoryPercentage: 1,
barPercentage: 0.9
}
]
},
options: {
responsive: true,
tooltips: {
mode: "index",
intersect: true
},
annotation: {
annotations: annotations
}
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.6.0/Chart.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/chartjs-plugin-annotation/0.5.7/chartjs-plugin-annotation.js"></script>
<canvas id="chart" height="90"></canvas>
we can use annotation plugin to do this
import annotationPlugin from "chartjs-plugin-annotation";
import {Chart} from 'chart.js';
Chart.register(annotationPlugin);
this code will add a box to our chart
{
type: 'box', #type of draw
drawTime: 'beforeDraw', #this will decide background or foreground
yMin: 5, #value min on y axis
yMax: 10, #value max on y axis
borderColor: 'rgb(242, 244, 248, 0.9)', #border color of the box
borderWidth: 1, #boarder width for box
backgroundColor: '#F2F4F8', #colour of the box
}
Out of this code
refer to this post here on how to do this: https://medium.com/#omi10859/alternative-background-lines-in-chartjs-a626ce4d3bcb
I'm using Chart.js to display some data using a bar chart.
My question is whether there is a way to extract the text of the tooltip and show it on a different div, so whenever I hover the bar chart I get the label and the value hovered in another place of the page.
I managed to alert the label or the value using the alert(label) function. but when I use the $('#mydiv').text(label) function, It does not work.
Here is my code :
<canvas id="widgetChart4"></canvas>
<id id="myDiv"></id>
<script>
var ctx = document.getElementById( "widgetChart4" );
ctx.height=50;
ctx.width=250;
var myChart = new Chart( ctx, {
type: 'bar',
data:
{
labels: [ "January", "February", "March", "April", "May", "June",
"July" ],
datasets: [
{
label: false,
data: [ 16, 32, 18, 26, 42, 33, 44 ]
}
]
},
options:
{
responsive: true,
tooltips:
{
callbacks:
{
label: function(tooltipItem, data) {
//this is working
alert( data['datasets'][0]['data'][tooltipItem['index']]);
//this is not working
$("#myDiv").text(data['datasets'][0]['data']
[tooltipItem['index']]);
return data['datasets'][0]['data'][tooltipItem['index']];
},
}
}
}
});
</script>
I managed to alert the label or the value using the alert(label)
function. but when I use the $('#mydiv').text(label) function, It does
not work.
I ran your code and it works perfectly so one possible reason why it's not working on your side is that you didn't import jQuery in your code.
var ctx = document.getElementById("widgetChart4");
ctx.height = 50;
ctx.width = 250;
var myChart = new Chart(ctx, {
type: 'bar',
data: {
labels: ["January", "February", "March", "April", "May", "June",
"July"
],
datasets: [{
label: false,
data: [16, 32, 18, 26, 42, 33, 44]
}]
},
options: {
responsive: true,
tooltips: {
callbacks: {
label: function(tooltipItem, data) {
$('#myDiv').html(data['datasets'][0]['data']
[tooltipItem['index']]);
return data['datasets'][0]['data'][tooltipItem['index']];
},
}
}
}
});
<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/2.7.3/Chart.min.js"></script>
<canvas id="widgetChart4"></canvas>
<div id="myDiv"></div>
I want to hide legends in Chart.js in label and tooltips.
I am using v2.5.0
I am trying this way but its not hiding legend in tooltips
<canvas id="myChart" width="400" height="250"></canvas>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.5.0/Chart.min.js"></script>
<script>
window.onload = function(e){
var ctx = document.getElementById("myChart").getContext("2d");
var data = {
labels: ["January", "February", "March", "April", "May", "June1", "July"],
datasets: [
{
fill: false,
lineTension: 0.3,
pointRadius: 15,
pointHitRadius: 15,
pointHoverRadius: 15,
data: [65, 59, 80, 81, 56, 55, 40],
spanGaps: false,
}
]
};
var options={
legend: {
display: false
},
tooltips: {
callbacks: {
label: function(tooltipItem, data) {
return tooltipItem.yLabel;
}
}
}
};
var myLineChart = new Chart(ctx, {
type: 'line',
data: data,
options: options
});
}
</script>
jsfiddle
I have also tried in global values like this
Chart.defaults.global.legend= false;
But legends are still shown in tooltips, Please see and suggest any possible way to do this.
Thanks
I found the solution by adding displayColors:false in tooltips option like this
tooltips: {
displayColors:false,
callbacks: {
label: function(tooltipItem) {
return tooltipItem.yLabel;
}
}
}
Now the legend are not shown, I hope it helps someone with similar issue.