爱心背景特效

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Happy Valentine's Day everyone !</title>
</head>
<style>
body{
overflow: hidden;
margin: 0;
}
h1{
position: fixed;
top: 50%;
left: 0;
width: 100%;
text-align: center;
transform:translateY(-50%);
font-family: 'Love Ya Like A Sister', cursive;
font-size: 40px;
color: #c70012;
padding: 0 20px;
}
@media (min-1200px){
h1{
font-size: 60px;
}
}
</style>
<body>
<canvas></canvas>
<h1>canvas heart</h1>

<script>
var canvas = document.querySelector("canvas"),
ctx = canvas.getContext("2d");

var ww,wh;

function onResize(){
ww = canvas.width = window.innerWidth;
wh = canvas.height = window.innerHeight;
}
ctx.strokeStyle = "red";
ctx.shadowBlur = 25;
ctx.shadowColor = "hsla(0, 100%, 60%,0.5)";
var precision = 100;
var hearts = [];
var mouseMoved = false;
function onMove(e){
mouseMoved = true;
if(e.type === "touchmove"){
hearts.push(new Heart(e.touches[0].clientX, e.touches[0].clientY));
hearts.push(new Heart(e.touches[0].clientX, e.touches[0].clientY));
}
else{
hearts.push(new Heart(e.clientX, e.clientY));
hearts.push(new Heart(e.clientX, e.clientY));
}
}
var Heart = function(x,y){
this.x = x || Math.random()*ww;
this.y = y || Math.random()*wh;
this.size = Math.random()*2 + 1;
this.shadowBlur = Math.random() * 10;
this.speedX = (Math.random()+0.2-0.6) * 8;
this.speedY = (Math.random()+0.2-0.6) * 8;
this.speedSize = Math.random()*0.05 + 0.01;
this.opacity = 1;
this.vertices = [];
for (var i = 0; i < precision; i++) {
var step = (i / precision - 0.5) * (Math.PI * 2);
var vector = {
x : (15 * Math.pow(Math.sin(step), 3)),
y : -(13 * Math.cos(step) - 5 * Math.cos(2 * step) - 2 * Math.cos(3 * step) - Math.cos(4 * step))
}
this.vertices.push(vector);
}
}
Heart.prototype.draw = function(){
this.size -= this.speedSize;
this.x += this.speedX;
this.y += this.speedY;
ctx.save();
ctx.translate(-1000,this.y);
ctx.scale(this.size, this.size);
ctx.beginPath();
for (var i = 0; i < precision; i++) {
var vector = this.vertices[i];
ctx.lineTo(vector.x, vector.y);
}
ctx.globalAlpha = this.size;
ctx.shadowBlur = Math.round((3 - this.size) * 10);
ctx.shadowColor = "hsla(0, 100%, 60%,0.5)";
ctx.shadowOffsetX = this.x + 1000;
ctx.globalCompositeOperation = "screen"
ctx.closePath();
ctx.fill()
ctx.restore();
};

function render(a){
requestAnimationFrame(render);

hearts.push(new Heart())
ctx.clearRect(0,0,ww,wh);
for (var i = 0; i < hearts.length; i++) {
hearts[i].draw();
if(hearts[i].size <= 0){
hearts.splice(i,1);
i--;
}
}
}
onResize();
window.addEventListener("mousemove", onMove);
window.addEventListener("touchmove", onMove);
window.addEventListener("resize", onResize);
requestAnimationFrame(render);
</script>
</body>
</html>
原文地址:https://www.cnblogs.com/feiyu159/p/7525953.html