基于HTML5 Canvas与粒子特效的520表白程序实现

核心代码结构分析

<!DOCTYPE html>
<html>
 <head>
  <meta charset="utf-8">
  <title>520</title>
  <style>
  html, body{padding:0px; margin:0px; background:#222; font-family: 'Karla', sans-serif; color:#FFF; height:100%; overflow:hidden;}
  canvas {width:100%; height:100%;}
  #text,#text_520{font-family:'楷体'; color:rgb(255,255,3); font-size:20px; position:fixed; left:10%; top:10%;}
  #text_520{font-size:100px; top:50%; left:50%;}
  img{position:fixed; top:0; left:0; width:100%;}
  #last{font-size:12px; bottom:10px; left:50%; position:fixed;}
  /*
  @keyframes drop {
   0% { 
    transform: translateY(-100px);
    opacity: 0;
   }
   90% {
    opacity: 1;
    transform:translateY(10px);
   }
   100% {
    transform:translateY(0px;)
   }
  }
  */
  </style>
 </head>
 <body>
  <canvas id="c"></canvas>
  <div id="text"></div>
  <div id="text_520">5 2 0</div>
  <img src="./timg.jpg" class="img" />
  <div id="last">版权所有：李晓珂</div>
  <script type="text/javascript" src="./jquery-1.11.0.min.js"></script>
  <script type="text/javascript">
   function isIE(){
    var u = navigator.userAgent;
    if((u.indexOf("compatible") > -1 && u.indexOf("MSIE") > -1) || (u.indexOf("Trident") > -1 && u.indexOf("rv:11.0") > -1)){
     alert("该浏览器暂不支持，请更换浏览器");
     window.open('','_self'); 
     window.close();
    }
    var audio = document.createElement("audio");
     audio.setAttribute("src","./520-love.mp3");
     audio.setAttribute("autoplay","autoplay");
   }
   isIE();
  </script>
  <script type="text/javascript">
    var textArr = [
     'I love three things in this world,',
     'the sun ,the moon and you.',
     'The sun for the day,',
     'the moon for the night,',
     'and you forever!',
     '',
     'If you were a teardrop,',
     'in my eye,',
     'for fear of losing you,',
     'I would never cry.',
     'And if the golden sun,',
     'should cease to shine its light,',
     'just one smile from you,',
     'would make my whole world bright.'
    ];
    var text_520 = document.getElementById('text_520');
    var height = (window.innerHeight - text_520.offsetHeight) / 2;
    var width = (window.innerWidth - text_520.offsetWidth) / 2;
    text_520.style.top = height + 'px';
    text_520.style.left = width + 'px';
    $('#text_520').hide();
    $('.img').hide();
    var m = 0;
    var n = 0;
    var text = document.getElementById('text');
    function typing(){
     if(m <= textArr[n].length) {
      text.innerHTML = text.innerHTML.substring(0,text.innerHTML.length-1) + textArr[n].substr(m++,1) + '_';
      setTimeout(typing,250);
     }else {
      if(n < textArr.length-1){
       text.innerHTML = text.innerHTML.substring(0,text.innerHTML.length-1) + "<br />_";
       n++;
       m = 0;
       typing();
      }else {
       text.innerHTML = text.innerHTML.substring(0,text.innerHTML.length-1);
       $('#text').fadeOut(5000);
       setTimeout(function(){$('#text_520').fadeIn(5000);},7000);
       setTimeout(function(){$('#text_520').fadeOut(5000); },7000);
       setTimeout(function(){$('.img').fadeIn(50000);},15000)
      }
     }
    }
    setTimeout(typing,5000);
   var ctx = document.querySelector('canvas').getContext('2d');
    ctx.canvas.width = window.innerWidth;
    ctx.canvas.height = window.innerHeight;
   var sparks = [];
   var fireworks = [];
   var walker;
   fireworks.pop();
   var i = 10;
   while(i--) fireworks.push(new Firework(Math.random()*window.innerWidth, window.innerHeight*Math.random()));
   // setInterval(render, 1000/50);
   render();
   function render() {
    setTimeout(render, 1000/50);
    ctx.fillStyle = 'rgba(0, 0, 0, 0.2)';
    ctx.fillRect(0, 0, ctx.canvas.width, ctx.canvas.height);
    // 上升效果
    for(var firework of fireworks) {
     if(firework.dead) continue;
     firework.move();
     firework.draw();
    }
    // 绽放效果
    for(var spark of sparks) {
     if(spark.dead) continue;
     spark.move();
     spark.draw();
    }
    if(Math.random() < 0.1) fireworks.push(new Firework());
    //ctx.height = ctx.height;
   }
   function Spark(x, y, color) {
    this.x = x;
    this.y = y;
    this.dir = Math.random() * (Math.PI*2);
    this.dead = false;
    this.color = color;
    this.speed = Math.random() * 3 + 3;
    walker = new Walker({ radius: 20, speed: 0.25 });
    this.gravity = 0.25;
    this.dur = this.speed / 0.15;
    this.move = function() {
     this.dur--;
     if(this.dur < 0) this.dead = true;
     if(this.speed < 0) return;
     if(this.speed > 0) this.speed -= 0.15;
     walk = walker.step();
     this.x += Math.cos(this.dir + walk) * this.speed;
     this.y += Math.sin(this.dir + walk) * this.speed;
     this.y += this.gravity;
     this.gravity += 0.05;
    }
    this.draw = function() {
     drawCircle(this.x, this.y, 2, this.color);
    }
   }
   function Firework(x, y) {
    this.xmove = Math.random()*2 - 1;
    this.x = x || Math.random() * ctx.canvas.width;
    this.y = y || ctx.canvas.height;
    this.height = Math.random()*ctx.canvas.height/2;
    this.dead = false;
    this.color = randomColor();
    this.move = function() {
     this.x += this.xmove;
     if(this.y > this.height) this.y -= 4; 
     else this.burst();
    }
    this.draw = function() {
     drawCircle(this.x, this.y, 3, this.color)
    }
    this.burst = function() {
     this.dead = true
     i = 100; while(i--) sparks.push(new Spark(this.x, this.y, this.color));
     sparks.pop();
    }
   }
   setTimeout(function (){window.open('','_self').close();},175000);
/*
   // 清除两个数组
   function clear(){
    if(sparks!=null || fireworks!=null){
     sparks.pop();
     fireworks.pop();
    }
    var sparks = [];
    var fireworks = [];
   }
   setInterval(clear,100);
    */
   function drawCircle(x, y, radius, color) {
    color = color || '#FFF';
    ctx.fillStyle = color;
    ctx.fillRect(x-radius/2, y-radius/2, radius, radius);
   }
   function randomColor(){
    return ['#6ae5ab','#88e3b2','#36b89b','#7bd7ec','#66cbe1'][Math.floor(Math.random() * 5)];
   }
   function Walker(options){
    this.step = function(){
     this.direction = Math.sign(this.target) * this.speed
     this.value += this.direction
     this.target
      ? this.target -= this.direction
      : (this.value)
      ? (this.wander) 
       ? this.target = this.newTarget() 
       : this.target = -this.value
      : this.target = this.newTarget() 
     return this.direction
    }
    this.newTarget = function() {
     return Math.round(Math.random()*(this.radius*2)-this.radius)
    }
    this.start = 0
    this.value = 0
    this.radius = options.radius
    this.target = this.newTarget()
    this.direction = Math.sign(this.target)
    this.wander = options.wander
    this.speed = options.speed || 1
   }
  </script>
 </body>
</html>