从动态 json 数据更新力有向图上的链接
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/11400241/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Updating links on a force directed graph from dynamic json data
提问by Rahul Rout
I am new to D3 and working on a force directed graph where the json data is dynamic. I am able to change the force graph upon receiving new data but that happens with a springing effect. The code that creates my force graph is :
我是 D3 的新手，正在研究一个力有向图，其中 json 数据是动态的。我能够在接收到新数据时更改力图，但这会产生弹性效果。创建我的力图的代码是：
<div class="graph"></div>
<script>
var w = 660,
h = 700,
r = 10;
var vis = d3.select(".graph")
.append("svg:svg")
.attr("width", w)
.attr("height", h)
.attr("pointer-events", "all")
.append('svg:g')
.call(d3.behavior.zoom().on("zoom", redraw))
.append('svg:g');
vis.append('svg:rect')
.attr('width', w)
.attr('height', h)
.attr('fill', 'rgba(1,1,1,0)');
function redraw() {
console.log("here", d3.event.translate, d3.event.scale);
vis.attr("transform", "translate(" + d3.event.translate + ")" +
" scale(" + d3.event.scale + ")");
};
var force = d3.layout.force()
.gravity(.05)
.charge(-200)
.linkDistance( 260 )
.size([w, h]);
var svg = d3.select(".text")
.append("svg")
.attr("width", w)
.attr("height", h);
d3.json(graph, function(json) {
var nodeList = json.nodes;
var link = vis.selectAll("line")
.data(json.links)
.enter()
.append("line")
.attr("stroke-opacity", function(d) {
if(d.label == 'is a') {
return '0.8';
} else {
return '0.2';
};
})
.attr("stroke-width", function(d) {
if(d.value !== null) {
return d.value;
} else {
return 2;
};
})
.style("stroke", function(d) {
if(d.color !== null) {
return d.color;
};
})
.on("mouseover", function() {
d3.select(this)
.style("stroke", "#999999")
.attr("stroke-opacity", "1.0");
})
.on("mouseout", function() {
d3.select(this)
.style("stroke", function(d) {
if(d.color !== null) {
return d.color;
};
})
.attr("stroke-opacity", function(d) {
if(d.label == 'is a') {
return '0.8';
} else {
return '0.2';
};
})
});
link.append("title")
.text(function(d) { return d.label } );
var node = vis.selectAll("g.node")
.data(json.nodes)
.enter()
.append("svg:g")
.attr("class","node")
.call(force.drag);
node.append("svg:circle")
.attr("r", function(d) {
if (d.size > 0) {
return 10+(d.size*2);
} else {
return 10;
}
})
.attr("id", function(d) { return "Node;"+d.id; } )
.style("fill", function(d) {
if(d.style == 'filled') {
return d.color;
};
})
.style("stroke", function(d) {
if(d.style !== 'filled') {
return d.color;
};
})
.style("stroke-width", "2")
.on("mouseover", function() {
d3.select(this).style("fill", "#999");
fade(.1);
})
.on("mouseout", function(d) {
if (d.style == 'filled') {
d3.select(this).style("fill",d.color);fade(1);
} else {
d3.select(this).style("stroke",d.color);
d3.select(this).style("fill","black");
}
fade(1);
});
node.append("title")
.text(function(d) { return d.Location; } );
force.nodes(json.nodes)
.links(json.links)
.on("tick", tick)
.alpha(1)
.start();
function tick() {
node.attr("cx", function(d) { return d.x; })
.attr("cy", function(d) { return d.y; })
.attr("transform", function(d) {
return "translate(" + d.x + "," + d.y + ")";
});
link.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; });
}
});
</script>
I am able to create a new graph when a new json string is received by recalling the whole function again. This creates a new graph in place of the old. I am unable to update the old graph with the new set of values as the values are received; the nodes in my graph do not change, just the relation among them changes.
通过再次调用整个函数，我可以在收到新的 json 字符串时创建一个新图形。这将创建一个新图来代替旧图。我无法在收到值时使用新值集更新旧图；我图中的节点没有变化，只是它们之间的关系发生了变化。
I did stumble upon an example (http://bl.ocks.org/1095795) where a new node is deleted and recreated, but the implementation is a bit different.
我确实偶然发现了一个示例 ( http://bl.ocks.org/1095795)，其中删除并重新创建了一个新节点，但实现方式略有不同。
Any pointers or help will be really appreciated.
任何指示或帮助将不胜感激。
回答by Rahul Rout
Well I could find the solution browsing through, posting it here for anyone needing help on this topic. The idea is to create an object of the graph and playing around with the nodes and links arrays. The JS code goes as:
好吧，我可以通过浏览找到解决方案，将其张贴在此处以供在此主题上需要帮助的任何人使用。这个想法是创建图形的对象并使用节点和链接数组。JS代码如下：
var graph;
function myGraph(el) {
// Add and remove elements on the graph object
this.addNode = function (id) {
nodes.push({"id":id});
update();
};
this.removeNode = function (id) {
var i = 0;
var n = findNode(id);
while (i < links.length) {
if ((links[i]['source'] == n)||(links[i]['target'] == n))
{
links.splice(i,1);
}
else i++;
}
nodes.splice(findNodeIndex(id),1);
update();
};
this.removeLink = function (source,target){
for(var i=0;i<links.length;i++)
{
if(links[i].source.id == source && links[i].target.id == target)
{
links.splice(i,1);
break;
}
}
update();
};
this.removeallLinks = function(){
links.splice(0,links.length);
update();
};
this.removeAllNodes = function(){
nodes.splice(0,links.length);
update();
};
this.addLink = function (source, target, value) {
links.push({"source":findNode(source),"target":findNode(target),"value":value});
update();
};
var findNode = function(id) {
for (var i in nodes) {
if (nodes[i]["id"] === id) return nodes[i];};
};
var findNodeIndex = function(id) {
for (var i=0;i<nodes.length;i++) {
if (nodes[i].id==id){
return i;
}
};
};
// set up the D3 visualisation in the specified element
var w = 500,
h = 500;
var vis = d3.select("#svgdiv")
.append("svg:svg")
.attr("width", w)
.attr("height", h)
.attr("id","svg")
.attr("pointer-events", "all")
.attr("viewBox","0 0 "+w+" "+h)
.attr("perserveAspectRatio","xMinYMid")
.append('svg:g');
var force = d3.layout.force();
var nodes = force.nodes(),
links = force.links();
var update = function () {
var link = vis.selectAll("line")
.data(links, function(d) {
return d.source.id + "-" + d.target.id;
});
link.enter().append("line")
.attr("id",function(d){return d.source.id + "-" + d.target.id;})
.attr("class","link");
link.append("title")
.text(function(d){
return d.value;
});
link.exit().remove();
var node = vis.selectAll("g.node")
.data(nodes, function(d) {
return d.id;});
var nodeEnter = node.enter().append("g")
.attr("class", "node")
.call(force.drag);
nodeEnter.append("svg:circle")
.attr("r", 16)
.attr("id",function(d) { return "Node;"+d.id;})
.attr("class","nodeStrokeClass");
nodeEnter.append("svg:text")
.attr("class","textClass")
.text( function(d){return d.id;}) ;
node.exit().remove();
force.on("tick", function() {
node.attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; });
link.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; });
});
// Restart the force layout.
force
.gravity(.05)
.distance(50)
.linkDistance( 50 )
.size([w, h])
.start();
};
// Make it all go
update();
}
function drawGraph()
{
graph = new myGraph("#svgdiv");
graph.addNode('A');
graph.addNode('B');
graph.addNode('C');
graph.addLink('A','B','10');
graph.addLink('A','C','8');
graph.addLink('B','C','15');
}
回答by coop
I took Rahuls great example, made some changes, and posted a bl.ock complete with animation over time if anyone is interested in a fully functioning example. Adding/removing links/nodes really should be easier than this, but still pretty cool.
我拿了 Rahuls 很好的例子，做了一些改变，如果有人对一个功能齐全的例子感兴趣，我会随着时间的推移发布一个完整的带有动画的块。添加/删除链接/节点确实应该比这更容易，但仍然很酷。
http://bl.ocks.org/ericcoopey/6c602d7cb14b25c179a4
http://bl.ocks.org/ericcoopey/6c602d7cb14b25c179a4
回答by Mozleron
In addition to calling drawGraph()in the ready function, you can also embed the posted code inside an inline <script></script>block.
除了调用drawGraph()ready 函数之外，您还可以将发布的代码嵌入到内联<script></script>块中。
This is how most of the tutorials on the d3 site handle it.
这就是 d3 站点上的大多数教程处理它的方式。
