为什么我的 UIView 不绕 z 轴旋转？

Question

我试图让我的 UIView 在 Swift 中绕 z 轴旋转。但由于某种原因，旋转轴并不像预期的那样：

    rotatedView.layer.anchorPoint = CGPoint(x: 0.5, y: 0.5)
    rotatedView.contentMode = .scaleToFill
    rotatedView.layer.transform = CATransform3DMakeRotation(rotatedObjectWrapper.object.rotation, 0, 0, 1)

如何让 UIView 绕 z 轴旋转？谢谢。

更新： 我调查后发现，当我使用 Stepper 元素控制旋转时，旋转是围绕 z 轴进行的。对于上下文，委托函数 delegate?.didRotateObject 更新 rotatedObjectWrapper.object.rotation 值。

滑块：

@IBAction func didChangeRotation(_ sender: UISlider) {
    delegate?.didRotateObject(to: Double(angleSlider.value))
}

步进器（更新 0.1 弧度）：

 @IBAction func didChangeStepper(_ sender: Any) {
    delegate?.didRotateObject(to: Double(stepper.value))
}

我尝试使用一些动画来改变旋转值，它有点绕 z 轴旋转，同时仍然有奇怪的旋转行为：

    UIView.animate(withDuration: 0.5, animations: {
      rotatedView.layer.transform = CATransform3DMakeRotation(rotatedObjectWrapper.object.rotation, 0, 0, 1)
    })

结果：

更新 2： 我正在尝试这个：

        testView = CustomObjectView(image: UIImage(named: "black"))    
        guard let testView = testView else { return }
        testView.frame = CGRect(x: rotatedObject.position.x, y: rotatedObject.position.y, width: rotatedObject.width, height: rotatedObject.height)
        testView.layer.transform = CATransform3DMakeRotation(rotatedObjectWrapper.object.rotation, 0, 0, 1)
        rotatedView.layer.transform = CATransform3DMakeRotation(rotatedObjectWrapper.object.rotation, 0, 0, 1)
        print(testView.layer.frame)
        print(rotatedView.layer.frame)
        rotatedView.layer.frame = testView.layer.frame
        print(rotatedView.layer.frame)
        print(")))))))")

testView 仍在正确旋转，而 rotatedView 仍在奇怪地旋转。两者之间的唯一区别是 rotatedView 是从这样的字典中获得的：

guard let rotatedView = objectsToViews[rotatedObjectWrapper] else { return }

我正在尝试一种骇人听闻的方式将 rotatedView.layer.frame 设置为等于 testView.layer.frame 但它不起作用。

Answer 1

此代码根据滑块的值围绕 z 轴旋转视图，您可以在操场上运行它：

import UIKit
import PlaygroundSupport

class MyViewController : UIViewController {
    
    var viewToRotate: UIView!
    override func loadView() {
        let view = UIView()
        view.backgroundColor = .white

        let label = UILabel()
        label.frame = CGRect(x: 150, y: 200, width: 200, height: 20)
        label.text = "Hello World!"
        label.sizeToFit()
        label.textColor = .black
        viewToRotate = label
        
        let slider = UISlider(frame: CGRect(x: 50, y: 300, width: 300, height: 40))
        slider.minimumValue = 0
        slider.maximumValue = .pi * 2
        slider.addTarget(self, action: #selector(updateRotation(_:)), for: .valueChanged)
        
        view.addSubview(label)
        view.addSubview(slider)
        self.view = view
    }
    
    @objc private func updateRotation(_ sender: UISlider) {
        viewToRotate?.layer.transform = CATransform3DMakeRotation(CGFloat(sender.value), 0, 0, 1)
    }
    
    
}
// Present the view controller in the Live View window
PlaygroundPage.current.liveView = MyViewController()

目前尚不清楚为什么您的代码无法正常工作，因为转换的设置方式相同，但它必须位于您问题中不存在的某些代码中。您为旋转传递的值是什么？是否有任何子层转换？

Answer 2

import UIKit

class ViewController: UIViewController {
    let rotatedView = UIView(frame: CGRect(x: 50, y: 50, width: 50, height: 50))
    
    var angle = 0.0
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        rotatedView.backgroundColor = .red
        view.addSubview(rotatedView)
        rotatedView.layer.anchorPoint = CGPoint(x: 0.5, y: 0.5)
           rotatedView.contentMode = .scaleToFill

        _ = Timer.scheduledTimer(timeInterval: 1/60, target: self, selector: #selector(updateFrame), userInfo: nil, repeats: true)
        
       
    }


    @objc func updateFrame(_ timer: Timer)
    {
        angle += 0.1
           rotatedView.layer.transform = CATransform3DMakeRotation(angle, 1, 0, 0)
    }
}