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
项目结构
html
javascript
完整代码及必要的配图
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。
<canvas id='cas' style="background-color:rgba(0,5,24,1)">浏览器不支持canvas</canvas><div class="city"><img src="city.png" alt="" /></div><img src="moon.png" alt="" id="moon" style="visibility: hidden;"/><div style="display:none"><div class="shape">孙叫兽祝大家</div><div class="shape">2022年</div><div class="shape">新年快乐</div><div class="shape">财富自由</div><div class="shape">合家幸福</div><div class="shape">万事如意</div><div class="shape">心想事成</div><div class="shape">财源广进</div></div>javascript
主要控制文字显示的位置，文字及烟花出现的频率。
var canvas = document.getElementById("cas");var ocas = document.createElement("canvas");var octx = ocas.getContext("2d");var ctx = canvas.getContext("2d");ocas.width = canvas.width = window.innerWidth;ocas.height = canvas.height = window.innerHeight;var bigbooms = [];window.onload = function(){initAnimate()}function initAnimate(){drawBg();lastTime = new Date();animate();}var lastTime;function animate(){ctx.save();ctx.fillStyle = "rgba(0,5,24,0.1)";ctx.fillRect(0,0,canvas.width,canvas.height);ctx.restore();var newTime = new Date();if(newTime-lastTime>500+(window.innerHeight-767)/2){var random = Math.random()*100>2?true:false;var x = getRandom(canvas.width/5 , canvas.width*4/5);var y = getRandom(50 , 200);if(random){var bigboom = new Boom(getRandom(canvas.width/3,canvas.width*2/3) ,2,"#FFF" , {x:x , y:y});bigbooms.push(bigboom)}else {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))]);bigbooms.push(bigboom)}lastTime = newTime;console.log(bigbooms)}stars.foreach(function(){this.paint();})drawMoon();bigbooms.foreach(function(index){var that = this;if(!this.dead){this._move();this._drawLight();}else{this.booms.foreach(function(index){if(!this.dead) {this.moveTo(index);}else if(index === that.booms.length-1){bigbooms[bigbooms.indexOf(that)] = null;}})}});raf(animate);}function drawMoon(){var moon = document.getElementById("moon");var centerX = canvas.width-200 , centerY = 100 , width = 80;if(moon.complete){ctx.drawImage(moon , centerX , centerY , width , width )}else {moon.onload = function(){ctx.drawImage(moon ,centerX , centerY , width , width)}}var index = 0;for(var i=0;i<10;i++){ctx.save();ctx.beginPath();ctx.arc(centerX+width/2 , centerY+width/2 , width/2+index , 0 , 2*Math.PI);ctx.fillStyle="rgba(240,219,120,0.005)";index+=2;ctx.fill();ctx.restore();}}Array.prototype.foreach = function(callback){for(var i=0;i<this.length;i++){if(this[i]!==null) callback.apply(this[i] , [i])}}var raf = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function (callback) { window.setTimeout(callback, 1000 / 60); };canvas.onclick = function(){var x = event.clientX;var y = event.clientY;var bigboom = new Boom(getRandom(canvas.width/3,canvas.width*2/3) ,2,"#FFF" , {x:x , y:y});bigbooms.push(bigboom)}// canvas.addEventLisener("touchstart" , function(event){// var touch = event.targetTouches[0];// var x = event.pageX;// var y = event.pageY;// var bigboom = new Boom(getRandom(canvas.width/3,canvas.width*2/3) ,2,"#FFF" , {x:x , y:y});// bigbooms.push(bigboom)// })var Boom = function(x,r,c,boomArea,shape){this.booms = [];this.x = x;this.y = (canvas.height+r);this.r = r;this.c = c;this.shape = shape || false;this.boomArea = boomArea;this.theta = 0;this.dead = false;this.ba = parseInt(getRandom(80 , 100));}Boom.prototype = {_paint:function(){ctx.save();ctx.beginPath();ctx.arc(this.x,this.y,this.r,0,2*Math.PI);ctx.fillStyle = this.c;ctx.fill();ctx.restore();},_move:function(){var dx = this.boomArea.x - this.x , dy = this.boomArea.y - this.y;this.x = this.x+dx*0.01;this.y = this.y+dy*0.01;if(Math.abs(dx)<=this.ba && Math.abs(dy)<=this.ba){if(this.shape){this._shapBoom();}else this._boom();this.dead = true;}else {this._paint();}},_drawLight:function(){ctx.save();ctx.fillStyle = "rgba(255,228,150,0.3)";ctx.beginPath();ctx.arc(this.x , this.y , this.r+3*Math.random()+1 , 0 , 2*Math.PI);ctx.fill();ctx.restore();},_boom:function(){var fragNum = getRandom(30 , 200);var style = getRandom(0,10)>=5? 1 : 2;var color;if(style===1){color = {a:parseInt(getRandom(128,255)),b:parseInt(getRandom(128,255)),c:parseInt(getRandom(128,255))}}var fanwei = parseInt(getRandom(300, 400));for(var i=0;i<fragNum;i++){if(style===2){color = {a:parseInt(getRandom(128,255)),b:parseInt(getRandom(128,255)),c:parseInt(getRandom(128,255))}}var a = getRandom(-Math.PI, Math.PI);var x = getRandom(0, fanwei) * Math.cos(a) + this.x;var y = getRandom(0, fanwei) * Math.sin(a) + this.y; var radius = getRandom(0 , 2)var frag = new Frag(this.x , this.y , radius , color , x , y );this.booms.push(frag);}},_shapBoom:function(){var that = this;putValue(ocas , octx , this.shape , 5, function(dots){var dx = canvas.width/2-that.x;var dy = canvas.height/2-that.y;for(var i=0;i<dots.length;i++){color = {a:dots[i].a,b:dots[i].b,c:dots[i].c}var x = dots[i].x;var y = dots[i].y;var radius = 1;var frag = new Frag(that.x , that.y , radius , color , x-dx , y-dy);that.booms.push(frag);}})}}function putValue(canvas , context , ele , dr , callback){context.clearRect(0,0,canvas.width,canvas.height);var img = new Image();if(ele.innerHTML.indexOf("img")>=0){img.src = ele.getElementsByTagName("img")[0].src;imgload(img , function(){context.drawImage(img , canvas.width/2 - img.width/2 , canvas.height/2 - img.width/2);dots = getimgData(canvas , context , dr);callback(dots);})}else {var text = ele.innerHTML;context.save();var fontSize =200;context.font = fontSize+"px 宋体 bold";context.textAlign = "center";context.textBaseline = "middle";context.fillStyle = "rgba("+parseInt(getRandom(128,255))+","+parseInt(getRandom(128,255))+","+parseInt(getRandom(128,255))+" , 1)";context.fillText(text , canvas.width/2 , canvas.height/2);context.restore();dots = getimgData(canvas , context , dr);callback(dots);}}function imgload(img , callback){if(img.complete){callback.call(img);}else {img.onload = function(){callback.call(this);}}}function getimgData(canvas , context , dr){var imgData = context.getImageData(0,0,canvas.width , canvas.height);context.clearRect(0,0,canvas.width , canvas.height);var dots = [];for(var x=0;x<imgData.width;x+=dr){for(var y=0;y<imgData.height;y+=dr){var i = (y*imgData.width + x)*4;if(imgData.data[i+3] > 128){var dot = {x:x , y:y , a:imgData.data[i] , b:imgData.data[i+1] , c:imgData.data[i+2]};dots.push(dot);}}}return dots;}function getRandom(a , b){return Math.random()*(b-a)+a;}var maxRadius = 1 , stars=[];function drawBg(){for(var i=0;i<100;i++){var r = Math.random()*maxRadius;var x = Math.random()*canvas.width;var y = Math.random()*2*canvas.height - canvas.height;var star = new Star(x , y , r);stars.push(star);star.paint()}}var Star = function(x,y,r){this.x = x;this.y=y;this.r=r;}Star.prototype = {paint:function(){ctx.save();ctx.beginPath();ctx.arc(this.x , this.y , this.r , 0 , 2*Math.PI);ctx.fillStyle = "rgba(255,255,255,"+this.r+")";ctx.fill();ctx.restore();}}var focallength = 250;var Frag = function(centerX , centerY , radius , color ,tx , ty){this.tx = tx;this.ty = ty;this.x = centerX;this.y = centerY;this.dead = false;this.centerX = centerX;this.centerY = centerY;this.radius = radius;this.color = color;}Frag.prototype = {paint:function(){ctx.save();ctx.beginPath();ctx.arc(this.x , this.y , this.radius , 0 , 2*Math.PI);ctx.fillStyle = "rgba("+this.color.a+","+this.color.b+","+this.color.c+",1)";ctx.fill()ctx.restore();},moveTo:function(index){this.ty = this.ty+0.3;var dx = this.tx - this.x , dy = this.ty - this.y;this.x = Math.abs(dx)<0.1 ? this.tx : (this.x+dx*0.1);this.y = Math.abs(dy)<0.1 ? this.ty : (this.y+dy*0.1);if(dx===0 && Math.abs(dy)<=80){this.dead = true;}this.paint();}}完整代码及必要的配图
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