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Generate and add a missing icon to the map

Generate and add a missing icon to the map

Dynamically generate a missing icon at runtime and add it to the map.

Generate and add a missing icon to the map
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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>Generate and add a missing 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 = 'wnicbAmnNkoMHNYUKWnlFHezV189FjmMwkNJ7hKW';
    var map = new goongjs.Map({
        container: 'map',
        style: 'https://tiles.goong.io/assets/goong_map_web.json'
    });

    map.on('styleimagemissing', function (e) {
        var id = e.id; // id of the missing image

        // check if this missing icon is one this function can generate
        var prefix = 'square-rgb-';
        if (id.indexOf(prefix) !== 0) return;

        // extract the color from the id
        var rgb = id.replace(prefix, '').split(',').map(Number);

        var width = 64; // The image will be 64 pixels square
        var bytesPerPixel = 4; // Each pixel is represented by 4 bytes: red, green, blue, and alpha.
        var data = new Uint8Array(width * width * bytesPerPixel);

        for (var x = 0; x < width; x++) {
            for (var y = 0; y < width; y++) {
                var offset = (y * width + x) * bytesPerPixel;
                data[offset + 0] = rgb[0]; // red
                data[offset + 1] = rgb[1]; // green
                data[offset + 2] = rgb[2]; // blue
                data[offset + 3] = 255; // alpha
            }
        }

        map.addImage(id, { width: width, height: width, data: data });
    });

    map.on('load', function () {
        map.addSource('points', {
            'type': 'geojson',
            'data': {
                'type': 'FeatureCollection',
                'features': [
                    {
                        'type': 'Feature',
                        'geometry': {
                            'type': 'Point',
                            'coordinates': [0, 0]
                        },
                        'properties': {
                            'color': '255,0,0'
                        }
                    },
                    {
                        'type': 'Feature',
                        'geometry': {
                            'type': 'Point',
                            'coordinates': [50, 0]
                        },
                        'properties': {
                            'color': '255,209,28'
                        }
                    },
                    {
                        'type': 'Feature',
                        'geometry': {
                            'type': 'Point',
                            'coordinates': [-50, 0]
                        },
                        'properties': {
                            'color': '242,127,32'
                        }
                    }
                ]
            }
        });

        map.addLayer({
            'id': 'points',
            'type': 'symbol',
            'source': 'points',
            'layout': {
                'icon-image': ['concat', 'square-rgb-', ['get', 'color']]
            }
        });
    });
</script>
</body>
</html>