前面的話
本文將詳細(xì)介紹SVG基本操作API，并使用這些API制作實(shí)例效果
基礎(chǔ)API
在javascript中，可以使用一些基本的API來對(duì)SVG進(jìn)行操作
【NS地址】
因?yàn)镾VG定義在其自身的命令空間下，而不是HTML的命名空間下，可以作為單獨(dú)的XML文件存在。所以需要使用自身的NS地址
有兩個(gè)常用的NS地址
var SVG_NS = "http://www.w3.org/2000/svg";var XLINK_NS = http://www.w3.org/1999/xlink;
【創(chuàng)建圖形】
document.createElementNS(SVG_NS,tagName);
【添加圖形】
element.appendChild(childElement)
【設(shè)置/獲取屬性】
element.setAttribute(name,value);element.getAttribute(name);
【設(shè)置xlink】
<a>、<textPath>等標(biāo)簽需要設(shè)置xlink屬性
element.setAttributeNS(XLINK_NS,'xlink:href',value);
封裝函數(shù)
將創(chuàng)建標(biāo)簽及添加屬性的操作封閉成一個(gè)函數(shù)，方便復(fù)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;}下面通過該函數(shù)，創(chuàng)建一個(gè)圓形
<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>實(shí)例
下面通過SVG基本操作API，創(chuàng)建一個(gè)可交互的SVG實(shí)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 id="box"></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:'前端開發(fā)', 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); //聲明步長(zhǎng)值 var step = 0; //聲明彈性距離 var len = r - r0; //聲明彈性系數(shù) var k = 0.7; //聲明損耗系數(shù) var z= 0.7; //聲明當(dāng)前值 var cur = r0; clearInterval(circle.timer); circle.timer = setInterval(function(){ //獲取當(dāng)前值cur cur = circle.getAttribute('r'); //更新彈性距離 len = r - cur; //彈力影響 step += len*k; //阻力影響 step = step*z; //賦值 circle.setAttribute('r',Number(cur) + step); //當(dāng)元素的步長(zhǎng)值接近于0，并且彈性距離接近于0時(shí)，停止定時(shí)器 if(Math.round(step) == 0 && Math.round(len) == 0){ circle.setAttribute('r',r); clearInterval(circle.timer); } },30);}</script>以上這篇使用SVG基本操作API的實(shí)例講解就是小編分享給大家的全部?jī)?nèi)容了，希望能給大家一個(gè)參考，也希望大家多多支持武林網(wǎng)。
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