rveciana - drop-shadow-map-using-canvas

Drop shadow map using Canvas

This example shows how to create the drop shadow effect in a map using Canvas.

Since the Canvas object already has the tools to do that, the code is really simple.

<!DOCTYPE html>
<meta charset="utf-8">

<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script src="http://d3js.org/topojson.v0.min.js"></script>

<script>
var width = 960,
    height = 500;

var projection = d3.geo.mercator()
    .scale(800)
    .rotate([80, -20, 0]);

var canvas = d3.select("body").append("canvas")
    .attr("width", width)
    .attr("height", height);

var context = canvas.node().getContext("2d");

var path = d3.geo.path()
.projection(projection)
.context(context);



d3.json("https://cdn.rawgit.com/mbostock/4090846/raw/8a7f176072d508218e120773943b595c998991be/world-50m.json", function(error, data) {

  var land = topojson.object(data, data.objects.land);

  context.fillStyle='#ccc'; 
  context.strokeStyle = '#aaa';

  context.save();
  context.beginPath();

  context.shadowBlur=5;
  context.shadowColor='#000'; 
  context.shadowOffsetX=5; 
  context.shadowOffsetY=5;  
  
  path(land);
  context.fill();
  context.restore();
  context.stroke();
  
});

</script>