d3.js——集群图的绘制
数据源：city.json：
{
"name":"中国",
"children":
[
{
"name":"浙江" ,
"children":
[
{"name":"杭州" },
{"name":"宁波" },
{"name":"温州" },
{"name":"绍兴" }
]
},
{
"name":"广西" ,
"children":
[
{
"name":"桂林",
"children":
[
{"name":"秀峰区"},
{"name":"叠彩区"},
{"name":"象山区"},
{"name":"七星区"}
]
},
{"name":"南宁"},
{"name":"柳州"},
{"name":"防城港"}
]
},
{
"name":"黑龙江",
"children":
[
{"name":"哈尔滨"},
{"name":"齐齐哈尔"},
{"name":"牡丹江"},
{"name":"大庆"}
]
},
{
"name":"新疆" ,
"children":
[
{"name":"乌鲁木齐"},
{"name":"克拉玛依"},
{"name":"吐鲁番"},
{"name":"哈密"}
]
}
]
}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>集群图</title>
</head>
<style>
.node circle {
fill: #fff;
stroke: steelblue;
stroke-width: 1.5px;
}
.node {
font: 12px sans-serif;
}
.link {
fill: none;
stroke: #ccc;
stroke-width: 1.5px;
}
</style>
<body>
<script src = "d3.js"></script>
<script src = "js/cluster.js"></script>
</body>
</html>咳咳，开始干正事咯~！！！
一、绘制前的准备
（1）定义数据转换函数：cluster
var width = 500,
height = 500;
var cluster = d3.layout.cluster()
.size([height,width-200]);（2）构造对角线生成器：diagonal，返回的函数会生成一条贝塞尔曲线，以此来连接source和target两端：
var diagonal = d3.svg.diagonal()
.projection(function(d){return [d.y, d.x];}); //投影projection转换点位置，默认返回[d.x,d.y]
（3）老掉牙的操作：
var svg = d3.select("body").append("svg")
.attr("width",width)
.attr("height",height)
.append("g")
.attr("transform","translate(40,0)");
二、读取json文件，并绘制集群图
d3.json("city.json",function(error,root){
var nodes = cluster.nodes(root);//计算簇布局并返回与根节点相关联的节点数组
var links = cluster.links(nodes);//返回：源-父节点和目标-子节点
console.log(nodes);
console.log(links);
//画点
var node = svg.selectAll(".node")
.data(nodes)
.enter()
.append("g")
.attr("class", "node")
.attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; })
//给点加圈圈
node.append("circle")
.attr("r", 4.5);
//给点加文字
node.append("text")
.attr("dx", function(d) { return d.children ? -8 : 8; })
.attr("dy", 3)
.style("text-anchor", function(d) { return d.children ? "end" : "start"; })
.text(function(d) { return d.name; });
//画线
var link = svg.selectAll(".link")
.data(links)
.enter()
.append("path")
.attr("class","link")
.attr("d",diagonal);
})
运行结果如下：
