cubic-bezier 三次贝塞尔曲线函数

实例代码

<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>CSS 贝塞尔曲线动画演示</title>
    <style>
        body {
            font-family: 'Arial', sans-serif;
            max-width: 800px;
            margin: 0 auto;
            padding: 20px;
            background-color: #f5f5f5;
        }
        
        h1 {
            color: #333;
            text-align: center;
            margin-bottom: 30px;
        }
        
        .demo-container {
            background-color: white;
            border-radius: 8px;
            padding: 20px;
            box-shadow: 0 2px 10px rgba(0,0,0,0.1);
        }
        
        .animation-track {
            height: 100px;
            margin: 40px 0;
            position: relative;
            background-color: #f0f0f0;
            border-radius: 4px;
            overflow: hidden;
        }
        
        .track-line {
            position: absolute;
            top: 50%;
            left: 0;
            right: 0;
            height: 2px;
            background-color: #ddd;
            transform: translateY(-50%);
        }
        
        .ball {
            width: 30px;
            height: 30px;
            background-color: #e74c3c;
            border-radius: 50%;
            position: absolute;
            left: 10px;
            top: 50%;
            transform: translateY(-50%);
            animation: move 3s infinite;
            box-shadow: 0 2px 5px rgba(0,0,0,0.2);
        }
        
        .label {
            margin-top: 10px;
            font-size: 14px;
            color: #666;
            font-weight: bold;
        }
        
        .value {
            font-family: monospace;
            color: #3498db;
            background-color: #f8f8f8;
            padding: 2px 5px;
            border-radius: 3px;
        }
        
        .curve-info {
            font-size: 12px;
            color: #999;
            margin-top: 5px;
        }
        
        @keyframes move {
            0% { left: 10px; }
            100% { left: calc(100% - 40px); }
        }
        
        /* 自定义贝塞尔曲线 */
        .custom-bezier { animation-timing-function: cubic-bezier(0.1, 0.7, 1.0, 0.1); }
        
        /* 预定义关键词的贝塞尔曲线 */
        .ease-bezier { animation-timing-function: cubic-bezier(0.25, 0.1, 0.25, 1); }
        .ease-in-bezier { animation-timing-function: cubic-bezier(0.42, 0, 1.0, 1); }
        .ease-out-bezier { animation-timing-function: cubic-bezier(0, 0, 0.58, 1); }
        .ease-in-out-bezier { animation-timing-function: cubic-bezier(0.42, 0, 0.58, 1); }
        
        /* 添加弹跳效果 */
        .ball::after {
            content: '';
            position: absolute;
            bottom: -8px;
            left: 50%;
            width: 20px;
            height: 5px;
            background-color: rgba(0,0,0,0.1);
            border-radius: 50%;
            transform: translateX(-50%) scale(0.8);
            filter: blur(1px);
            animation: shadow 3s infinite;
        }
        
        @keyframes shadow {
            0%, 100% { transform: translateX(-50%) scale(0.8); opacity: 0.6; }
            50% { transform: translateX(-50%) scale(1.2); opacity: 0.3; }
        }
    </style>
</head>
<body>
    <h1>CSS 贝塞尔曲线动画时间函数演示</h1>
    
    <div class="demo-container">
        <div class="animation-track">
            <div class="track-line"></div>
            <div class="ball custom-bezier"></div>
        </div>
        <div class="label">自定义曲线: <span class="value">cubic-bezier(0.1, 0.7, 1.0, 0.1)</span></div>
        <div class="curve-info">快速加速，突然停止，适合弹跳效果</div>
        
        <div class="animation-track">
            <div class="track-line"></div>
            <div class="ball ease-bezier"></div>
        </div>
        <div class="label">ease 曲线: <span class="value">cubic-bezier(0.25, 0.1, 0.25, 1)</span></div>
        <div class="curve-info">标准缓动，慢-快-慢</div>
        
        <div class="animation-track">
            <div class="track-line"></div>
            <div class="ball ease-in-bezier"></div>
        </div>
        <div class="label">ease-in 曲线: <span class="value">cubic-bezier(0.42, 0, 1.0, 1)</span></div>
        <div class="curve-info">慢速开始，快速结束</div>
        
        <div class="animation-track">
            <div class="track-line"></div>
            <div class="ball ease-out-bezier"></div>
        </div>
        <div class="label">ease-out 曲线: <span class="value">cubic-bezier(0, 0, 0.58, 1)</span></div>
        <div class="curve-info">快速开始，慢速结束</div>
        
        <div class="animation-track">
            <div class="track-line"></div>
            <div class="ball ease-in-out-bezier"></div>
        </div>
        <div class="label">ease-in-out 曲线: <span class="value">cubic-bezier(0.42, 0, 0.58, 1)</span></div>
        <div class="curve-info">慢速开始和结束，中间加速</div>
    </div>
    
    <script>
        // 添加小球运动轨迹可视化
        document.addEventListener('DOMContentLoaded', function() {
            const tracks = document.querySelectorAll('.animation-track');
            
            tracks.forEach(track => {
                const canvas = document.createElement('canvas');
                canvas.width = track.offsetWidth;
                canvas.height = 50;
                canvas.style.position = 'absolute';
                canvas.style.bottom = '-55px';
                canvas.style.left = '0';
                track.appendChild(canvas);
                
                const ctx = canvas.getContext('2d');
                ctx.strokeStyle = '#3498db';
                ctx.lineWidth = 2;
                
                const ball = track.querySelector('.ball');
                const timingFunction = getComputedStyle(ball).animationTimingFunction;
                
                // 绘制贝塞尔曲线
                if (timingFunction.startsWith('cubic-bezier')) {
                    const points = timingFunction.match(/[\d.]+/g).map(parseFloat);
                    
                    ctx.beginPath();
                    ctx.moveTo(0, 50);
                    
                    // 简化的曲线绘制（实际应该计算时间-位置关系）
                    for (let x = 0; x <= canvas.width; x++) {
                        const t = x / canvas.width;
                        // 三次贝塞尔曲线计算
                        const y = 50 * (1 - Math.pow(1-t, 3)*points[1] + 
                                       3*Math.pow(1-t, 2)*t*points[3] + 
                                       3*(1-t)*Math.pow(t, 2)*points[5] + 
                                       Math.pow(t, 3)*points[7]);
                        ctx.lineTo(x, y);
                    }
                    
                    ctx.stroke();
                }
            });
        });
    </script>
</body>
</html>