从UIView掩码中剪切UIImage

import UIKit

func imageFromViewWithMask(view: UIView, maskImage: UIImage) -> UIImage? {
    // 创建一个与视图大小相同的图形上下文
    UIGraphicsBeginImageContextWithOptions(view.bounds.size, false, 0.0)
    guard let context = UIGraphicsGetCurrentContext() else { return nil }
    
    // 将视图绘制到上下文中
    view.layer.render(in: context)
    
    // 获取当前图形上下文的图像
    let image = UIGraphicsGetImageFromCurrentImageContext()
    
    // 结束图形上下文
    UIGraphicsEndImageContext()
    
    // 创建一个新的图形上下文，用于应用掩码
    UIGraphicsBeginImageContextWithOptions(image?.size ?? CGSize.zero, false, 0.0)
    guard let contextWithMask = UIGraphicsGetCurrentContext() else { return nil }
    
    // 绘制原始图像
    image?.draw(in: CGRect(origin: .zero, size: (image?.size ?? CGSize.zero)))
    
    // 应用掩码
    let maskRef = maskImage.cgImage?.maskingColors(UIColor.black.cgColor)
    contextWithMask.clip(to: CGRect(origin: .zero, size: (image?.size ?? CGSize.zero)), mask: maskRef!)
    
    // 获取应用掩码后的图像
    let maskedImage = UIGraphicsGetImageFromCurrentImageContext()
    
    // 结束图形上下文
    UIGraphicsEndImageContext()
    
    return maskedImage
}

// 示例使用
let view = UIView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))
view.backgroundColor = .red

let maskImage = UIImage(named: "mask.png")!

if let maskedImage = imageFromViewWithMask(view: view, maskImage: maskImage) {
    // 使用 maskedImage
}