from PIL import Image

def resize_image(input_path, output_path, width, height):
    with Image.open(input_path) as img:
        # 保持宽高比的调整
        img.thumbnail((width, height))
        # 或者强制调整到指定尺寸
        # resized_img = img.resize((width, height))
        img.save(output_path)

# 使用示例
resize_image('input.jpg', 'output.jpg', 800, 600)

function resizeImage(file, maxWidth, maxHeight, callback) {
    const reader = new FileReader();
    reader.onload = function(e) {
        const img = new Image();
        img.onload = function() {
            const canvas = document.createElement('canvas');
            let width = img.width;
            let height = img.height;
            
            // 保持比例调整
            if (width > maxWidth) {
                height *= maxWidth / width;
                width = maxWidth;
            }
            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);
            callback(canvas.toDataURL('image/jpeg'));
        };
        img.src = e.target.result;
    };
    reader.readAsDataURL(file);
}