2π
β
In v3 you can get rounded corners natively by using the borderRadius
option:
const 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"],
borderRadius: 1000
}]
},
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/3.8.0/chart.js"></script>
</body>
EDIT:
Based on answer from wahab memon but edited so it applies to all elements:
Chart.defaults.elements.arc.borderWidth = 0;
Chart.defaults.datasets.doughnut.cutout = '85%';
var chartInstance = new Chart(document.getElementById("chartJSContainer"), {
type: 'doughnut',
data: {
labels: [
'Label 1',
'Label 2',
'Label 3',
'Label 4'
],
datasets: [{
label: 'My First Dataset',
data: [22, 31, 26, 19],
backgroundColor: [
'#000000',
'#ffff00',
'#aaaaaa',
'#ff0000'
]
}]
},
plugins: [{
afterUpdate: function(chart) {
const arcs = chart.getDatasetMeta(0).data;
arcs.forEach(function(arc) {
arc.round = {
x: (chart.chartArea.left + chart.chartArea.right) / 2,
y: (chart.chartArea.top + chart.chartArea.bottom) / 2,
radius: (arc.outerRadius + arc.innerRadius) / 2,
thickness: (arc.outerRadius - arc.innerRadius) / 2,
backgroundColor: arc.options.backgroundColor
}
});
},
afterDraw: (chart) => {
const {
ctx,
canvas
} = chart;
chart.getDatasetMeta(0).data.forEach(arc => {
const startAngle = Math.PI / 2 - arc.startAngle;
const endAngle = Math.PI / 2 - arc.endAngle;
ctx.save();
ctx.translate(arc.round.x, arc.round.y);
ctx.fillStyle = arc.options.backgroundColor;
ctx.beginPath();
ctx.arc(arc.round.radius * Math.sin(endAngle), arc.round.radius * Math.cos(endAngle), arc.round.thickness, 0, 2 * Math.PI);
ctx.closePath();
ctx.fill();
ctx.restore();
});
}
}]
});
<script src="https://cdn.jsdelivr.net/npm/chart.js@3.8.0/dist/chart.js"></script>
<body>
<canvas id="chartJSContainer" width="200" height="200"></canvas>
</body>
Source:stackexchange.com