2022将至，前端程序员们应该一起放个烟花庆祝一下，走起
【摘要】
前言：小时候，在我印象中，每到快过年的时候就有很多卖炮仗的，一般也就是阳历的12月份到明年的正月15号卖炮仗的商家比较多，省下买辣条的钱去买炮仗，在老家也就过年和除夕两天及正月15日这几天放烟花和炮仗比较猛，现在年纪大了，听不得炮仗那种噪声了，也考虑到环保，工作之后的程序员以代码的形式演绎一下烟花的效果。
目录
效果图...
前言：小时候，在我印象中，每到快过年的时候就有很多卖炮仗的，一般也就是阳历的12月份到明年的正月15号卖炮仗的商家比较多，省下买辣条的钱去买炮仗，在老家也就过年和除夕两天及正月15日这几天放烟花和炮仗比较猛，现在年纪大了，听不得炮仗那种噪声了，也考虑到环保，工作之后的程序员以代码的形式演绎一下烟花的效果。
目录
效果图
首先我们下看一段小视频
前端程序员自制春节元宵烟花
项目结构
一个网页+两个配图
html
引入两个背景图片衬托一下，先写几段话用于在播放烟花的字幕，可以根据自己的兴趣随意添加，直接复制粘帖修改文字即可。
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<canvas id='cas' style="background-color:rgba(0,5,24,1)">浏览器不支持canvas</canvas>
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<div class="city"><img src="city.png" alt="" /></div>
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<img src="moon.png" alt="" id="moon" style="visibility: hidden;"/>
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<div style="display:none">
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<div class="shape">孙叫兽祝大家</div>
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<div class="shape">2022年</div>
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<div class="shape">新年快乐</div>
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<div class="shape">财富自由</div>
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<div class="shape">合家幸福</div>
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<div class="shape">万事如意</div>
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<div class="shape">心想事成</div>
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<div class="shape">财源广进</div>
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</div>
javascript
主要控制文字显示的位置，文字及烟花出现的频率。
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var canvas = document.getElementById("cas");
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var ocas = document.createElement("canvas");
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var octx = ocas.getContext("2d");
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var ctx = canvas.getContext("2d");
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ocas.width = canvas.width = window.innerWidth;
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ocas.height = canvas.height = window.innerHeight;
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var bigbooms = [];
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window.onload = function(){
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initAnimate()
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}
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function initAnimate(){
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drawBg();
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lastTime = new Date();
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animate();
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}
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var lastTime;
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function animate(){
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ctx.save();
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ctx.fillStyle = "rgba(0,5,24,0.1)";
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ctx.fillRect(0,0,canvas.width,canvas.height);
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ctx.restore();
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var newTime = new Date();
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if(newTime-lastTime>500+(window.innerHeight-767)/2){
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var random = Math.random()*100>2?true:false;
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var x = getRandom(canvas.width/5 , canvas.width*4/5);
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var y = getRandom(50 , 200);
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if(random){
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var bigboom = new Boom(getRandom(canvas.width/3,canvas.width*2/3) ,2,"#FFF" , {x:x , y:y});
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bigbooms.push(bigboom)
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}
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else {
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var bigboom = new Boom(getRandom(canvas.width/3,canvas.width*2/3) ,2,"#FFF" , {x:canvas.width/2 , y:200} , document.querySelectorAll(".shape")[parseInt(getRandom(0, document.querySelectorAll(".shape").length))]);
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bigbooms.push(bigboom)
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}
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lastTime = newTime;
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console.log(bigbooms)
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}
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stars.foreach(function(){
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this.paint();
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})
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drawMoon();
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bigbooms.foreach(function(index){
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var that = this;
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if(!this.dead){
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this._move();
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this._drawLight();
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}
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else{
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this.booms.foreach(function(index){
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if(!this.dead) {
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this.moveTo(index);
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}
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else if(index === that.booms.length-1){
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bigbooms[bigbooms.indexOf(that)] = null;
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}
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})
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}
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});
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raf(animate);
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}
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function drawMoon(){
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var moon = document.getElementById("moon");
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var centerX = canvas.width-200 , centerY = 100 , width = 80;
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if(moon.complete){
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ctx.drawImage(moon , centerX , centerY , width , width )
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}
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else {
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moon.onload = function(){
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ctx.drawImage(moon ,centerX , centerY , width , width)
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}
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}
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var index = 0;
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for(var i=0;i<10;i++){
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ctx.save();
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ctx.beginPath();
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ctx.arc(centerX+width/2 , centerY+width/2 , width/2+index , 0 , 2*Math.PI);
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ctx.fillStyle="rgba(240,219,120,0.005)";
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index+=2;
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ctx.fill();
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ctx.restore();
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}
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}
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Array.prototype.foreach = function(callback){
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for(var i=0;i<this.length;i++){
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if(this[i]!==null) callback.apply(this[i] , [i])
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}
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}
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var raf = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function (callback) { window.setTimeout(callback, 1000 / 60); };
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canvas.onclick = function(){
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var x = event.clientX;
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var y = event.clientY;
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var bigboom = new Boom(getRandom(canvas.width/3,canvas.width*2/3) ,2,"#FFF" , {x:x , y:y});
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bigbooms.push(bigboom)
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}
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// canvas.addEventLisener("touchstart" , function(event){
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// var touch = event.targetTouches[0];
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// var x = event.pageX;
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// var y = event.pageY;
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// var bigboom = new Boom(getRandom(canvas.width/3,canvas.width*2/3) ,2,"#FFF" , {x:x , y:y});
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// bigbooms.push(bigboom)
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// })
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var Boom = function(x,r,c,boomArea,shape){
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this.booms = [];
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this.x = x;
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this.y = (canvas.height+r);
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this.r = r;
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this.c = c;
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this.shape = shape || false;
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this.boomArea = boomArea;
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this.theta = 0;
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this.dead = false;
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this.ba = parseInt(getRandom(80 , 100));
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}
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Boom.prototype = {
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_paint:function(){
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ctx.save();
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ctx.beginPath();
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ctx.arc(this.x,this.y,this.r,0,2*Math.PI);
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ctx.fillStyle = this.c;
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ctx.fill();
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ctx.restore();
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},
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_move:function(){
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var dx = this.boomArea.x - this.x , dy = this.boomArea.y - this.y;
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this.x = this.x+dx*0.01;
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this.y = this.y+dy*0.01;
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if(Math.abs(dx)<=this.ba && Math.abs(dy)<=this.ba){
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if(this.shape){
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this._shapBoom();
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}
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else this._boom();
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this.dead = true;
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}
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else {
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this._paint();
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}
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},
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_drawLight:function(){
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ctx.save();
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ctx.fillStyle = "rgba(255,228,150,0.3)";
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ctx.beginPath();
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ctx.arc(this.x , this.y , this.r+3*Math.random()+1 , 0 , 2*Math.PI);
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ctx.fill();
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ctx.restore();
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},
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_boom:function(){
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var fragNum = getRandom(30 , 200);
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var style = getRandom(0,10)>=5? 1 : 2;
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var color;
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if(style===1){
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color = {
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a:parseInt(getRandom(128,255)),
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b:parseInt(getRandom(128,255)),
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c:parseInt(getRandom(128,255))
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}
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}
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var fanwei = parseInt(getRandom(300, 400));
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for(var i=0;i<fragNum;i++){
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if(style===2){
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color = {
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a:parseInt(getRandom(128,255)),
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b:parseInt(getRandom(128,255)),
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c:parseInt(getRandom(128,255))
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}
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}
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var a = getRandom(-Math.PI, Math.PI);
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var x = getRandom(0, fanwei) * Math.cos(a) + this.x;
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var y = getRandom(0, fanwei) * Math.sin(a) + this.y;
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var radius = getRandom(0 , 2)
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var frag = new Frag(this.x , this.y , radius , color , x , y );
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this.booms.push(frag);
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}
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},
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_shapBoom:function(){
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var that = this;
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putValue(ocas , octx , this.shape , 5, function(dots){
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var dx = canvas.width/2-that.x;
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var dy = canvas.height/2-that.y;
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for(var i=0;i<dots.length;i++){
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color = {a:dots[i].a,b:dots[i].b,c:dots[i].c}
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var x = dots[i].x;
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var y = dots[i].y;
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var radius = 1;
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var frag = new Frag(that.x , that.y , radius , color , x-dx , y-dy);
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that.booms.push(frag);
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}
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})
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}
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}
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function putValue(canvas , context , ele , dr , callback){
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context.clearRect(0,0,canvas.width,canvas.height);
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var img = new Image();
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if(ele.innerHTML.indexOf("img")>=0){
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img.src = ele.getElementsByTagName("img")[0].src;
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imgload(img , function(){
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context.drawImage(img , canvas.width/2 - img.width/2 , canvas.height/2 - img.width/2);
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dots = getimgData(canvas , context , dr);
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callback(dots);
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})
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}
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else {
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var text = ele.innerHTML;
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context.save();
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var fontSize =200;
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context.font = fontSize+"px 宋体 bold";
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context.textAlign = "center";
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context.textBaseline = "middle";
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context.fillStyle = "rgba("+parseInt(getRandom(128,255))+","+parseInt(getRandom(128,255))+","+parseInt(getRandom(128,255))+" , 1)";
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context.fillText(text , canvas.width/2 , canvas.height/2);
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context.restore();
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dots = getimgData(canvas , context , dr);
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callback(dots);
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}
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}
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function imgload(img , callback){
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if(img.complete){
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callback.call(img);
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}
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else {
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img.onload = function(){
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callback.call(this);
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}
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}
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}
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function getimgData(canvas , context , dr){
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var imgData = context.getImageData(0,0,canvas.width , canvas.height);
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context.clearRect(0,0,canvas.width , canvas.height);
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var dots = [];
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for(var x=0;x<imgData.width;x+=dr){
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for(var y=0;y<imgData.height;y+=dr){
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var i = (y*imgData.width + x)*4;
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if(imgData.data[i+3] > 128){
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var dot = {x:x , y:y , a:imgData.data[i] , b:imgData.data[i+1] , c:imgData.data[i+2]};
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dots.push(dot);
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}
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}
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}
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return dots;
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}
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function getRandom(a , b){
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return Math.random()*(b-a)+a;
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}
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var maxRadius = 1 , stars=[];
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function drawBg(){
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for(var i=0;i<100;i++){
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var r = Math.random()*maxRadius;
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var x = Math.random()*canvas.width;
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var y = Math.random()*2*canvas.height - canvas.height;
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var star = new Star(x , y , r);
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stars.push(star);
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star.paint()
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}
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}
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var Star = function(x,y,r){
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this.x = x;this.y=y;this.r=r;
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}
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Star.prototype = {
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paint:function(){
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ctx.save();
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ctx.beginPath();
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ctx.arc(this.x , this.y , this.r , 0 , 2*Math.PI);
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ctx.fillStyle = "rgba(255,255,255,"+this.r+")";
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ctx.fill();
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ctx.restore();
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}
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}
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var focallength = 250;
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var Frag = function(centerX , centerY , radius , color ,tx , ty){
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this.tx = tx;
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this.ty = ty;
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this.x = centerX;
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this.y = centerY;
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this.dead = false;
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this.centerX = centerX;
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this.centerY = centerY;
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this.radius = radius;
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this.color = color;
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}
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Frag.prototype = {
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paint:function(){
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ctx.save();
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ctx.beginPath();
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ctx.arc(this.x , this.y , this.radius , 0 , 2*Math.PI);
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ctx.fillStyle = "rgba("+this.color.a+","+this.color.b+","+this.color.c+",1)";
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ctx.fill()
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ctx.restore();
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},
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moveTo:function(index){
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this.ty = this.ty+0.3;
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var dx = this.tx - this.x , dy = this.ty - this.y;
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this.x = Math.abs(dx)<0.1 ? this.tx : (this.x+dx*0.1);
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this.y = Math.abs(dy)<0.1 ? this.ty : (this.y+dy*0.1);
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if(dx===0 && Math.abs(dy)<=80){
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this.dead = true;
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}
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this.paint();
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}
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}
完整代码及必要的配图
好啦，本期内容就分享到这里，我们下期见！
文章来源: sunmenglei.blog.csdn.net，作者：孙叫兽，版权归原作者所有，如需转载，请联系作者。
原文链接：sunmenglei.blog.csdn.net/article/details/122484504
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