使用UIPanGestureRecognizer旋轉ImageView Swift 3

Question

我想旋轉一個ImageView我取決於它的X座標。基本上，我希望它在x = 300時旋轉0º，當x = 190時旋轉180º。

我不得不以編程方式編程UIPanGestureRecognizer。下面是代碼我現在有現在：

@objc func personDrag(recognizer: UIPanGestureRecognizer) { 

    let rotationSub: CGFloat = 1 

    let translation = recognizer.translation(in: rView) 
    if let view = recognizer.view { 
     view.center = CGPoint(x:view.center.x + translation.x, y:view.center.y + translation.y) 
     view.transform = view.transform.rotated(by: CGFloat.pi - rotationSub) 
    } 
    recognizer.setTranslation(CGPoint.zero, in: rView) 

} 

我會嘗試1每次搖一次改變旋轉程度，但它並沒有真正的工作/有意義。任何幫助，將不勝感激。非常感謝！

乾杯，西奧

Answer 1

可以建立在此的實現：

import UIKit 

class ViewController: UIViewController { 

    @IBOutlet weak var imageview: UIImageView! 

    private var currentRotation: Rotation = .none 

    /* Certain rotation points (rotation of 0º when x = 300 and a rotation of 180º when x = 190) */ 
    enum Rotation { 
     case none, xPoint190, xPoint300 
    } 

    override func viewDidLoad() { 
     super.viewDidLoad() 

     let gestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(handlePan)) 
     imageview.addGestureRecognizer(gestureRecognizer) 
     imageview.isUserInteractionEnabled = true 
    } 

    @IBAction func handlePan(_ gestureRecognizer: UIPanGestureRecognizer) { 
     guard gestureRecognizer.state == .began || gestureRecognizer.state == .changed else { 
      return 
     } 

     guard let imgView = gestureRecognizer.view else { 
      return 
     } 

     let translation = gestureRecognizer.translation(in: self.view) 
     imgView.center = CGPoint(x: imgView.center.x + translation.x, y: imgView.center.y + translation.y) 
     gestureRecognizer.setTranslation(CGPoint.zero, in: self.view) 

     let angle: CGFloat = self.degreesToRadians(180.0) 

     /* After reaching x point case - rotating and setting rotation occured to prohibit further rotation */ 

     if imgView.layer.frame.origin.x <= 190, currentRotation != .xPoint190 { 

     imgView.transform = imgView.transform.rotated(by: angle) 
     currentRotation = .xPoint190 

    } else if imgView.layer.frame.origin.x >= 300, currentRotation != .xPoint300 { 

     imgView.transform = imgView.transform.rotated(by: angle) 
     currentRotation = .xPoint300 
    } 


    private func degreesToRadians(_ deg: CGFloat) -> CGFloat { 
     return deg * CGFloat.pi/180 
    } 
}