Add an animated icon to the map | Goong Documents

Add an animated icon to the map that was generated at runtime with the Canvas API.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>Add an animated icon to the map</title>
<meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no" />
<script src="https://cdn.jsdelivr.net/npm/@goongmaps/goong-js@1.0.9/dist/goong-js.js"></script>
<link href="https://cdn.jsdelivr.net/npm/@goongmaps/goong-js@1.0.9/dist/goong-js.css" rel="stylesheet" />
<style>
	body { margin: 0; padding: 0; }
	#map { position: absolute; top: 0; bottom: 0; width: 100%; }
</style>
</head>
<body>
<div id="map"></div>
 
<script>
goongjs.accessToken = '8qzxZAuxcsctSlmOszInchP1A5GrmRBHJwCBCjO6';
var map = new goongjs.Map({
container: 'map',
style: 'https://tiles.goong.io/assets/goong_map_web.json'
});
 
var size = 200;
 
// implementation of CustomLayerInterface to draw a pulsing dot icon on the map
// see https://docs.goong.io/javascript/properties/#customlayerinterface for more info
var pulsingDot = {
width: size,
height: size,
data: new Uint8Array(size * size * 4),
 
// get rendering context for the map canvas when layer is added to the map
onAdd: function () {
var canvas = document.createElement('canvas');
canvas.width = this.width;
canvas.height = this.height;
this.context = canvas.getContext('2d');
},
 
// called once before every frame where the icon will be used
render: function () {
var duration = 1000;
var t = (performance.now() % duration) / duration;
 
var radius = (size / 2) * 0.3;
var outerRadius = (size / 2) * 0.7 * t + radius;
var context = this.context;
 
// draw outer circle
context.clearRect(0, 0, this.width, this.height);
context.beginPath();
context.arc(
this.width / 2,
this.height / 2,
outerRadius,
0,
Math.PI * 2
);
context.fillStyle = 'rgba(255, 200, 200,' + (1 - t) + ')';
context.fill();
 
// draw inner circle
context.beginPath();
context.arc(
this.width / 2,
this.height / 2,
radius,
0,
Math.PI * 2
);
context.fillStyle = 'rgba(255, 100, 100, 1)';
context.strokeStyle = 'white';
context.lineWidth = 2 + 4 * (1 - t);
context.fill();
context.stroke();
 
// update this image's data with data from the canvas
this.data = context.getImageData(
0,
0,
this.width,
this.height
).data;
 
// continuously repaint the map, resulting in the smooth animation of the dot
map.triggerRepaint();
 
// return `true` to let the map know that the image was updated
return true;
}
};
 
map.on('load', function () {
map.addImage('pulsing-dot', pulsingDot, { pixelRatio: 2 });
 
map.addSource('points', {
'type': 'geojson',
'data': {
'type': 'FeatureCollection',
'features': [
{
'type': 'Feature',
'geometry': {
'type': 'Point',
'coordinates': [0, 0]
}
}
]
}
});
map.addLayer({
'id': 'points',
'type': 'symbol',
'source': 'points',
'layout': {
'icon-image': 'pulsing-dot'
}
});
});
</script>
 
</body>
</html>