如何使用UIImagePicker / Swift调整照片大小

import UIKit

class ViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    // ...
}

let imagePicker = UIImagePickerController()

imagePicker.sourceType = .photoLibrary

imagePicker.delegate = self

present(imagePicker, animated: true, completion: nil)

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
    if let selectedImage = info[.originalImage] as? UIImage {
        // 在这里对照片进行大小调整
        let resizedImage = resizeImage(selectedImage, targetSize: CGSize(width: 500, height: 500))
        // 处理调整后的照片
        // ...
    }
    dismiss(animated: true, completion: nil)
}

func resizeImage(_ image: UIImage, targetSize: CGSize) -> UIImage {
    let size = image.size
    
    let widthRatio  = targetSize.width  / size.width
    let heightRatio = targetSize.height / size.height
    
    var newSize: CGSize
    if widthRatio > heightRatio {
        newSize = CGSize(width: size.width * heightRatio, height: size.height * heightRatio)
    } else {
        newSize = CGSize(width: size.width * widthRatio, height: size.height * widthRatio)
    }
    
    let rect = CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height)
    
    UIGraphicsBeginImageContextWithOptions(newSize, false, 1.0)
    image.draw(in: rect)
    let newImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    
    return newImage ?? UIImage()
}