D3.js学习笔记十五:D3.js树图(Tree)展开和折叠

构图(d3.layout)——树图(Tree)的展开和折叠

树的基本操作就是展开和折叠，在D3里面，树的展开和折叠是通过设置树的子节点属性来实现的，tree.nodes(root)返回树的当前节点集合，通过操作这个集合，可以实现节点的动态变化。

• children - the array of child nodes, or null for leaf nodes.
• x - the computed x-coordinate of the node position.
• y - the computed y-coordinate of the node position.

取得节点集合可用如下代码：

var nodes = tree.nodes(root).reverse(); var links = tree.links(nodes);

为了能够区分节点是新加入的还是冗余的，我们为节点数据集指定id属性，然后我们就可以通过这个属性，使用.exit()来获取冗余节点：

var node = svg.selectAll("g.node") .data(nodes,function(d){return d.id|| (d.id = ++index);});

为了能够保证动画的流畅，我们需要记录节点的当前位置，当节点数目变化，产生新的坐标以后，我们使用当前位置过渡到新的位置：

nodes.forEach(function(d) { d.x0 = d.x; d.y0 = d.y; });

树的展开和折叠代码如下：

< script type = "text/javascript" >//图像区域大小
var R = 600;
//动画持续时间
var duration = 1000;
//节点编号
var index = 0;
//动画时长
var duration = 1000;//定义一个Tree对象,定义旋转角度和最大半径
var tree = d3.layout.tree()
.size([360, R / 2 - 120])
.separation(function(a, b) {
return (a.parent == b.parent ? 1 : 2) / a.depth;
});

//定义布局方向
var diagonal = d3.svg.diagonal()
.projection(function(d) {
var r = d.y,
a = (d.x - 90) / 180 * Math.PI;
return [r * Math.cos(a), r * Math.sin(a)];
});

//新建画布，移动到圆心位置
var svg = d3.select("body").append("svg")
.attr("width", R)
.attr("height", R)
.append("g")
.attr("transform", function(d) {
return "translate(" + R / 2 + "," + R / 2 + ")";
});

//根据JSON数据生成树
d3.json("treeDataC.php", function(error, data) {

var root = data;

//根据数据生成nodes集合
var nodes = tree.nodes(data);

//记录现在的位置
nodes.forEach(function(d) {
d.x0 = d.x;
d.y0 = d.y;
});

//获取node集合的关系集合
var links = tree.links(nodes);

//根据node集合生成节点,添加id是为了区分是否冗余的节点
var node = svg.selectAll(".node")
.data(nodes, function(d) {
return d.id || (d.id = ++index);
});

//为关系集合设置贝塞尔曲线连接
var link = svg.selectAll(".link")
.data(links, function(d) {
return d.target.id;
})
.enter()
.append("path")
.attr("class", "link")
.attr("d", diagonal);

node.enter()
.append("g")
.attr("class", "node")
.attr("transform", function(d) {
return "rotate(" + (d.x - 90) + ")translate(" + d.y + ")";
})
.on("click", nodeClick);

//为节点添加圆形标记,如果有子节点为红色，否则绿色
node.append("circle")
.attr("fill", function(d) {
return d.children == null ? "#0F0" : "#F00";
})
.attr("r", 5);

//为节点添加说明文字
node.append("text")
.attr("dy", ".4em")
.text(function(d) {
return d.level;
})
.attr("text-anchor", function(d) {
return d.x < 180 ? "start" : "end";
})
.attr("transform", function(d) {
return d.x < 180 ? "translate(8)" : "rotate(180)translate(-8)";
});

//点击的话，隐藏或者显示子节点
function nodeClick(d) {
if (d.children) {
d._children = d.children;
d.children = null;
} else {
d.children = d._children;
d._children = null;
}
update(d);
}

//更新显示
function update(source) {
//取得现有的节点数据,因为设置了Children属性，没有Children的节点将被删除
var nodes = tree.nodes(root).reverse();
var links = tree.links(nodes);

//为节点更新数据
var node = svg.selectAll("g.node")
.data(nodes, function(d) {
return d.id || (d.id = ++index);
});

//为链接更新数据
var link = svg.selectAll("path.link").data(links, function(d) {
return d.target.id;
});

//更新链接
link.enter()
.append("path")
.attr("class", "link")
.attr("d", function(d) {
var o = {
x: source.x,
y: source.y
};
return diagonal({
source: o,
target: o
});
});

link.transition()
.duration(duration)
.attr("d", diagonal);

//移除无用的链接
link.exit()
.transition()
.duration(duration)
.attr("d", function(d) {
var o = {
x: source.x,
y: source.y
};
return diagonal({
source: o,
target: o
});
})
.remove();

//更新节点集合
var nodeEnter = node.enter()
.append("g")
.attr("class", "node")
.attr("transform", function(d) {
return "rotate(" + (source.x0 - 90) + ")translate(" + source.y0 + ")";
})
.on("click", nodeClick);

//为节点添加圆形标记,如果有子节点为红色，否则绿色
node.append("circle")
.attr("fill", function(d) {
return d.children == null && d._children == null ? "#0F0" : "#F00";
})
.attr("r", 5);

//为节点添加说明文字
node.append("text")
.attr("dy", ".4em")
.text(function(d) {
return d.level;
})
.attr("text-anchor", function(d) {
return d.x < 180 ? "start" : "end";
})
.attr("transform", function(d) {
return d.x < 180 ? "translate(8)" : "rotate(180)translate(-8)";
});

//节点动画
var nodeUpdate = node.transition()
.duration(duration)
.attr("transform", function(d) {
return "rotate(" + (d.x - 90) + ")translate(" + d.y + ")";
});

//将无用的子节点删除
var nodeExit = node.exit()
.transition()
.duration(duration)
.attr("transform", function(d) {
return "rotate(" + (source.x - 90) + ")translate(" + source.y + ")";
})
.remove();

//记录下当前位置,为下次动画记录初始值
nodes.forEach(function(d) {
d.x0 = d.x;
d.y0 = d.y;
});
}
}); < /script>

	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	<title>画一个树图(Tree)</title>
	<script type="text/javascript" src="js/d3.js"></script>
	</head>
	<style>
	.node circle {
	stroke: steelblue;
	stroke-width: 1px;
	cursor:pointer;
	}
	.node {
	font: 12px sans-serif;
	display:block;
	}
	.hidenode {
	font: 12px sans-serif;
	display:none;
	}
	.link {
	fill: none;
	stroke: #ccc;
	stroke-width: 1px;
	}
	</style>
	<body>
	<script type="text/javascript">
	//图像区域大小
	var R = 600;
	//动画持续时间
	var duration=1000;
	//节点编号
	var index=0;
	//定义一个Tree对象,定义旋转角度和最大半径
	var tree = d3.layout.tree()
	.size([360,R/2-120])
	.separation(function(a,b) { return (a.parent == b.parent ? 1 : 2)/a.depth;});
	//定义布局方向
	var diagonal = d3.svg.diagonal()
	.projection(function(d) {
	var r = d.y, a = (d.x-90) / 180 * Math.PI;
	return [r * Math.cos(a), r * Math.sin(a)];
	});
	//新建画布，移动到圆心位置
	var svg = d3.select("body").append("svg")
	.attr("width", R)
	.attr("height", R)
	.append("g")
	.attr("transform", function(d){ return "translate("+R/2+"," + R/2 + ")";});
	//根据JSON数据生成树
	d3.json("treeDataC.php", function(error, data) {
	var root=data;
	//根据数据生成nodes集合
	var nodes = tree.nodes(data);
	//记录现在的位置
	nodes.forEach(function(d){
	d.x0 = d.x;
	d.y0 = d.y;
	});
	//获取node集合的关系集合
	var links = tree.links(nodes);
	//根据node集合生成节点,添加id是为了区分是否冗余的节点
	var node = svg.selectAll(".node")
	.data(nodes,function(d){return d.id|| (d.id = ++index);});
	//为关系集合设置贝塞尔曲线连接
	var link=svg.selectAll(".link")
	.data(links, function(d) { return d.target.id;})
	.enter()
	.append("path")
	.attr("class", "link")
	.attr("d",diagonal);
	node.enter()
	.append("g")
	.attr("class", "node")
	.attr("transform",function(d){return "rotate(" + (d.x-90) + ")translate(" + d.y + ")"; })
	.on("click",nodeClick);
	//为节点添加圆形标记,如果有子节点为红色，否则绿色
	node.append("circle")
	.attr("fill",function(d){return d.children==null?"#0F0":"#F00";})
	.attr("r", 5);
	//为节点添加说明文字
	node.append("text")
	.attr("dy", ".4em")
	.text(function(d){return d.level;})
	.attr("text-anchor", function(d) { return d.x < 180 ? "start" : "end"; })
	.attr("transform", function(d) { return d.x < 180 ? "translate(8)" : "rotate(180)translate(-8)"; });
	//点击的话，隐藏或者显示子节点
	function nodeClick(d)
	{
	if (d.children)
	{
	d._children = d.children;
	d.children = null;
	}
	else
	{
	d.children = d._children;
	d._children = null;
	}
	update(d);
	}
	//更新显示
	function update(source)
	{
	//取得现有的节点数据,因为设置了Children属性，没有Children的节点将被删除
	var nodes = tree.nodes(root).reverse();
	var links = tree.links(nodes);
	//为节点更新数据
	var node = svg.selectAll("g.node")
	.data(nodes,function(d){return d.id|| (d.id = ++index);});
	//为链接更新数据
	var link = svg.selectAll("path.link").data(links, function(d) {return d.target.id;});
	//更新链接
	link.enter()
	.append("path")
	.attr("class", "link")
	.attr("d", function(d) {
	var o = {x: source.x, y: source.y};
	return diagonal({source: o, target: o});
	});
	link.transition()
	.duration(duration)
	.attr("d",diagonal);
	//移除无用的链接
	link.exit()
	.transition()
	.duration(duration)
	.attr("d", function(d) {
	var o = {x: source.x, y: source.y};
	return diagonal({source: o, target: o});
	})
	.remove();
	//更新节点集合
	var nodeEnter = node.enter()
	.append("g")
	.attr("class", "node")
	.attr("transform",function(d){return "rotate(" + (source.x0-90) + ")translate(" + source.y0 + ")"; })
	.on("click",nodeClick);
	//为节点添加圆形标记,如果有子节点为红色，否则绿色
	node.append("circle")
	.attr("fill",function(d){return d.children==null && d._children==null?"#0F0":"#F00";})
	.attr("r", 5);
	//为节点添加说明文字
	node.append("text")
	.attr("dy", ".4em")
	.text(function(d){return d.level;})
	.attr("text-anchor", function(d) { return d.x < 180 ? "start" : "end"; })
	.attr("transform", function(d) { return d.x < 180 ? "translate(8)" : "rotate(180)translate(-8)"; });
	//节点动画
	var nodeUpdate = node.transition()
	.duration(duration)
	.attr("transform", function(d) { return "rotate(" + (d.x-90) + ")translate(" + d.y + ")"; });
	//将无用的子节点删除
	var nodeExit =node.exit()
	.transition()
	.duration(duration)
	.attr("transform", function(d){return "rotate(" + (source.x-90) + ")translate(" + source.y + ")"; })
	.remove();
	//记录下当前位置,为下次动画记录初始值
	nodes.forEach(function(d) {
	d.x0 = d.x;
	d.y0 = d.y;
	});
	}
	});
	</script>
	</body>
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