创建一个背景粒子特效需要综合运用HTML5、CSS3和JavaScript。以下是一个简单的示例，演示如何使用HTML5的<canvas>元素和JavaScript来创建一个粒子动画背景。
HTML
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>粒子特效背景</title>
<link rel="stylesheet" href="styles.css">
</head>
<body>
<canvas id="particleCanvas"></canvas>
<script src="script.js"></script>
</body>
</html>
CSS (styles.css)
body, html {
margin: 0;
padding: 0;
overflow: hidden;
width: 100%;
height: 100%;
}
canvas {
position: absolute;
top: 0;
left: 0;
}
JavaScript (script.js)
const canvas = document.getElementById('particleCanvas');
const ctx = canvas.getContext('2d');
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
class Particle {
constructor() {
this.x = Math.random() * canvas.width;
this.y = Math.random() * canvas.height;
this.size = Math.random() * 5 + 1;
this.speedX = (Math.random() - 0.5) * 4;
this.speedY = (Math.random() - 0.5) * 4;
}
draw() {
ctx.fillStyle = 'rgba(173,216,230, 0.8)';
ctx.strokeStyle = 'rgba(173,216,230, 0.8)';
ctx.lineWidth = 2;
ctx.beginPath();
ctx.arc(this.x, this.y, this.size, 0, Math.PI * 2);
ctx.closePath();
ctx.fill();
}
update() {
this.x += this.speedX;
this.y += this.speedY;
if (this.x < 0 || this.x > canvas.width || this.y < 0 || this.y > canvas.height) {
this.x = Math.random() * canvas.width;
this.y = Math.random() * canvas.height;
}
}
}
const particles = [];
for (let i = 0; i < 100; i++) {
particles.push(new Particle());
}
function animate() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
for (let i = 0; i < particles.length; i++) {
particles[i].draw();
particles[i].update();
}
requestAnimationFrame(animate);
}
animate();
window.addEventListener('resize', () => {
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
});
这段代码创建了一个包含100个粒子的系统，每个粒子都有自己的位置、大小和速度。粒子在画布上移动，并在碰到画布边缘时重新定位到随机位置。通过调整粒子的属性（如颜色、大小和速度），你可以自定义动画的外观和行为。
标签：特效,canvas,粒子,random,ctx,height,width,html5,Math From： https://www.cnblogs.com/ai888/p/18629472