chart = {
var data = {
name : "root",
children : [
{ name: '1', size: 100 },
{ name: '2', size: 85 },
{ name: '3', size: 70 },
{ name: '4', size: 55 },
{ name: '5', size: 40 },
{ name: '6', size: 25 },
{ name: '7', size: 10 },
]
}
var canvas = d3.create("svg")
.attr('width', w)
.attr('height', h);
var nodes = pack (data);
canvas.selectAll('circle')
.data(nodes.children)
.enter().append('circle')
.attr('cx', function(d) { return d.x; })
.attr('cy', function(d) { return d.y; })
.attr('r', function(d) { return d.r; })
.attr('fill', 'white')
.attr('stroke', 'grey');
return canvas.node();
}