Created
October 5, 2016 17:17
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<!doctype html> | |
<html lang="en"> | |
<head> | |
<meta charset="UTF-8"> | |
<meta name="viewport" | |
content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0"> | |
<meta http-equiv="X-UA-Compatible" content="ie=edge"> | |
<title>Document</title> | |
<style> | |
html, body { | |
padding: 0; | |
margin: 0; | |
} | |
div { | |
position: fixed; | |
top: 0; | |
left: 0; | |
width: 100%; | |
height: 100%; | |
z-index: 1; | |
background-image: url(test.jpg); | |
background-size: cover; | |
} | |
canvas { | |
position: fixed; | |
top: 0; | |
left: 0; | |
z-index: 10; | |
} | |
</style> | |
</head> | |
<body> | |
<div></div> | |
<canvas id="t" style="width: 100%; height: 100%"></canvas> | |
<script> | |
(() => { | |
const $cvs = document.getElementById('t'); | |
const width = $cvs.width = window.screen.availWidth; $cvs.style.width = `${width}px`; | |
const height = $cvs.height = window.screen.availHeight; $cvs.style.height = `${height}px`; | |
const ctx = $cvs.getContext('2d'); | |
const endAngle = Math.PI * 2; | |
let cols = false; | |
let rows = false; | |
let xOffset = false; | |
let yOffset = false; | |
let count = false; | |
function drawCircles(spaceBetween, R) { | |
ctx.globalCompositeOperation = 'destination-out'; | |
ctx.fillStyle = '#000'; | |
ctx.beginPath(); | |
if (!cols) { | |
cols = Math.ceil(width / spaceBetween) + 1; | |
rows = Math.ceil(height / spaceBetween); | |
xOffset = width / cols - (width - (cols * spaceBetween - 1)) / cols; | |
yOffset = height / rows - (height - (rows * spaceBetween + 1)) / rows; | |
count = cols * rows; | |
} | |
for (let i = 0; i < count; i++) { | |
const nxOffset = xOffset * (i%cols); | |
const nyOffset = yOffset * parseInt(i/cols); | |
i % cols === 0 && ctx.moveTo(nxOffset, nyOffset); | |
ctx.arc(nxOffset, nyOffset, Math.abs(Math.sin(i/count*10*Math.cos(i)) * R), 0, endAngle); | |
} | |
ctx.closePath(); | |
ctx.fill(); | |
} | |
function drawWhite() { | |
ctx.globalCompositeOperation = 'source-out'; | |
ctx.fillStyle = 'rgba(255, 255, 255, .5)'; | |
ctx.fillRect(0, 0, width, height); | |
} | |
const R = 20; | |
function animate(t) { | |
const newR = R - Math.abs(Math.sin(t/500) * R); | |
if (newR > 0) { | |
drawWhite(); | |
drawCircles(40, newR); | |
} | |
window.requestAnimationFrame(animate); | |
} | |
animate(); | |
})() | |
</script> | |
</body> | |
</html> |
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