手机相册js

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>手机相册示例</title>
</head>
<body>
    <input type="file" id="fileInput" accept="image/*" multiple>
    <div id="preview"></div>

    <script>
        document.getElementById('fileInput').addEventListener('change', function(event) {
            const files = event.target.files;
            const preview = document.getElementById('preview');
            preview.innerHTML = ''; // 清空之前的预览

            for (let i = 0; i < files.length; i++) {
                const file = files[i];
                if (file.type.startsWith('image/')) {
                    const reader = new FileReader();
                    reader.onload = function(e) {
                        const img = document.createElement('img');
                        img.src = e.target.result;
                        img.style.width = '100px'; // 设置预览图片的宽度
                        preview.appendChild(img);
                    };
                    reader.readAsDataURL(file);
                }
            }
        });
    </script>
</body>
</html>

function compressImage(file, maxWidth, maxHeight, quality) {
    return new Promise((resolve, reject) => {
        const img = new Image();
        img.src = URL.createObjectURL(file);
        img.onload = () => {
            const canvas = document.createElement('canvas');
            let width = img.width;
            let height = img.height;

            if (width > height) {
                if (width > maxWidth) {
                    height *= maxWidth / width;
                    width = maxWidth;
                }
            } else {
                if (height > maxHeight) {
                    width *= maxHeight / height;
                    height = maxHeight;
                }
            }

            canvas.width = width;
            canvas.height = height;
            const ctx = canvas.getContext('2d');
            ctx.drawImage(img, 0, 0, width, height);

            canvas.toBlob((blob) => {
                resolve(blob);
            }, 'image/jpeg', quality);
        };
        img.onerror = reject;
    });
}

// 服务器端设置CORS头示例（Node.js）
app.use((req, res, next) => {
    res.header('Access-Control-Allow-Origin', '*');
    res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept');
    next();
});