Chart js show data on hovering legend - javascript

I have a pie chart and I want to get the number/data of each section of pie chart when hovered upon. I have seen the implementation of this in version 2.9.x but in version 3.x it is not working. I have also tried doing this here:
var pieChartHome = new Chart(
"myChart",
{
type: 'doughnut',
data: {
labels: ['One', 'Two', 'Three'],
datasets: [{
data: [4, 5, 3],
backgroundColor: ['rgba(255, 99, 132, 0.2)', 'rgba(255, 159, 64, 0.2)', 'rgba(54, 162, 235, 0.2)'],
borderColor: ['rgb(255, 99, 132)', 'rgb(255, 159, 64)', 'rgb(54, 162, 235)'],
hoverBackgroundColor: ['rgba(255, 99, 132, 0.4)', 'rgba(255, 159, 64, 0.4)', 'rgba(54, 162, 235, 0.4)'],
borderWidth: 1,
hoverBorderWidth: 3
}]
},
options: {
responsive:false,
plugins: {
legend: {
position:'right',
onHover: (evt, legendItem,legend) => {
const index = pieChartHome.data.labels.indexOf(legendItem.text);
const rect = pieChartHome.canvas.getBoundingClientRect();
const point = pieChartHome.getDatasetMeta(0).data[index].getCenterPoint();
const e = new MouseEvent('mousemove', {
clientX: rect.left + point.x,
clientY: rect.top + point.y
});
pieChartHome.canvas.dispatchEvent(e);
},
}
}
},
}
);
<script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
<div>
<canvas id="myChart"></canvas>
</div>
But this shows me flickering data and not something like this:
Chart.js - show tooltip when hovering on legend


You can set the tooltip via chart.js public methods itself:
var options = {
type: 'doughnut',
data: {
labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
datasets: [{
label: '# of Votes',
data: [12, 19, 3, 5, 2, 3],
backgroundColor: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"]
}]
},
options: {
plugins: {
legend: {
position: 'left',
onHover: (evt, item, legend) => {
const chart = legend.chart;
const tooltip = chart.tooltip;
const chartArea = chart.chartArea;
tooltip.setActiveElements([{
datasetIndex: 0,
index: item.index,
}], {
x: (chartArea.left + chartArea.right) / 2,
y: (chartArea.top + chartArea.bottom) / 2,
});
chart.update();
},
}
}
}
}
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/3.4.1/chart.js"></script>
</body>

Related

How to show Label with each line in Chart.js v3? [duplicate]

This question already has an answer here:
How do I show labels along with lines in Chart.js v3? [duplicate]
(1 answer)
Closed last month.
Like this one:
The label property in datasets is not working and shows nothing:
datasets: [{
label: 'Line 1',
data: [65, 59, 80, 81, 56, 55, 40],
backgroundColor: 'rgba(255, 99, 132, 0.2)',
borderColor: 'rgba(255, 99, 132, 1)',
borderWidth: 2
},
{
label: 'Line 2',
data: [28, 48, 40, 19, 86, 27, 90],
backgroundColor: 'rgba(153, 102, 255, 0.2)',
borderColor: 'rgba(153, 102, 255, 1)',
borderWidth: 2
}]
},
The complete code is given below:
<!DOCTYPE html>
<html>
<head>
<title> Example</title>
<script src="https://code.jquery.com/jquery-3.6.3.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.8.1/chart.min.js"></script>
</head>
<body>
<canvas id="myChart"></canvas>
<script>
var ctx = document.getElementById('myChart').getContext('2d');
var myChart = new Chart(ctx, {
type: 'line',
data: {
labels: ['January', 'February', 'March', 'April', 'May', 'June', 'July'],
datasets: [{
label: 'Line 1',
data: [65, 59, 80, 81, 56, 55, 40],
backgroundColor: 'rgba(255, 99, 132, 0.2)',
borderColor: 'rgba(255, 99, 132, 1)',
borderWidth: 2
},
{
label: 'Line 2',
data: [28, 48, 40, 19, 86, 27, 90],
backgroundColor: 'rgba(153, 102, 255, 0.2)',
borderColor: 'rgba(153, 102, 255, 1)',
borderWidth: 2
}]
},
options: {
scales: {
y: {
beginAtZero: true
}
},
legend: {
display: false
}
}
});
</script>
</body>
</html>

Well if a plugin like https://www.chartjs.org/chartjs-plugin-annotation/2.0.0/ doesn't solve the problem (Check out this answer for a demo), I would write my own specific plugin, that draws on the chart, after rendering was completed (see demo below for details).
And to be on the save side, I would add some padding to the right of the chart, to prevent a cut off, as done in the demo (link to the documentation).
Here a demo, how a very basic plugin could like:
(chart data from the question)
var miniLabelPlugin = {
id: 'miniLabelPlugin',
afterRender: function(chart, args, options) {
const { ctx } = chart;
chart.config.data.datasets.forEach((dataSet, index) => {
let lastPoint = chart.getDatasetMeta(index).data[chart.getDatasetMeta(index).data.length - 1];
let lastValue = dataSet.data[dataSet.data.length -1]
console.info(dataSet.data, lastPoint)
ctx.fillStyle = options.textColor;
ctx.font = options.font;
ctx.fillText(`${lastValue}`, lastPoint.x + options.paddingLeft, lastPoint.y);
});
},
defaults: {
paddingLeft: 10,
font: "10px Arial",
textColor: "black"
}
}
const config ={
type: 'line',
data: {
labels: ['January', 'February', 'March', 'April', 'May', 'June', 'July'],
datasets: [{
label: 'Line 1',
data: [65, 59, 80, 81, 56, 55, 40],
backgroundColor: 'rgba(255, 99, 132, 0.2)',
borderColor: 'rgba(255, 99, 132, 1)',
borderWidth: 2
},
{
label: 'Line 2',
data: [28, 48, 40, 19, 86, 27, 90],
backgroundColor: 'rgba(153, 102, 255, 0.2)',
borderColor: 'rgba(153, 102, 255, 1)',
borderWidth: 2
}]
},
// here the plugin is added to the chart
plugins: [miniLabelPlugin],
options: {
scales: {
y: {
beginAtZero: true
}
},
plugins:{
legend: {
display: false
},
},
layout: {
padding: {
right: 50
}
}
}
};
new Chart(
document.getElementById('chart'),
config
);
<script src="//cdn.jsdelivr.net/npm/chart.js"></script>
<div class="chart" style="height:184px; width:350px;">
<canvas id="chart" ></canvas>
</div>

For static labels you need to add "animation" key like
import {
Chart,
Sample
} from "chart.js";
import {
map
} from "lodash";
import {
data
} from "../data";
var ctx = document.getElementById("myChart");
const d = map(data, (data, index) => {
return {
data: [data],
backgroundColor: "blue",
pointRadius: 2,
fill: "start"
};
});
const dd = map(data, data => {
return data.y;
});
console.log(dd);
var myChart = new Chart(ctx, {
type: 'line',
data: {
labels: ['January', 'February', 'March', 'April', 'May', 'June', 'July'],
datasets: [{
label: 'Line 1',
data: [6, 59, 80, 81, 56, 55, 40],
backgroundColor: 'rgba(255, 99, 132, 0.2)',
borderColor: 'rgba(255, 99, 132, 1)',
borderWidth: 2
},
{
label: 'Line 2',
data: [5, 20, 40, 19, 86, 27, 90],
backgroundColor: 'rgba(153, 102, 255, 0.2)',
borderColor: 'rgba(153, 102, 255, 1)',
borderWidth: 2
}
]
},
options: {
animation: {
onComplete: function() {
const chartInstance = myChart,
ctx = chartInstance.ctx;
ctx.font = Chart.helpers.fontString(
18,
Chart.defaults.global.defaultFontStyle,
Chart.defaults.global.defaultFontFamily
);
ctx.textAlign = "center";
ctx.textBaseline = "bottom";
this.data.datasets.forEach(function(dataset, i) {
const meta = chartInstance.controller.getDatasetMeta(i);
meta.data.forEach(function(bar, index) {
const data = dataset.data[index];
ctx.fillStyle = "#000";
ctx.fillText(data, bar._model.x, bar._model.y - 2);
});
});
}
},
tooltips: {
enabled: true
},
scales: {
y: {
beginAtZero: true
}
},
legend: {
display: false
}
}
});
Goodluck!

How make border radius for chart area chart.js?

How make border radius for chart area chart.js
I need to make a border radius of 16px for the chart area
Maybe there is a plugin?
I am using chart.js V3.7.
I am using chart.js V3.7
How make border radius for chart area chart.js
I need to make a border radius of 16px for the chart area
Maybe there is a plugin?
I am using chart.js V3.7.
const ctx = document.getElementById('myChart').getContext('2d');
var gradient = ctx.createLinearGradient(0, 0, 0, 400)
gradient.addColorStop(0, 'rgba(244, 192, 56, 0.3)')
gradient.addColorStop(0.35, 'rgba(244, 192, 56, 0.3)')
gradient.addColorStop(1, 'rgba(244, 192, 56, 0)');
const plugin = {
id: 'background',
beforeDraw: (chart, args, opts) => {
if (!opts.color) {
return;
}
const {
ctx,
chartArea
} = chart;
ctx.fillStyle = opts.color;
ctx.fillRect(chartArea.left, chartArea.top, chartArea.width, chartArea.height)
}
};
Chart.register(plugin);
var config = {
type: 'line',
data: {
labels: [['05.08', '2021'], ['06.08', '2021'], ['07.08', '2021'], ['08.08', '2021'], ['09.08', '2021'], ['10.08', '2021'], ['11.08', '2021'], ['12.08', '2021'], ['13.08', '2021'], ['14.08', '2021'], ['15.08', '2021']],
datasets: [{
data: [130, 260, 240, 270, 249, 310, 295, 330, 247, 280, 265, 265,],
fill: true,
backgroundColor: gradient,
borderColor: [
'#F4C038',
],
borderWidth: 4,
pointRadius: 6,
pointBackgroundColor: '#272E3B',
pointHoverBorderColor: '#fff',
pointBorderWidth: 4,
pointHoverBorderWidth: 4,
}]
},
options: {
responsive: true,
tension: 0.25,
plugins: {
background: {
color: '#272E3B'
},
legend: {
display: false,
labels: {
font: {
size: 14,
family: "Rubik"
}
}
}
},
scales: {
y: {
grid: {
color: '#3D4554',
borderColor: '#3D4554',
tickColor: 'transparent',
},
ticks: {
padding: 38,
callback: function(value) {
return '$' + value;
},
color: "rgba(255, 255, 255, 0.5)",
font: {
size: 16,
family: "Rubik",
weight: 300
},
}
},
x: {
grid: {
color: '#3D4554',
borderColor: '#3D4554',
tickColor: 'transparent',
},
ticks: {
padding: 16,
color: "rgba(255, 255, 255, 0.5)",
font: {
size: 14,
family: "Rubik",
weight: 300
},
}
}
},
}
};
new Chart(ctx, config);

There is no plugin but you can write your own like so:
const plugin = {
id: 'border',
beforeDraw(chart, args, options) {
const {
ctx,
chartArea: {
left,
top,
width,
height
}
} = chart;
ctx.save();
ctx.strokeStyle = options.color;
ctx.lineWidth = options.width;
ctx.setLineDash(options.dash || []);
ctx.lineDashOffset = options.offset;
ctx.strokeRect(left, top, width, height);
ctx.restore();
}
};
const options = {
type: 'line',
data: {
labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
datasets: [{
label: '# of Votes',
data: [12, 19, 3, 5, 2, 3],
borderColor: 'orange'
},
{
label: '# of Points',
data: [7, 11, 5, 8, 3, 7],
borderColor: 'pink'
}
]
},
options: {
plugins: {
border: {
color: 'red',
width: 16
}
}
},
plugins: [plugin]
}
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>

To add the border to the chart area in chart.js, we need to use the chartAreaBorder plugin
const chartAreaBorder = {
id: 'chartAreaBorder',
beforeDraw(chart, args, options) {
const {ctx, chartArea: {left, top, width, height}} = chart;
ctx.save();
ctx.strokeStyle = options.borderColor;
ctx.lineWidth = options.borderWidth;
ctx.setLineDash(options.borderDash || []);
ctx.lineDashOffset = options.borderDashOffset;
ctx.strokeRect(left, top, width, height);
ctx.restore();
}
};
Paste the above piece of code before creating your chart and
Then use the following code for creating your chart and border around it,
const ctx = document.getElementById('dynamic-chart').getContext('2d');
const myChart = new Chart(ctx, {
type: 'Your_Chart_Type_Here',
data: {
labels:Your_Data_Here,
datasets: [{
label: 'Your Data Here',
data: 'Your_Data_Here,
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: {
plugins:{
chartAreaBorder:{
borderColor:'red',
borderWidth:2,
borderDash:[5,5],
borderDashOffset:2,
}
}
}
},
plugins:[chartAreaBorder]
});
Result is as follow
This Code will give the border to chartArea. I hope this sorted out your problem.

How add the sizes of the slices in the pie chart (at the top) in Chart.js?

I am starting to learn the chart.js library.
I drew a pie chart (like "pie"). When you hover over the slices of the diagram, a number appears in the pop-up window that sets the size of the sector.
new chart(
document.getElementById('diagram_1').getContext('2d'), {
type: 'pie',
data: {
labels: [
'Завершенная задача',
'Новая задача',
'Ошибка выполнения'
],
datasets: [{
label: '# of Votes',
data: [#successful_tasks, #new_tasks, #error_tasks],
backgroundColor: [
'rgba(54, 162, 235, 0.2)',
'rgba(255, 206, 86, 0.2)',
'rgba(255, 99, 132, 0.2)'
],
borderColor: [
'rgba(54, 162, 235, 1)',
'rgba(255, 206, 86, 1)',
'rgba(255, 99, 132, 1)'
],
borderWidth: 1
}]
},
options: {
scales: {
y: {
beginAtZero: true
}
},
responsive: false
}
}
)
How can you make this number still displayed at the top, where the sectors are listed (I marked this place with a red circle in the picture)?
I can add the required number to the labels array
...
data: {
labels: [
'Завершенная задача: ' + #successful_tasks,
'Новая задача: ' + #new_tasks,
'Ошибка выполнения: ' + #error_tasks
],
...
But then this number will appear twice in the tooltip

You can use the plugin system for this:
var options = {
type: 'pie',
data: {
labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
datasets: [{
label: '# of Votes',
data: [12, 19, 3, 5, 2, 3],
backgroundColor: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"]
}]
},
options: {
plugins: {
customNumber: {
textColor: 'red',
xOffset: 10,
yOffset: 0,
font: '24px Comic Sans MS'
}
}
},
plugins: [{
id: 'customNumber',
afterDraw: (chart, args, opts) => {
const hoveredSlice = chart._active[0];
const {
ctx,
chartArea: {
right
}
} = chart;
if (!hoveredSlice) {
return;
}
ctx.font = opts.font || '24px verdana, sans-serif'
ctx.fillStyle = opts.textColor || 'black'
const val = chart.data.datasets[hoveredSlice.datasetIndex].data[hoveredSlice.index];
const meassures = ctx.measureText(val);
const height = ctx.measureText('M').width;
ctx.fillText(val, (right - meassures.width - (opts.xOffset || 0)), height + (opts.yOffset || 0))
}
}]
}
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>

I found the answer. My project is written in CoffeeScript, but I think it would be more useful for the StackOverflow community to post the code in JS.
options: {
legend: {
labels: {
generateLabels: function(chart) {
var data = chart.data;
if (data.labels.length && data.datasets.length) {
return data.labels.map(function(label, i) {
var meta = chart.getDatasetMeta(0);
var ds = data.datasets[0];
var arc = meta.data[i];
var custom = arc && arc.custom || {};
var getValueAtIndexOrDefault = Chart.helpers.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);
var value = chart.config.data.datasets[arc._datasetIndex].data[arc._index];
return {
text: label + ": " + value,
fillStyle: fill,
strokeStyle: stroke,
lineWidth: bw,
hidden: isNaN(ds.data[i]) || meta.data[i].hidden,
index: i
};
});
} else {
return [];
}
}
}
}
}

how to populate data in chart.js

I'm trying to visualize the following dataset with chart.js
var data =
{
"count": 2,
"result": {
"2020-01-22": {
"confirmed": 12,
"deaths": 5,
"recovered": 4
},
"2020-01-23": {
"confirmed": 20,
"deaths": 3,
"recovered": 2
}
}
}
So far I've figured out how to use the dates as label.
var chart = new Chart(ctx, {
// The type of chart we want to create
type: 'line',
data: { // mapping the dates as labels
labels: Object.entries(data.result).map( (item) => item[0]),
datasets: [{
label: 'My First dataset',
backgroundColor: 'rgb(255, 99, 132)',
borderColor: 'rgb(255, 99, 132)',
data: ??
},{
label: 'My Second dataset',
backgroundColor: 'rgb(255, 99, 132)',
borderColor: 'rgb(255, 99, 132)',
data: ??
},{
label: 'My Third dataset',
backgroundColor: 'rgb(255, 99, 132)',
borderColor: 'rgb(255, 99, 132)',
data: ??
}]
}, // Configuration options go here
options: {}
});
I'd like to display the values of 'confirmed', 'deaths' and 'recovered' as three lines within this chart. Therefore I would include three different datasets right? How would I access the required information from json as array to populate the data arrays?
Thanks for your support

just map the key and values to appropriate arrays and consume them as datasets and labels.
var data = {
"count": 2,
"result": {
"2020-01-22": {
"confirmed": 12,
"deaths": 5,
"recovered": 4
},
"2020-01-23": {
"confirmed": 20,
"deaths": 3,
"recovered": 2
}
}
}
var dates = Object.keys(data["result"]).map(x => x);
var confirm = Object.values(data.result).map(x => x.confirmed);
var deaths = Object.values(data.result).map(x => x.deaths);
var recovered = Object.values(data.result).map(x => x.recovered);
var ctx = document.getElementById('myChart').getContext('2d');
var myChart = new Chart(ctx, {
type: 'bar',
data: {
labels: dates,
datasets: [{
label: 'confirmed',
data: confirm,
backgroundColor: 'rgba(255, 99, 132, 0.2)',
borderColor: 'rgba(255, 99, 132, 1)',
borderWidth: 1
},
{
label: 'Deaths',
data: deaths,
backgroundColor: 'rgba(54, 162, 235, 0.2)',
borderColor: 'rgba(54, 162, 235, 1)',
borderWidth: 1
}, {
label: 'recovered',
data: recovered,
backgroundColor: 'rgba(255, 206, 86, 0.2)',
borderColor: 'rgba(255, 206, 86, 1)',
borderWidth: 1
}
]
},
options: {
scales: {
yAxes: [{
ticks: {
beginAtZero: true
}
}]
}
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.3/Chart.min.js"></script>
<canvas id="myChart" width="100" height="50"></canvas>

Chart.js piechart, only have border on the outside of arc

I have a pie chart made with chart.js and currently i'm wondering if its possible to only have a border for the outside of the circle / arc like so:
I tried the following configurations but it applies border the to the whole segment.
options: {
elements: {
arc: {
borderWidth: 0
}
}
}
and also:
data: {
datasets: [{
data: [male_data , female_data],
backgroundColor: pieColors1,
borderWidth: [10, 0, 0, 0, 0]
}]
},
but this is what im getting:

I guess you have to create your own color image (Solid color with white strip on top) and pass it in as a canvas image.
Below is a modified example I've made based on the sample given from the chart.js documentation and a random picture found on the net.
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.0.0/Chart.js"></script>
<canvas id="myChart" width="400" height="400"></canvas>
<script>
var img = new Image();
img.src = 'http://www.worktop-express.co.uk/media/gbu0/metro-tiles-white-sparkle-worktops-100717.jpg';
img.onload = function() {
var ctx = document.getElementById("myChart").getContext('2d');
var fillPattern = ctx.createPattern(img, 'repeat');
var myChart = new Chart(ctx, {
type: 'pie',
data: {
labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
datasets: [{
label: '# of Votes',
data: [12, 19, 3, 5, 2, 3],
backgroundColor: [
'rgba(255, 99, 132, 10)',
'rgba(54, 162, 235, 0.2)',
'rgba(255, 206, 86, 0.2)',
'rgba(75, 192, 192, 0.2)',
'rgba(153, 102, 255, 0.2)',
fillPattern
],
borderColor: [
'rgba(0,0,0,100)',
'rgba(0,0,0,100)',
'rgba(0,0,0,100)',
'rgba(0,0,0,100)',
'rgba(0,0,0,100)',
'rgba(0,0,0,100)'
],
borderWidth: 0
}]
},
options: {
scales: {
yAxes: [{
ticks: {
beginAtZero:true
}
}]
}
}
});
}
</script>

<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.0.0/Chart.js"></script>
<canvas id="myChart" width="400" height="400"></canvas>
<script>
var img = new Image();
img.src = 'http://www.worktop-express.co.uk/media/gbu0/metro-tiles-white-sparkle-worktops-100717.jpg';
img.onload = function() {
var ctx = document.getElementById("myChart").getContext('2d');
var fillPattern = ctx.createPattern(img, 'repeat');
var myChart = new Chart(ctx, {
type: 'pie',
data: {
labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
datasets: [{
label: '# of Votes',
data: [12, 19, 3, 5, 2, 3],
backgroundColor: [
'rgba(255, 99, 132, 10)',
'rgba(54, 162, 235, 0.2)',
'rgba(255, 206, 86, 0.2)',
'rgba(75, 192, 192, 0.2)',
'rgba(153, 102, 255, 0.2)',
fillPattern
],
borderColor: [
'rgba(0,0,0,100)',
'rgba(0,0,0,100)',
'rgba(0,0,0,100)',
'rgba(0,0,0,100)',
'rgba(0,0,0,100)',
'rgba(0,0,0,100)'
],
borderWidth: 1
}]
},
options: {
scales: {
yAxes: [{
ticks: {
beginAtZero:true
}
}]
}
}
});
}
</script>

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