example.html

<!DOCTYPE html>
<html>
<head>
  <title>Leaflet.Canvas example</title>
  <!-- based on leaflet quick example: http://leafletjs.com/examples/quick-start-example.html -->
  <meta charset="utf-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0">

  <link rel="stylesheet" href="http://cdn.leafletjs.com/leaflet-0.6.4/leaflet.css" />
  <!--[if lte IE 8]>
     <link rel="stylesheet" href="http://cdn.leafletjs.com/leaflet-0.6.4/leaflet.ie.css" />
  <![endif]-->
  <style> 
    html, body, #map { height: 100%; padding: 0; margin: 0;}
  </style>
</head>
<body>
  <div id="map"></div>

  <script src="http://cdn.leafletjs.com/leaflet-0.6.4/leaflet.js"></script>
  <script src="leaflet_canvas_layer.js"></script>
  <script>

    var map = L.map('map').setView([0.0, -40.0], 2);

    L.tileLayer('http://{s}.tile.stamen.com/toner/{z}/{x}/{y}.png', {
      maxZoom: 18,
      attribution: 'Map data &copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors, <a href="http://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a>, Imagery <a href="http://stamen.com">Stamen</a>'
    }).addTo(map);

    var BigPointLayer = L.CanvasLayer.extend({

      renderCircle: function(ctx, point, radius) {
        ctx.fillStyle = 'rgba(255, 60, 60, 0.2)';
        ctx.strokeStyle = 'rgba(255, 60, 60, 0.9)';
        ctx.beginPath();
        ctx.arc(point.x, point.y, radius, 0, Math.PI * 2.0, true, true);
        ctx.closePath();
        ctx.fill();
        ctx.stroke();
      },

      render: function() {
        var canvas = this.getCanvas();
        var ctx = canvas.getContext('2d');

        // clear canvas
        ctx.clearRect(0, 0, canvas.width, canvas.height);

        // get center from the map (projected)
        var point = this._map.latLngToContainerPoint(new L.LatLng(0, 0));

        // render
        this.renderCircle(ctx, point, (1.0 + Math.sin(Date.now()*0.001))*300);

        this.redraw();

      }
    });

    var layer = new BigPointLayer();
    layer.addTo(map);

  </script>
</body>
</html>