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| <!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>元宵节快乐</title>
<style>
body { padding: 0; margin: 0; overflow: hidden; background-color: #000;
}
canvas { padding: 0; margin: 0; }
footer{
text-align:center;
}
footer h2{
color:#FFFF00;
font-size:12px;
}
</style>
<script type="text/javascript">
var PI = Math.PI;
var PI_2 = PI * 2;
var defaultConfig = {
duration: 2000,
delay: 0,
radius: 5,
amount: 100,
speed: 12,
gravity: 0.05,
friction: 0.96,
reduction: 0.98,
left: 0.5,
top: 0.3,
color: "#ff0000"
};
window.addEventListener("load",
function() {
try{
Canvas.canvas = document.querySelector("canvas");
Canvas.canvas.width = document.documentElement.clientWidth;
Canvas.canvas.height = document.documentElement.clientHeight - 40;
Canvas.context = Canvas.canvas.getContext("2d");
Canvas.context.fillStyle = "rgba(0, 0, 0, 0.05)";
}catch(e){
document.querySelector("h2").text = "您的浏览器暂不支持，请升级后观看！";
}
var num = 20;
for (var i = 0; i < num; i++) {
Canvas.add(new Firework({
duration: 800,
delay: 50 * i,
amount: 20,
left: 1 / num * i,
top: 0.3,
gravity: 0.5,
reduction: 1,
radius: 2,
friction: 0.9,
speed: 15,
color: "#ff6"
}));
}
Canvas.start();
},
false);
function Firework(config) {
this.setConfig(config || {});
this.particleImage = createParticleImage(this.radius, this.color);
this.diameter = this.radius * 2;
this.isActive = true;
this.fadeoutOpacity = 1;
}
Firework.prototype = {
setConfig: function(config) {
for (var key in defaultConfig) {
if (config[key] === undefined) {
this[key] = defaultConfig[key];
} else {
this[key] = config[key];
}
}
},
initParticles: function() {
this.particles = [];
var x = this.canvas.width * this.left;
var y = this.canvas.height * this.top;
var maxSpeed = (this.speed / 2) * (this.speed / 2);
while (this.particles.length < this.amount) {
var vx = (Math.random() - 0.5) * this.speed;
var vy = (Math.random() - 0.5) * this.speed;
if (vx * vx + vy * vy <= maxSpeed) {
this.particles.push(new Particle(x, y, vx, vy));
}
}
},
update: function(passed) {
if (this.isActive === false || this.started(passed) === false) return;
if (this.ended(passed)) {
this.fadeout();
return;
}
this.move();
this.render();
},
move: function() {
var particles = this.particles;
var particle;
for (var i = 0,
len = particles.length; i < len; i++) {
particle = particles[i];
particle.vx *= this.friction;
particle.vy = particle.vy * this.friction + this.gravity;
particle.x += particle.vx;
particle.y += particle.vy;
}
},
render: function() {
this.context.globalAlpha = 1;
this.renderParticles();
},
renderParticles: function() {
var diameter = this.diameter *= this.reduction;
var context = this.context;
var particles = this.particles;
var particleImage = this.particleImage;
var p;
for (var i = 0,
len = particles.length; i < len; i++) {
p = particles[i];
context.drawImage(particleImage, p.x, p.y, diameter, diameter);
}
},
started: function(passed) {
return this.delay < passed;
},
ended: function(passed) {
return this.duration + this.delay < passed;
},
fadeout: function() {
this.fadeoutOpacity -= 0.1;
if (this.fadeoutOpacity <= 0) {
this.isActive = false;
return;
}
this.move();
this.context.globalAlpha = this.fadeoutOpacity;
this.renderParticles();
}
};
function Particle(x, y, vx, vy) {
this.x = x;
this.y = y;
this.vx = vx;
this.vy = vy;
}
var Canvas = {
fireworks: [],
add: function(firework) {
firework.canvas = this.canvas;
firework.context = this.context;
firework.initParticles();
this.fireworks.push(firework);
},
start: function() {
this.startTime = Number(new Date());
this.update();
},
fill: function() {
this.context.globalAlpha = 1;
this.context.fillRect(0, 0, this.canvas.width, this.canvas.height);
},
update: function() {
this.fill();
var passed = new Date() - this.startTime;
var activeFireworkCount = 0;
this.fireworks.forEach(function(firework) {
if (firework.isActive) {
firework.update(passed);
activeFireworkCount++;
}
}.bind(this));
if (0 < activeFireworkCount) {
requestAnimationFrame(this.update.bind(this));
} else {
requestAnimationFrame(this.fadeout.bind(this, 20));
}
},
fadeout: function(count) {
if (count < 0) {
this.context.fillStyle = "black";
this.context.fillRect(0, 0, this.canvas.width, this.canvas.height);
drawText();
return;
}
this.context.globalAlpha = 1;
this.context.fillStyle = "rgba(0, 0, 0, 0.15)";
this.fill();
requestAnimationFrame(this.fadeout.bind(this, count - 1));
}
};
function drawText(){
setInterval(exupdate, 1000 / 60);
}
if (Function.prototype.bind === undefined) {
Function.prototype.bind = function(obj) {
var slice = [].slice,
args = slice.call(arguments, 1),
self = this,
bound = function() {
return self.apply(obj || window, args.concat(slice.call(arguments)));
};
bound.prototype = this.prototype;
return bound;
};
}
function createParticleImage(radius, color) {
var size = radius * 2;
var canvas = document.createElement("canvas");
canvas.width = canvas.height = size;
var context = canvas.getContext("2d");
var gradient = context.createRadialGradient(radius, radius, 0, radius, radius, size);
gradient.addColorStop(0, "white");
gradient.addColorStop(0.1, "white");
gradient.addColorStop(0.3, color);
gradient.addColorStop(1, "rgba(0, 0, 0, 0)");
context.fillStyle = gradient;
context.beginPath();
context.arc(radius, radius, radius, 0, PI_2, true);
context.fill();
var particle = new Image();
particle.src = canvas.toDataURL();
return particle;
}
(function(w, r) {
w['r' + r] = w['r' + r] || w['webkitR' + r] || w['mozR' + r] || w['msR' + r] || w['oR' + r] ||
function(c) {
w.setTimeout(c, 1000 / 60);
};
})(window, 'equestAnimationFrame');
function exupdate() {
var canvas = document.getElementById("firework");
var cxt = canvas.getContext("2d");
var width = document.documentElement.clientWidth;
var height = document.documentElement.clientHeight;
if (Math.random() < 0.1) {
explode(Math.random() * width, Math.random() * height, randomColor());
}
cxt.clearRect(0, 0, width, height);
for (var i = particles.length - 1; i >= 0; i--) {
var p = particles[i];
p.vx *= p.deceleration;
p.vy *= p.deceleration;
p.vy += p.gravity;
p.x += p.vx;
p.y += p.vy;
p.energy *= p.deceleration;
p.a = Math.atan2(p.vy, p.vx);
p.tx = p.x + p.length * Math.cos(p.a);
p.ty = p.y + p.length * Math.sin(p.a);
if (p.energy < 0.05) {
particles.splice(i, 1);
} else {
cxt.beginPath();
cxt.fillStyle = p.color;
cxt.fillRect(p.x, p.y, p.tx - p.x, p.ty - p.y);
cxt.fill();
cxt.stroke();
cxt.closePath();
}
}
var x = parseInt(width)/2;
var y = parseInt(height)/2
cxt.font = "60px 宋体 bold";
cxt.textAlign = 'center';
cxt.fillStyle = colors[parseInt(cIndex)%25];
cxt.fillText('元宵节快乐！', x, y, 400);
if(timeTick >10){
cIndex = parseInt(cIndex) + 1;
timeTick = 0;
}
timeTick = parseInt(timeTick) + 1;
}
var colors = ["#fff","#ccc","#ff0000","#00ff00","#0000ff","#00ffff","#ffff00","#FF7F00","#FF1493","#9B30FF","#9AFF9A",
"#FFC1C1","#FFE1FF","#8B7B8B","#8B6969","#548B54","#551A8B","#8B0A50","#8B4500","#8b8b00","#008b8b","#00008b",
"#008b00","#8b0000","#666","#000"];
var cIndex = 0;
var timeTick = 0;
var particles = [];
function explode(x, y, color) {
var c = 400;
while (c-- >0 ) {
var p = {};
p.energy = Math.random() * 5;
var angle = Math.random() * Math.PI * 2;
var v = Math.random() * 10;
p.vx = Math.cos(angle) * v;
p.vy = Math.sin(angle) * v;
p.x = x;
p.y = y;
p.color = color;
p.deceleration = 0.95;
p.gravity = 0.05;
p.length = 4;
particles.push(p);
}
}
function randomColor() {
return "#" + parseInt(Math.random()*9) + "" + parseInt(Math.random()*9) + ""
+ parseInt(Math.random()*9) + "" + parseInt(Math.random()*9) + ""
+ parseInt(Math.random()*9) + "" + parseInt(Math.random()*9);
}
</script>
</head>
<body>
<canvas id="firework">
</canvas>
<footer>
</footer>
</body>
</html>
|
