chart.js
Version:
Simple HTML5 charts using the canvas element.
133 lines (120 loc) • 4.76 kB
HTML
<html>
<head>
<title>Labelling Data Points</title>
<script src="../../dist/Chart.bundle.js"></script>
<script src="../utils.js"></script>
<style>
canvas {
-moz-user-select: none;
-webkit-user-select: none;
-ms-user-select: none;
}
</style>
</head>
<body>
<div style="width: 75%">
<canvas id="canvas"></canvas>
</div>
<button id="randomizeData">Randomize Data</button>
<script>
var color = Chart.helpers.color;
var barChartData = {
labels: ["January", "February", "March", "April", "May", "June", "July"],
datasets: [{
type: 'bar',
label: 'Dataset 1',
backgroundColor: color(window.chartColors.red).alpha(0.2).rgbString(),
borderColor: window.chartColors.red,
data: [
randomScalingFactor(),
randomScalingFactor(),
randomScalingFactor(),
randomScalingFactor(),
randomScalingFactor(),
randomScalingFactor(),
randomScalingFactor()
]
}, {
type: 'line',
label: 'Dataset 2',
backgroundColor: color(window.chartColors.blue).alpha(0.2).rgbString(),
borderColor: window.chartColors.blue,
data: [
randomScalingFactor(),
randomScalingFactor(),
randomScalingFactor(),
randomScalingFactor(),
randomScalingFactor(),
randomScalingFactor(),
randomScalingFactor()
]
}, {
type: 'bar',
label: 'Dataset 3',
backgroundColor: color(window.chartColors.green).alpha(0.2).rgbString(),
borderColor: window.chartColors.green,
data: [
randomScalingFactor(),
randomScalingFactor(),
randomScalingFactor(),
randomScalingFactor(),
randomScalingFactor(),
randomScalingFactor(),
randomScalingFactor()
]
}]
};
// Define a plugin to provide data labels
Chart.plugins.register({
afterDatasetsDraw: function(chart, easing) {
// To only draw at the end of animation, check for easing === 1
var ctx = chart.ctx;
chart.data.datasets.forEach(function (dataset, i) {
var meta = chart.getDatasetMeta(i);
if (!meta.hidden) {
meta.data.forEach(function(element, index) {
// Draw the text in black, with the specified font
ctx.fillStyle = 'rgb(0, 0, 0)';
var fontSize = 16;
var fontStyle = 'normal';
var fontFamily = 'Helvetica Neue';
ctx.font = Chart.helpers.fontString(fontSize, fontStyle, fontFamily);
// Just naively convert to string for now
var dataString = dataset.data[index].toString();
// Make sure alignment settings are correct
ctx.textAlign = 'center';
ctx.textBaseline = 'middle';
var padding = 5;
var position = element.tooltipPosition();
ctx.fillText(dataString, position.x, position.y - (fontSize / 2) - padding);
});
}
});
}
});
window.onload = function() {
var ctx = document.getElementById("canvas").getContext("2d");
window.myBar = new Chart(ctx, {
type: 'bar',
data: barChartData,
options: {
responsive: true,
title: {
display: true,
text: 'Chart.js Combo Bar Line Chart'
},
}
});
};
document.getElementById('randomizeData').addEventListener('click', function() {
barChartData.datasets.forEach(function(dataset) {
dataset.data = dataset.data.map(function() {
return randomScalingFactor();
})
});
window.myBar.update();
});
</script>
</body>
</html>