如何使用D3布局非树层次结构 [英] How to layout a non-tree hierarchy with D3

问题描述

D3有许多针对严格树的有向图的布局，例如：

D3 has a variety of layouts for directed graphs that are strict trees, such as the following:

A
|\
B C
 / \
D   E

我需要绘制一个不是树的节点的层次结构，而是一个有向无环图。这是一个树布局的问题，因为几个分支收敛：

I need to draw a hierarchy of nodes that is not a tree, but is a directed acyclic graph. This is a problem for a tree layout, because several of the branches converge:

A
|\
B C
 \|
  D

有没有人知道一般层次结构的D3布局？或者，一些聪明的黑客到现有的treelayout？我已经注意到GraphVis处理这种情况很好，但D3生成一个更适合这里的要求的图。

Does anyone know of a D3 layout for general hierarchies? Or alternatively, some clever hack to the existing treelayout? I've noticed GraphVis handles this situation well, but D3 produces a graph that better suits the requirements here.

推荐答案

我已经提供了一个 example in a jsFiddle 。这个例子是相当简单的，需要做一点工作以适应更复杂的例子。

I've provided an example in a jsFiddle. The example is pretty simplistic and would need to be worked a little bit to accommodate more complex examples.

此示例可以重新工作，以便以相对较少的努力处理分层数据。

The example could be re-worked to process hierarchical data as well with relatively little effort.

我在jsFiddle中使用的代码：

Here is the code I have used in the jsFiddle:

 // Sample data set
var json = {
    nodes: [{
        name: 'A'},
    {
        name: 'B'},
    {
        name: 'C'},
    {
        name: 'D'}],
    links: [{
        source: 'A',
        target: 'B'},
    {
        source: 'A',
        target: 'C'},
    {
        source: 'B',
        target: 'D'},
    {
        source: 'C',
        target: 'D'}
                                                                                   ]

};

var vis = d3.select('#vis').attr('transform', 'translate(20, 20)');

// Build initial link elements - Build first so they are under the nodes
var links = vis.selectAll('line.link').data(json.links);
links.enter().append('line').attr('class', 'link').attr('stroke', '#000');

// Build initial node elements
var nodes = vis.selectAll('g.node').data(json.nodes);
nodes.enter().append('g').attr('class', 'node').append('circle').attr('r', 10).append('title').text(function(d) {
    return d.name;
});

// Store nodes in a hash by name
var nodesByName = {};
nodes.each(function(d) {
    nodesByName[d.name] = d;
});

// Convert link references to objects
links.each(function(link) {
    link.source = nodesByName[link.source];
    link.target = nodesByName[link.target];
    if (!link.source.links) {
        link.source.links = [];
    }
    link.source.links.push(link.target);
    if (!link.target.links) {
        link.target.links = [];
    }
    link.target.links.push(link.source);
});

// Compute positions based on distance from root
var setPosition = function(node, i, depth) {
    if (!depth) {
        depth = 0;
    }
    if (!node.x) {
        node.x = (i + 1) * 40;
        node.y = (depth + 1) * 40;
        if (depth <= 1) {
            node.links.each(function(d, i2) {
                setPosition(d, i2, depth + 1);
            });
        }

    }

};
nodes.each(setPosition);

// Update inserted elements with computed positions
nodes.attr('transform', function(d) {
    return 'translate(' + d.x + ', ' + d.y + ')';
});

links.attr('x1', function(d) {
    return d.source.x;
}).attr('y1', function(d) {
    return d.source.y;
}).attr('x2', function(d) {
    return d.target.x;
}).attr('y2', function(d) {
    return d.target.y;
});

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