html5 canvas生日快乐文字烟花背景动画特效代码下载
1. 引入JS
<script src="js/jquery.min.js"></script><script src="js/canvas.js"></script><script src="js/deepCopy.js"></script><script src="js/Firework.js"></script>
2. HTML代码
<canvas id="canvas" width="500" height="500"></canvas> <script>var canvas = $$("canvas"), ctx = canvas.getContext("2d"), g = 0.25,//模拟重力加速度 n = 5,//一次性发射的烟火的数量 fireworkList = [],//存放所有烟火对象 //烟火形状 圆形 椭圆形 爱心形 fireworkTypeList = [createCircleFirework, createEllipseFirework, createHeartFirework], totalNum = 0,//发射烟火的总数量 surprise_num = 25,//当发射烟火数量达到25时,发射生日快乐字样的烟火 flag = true;//是否发射生日快乐字样的烟火canvas.width = $(window).width() - 15;canvas.height = $(window).height() - 20;var init = function(firework,params){//初始化一个烟火 var beforeBalst = firework.getBeforeBalst(); firework.setCtx(ctx); firework.setStatus(1);//状态为点燃引线 firework.setNum(100 + Math.floor(20 * Math.random()));//爆炸之后的烟花数量 firework.setRoundness(getType(params) == "object" ? (getType(params.roundness) == "number" ? params.roundness : 0.25) : 0.25);//默认的规则度是0.25,这样爆炸的烟花与真实的最像 //firework.setFireworkType(getType(params) == "object" ? params.fireworkType : fireworkTypeList[Math.floor(Math.random() * fireworkTypeList.length)]);//从三种形状中随机烟花形状 firework.setFireworkType(getType(params) == "object" ? params.fireworkType : createCircleFirework);//默认圆形烟花 firework.setDelay(Math.floor(30 * Math.random()));//引线燃烧的时间,单位为帧, 最多30帧,即0.5s beforeBalst.setAnimate({ quiescence : {//发射位置为底部中间 x : canvas.width / 2, y : canvas.height, deg : 0, zoom : 1 },move : {//发射速度向量 vx : -7 + 14 * Math.random(), vy : -22 + 4 * Math.random(), pal : 0, scale : 0 },translate : {//发射加速度,有一个为g的重力加速度 ax : 0, ay : g, apal : 0, scale : 0 } }); beforeBalst.setR(3);//烟火半径为3像素 beforeBalst.setColor("#FFFFFF");//白色 beforeBalst.setLife(50 + Math.floor(Math.random() * 50));//烟花从发射到爆炸的时间,单位为帧,即50-100帧后爆炸 beforeBalst.setBase();//记录烟花发射的初始状态}for(var i = 0; i < n; i++){//初始化n个烟火 var firework = Firework.getInstance(); init(firework); fireworkList.push(firework); totalNum++;}var draw = function(){//描绘每一帧烟火的状态 //整个canvas充满黑幕,模拟黑夜 ctx.globalCompositeOperation = 'source-over'; ctx.globalAlpha = 0.2; ctx.fillStyle = '#000003'; ctx.fillRect(0, 0, canvas.width, canvas.height); //描绘每个烟火的状态 ctx.globalCompositeOperation = 'screen'; $.each(fireworkList,function(index,value){ value.draw(); });};var update = function(){//更新每一帧烟火的状态 for(var i = fireworkList.length - 1; i >= 0; i--){ fireworkList[i].update();//更新 if(fireworkList[i].getStatus() == 5){//烟火消失 fireworkList.splice(i,1);//在烟火集合中将这个烟火去除掉 if(totalNum < surprise_num){//当发射烟火数量没到25 var firework = Firework.getInstance();//继续生成新的烟火 init(firework); fireworkList.push(firework); totalNum++; } if(fireworkList.length == 0 && flag){//发射生日快乐烟火和一箭穿心烟火 var firework = Firework.getInstance(); init(firework,{fireworkType:createCustomFirework,roundness:1}); fireworkList.push(firework); var firework2 = Firework.getInstance(); init(firework2,{fireworkType:createDoubleHeartFirework,roundness:1}); fireworkList.push(firework2); flag = false; } } }}var loop = function(){ draw(); update(); requestAnimationFrame(function(){//每秒触发60次的方法,因此动画是60帧的 loop(); });};loop();</script>
