怦然心动
今天是七夕，一个牛郎和织女鹊桥相会的日子。 还有他们的孩子也跟他们在一起。
感谢你们一直陪伴至今，我不善于表达，我对你们的感激都在这张画布里。
代码不算多，特效也不是很花哨，情人节她更在意的是你口中的甜言蜜语，这个动画是你们交流的开端。 祝愿你们心心念念的人也在念着你们，愿你们web学习一帆风顺，无往不利。
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>砰砰砰</title>
<style>
body {
background: #000800;
}
canvas {
margin: 0 auto;
display: block;
}
</style>
</head>
<body>
<canvas></canvas>
<div style="text-align:center;margin:50px 0; font:normal 14px/24px 'MicroSoft YaHei';color:#ffffff">
</body>
<script>
let canvas = document.querySelector('canvas'),
speedSelect = document.querySelector('#speed'),
width = 300,
height = 300,
ctx = canvas.getContext('2d'),
pSystemSize = 1000,
deform = {a:100, s:0.4, min:-200, max:200, dir:1}; // a=4 is natural if not animated;
const mcos = Math.cos,
msin = Math.sin,
mpow = Math.pow,
PI180=Math.PI / 180,
tau = Math.PI * 2;
canvas.width = width;
canvas.height = height;
ctx.lineWidth = 1;
const ParticleSystem = function(num){
this.scalar = 8;
this.numParticles = num;
this.allParticles = [];
this.x = width * .5;
this.y = height * .5;
this.generate();
}
ParticleSystem.prototype.generate = function(){
for(let i=0; i<this.numParticles; i ){
let vo = {};
vo.degrees = (360 / this.numParticles) * i * PI180;
vo.parent = this;
vo.x = width / 2;
vo.y = height / 2;
vo.vx = 0;
vo.vy = 0;
this.allParticles.push(new Particle(vo));
}
}
ParticleSystem.prototype.update = function(){
for(let i=0; i<this.allParticles.length; i ){
this.allParticles[i].update();
}
}
const Particle = function(vo){
this.degrees = vo.degrees;
this.parent = vo.parent;
this.x = vo.x;
this.y = vo.y;
this.vx = 0;
this.vy = 0;
this.colour = 'hsl(' (Math.round((this.degrees * (180/Math.PI)))) ',100%,50%)';
}
Particle.prototype.update = function(){
// http://mathworld.wolfram.com/HeartCurve.html
this.vx = 16 * mpow(msin(this.degrees), 3) * deform.dir;
this.vy = ((13 * mcos(this.degrees)) -
(6 * mcos(2 * this.degrees)) - // 5
(2 * mcos(3 * this.degrees)) -
(mcos(deform.a * this.degrees))) * -1;
// update position
this.x = this.vx * this.parent.scalar this.parent.x;
this.y = this.vy * this.parent.scalar this.parent.y;
}
function update(){
if(deform.dir === 1){
if(deform.a > deform.min){
deform.a -= deform.s;
}
else{
flipDirection();
}
}
else{
if(deform.a < deform.max){
deform.a = deform.s;
}
else{
flipDirection();
}
}
system.update();
}
function flipDirection(){
deform.dir *= -1;
}
function draw(){
ctx.clearRect(0, 0, width, height);
ctx.save();
for(let i=0; i<system.numParticles; i ){
let p = system.allParticles[i];
ctx.fillStyle = p.colour;
ctx.beginPath();
ctx.arc(p.x, p.y, 1, 0, tau, false);
ctx.fill();
}
ctx.restore();
}
function animate(){
update();
draw();
requestAnimationFrame(animate);
}
let system = new ParticleSystem(pSystemSize);
animate();
</script>
</html>
