前言
了解了D3.js的基本開發和組件以后，我們開始應用它激動人心之處：絢麗的預定義圖形，應用D3.js，我們在它的示例文件的基礎上稍加變動即可應用于我們的數據可視化工作中，D3.js將后臺的運算已經預定義好，我們只需少量代碼和規范的數據，就能做出很花哨（請原諒我的用詞不當）的效果。
力學圖（也稱為導向圖，也有叫網絡拓補圖的，反正就是通過排斥得到關系遠近的結構）在社交網絡研究、信息傳播途徑等群體關系研究中應用非常廣泛，它可以直觀地反映群體與群體之間聯系的渠道、交集多少，群體內部成員的聯系強度等。
本文實現如下面的效果(用非IE瀏覽器可以看到效果)：
代碼有點長，但是也不復雜，可以參考如下代碼：
<!DOCTYPE html><html><head><script type="text/javascript" src="http://mbostock.github.com/d3/d3.v2.js?2.9.1"></script><style type="text/css">.link { stroke: green; stroke-linejoin:bevel;}.link_error{ stroke:red; stroke-linejoin:bevel;}.nodetext { font: 12px sans-serif; -webkit-user-select:none; -moze-user-select:none; stroke-linejoin:bevel; }#container{ width:800px; height:600px; border:1px solid gray; border-radius:5px; position:relative; margin:20px;}</style></head><body> <div id='container'></div><script type="text/javascript">function Topology(ele){ typeof(ele)=='string' && (ele=document.getElementById(ele)); var w=ele.clientWidth, h=ele.clientHeight, self=this; this.force = d3.layout.force().gravity(.05).distance(200).charge(-800).size([w, h]); this.nodes=this.force.nodes(); this.links=this.force.links(); this.clickFn=function(){}; this.vis = d3.select(ele).append("svg:svg") .attr("width", w).attr("height", h).attr("pointer-events", "all"); this.force.on("tick", function(x) { self.vis.selectAll("g.node") .attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; }); self.vis.selectAll("line.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; }); });}Topology.prototype.doZoom=function(){ d3.select(this).select('g').attr("transform","translate(" + d3.event.translate + ")"+ " scale(" + d3.event.scale + ")");}//增加節點Topology.prototype.addNode=function(node){ this.nodes.push(node);}Topology.prototype.addNodes=function(nodes){ if (Object.prototype.toString.call(nodes)=='[object Array]' ){ var self=this; nodes.forEach(function(node){ self.addNode(node); }); }}//增加連線Topology.prototype.addLink=function(source,target){ this.links.push({source:this.findNode(source),target:this.findNode(target)});}//增加多個連線Topology.prototype.addLinks=function(links){ if (Object.prototype.toString.call(links)=='[object Array]' ){ var self=this; links.forEach(function(link){ self.addLink(link['source'],link['target']); }); }}//刪除節點Topology.prototype.removeNode=function(id){ var i=0, n=this.findNode(id), links=this.links; while ( i < links.length){ links[i]['source']==n || links[i]['target'] ==n ? links.splice(i,1) : ++i; } this.nodes.splice(this.findNodeIndex(id),1);}//刪除節點下的子節點，同時清除link信息Topology.prototype.removeChildNodes=function(id){ var node=this.findNode(id), nodes=this.nodes; links=this.links, self=this; var linksToDelete=[], childNodes=[]; links.forEach(function(link,index){ link['source']==node && linksToDelete.push(index) && childNodes.push(link['target']); }); linksToDelete.reverse().forEach(function(index){ links.splice(index,1); }); var remove=function(node){ var length=links.length; for(var i=length-1;i>=0;i--){ if (links[i]['source'] == node ){ var target=links[i]['target']; links.splice(i,1); nodes.splice(self.findNodeIndex(node.id),1); remove(target); } } } childNodes.forEach(function(node){ remove(node); }); //清除沒有連線的節點 for(var i=nodes.length-1;i>=0;i--){ var haveFoundNode=false; for(var j=0,l=links.length;j<l;j++){ ( links[j]['source']==nodes[i] || links[j]['target']==nodes[i] ) && (haveFoundNode=true) } !haveFoundNode && nodes.splice(i,1); }}//查找節點Topology.prototype.findNode=function(id){ var nodes=this.nodes; for (var i in nodes){ if (nodes[i]['id']==id ) return nodes[i]; } return null;}//查找節點所在索引號Topology.prototype.findNodeIndex=function(id){ var nodes=this.nodes; for (var i in nodes){ if (nodes[i]['id']==id ) return i; } return -1;}//節點點擊事件Topology.prototype.setNodeClickFn=function(callback){ this.clickFn=callback;}//更新拓撲圖狀態信息Topology.prototype.update=function(){ var link = this.vis.selectAll("line.link") .data(this.links, function(d) { return d.source.id + "-" + d.target.id; }) .attr("class", function(d){ return d['source']['status'] && d['target']['status'] ? 'link' :'link link_error'; }); link.enter().insert("svg:line", "g.node") .attr("class", function(d){ return d['source']['status'] && d['target']['status'] ? 'link' :'link link_error'; }); link.exit().remove(); var node = this.vis.selectAll("g.node") .data(this.nodes, function(d) { return d.id;}); var nodeEnter = node.enter().append("svg:g") .attr("class", "node") .call(this.force.drag); //增加圖片，可以根據需要來修改 var self=this; nodeEnter.append("svg:image") .attr("class", "circle") .attr("xlink:href", function(d){ //根據類型來使用圖片 return d.expand ? "http://ww2.sinaimg.cn/large/412e82dbjw1dsbny7igx2j.jpg" : "http://ww4.sinaimg.cn/large/412e82dbjw1dsbnxezrrpj.jpg"; }) .attr("x", "-32px") .attr("y", "-32px") .attr("width", "64px") .attr("height", "64px") .on('click',function(d){ d.expand && self.clickFn(d);}) nodeEnter.append("svg:text") .attr("class", "nodetext") .attr("dx", 15) .attr("dy", -35) .text(function(d) { return d.id }); node.exit().remove(); this.force.start();}var topology=new Topology('container');var nodes=[ {id:'10.4.42.1',type:'router',status:1}, {id:'10.4.43.1',type:'switch',status:1,expand:true}, {id:'10.4.44.1',type:'switch',status:1}, {id:'10.4.45.1',type:'switch',status:0}];var childNodes=[ {id:'10.4.43.2',type:'switch',status:1}, {id:'10.4.43.3',type:'switch',status:1}];var links=[ {source:'10.4.42.1',target:'10.4.43.1'}, {source:'10.4.42.1',target:'10.4.44.1'}, {source:'10.4.42.1',target:'10.4.45.1'}];var childLinks=[ {source:'10.4.43.1',target:'10.4.43.2'}, {source:'10.4.43.1',target:'10.4.43.3'}, {source:'10.4.43.2',target:'10.4.43.3'}]topology.addNodes(nodes);topology.addLinks(links);//可展開節點的點擊事件topology.setNodeClickFn(function(node){ if(!node['_expanded']){ expandNode(node.id); node['_expanded']=true; }else{ collapseNode(node.id); node['_expanded']=false; }});topology.update();function expandNode(id){ topology.addNodes(childNodes); topology.addLinks(childLinks); topology.update();}function collapseNode(id){ topology.removeChildNodes(id); topology.update();}</script></body></html>總結
以上就是這篇文章的全部內容了，希望本文的內容對大家的學習或者工作能帶來一定的幫助，如果有疑問大家可以了留言交流。
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