用屏幕縱橫比裁剪UIImage的一部分

Question

我一直在爲此奮鬥了很長一段時間。當你選擇你的壁紙時，我想讓圖像裁剪器與iOS中包含的圖像裁剪器類似。基本上我希望用戶從屏幕上縮放和縱橫比的圖像中裁剪的區域（以便用戶以後可以將圖像用作牆紙）。就像這樣：

https://gfycat.com/TornMaleAlligatorsnappingturtle

我已經成功地與UIScrollView中和的UIImageView創建接口：

import UIKit 

class ViewController: UIViewController, UIScrollViewDelegate { 

var scrollView: UIScrollView! 
var imageView: UIImageView! 

var croppedImage: UIImage? 

@IBOutlet weak var cropButton: UIButton! { 
    didSet{ 
     cropButton.backgroundColor = UIColor.gray 
    } 
} 


override func viewDidLoad() { 

    super.viewDidLoad() 

    let image = UIImage(named: "mountains")! 

    imageView = UIImageView(image: image) 
    imageView.frame = CGRect(origin: CGPoint(x: 0, y: 0), size:image.size) 
    imageView.contentMode = .scaleAspectFill 

    scrollView = UIScrollView(frame: view.bounds) 
    scrollView.backgroundColor = UIColor.black 
    scrollView.contentSize = imageView.bounds.size 

    scrollView.delegate = self 

    setZoomScale() 
    //centerScrollViewContents() 

    scrollView.addSubview(imageView) 
    view.addSubview(scrollView) 
    view.bringSubview(toFront: cropButton) 

} 

func viewForZooming(in scrollView: UIScrollView) -> UIView? { 
    return imageView 
} 

@IBAction func crop(_ sender: UIButton) { 

    let rect = CGRect(x: ?, y: ?, width: ?, height: ?) 
    let croppedCGImage = imageView.image?.cgImage?.cropping(to: rect) 
    self.croppedImage = UIImage(cgImage: croppedCGImage!) 
} 

func setZoomScale() { 
    let imageViewSize = imageView.bounds.size 
    let scrollViewSize = scrollView.bounds.size 
    //let widthScale = scrollViewSize.width/imageViewSize.width 
    let heightScale = scrollViewSize.height/imageViewSize.height 

    scrollView.minimumZoomScale = heightScale //min(widthScale, heightScale) 
    scrollView.maximumZoomScale = 3 
    scrollView.zoomScale = heightScale 

    print(heightScale) 
} 
}. 

我可以在圖像周圍縮放和平移沒有問題。問題是我不知道如何創建CGRect矩形來表示向用戶顯示的區域，這也是我想從原始圖像裁剪的區域。任何想法將讓我擺脫我的苦難，非常感謝！

Answer 1

snapshotImageFromMyView是輸出圖像

self.btn.isHidden = true 

DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) { 
     UIGraphicsBeginImageContextWithOptions(self.YourView.bounds.size, self.YourView.isOpaque, 0.0) 
     self.YourView.drawHierarchy(in: self.YourView.bounds, afterScreenUpdates: false) 
    let snapshotImageFromMyView = UIGraphicsGetImageFromCurrentImageContext() 
    UIGraphicsEndImageContext() 

}