debug/canvas.html

<!DOCTYPE html>
<html>
<head>
    <title>Mapbox GL JS debug page</title>
    <meta charset='utf-8'>
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
    <link rel='stylesheet' href='../dist/mapbox-gl.css' />
    <style>
        body { margin: 0; padding: 0; }
        html, body, #map { height: 100%; }
    </style>
</head>

<body>
<canvas id="testCanvasID" width="200" height="100"
style="border:10px solid blue;">
Canvas not supported
</canvas>
<div id='map'></div>
<script src='../dist/mapbox-gl-dev.js'></script>
<script src='../debug/access_token_generated.js'></script>
<script>

function drawToCanvas() {
    var canvas = document.getElementById('testCanvasID');
    if (canvas.getContext) {
        var ctx = canvas.getContext('2d');

        ctx.fillStyle = 'rgb(200, 0, 0)';
        ctx.fillRect(10, 10, 50, 50);

        ctx.fillStyle = 'rgba(0, 0, 200, 0.5)';
        ctx.fillRect(30, 30, 50, 50);
    }
}

var canvasStyle = {
    "version": 8,
    "sources": {
        "canvas": {
            "type": "canvas",
            "canvas": "testCanvasID",
            "animate": false,
            "coordinates": [
                [-122.51596391201019, 37.56238816766053],
                [-122.51467645168304, 37.56410183312965],
                [-122.51309394836426, 37.563391708549425],
                [-122.51423120498657, 37.56161849366671]
            ]
        }
    },
    "layers": [{
        "id": "background",
        "type": "background",
        "paint": {
            "background-color": "rgb(4,7,14)"
        }
    }, {
        "id": "canvas",
        "type": "raster",
        "source": "canvas"
    }]
};

var map = new mapboxgl.Map({
    container: 'map',
    minZoom: 14,
    zoom: 17,
    center: [-122.514426, 37.562984],
    bearing: -96,
    style: canvasStyle,
    hash: false
});

drawToCanvas();

</script>
</body>
</html>