黑客帝国中的经典代码雨场景一直是许多开发者心中的梦想。在本文中，我将带大家一步步使用 HTML5 的 Canvas 技术来实现这个特效，并且额外加入一个控制面板，方便实时调整颜色、速度、字体大小等参数。
效果预览
- 绿色字符如雨般流下，随机切换字符内容。
- 实时调整颜色、字符集、速度、字体大小和字符密度。
- 炫酷的控制面板，鼠标悬浮即可操作。
实现过程
1、基础 HTML 和 CSS
我们先创建一个简单的 HTML 页面，并用 CSS 设置画布和控制面板的样式：
<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Canvas 黑客帝国代码雨</title>
<style>
* {
margin: 0;
padding: 0;
box-sizing: border-box;
}
body,
html {
height: 100%;
margin: 0;
background-color: #000;
font-family: Arial, sans-serif;
}
canvas {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
}
.controls {
position: absolute;
top: 20px;
right: 20px;
background: rgba(0, 0, 0, 0.8);
padding: 20px;
border-radius: 12px;
box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
color: #fff;
font-size: 14px;
opacity: 0; /* 默认隐藏 */
transition: opacity 0.3s ease-in-out;
width: 250px;
}
.controls:hover {
opacity: 1;
}
.controls label {
display: flex;
justify-content: space-between;
margin-bottom: 12px;
align-items: center;
}
.controls input,
.controls select {
margin-left: 10px;
flex: 1;
padding: 5px;
border-radius: 5px;
border: 1px solid #ccc;
}
.controls input[type="range"] {
width: 70%;
}
.controls input[type="color"],
.controls select {
width: 30%;
}
.controls .range-container {
display: flex;
justify-content: space-between;
align-items: center;
}
.controls h3 {
font-size: 18px;
margin-bottom: 15px;
text-align: center;
}
</style>
</head>
<body>
<canvas id="rain"></canvas>
<div class="controls">
<h3>代码雨设置</h3>
<label>
颜色:
<input type="color" id="color-picker" value="#0F0">
</label>
<label>
字符集:
<select id="char-set">
<option value="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789@#$%^&*()">默认</option>
<option value="ABCDEFGHIJKLMNOPQRSTUVWXYZ">字母</option>
<option value="0123456789">数字</option>
</select>
</label>
<label class="range-container">
速度:
<input type="range" id="speed-range" min="5" max="50" value="30">
<span id="speed-value">30</span> 毫秒
</label>
<label class="range-container">
字体大小:
<input type="range" id="font-size-range" min="10" max="30" value="16">
<span id="font-size-value">16</span> px
</label>
<label class="range-container">
字符密度:
<input type="range" id="density-range" min="1" max="3" value="2">
<span id="density-value">2</span>
</label>
</div>
</body>
</html>
2、编写 JavaScript 动画逻辑
const canvas = document.getElementById('rain');
const ctx = canvas.getContext('2d');
let config = {
color: '#0F0',
charSet: 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789@#$%^&*()',
speed: 30,
fontSize: 16,
density: 2,
};
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
const updateCanvasSettings = () => {
const spacing = config.fontSize / config.density;
return Math.floor(canvas.width / spacing);
};
let columns = updateCanvasSettings();
let drops = Array(columns).fill(0);
const colorPicker = document.getElementById('color-picker');
const charSetSelect = document.getElementById('char-set');
const speedRange = document.getElementById('speed-range');
const fontSizeRange = document.getElementById('font-size-range');
const densityRange = document.getElementById('density-range');
const speedValue = document.getElementById('speed-value');
const fontSizeValue = document.getElementById('font-size-value');
const densityValue = document.getElementById('density-value');
colorPicker.addEventListener('input', (e) => config.color = e.target.value);
charSetSelect.addEventListener('change', (e) => config.charSet = e.target.value);
speedRange.addEventListener('input', (e) => {
config.speed = parseInt(e.target.value);
speedValue.textContent = config.speed;
});
fontSizeRange.addEventListener('input', (e) => {
config.fontSize = parseInt(e.target.value);
fontSizeValue.textContent = config.fontSize;
columns = updateCanvasSettings();
drops = Array(columns).fill(0);
});
densityRange.addEventListener('input', (e) => {
config.density = parseInt(e.target.value);
densityValue.textContent = config.density;
columns = updateCanvasSettings();
drops = Array(columns).fill(0);
});
function draw() {
ctx.fillStyle = 'rgba(0, 0, 0, 0.05)';
ctx.fillRect(0, 0, canvas.width, canvas.height);
ctx.fillStyle = config.color;
ctx.font = `${config.fontSize}px monospace`;
const spacing = config.fontSize / config.density;
for (let i = 0; i < columns; i++) {
const char = config.charSet[Math.floor(Math.random() * config.charSet.length)];
ctx.fillText(char, i * spacing, drops[i] * config.fontSize);
if (drops[i] * config.fontSize > canvas.height || Math.random() > 0.975) {
drops[i] = 0;
}
drops[i]++;
}
setTimeout(() => requestAnimationFrame(draw), config.speed);
}
draw();
总结
通过简单的 HTML、CSS 和 JavaScript，你不仅可以复刻经典的黑客帝国代码雨，还能通过加入控制面板让这个特效更加灵活和炫酷。如果你喜欢这篇文章，不妨点赞、收藏或分享，让更多人看到！
🎉 快去尝试下吧，制作属于你的代码雨特效！
