html爱心特效代码

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html爱心特效代码

<!DOCTYPE HTML PUBLIC “-//W3C//DTD HTML 4.0 Transitional//EN”>
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<META NAME=”Generator” CONTENT=”EditPlus”>
<META NAME=”Author” CONTENT=””>
<META NAME=”Keywords” CONTENT=””>
<META NAME=”Description” CONTENT=””>
<style>
html, body {

height: 100%;
padding: 0;
margin: 0;
background: #000;
}
canvas {

position: absolute;
width: 100%;
height: 100%;
}
</style>
</HEAD>

<BODY>
<canvas id=”pinkboard”></canvas>
<script>
/*
* Settings
*/
var settings = {

particles: {

length: 500, // maximum amount of particles
duration: 2, // particle duration in sec
velocity: 100, // particle velocity in pixels/sec
effect: -0.75, // play with this for a nice effect
size: 30, // particle size in pixels
},
};

/*
* RequestAnimationFrame polyfill by Erik Möller
*/
(function(){var b=0;var c=[“ms”,”moz”,”webkit”,”o”];for(var a=0;a<c.length&&!window.requestAnimationFrame;++a){window.requestAnimationFrame=window[c[a]+”RequestAnimationFrame”];window.cancelAnimationFrame=window[c[a]+”CancelAnimationFrame”]||window[c[a]+”CancelRequestAnimationFrame”]}if(!window.requestAnimationFrame){window.requestAnimationFrame=function(h,e){var d=new Date().getTime();var f=Math.max(0,16-(d-b));var g=window.setTimeout(function(){h(d+f)},f);b=d+f;return g}}if(!window.cancelAnimationFrame){window.cancelAnimationFrame=function(d){clearTimeout(d)}}}());

/*
* Point class
*/
var Point = (function() {

function Point(x, y) {

this.x = (typeof x !== ‘undefined’) ? x : 0;
this.y = (typeof y !== ‘undefined’) ? y : 0;
}
Point.prototype.clone = function() {

return new Point(this.x, this.y);
};
Point.prototype.length = function(length) {

if (typeof length == ‘undefined’)
return Math.sqrt(this.x * this.x + this.y * this.y);
this.normalize();
this.x *= length;
this.y *= length;
return this;
};
Point.prototype.normalize = function() {

var length = this.length();
this.x /= length;
this.y /= length;
return this;
};
return Point;
})();

/*
* Particle class
*/
var Particle = (function() {

function Particle() {

this.position = new Point();
this.velocity = new Point();
this.acceleration = new Point();
this.age = 0;
}
Particle.prototype.initialize = function(x, y, dx, dy) {

this.position.x = x;
this.position.y = y;
this.velocity.x = dx;
this.velocity.y = dy;
this.acceleration.x = dx * settings.particles.effect;
this.acceleration.y = dy * settings.particles.effect;
this.age = 0;
};
Particle.prototype.update = function(deltaTime) {

this.position.x += this.velocity.x * deltaTime;
this.position.y += this.velocity.y * deltaTime;
this.velocity.x += this.acceleration.x * deltaTime;
this.velocity.y += this.acceleration.y * deltaTime;
this.age += deltaTime;
};
Particle.prototype.draw = function(context, image) {

function ease(t) {

return (–t) * t * t + 1;
}
var size = image.width * ease(this.age / settings.particles.duration);
context.globalAlpha = 1 – this.age / settings.particles.duration;
context.drawImage(image, this.position.x – size / 2, this.position.y – size / 2, size, size);
};
return Particle;
})();

/*
* ParticlePool class
*/
var ParticlePool = (function() {

var particles,
firstActive = 0,
firstFree = 0,
duration = settings.particles.duration;

function ParticlePool(length) {

// create and populate particle pool
particles = new Array(length);
for (var i = 0; i < particles.length; i++)
particles[i] = new Particle();
}
ParticlePool.prototype.add = function(x, y, dx, dy) {

particles[firstFree].initialize(x, y, dx, dy);

// handle circular queue
firstFree++;
if (firstFree == particles.length) firstFree = 0;
if (firstActive == firstFree ) firstActive++;
if (firstActive == particles.length) firstActive = 0;
};
ParticlePool.prototype.update = function(deltaTime) {

var i;

// update active particles
if (firstActive < firstFree) {

for (i = firstActive; i < firstFree; i++)
particles[i].update(deltaTime);
}
if (firstFree < firstActive) {

for (i = firstActive; i < particles.length; i++)
particles[i].update(deltaTime);
for (i = 0; i < firstFree; i++)
particles[i].update(deltaTime);
}

// remove inactive particles
while (particles[firstActive].age >= duration && firstActive != firstFree) {

firstActive++;
if (firstActive == particles.length) firstActive = 0;
}


};
ParticlePool.prototype.draw = function(context, image) {

// draw active particles
if (firstActive < firstFree) {

for (i = firstActive; i < firstFree; i++)
particles[i].draw(context, image);
}
if (firstFree < firstActive) {

for (i = firstActive; i < particles.length; i++)
particles[i].draw(context, image);
for (i = 0; i < firstFree; i++)
particles[i].draw(context, image);
}
};
return ParticlePool;
})();

/*
* Putting it all together
*/
(function(canvas) {

var context = canvas.getContext(‘2d’),
particles = new ParticlePool(settings.particles.length),
particleRate = settings.particles.length / settings.particles.duration, // particles/sec
time;

// get point on heart with -PI <= t <= PI
function pointOnHeart(t) {

return new Point(
160 * Math.pow(Math.sin(t), 3),
130 * Math.cos(t) – 50 * Math.cos(2 * t) – 20 * Math.cos(3 * t) – 10 * Math.cos(4 * t) + 25
);
}

// creating the particle image using a dummy canvas
var image = (function() {

var canvas = document.createElement(‘canvas’),
context = canvas.getContext(‘2d’);
canvas.width = settings.particles.size;
canvas.height = settings.particles.size;
// helper function to create the path
function to(t) {

var point = pointOnHeart(t);
point.x = settings.particles.size / 2 + point.x * settings.particles.size / 350;
point.y = settings.particles.size / 2 – point.y * settings.particles.size / 350;
return point;
}
// create the path
context.beginPath();
var t = -Math.PI;
var point = to(t);
context.moveTo(point.x, point.y);
while (t < Math.PI) {

t += 0.01; // baby steps!
point = to(t);
context.lineTo(point.x, point.y);
}
context.closePath();
// create the fill
context.fillStyle = ‘#ea80b0’;
context.fill();
// create the image
var image = new Image();
image.src = canvas.toDataURL();
return image;
})();

// render that thing!
function render() {

// next animation frame
requestAnimationFrame(render);

// update time
var newTime = new Date().getTime() / 1000,
deltaTime = newTime – (time || newTime);
time = newTime;

// clear canvas
context.clearRect(0, 0, canvas.width, canvas.height);

// create new particles
var amount = particleRate * deltaTime;
for (var i = 0; i < amount; i++) {

var pos = pointOnHeart(Math.PI – 2 * Math.PI * Math.random());
var dir = pos.clone().length(settings.particles.velocity);
particles.add(canvas.width / 2 + pos.x, canvas.height / 2 – pos.y, dir.x, -dir.y);
}

// update and draw particles
particles.update(deltaTime);
particles.draw(context, image);
}

// handle (re-)sizing of the canvas
function onResize() {

canvas.width = canvas.clientWidth;
canvas.height = canvas.clientHeight;
}
window.onresize = onResize;

// delay rendering bootstrap
setTimeout(function() {

onResize();
render();
}, 10);
})(document.getElementById(‘pinkboard’));
</script>
</BODY>
</HTML>