在javascript中，可以使用一些基本的API来对SVG进行操作
【NS地址】
因为SVG定义在其自身的命令空间下，而不是HTML的命名空间下，可以作为单独的XML文件存在。所以需要使用自身的NS地址
有两个常用的NS地址
var SVG_NS = "http://www.w3.org/2000/svg"; var XLINK_NS = ;
【创建图形】
document.createElementNS(SVG_NS,tagName);
【添加图形】
element.appendChild(childElement)
【设置/获取属性】
element.setAttribute(name,value); element.getAttribute(name);
【设置xlink】
<a>、<textPath>等标签需要设置xlink属性
element.setAttributeNS(XLINK_NS,'xlink:href',value);
封装函数
将创建标签及添加属性的操作封闭成一个函数，方便复用
function createTag(tag,objAttr){ var oTag = document.createElementNS('http://www.w3.org/2000/svg',tag); for(var attr in objAttr){ if(attr == 'xlink:href'){ oTag.setAttributeNS("http://www.w3.org/1999/xlink",attr,objAttr[attr]); }else{ oTag.setAttribute(attr,objAttr[attr]); } } return oTag; }
下面通过该函数，创建一个圆形
<script> function createTag(tag,objAttr){ var oTag = document.createElementNS('http://www.w3.org/2000/svg',tag); for(var attr in objAttr){ if(attr == 'xlink:href'){ oTag.setAttributeNS("http://www.w3.org/1999/xlink",attr,objAttr[attr]); }else{ oTag.setAttribute(attr,objAttr[attr]); } } return oTag; } var oSvg = createTag('svg',{'version':'1.1','xmls':'http://www.w3.org/2000/svg',height:'70'}); var oCircle = createTag('circle',{'cx':'25','cy':'25','r':20,'fill':'pink'}); oSvg.appendChild(oCircle); document.body.appendChild(oSvg); </script>
实例
下面通过SVG基本操作API，创建一个可交互的SVG实例
<style> #box{ height: 300px; width: 300px; background: hsl(20,40%,90%); background-image:linear-gradient(90deg,#fb3 11px,transparent 0), linear-gradient(90deg,#ab4 23px,transparent 0), linear-gradient(90deg,#655 41px,transparent 0); background-size: 41px 100%,61px 100%,83px 100%; } </style> <div></div> <script> var oSvg = createTag('svg',{'version':'1.1','xmls':'http://www.w3.org/2000/svg',height:'100%',width:'100%'}); var oBox = document.getElementById('box'); var W = parseInt(getComputedStyle(oBox).width); var H = parseInt(getComputedStyle(oBox).height); var appearance = { 'dis':H/3, 'r0':H/8,'r':H/10, 'x0':W/2,'y0':H/2, 'fontSize':H/20, 'bg0':'hsla(0,0%,100%,.6)','bg':'hsla(0,0%,100%,.3)', 'color0':'hsl(210,13%,30%)','color':'hsl(210,13%,30%)', 'borderColor0':'rgba(0,0,0,0.3)','bordercolor':'rgba(0,0,0,0.3)', 'strokWidth0':3,'strokWidth':2, 'lineColor':'rgba(0,0,0,0.3)','lineWidth':1,'lineDashed':'5,5' } var data = { text:'前端开发', children:[ {text:'HTML',url:'http://www.cnblogs.com/xiaohuochai/p/5203223.html'}, {text:'CSS',url:'http://www.cnblogs.com/xiaohuochai/p/5249139.html'}, {text:'JS',url:'http://www.cnblogs.com/xiaohuochai/p/5613593.html'}, {text:'ES6',url:'http://www.cnblogs.com/xiaohuochai/p/7233392.html'}, {text:'HTTP',url:'http://www.cnblogs.com/xiaohuochai/p/6392010.html'}, {text:'NodeJS',url:'http://www.cnblogs.com/xiaohuochai/p/6940560.html'}, {text:'前端工具',url:'http://www.cnblogs.com/xiaohuochai/p/6666415.html'}, ], } addChildenTags(); addCenterTag(); oBox.appendChild(oSvg); function createTag(tag,objAttr){ var oTag = document.createElementNS('http://www.w3.org/2000/svg',tag); for(var attr in objAttr){ if(attr == 'xlink:href'){ oTag.setAttributeNS("http://www.w3.org/1999/xlink",attr,objAttr[attr]); }else{ oTag.setAttribute(attr,objAttr[attr]); } } return oTag; } function addCenterTag(){ var oG = createTag('g',{'style':'cursor:default'}); var oCircle = createTag('circle',{'cx':appearance.x0,'cy':appearance.y0,'r':appearance.r0,'fill':appearance.bg0,'stroke':appearance.borderColor0,'stroke-width':appearance.strokWidth0}); var oText = createTag('text',{'x':appearance.x0,'y':appearance.y0,'font-size':appearance.fontSize,'text-anchor':'middle','dominant-baseline':'middle','stroke-width':appearance.strokWidth0}); oText.innerHTML = data.text; oG.appendChild(oCircle); oG.appendChild(oText); oSvg.appendChild(oG); } function addChildenTags(){ var children = data.children; var length = children.length; var deg = (360/length)*(2*Math.PI)/360; for(var i = 0; i < children.length;i++){ var cos = Math.cos(deg*i - 90); var sin = Math.sin(deg*i - 90); var x = appearance.x0 + appearance.dis*cos; var y = appearance.y0 + appearance.dis*sin; var oA = createTag('a',{'xlink:href':children[i].url,'target':'_black'}); var oG = createTag('g',{'style':'cursor:pointer'}); oG.index = i; var oLine = createTag('line',{'x1':x-appearance.r*cos,y1:y-appearance.r*sin,x2:appearance.x0+appearance.r0*cos,y2:appearance.y0+appearance.r0*sin,'stroke':appearance.lineColor,'stroke-width':appearance.lineWidth,'stroke-dasharray':appearance.lineDashed,'style':'transition:.5s'}); var oLineHelper = createTag('line',{'x1':x-appearance.r*cos,y1:y-appearance.r*sin,x2:appearance.x0+appearance.r0*cos,y2:appearance.y0+appearance.r0*sin,'stroke':'transparent','stroke-width':10}); var oCircle = createTag('circle',{'cx':x,'cy':y,'r':appearance.r,'fill':appearance.bg,'stroke':appearance.bordercolor,'stroke-width':appearance.strokWidth,'class':'frostedglass'}); var oText = createTag('text',{'x':x,'y':y,'font-size':appearance.fontSize,'text-anchor':'middle','dominant-baseline':'middle','stroke-width':appearance.strokWidth,fill:appearance.color}); oText.innerHTML = children[i].text; oG.appendChild(oLine); oG.appendChild(oLineHelper); oG.appendChild(oCircle); oG.appendChild(oText); oA.appendChild(oG); oSvg.appendChild(oA); oG.onmouseenter = function(){ elasticMove(this,appearance.r*1.2); var line = this.children[0]; line.removeAttribute('stroke-dasharray'); line.setAttribute('stroke-width',appearance.lineWidth*3); line.setAttribute('x1',appearance.x0+(appearance.dis - appearance.r0)*Math.cos(deg*this.index - 90)); line.setAttribute('y1',appearance.y0+(appearance.dis - appearance.r0)*Math.sin(deg*this.index - 90)); } oG.onmouseleave = function(){ elasticMove(this,appearance.r); var line = this.children[0]; line.setAttribute('stroke-width',appearance.lineWidth); line.setAttribute('stroke-dasharray',appearance.lineDashed); line.setAttribute('x1',appearance.x0+(appearance.dis - appearance.r)*Math.cos(deg*this.index - 90)); line.setAttribute('y1',appearance.y0+(appearance.dis - appearance.r)*Math.sin(deg*this.index - 90)); } } } function elasticMove(obj,str){ var circle = obj.getElementsByTagName('circle')[0]; var r0 = circle.getAttribute('r'); var r = Number(str); //声明步长值 var step = 0; //声明弹性距离 var len = r - r0; //声明弹性系数 var k = 0.7; //声明损耗系数 var z= 0.7; //声明当前值 var cur = r0; clearInterval(circle.timer); circle.timer = setInterval(function(){ //获取当前值cur cur = circle.getAttribute('r'); //更新弹性距离 len = r - cur; //弹力影响 step += len*k; //阻力影响 step = step*z; //赋值 circle.setAttribute('r',Number(cur) + step); //当元素的步长值接近于0，并且弹性距离接近于0时，停止定时器 if(Math.round(step) == 0 && Math.round(len) == 0){ circle.setAttribute('r',r); clearInterval(circle.timer); } },30); } </script>
以上这篇使用SVG基本操作API的实例讲解就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持脚本之家。
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