Chart.js 円グラフのサンプル
<div style="width: 300px;">
<canvas id="myChart"></canvas>
</div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.1/Chart.min.js"></script>
var ctx = document.getElementById('myChart');
var myChart = new Chart(ctx, {
type: 'pie',
data: {
labels: ['赤党', '緑党', '青党'],
datasets: [{
label: '投票数',
data: [10000, 5000, 7000],
backgroundColor: [
'rgba(255, 0, 0, 0.2)',
'rgba(0, 255, 255, 0.2)',
'rgba(0, 0, 255, 0.2)'
],
borderColor: [
'red',
'green',
'blue'
],
borderWidth: 1
}]
},
options: {
tooltips: {
callbacks: {
label: function(item, data) {
var dataset = data.datasets[item.datasetIndex];
var total = dataset.data.reduce(function(prev, current) {
return prev + current;
});
var current = dataset.data[item.index];
var percentage = Math.floor(((current / total) * 100) + 0.5);
return percentage + "%";
}
}
}
}
});