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Q:Drawing multiple edges between two nodes with d3

Q:绘制多个边缘节点之间的D3

I've been following Mike Bostock's code from this example to learn how to draw directed graphs in d3 and was wondering how I would structure the code so that I could add multiple edges between two nodes in the graph. For example, if the dataset in the example above were defined as

var links = [{source: "Microsoft", target: "Amazon", type: "licensing"},
             {source: "Microsoft", target: "Amazon", type: "suit"},
             {source: "Samsung", target: "Apple", type: "suit"},
             {source: "Microsoft", target: "Amazon", type: "resolved"}];

and then run through the code, all I see is one line. All the paths are being drawn correctly in the html code, however they all have the same coordinates and orientation which causes the visual to look like 1 line. What kind of code restructuring would need to be done in this example to allow for the 3 edges to not be drawn on top of each other?

我一直跟随Mike Bostock的代码从这个例子中学习如何在D3画有向图和想知道我会如何组织代码以便我可以添加多个边缘图中的两个节点之间。例如,如果上面示例中的数据集被定义为

var links = [{source: "Microsoft", target: "Amazon", type: "licensing"},
             {source: "Microsoft", target: "Amazon", type: "suit"},
             {source: "Samsung", target: "Apple", type: "suit"},
             {source: "Microsoft", target: "Amazon", type: "resolved"}];

然后通过代码运行,我看到的是一行。所有的路都被正确的HTML代码,但是他们都有像1线相同的坐标和方向,使视觉。什么样的代码重组需要在这个例子中做,以允许3个边缘不被绘制在彼此顶部?

answer1: 回答1:

In fact, the original visualization is a prime example of one method to show multiple links between nodes, that is - using arcs rather than direct paths, so you can see both incoming and outgoing links.

This concept can be extended to show multiple of each of these types of links by changing the radius values of subsequent svg path(arc) elements representing the link. A basic example being

dr = 75/d.linknum;

Where d.linknum represents the number of the successive link. dr is later used as the rx and ry amounts for the arc being drawn.

Full implementation here: http://jsfiddle.net/7HZcR/3/

事实上,原来的可视化是一个例子,一个方法来显示多个节点之间的链接,即-使用弧,而不是直接的路径,所以你可以看到传入和传出的链接。

这个概念可以扩展到显示这些链接类型多通过改变随后的SVG路径的半径值(ARC)代表链接元素。一个基本的例子

dr = 75/d.linknum;

在d.linknum代表连续的链接数。DR是后来作为RX,RY的电弧被吸引量。

全面实施http://jsfiddle.net/7hzcr/3/这里:

answer2: 回答2:

Here is the source for the answer above if anyone ever needs it :

var links = [{source: "Microsoft", target: "Amazon", type: "licensing"},
             {source: "Microsoft", target: "Amazon", type: "suit"},
             {source: "Samsung", target: "Apple", type: "suit"},
             {source: "Microsoft", target: "Amazon", type: "resolved"}];
//sort links by source, then target
links.sort(function(a,b) {
    if (a.source > b.source) {return 1;}
    else if (a.source < b.source) {return -1;}
    else {
        if (a.target > b.target) {return 1;}
        if (a.target < b.target) {return -1;}
        else {return 0;}
    }
});
//any links with duplicate source and target get an incremented 'linknum'
for (var i=0; i<links.length; i++) {
    if (i != 0 &&
        links[i].source == links[i-1].source &&
        links[i].target == links[i-1].target) {
            links[i].linknum = links[i-1].linknum + 1;
        }
    else {links[i].linknum = 1;};
};

var nodes = {};

// Compute the distinct nodes from the links.
links.forEach(function(link) {
  link.source = nodes[link.source] || (nodes[link.source] = {name: link.source});
  link.target = nodes[link.target] || (nodes[link.target] = {name: link.target});
});

var w = 600,
    h = 600;

var force = d3.layout.force()
    .nodes(d3.values(nodes))
    .links(links)
    .size([w, h])
    .linkDistance(60)
    .charge(-300)
    .on("tick", tick)
    .start();

var svg = d3.select("body").append("svg:svg")
    .attr("width", w)
    .attr("height", h);

// Per-type markers, as they don't inherit styles.
svg.append("svg:defs").selectAll("marker")
    .data(["suit", "licensing", "resolved"])
  .enter().append("svg:marker")
    .attr("id", String)
    .attr("viewBox", "0 -5 10 10")
    .attr("refX", 15)
    .attr("refY", -1.5)
    .attr("markerWidth", 6)
    .attr("markerHeight", 6)
    .attr("orient", "auto")
  .append("svg:path")
    .attr("d", "M0,-5L10,0L0,5");

var path = svg.append("svg:g").selectAll("path")
    .data(force.links())
  .enter().append("svg:path")
    .attr("class", function(d) { return "link " + d.type; })
    .attr("marker-end", function(d) { return "url(#" + d.type + ")"; });

var circle = svg.append("svg:g").selectAll("circle")
    .data(force.nodes())
  .enter().append("svg:circle")
    .attr("r", 6)
    .call(force.drag);

var text = svg.append("svg:g").selectAll("g")
    .data(force.nodes())
  .enter().append("svg:g");

// A copy of the text with a thick white stroke for legibility.
text.append("svg:text")
    .attr("x", 8)
    .attr("y", ".31em")
    .attr("class", "shadow")
    .text(function(d) { return d.name; });

text.append("svg:text")
    .attr("x", 8)
    .attr("y", ".31em")
    .text(function(d) { return d.name; });

// Use elliptical arc path segments to doubly-encode directionality.
function tick() {
  path.attr("d", function(d) {
    var dx = d.target.x - d.source.x,
        dy = d.target.y - d.source.y,
        dr = 75/d.linknum;  //linknum is defined above
    return "M" + d.source.x + "," + d.source.y + "A" + dr + "," + dr + " 0 0,1 " + d.target.x + "," + d.target.y;
  });

  circle.attr("transform", function(d) {
    return "translate(" + d.x + "," + d.y + ")";
  });

  text.attr("transform", function(d) {
    return "translate(" + d.x + "," + d.y + ")";
  });
}
path.link {
  fill: none;
  stroke: #666;
  stroke-width: 1.5px;
}

marker#licensing {
  fill: green;
}

path.link.licensing {
  stroke: green;
}

path.link.resolved {
  stroke-dasharray: 0,2 1;
}

circle {
  fill: #ccc;
  stroke: #333;
  stroke-width: 1.5px;
}

text {
  font: 10px sans-serif;
  pointer-events: none;
}

text.shadow {
  stroke: #fff;
  stroke-width: 3px;
  stroke-opacity: .8;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>
<div id="chart"></div>

这里是答案的来源,如果有人需要它:

var links = [{source: "Microsoft", target: "Amazon", type: "licensing"},
             {source: "Microsoft", target: "Amazon", type: "suit"},
             {source: "Samsung", target: "Apple", type: "suit"},
             {source: "Microsoft", target: "Amazon", type: "resolved"}];
//sort links by source, then target
links.sort(function(a,b) {
    if (a.source > b.source) {return 1;}
    else if (a.source < b.source) {return -1;}
    else {
        if (a.target > b.target) {return 1;}
        if (a.target < b.target) {return -1;}
        else {return 0;}
    }
});
//any links with duplicate source and target get an incremented 'linknum'
for (var i=0; i<links.length; i++) {
    if (i != 0 &&
        links[i].source == links[i-1].source &&
        links[i].target == links[i-1].target) {
            links[i].linknum = links[i-1].linknum + 1;
        }
    else {links[i].linknum = 1;};
};

var nodes = {};

// Compute the distinct nodes from the links.
links.forEach(function(link) {
  link.source = nodes[link.source] || (nodes[link.source] = {name: link.source});
  link.target = nodes[link.target] || (nodes[link.target] = {name: link.target});
});

var w = 600,
    h = 600;

var force = d3.layout.force()
    .nodes(d3.values(nodes))
    .links(links)
    .size([w, h])
    .linkDistance(60)
    .charge(-300)
    .on("tick", tick)
    .start();

var svg = d3.select("body").append("svg:svg")
    .attr("width", w)
    .attr("height", h);

// Per-type markers, as they don't inherit styles.
svg.append("svg:defs").selectAll("marker")
    .data(["suit", "licensing", "resolved"])
  .enter().append("svg:marker")
    .attr("id", String)
    .attr("viewBox", "0 -5 10 10")
    .attr("refX", 15)
    .attr("refY", -1.5)
    .attr("markerWidth", 6)
    .attr("markerHeight", 6)
    .attr("orient", "auto")
  .append("svg:path")
    .attr("d", "M0,-5L10,0L0,5");

var path = svg.append("svg:g").selectAll("path")
    .data(force.links())
  .enter().append("svg:path")
    .attr("class", function(d) { return "link " + d.type; })
    .attr("marker-end", function(d) { return "url(#" + d.type + ")"; });

var circle = svg.append("svg:g").selectAll("circle")
    .data(force.nodes())
  .enter().append("svg:circle")
    .attr("r", 6)
    .call(force.drag);

var text = svg.append("svg:g").selectAll("g")
    .data(force.nodes())
  .enter().append("svg:g");

// A copy of the text with a thick white stroke for legibility.
text.append("svg:text")
    .attr("x", 8)
    .attr("y", ".31em")
    .attr("class", "shadow")
    .text(function(d) { return d.name; });

text.append("svg:text")
    .attr("x", 8)
    .attr("y", ".31em")
    .text(function(d) { return d.name; });

// Use elliptical arc path segments to doubly-encode directionality.
function tick() {
  path.attr("d", function(d) {
    var dx = d.target.x - d.source.x,
        dy = d.target.y - d.source.y,
        dr = 75/d.linknum;  //linknum is defined above
    return "M" + d.source.x + "," + d.source.y + "A" + dr + "," + dr + " 0 0,1 " + d.target.x + "," + d.target.y;
  });

  circle.attr("transform", function(d) {
    return "translate(" + d.x + "," + d.y + ")";
  });

  text.attr("transform", function(d) {
    return "translate(" + d.x + "," + d.y + ")";
  });
}
path.link {
  fill: none;
  stroke: #666;
  stroke-width: 1.5px;
}

marker#licensing {
  fill: green;
}

path.link.licensing {
  stroke: green;
}

path.link.resolved {
  stroke-dasharray: 0,2 1;
}

circle {
  fill: #ccc;
  stroke: #333;
  stroke-width: 1.5px;
}

text {
  font: 10px sans-serif;
  pointer-events: none;
}

text.shadow {
  stroke: #fff;
  stroke-width: 3px;
  stroke-opacity: .8;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>
<div id="chart"></div>
html  graph  svg  d3.js  edges