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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>
</head>
<body style="background: #000;width: 100%;height: 100%">
<div style="height:500px" id="smarts"></div>
</body>
<script>
circleMagic();
function circleMagic(options) {
let width;
let height;
let canvas;
let ctx;
let animateHeader = true;
const circles = [];
const settings = options || {
color: "rgba(255,255,255,.5)",
radius: 10,
density: 0.3,
clearOffset: 0.2,
};
const container = document.getElementById("smarts");
initContainer();
addListeners();
function initContainer() {
width = container.offsetWidth;
height = container.offsetHeight - 120;
initCanvas();
canvas = document.getElementById("homeTopCanvas");
canvas.width = width;
canvas.height = height;
canvas.style.position = "absolute";
canvas.style.left = "0";
canvas.style.bottom = "0";
ctx = canvas.getContext("2d");
for (let x = 0; x < width * settings.density; x++) {
const c = new Circle();
circles.push(c);
}
animate();
}
function initCanvas() {
const canvasElement = document.createElement("canvas");
canvasElement.id = "homeTopCanvas";
canvasElement.style.pointerEvents = "none";
container.appendChild(canvasElement);
canvasElement.parentElement.style.overflow = "hidden";
}
function addListeners() {
window.addEventListener("scroll", scrollCheck, false);
window.addEventListener("resize", resize, false);
}
function scrollCheck() {
if (document.body.scrollTop > height) {
animateHeader = false;
} else {
animateHeader = true;
}
}
function resize() {
width = container.clientWidth;
height = container.clientHeight;
container.height = height + "px";
canvas.width = width;
canvas.height = height;
}
function animate() {
if (animateHeader) {
ctx.clearRect(0, 0, width, height);
for (const i in circles) {
circles[i].draw();
}
}
requestAnimationFrame(animate);
}
function randomColor() {
const r = Math.floor(Math.random() * 255);
const g = Math.floor(Math.random() * 255);
const b = Math.floor(Math.random() * 255);
const alpha = Math.random().toPrecision(2);
return "rgba(" + r + ", " + g + ", " + b + ", " + alpha + ")";
}
function Circle() {
const that = this;
(function () {
that.pos = {};
init();
})();
function init() {
that.pos.x = Math.random() * width;
that.pos.y = height + Math.random() * 100;
that.alpha = 0.1 + Math.random() * settings.clearOffset;
that.scale = 0.1 + Math.random() * 0.3;
that.speed = Math.random();
if (settings.color === "random") {
that.color = randomColor();
} else {
that.color = settings.color;
}
}
this.draw = function () {
if (that.alpha <= 0) {
init();
}
that.pos.y -= that.speed;
that.alpha -= 0.0005;
ctx.beginPath();
ctx.arc(
that.pos.x,
that.pos.y,
that.scale * settings.radius,
0,
2 * Math.PI,
false
);
ctx.fillStyle = that.color;
ctx.fill();
ctx.closePath();
};
}
}
</script>
</html>
|
