在UIScrollView中旋转UIImageView

Question

我在UIScrollView中有一个UIImageView。最终目标是在UIScrollView的范围内旋转、平移和缩放图像。平移和缩放效果都很好。旋转最初起作用，但在旋转完成后，进行捏缩缩放，图像旋转将重置为0，图像将移位到UIScrollView之外。

任何建议都是我可能错过的

@IBOutlet weak var innerScrollView: UIScrollView!
        private weak var innerImageView: UIImageView?
        var beforeImage: UIImage?

        // MARK: -
        // MARK: UIViewController       
        override func viewDidLoad() {
            super.viewDidLoad()
            innerScrollView.delegate = self
            configureScrollView(innerScrollView, image: beforeImage)
            let recognizer = UIRotationGestureRecognizer(target: self, action: "rotateRecognizer:")
            if let imageView = innerImageView {
                imageView.addGestureRecognizer(recognizer)
            }
        }
        override func viewWillAppear(animated: Bool) {
            super.viewWillAppear(animated)
            resetScrollView(innerScrollView)
        }

        // MARK: -
        // MARK: Private Helpers
        private func resetScrollView(scrollView: UIScrollView) {
            let scaleWidth = scrollView.frame.size.width / scrollView.contentSize.width
            let scaleHeight = scrollView.frame.size.height / scrollView.contentSize.height
            let minScale = min(scaleHeight, scaleWidth)
            scrollView.minimumZoomScale = minScale
            scrollView.maximumZoomScale = 1.0
            scrollView.zoomScale = minScale
            centerScrollViewContents()
        }
        private func configureScrollView(scrollView: UIScrollView, image: UIImage?) {
            guard let img = image else {
                return
            }
            let imageView = UIImageView(image: image)
            imageView.userInteractionEnabled = true
            imageView.frame = CGRect(origin: CGPoint(x: 0, y: 0), size: img.size)
            scrollView.addSubview(imageView)
            scrollView.contentSize = img.size
            innerImageView = imageView
        }
        private func centerScrollViewContents() {
            let boundsSize = innerScrollView.bounds.size
            var contentsFrame = innerImageView!.frame
            if contentsFrame.size.width < boundsSize.width {
                contentsFrame.origin.x = (boundsSize.width - contentsFrame.size.width) / 2.0
            } else {
                contentsFrame.origin.x = 0.0
            }
            if contentsFrame.size.height < boundsSize.height {
                contentsFrame.origin.y = (boundsSize.height - contentsFrame.size.height) / 2.0
            } else {
                contentsFrame.origin.y = 0.0
            }
            innerImageView!.frame = contentsFrame
        }
        func rotateRecognizer(recognizer: UIRotationGestureRecognizer) {
            print("The content Offset is (innerScrollView.contentOffset)")
            guard let recView = recognizer.view else {
                return
            }
            recView.transform = CGAffineTransformRotate(recView.transform, recognizer.rotation);
            recognizer.rotation = 0;
        }

        // MARK: -
        // MARK: UIGestureRecognizer Delegate Protocol
        func viewForZoomingInScrollView(scrollView: UIScrollView) -> UIView? {
            if let imageView = scrollView.subviews.first as? UIImageView {
                return imageView
            }
            return nil
        }

Answer 1

我成功了。这里还有另一个提议的解决方案，但我的不同。

缩放和平移在滚动视图中很容易，但当添加旋转时，它会立即重置，就像你说的那样（我也遇到过这种情况）。我所做的是完全放弃scrollView的手势，而不依赖于它的代理。我添加了自己的手势识别器，用于平移、缩放和旋转。然后，你可以随心所欲地将它们组合在一起：让其中两个同时感知变化，甚至三个都感知变化。在我的解决方案中，我希望平移被单独感知，缩放和旋转被一起感知。你可以通过以下方法来完成：

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool 

请参阅下面我的代码的其余部分。当然，在我的示例中，我有一个UIView，而不是图像视图，但从转换的角度来看，这并不重要。

private struct Constants {
    private init() {}
    static let minZoom = CGFloat(0.3)
    static let maxZoom = CGFloat(6)
}
private var activeView: UIView
private var savedTransform: CGAffineTransform
// Represents rotation performed since the last transform save
private var editedRotation = TransformConstants.defaultRotation
// Represents scaling performed since the last transform save
private var editedScale = TransformConstants.defaultScale
override func didPan(recognizer: UIPanGestureRecognizer) {
    let translation = recognizer.translation(in: activeView)
    activeView.transform = savedTransform.translatedBy(x: translation.x, y: translation.y)
    if shouldSaveGestures(recognizer: recognizer) {
      saveChanges(operation: .pan)
      return
    }
}
override func didPinch(recognizer: UIPinchGestureRecognizer) {
    if shouldSaveGestures(recognizer: recognizer) {
      saveChanges(operation: .zoom)
      return
    }
    var scale = recognizer.scale
    if Constants.minZoom > scale * savedTransform.getScale().x {
      scale = Constants.minZoom / savedTransform.getScale().x
    } else if scale * savedTransform.getScale().x > Constants.maxZoom {
      scale = Constants.maxZoom / savedTransform.getScale().x
    }
    activeView.transform = savedTransform.scaledBy(x: scale, y: scale).rotated(by: editedRotation)
    editedScale = CGPoint(x: scale, y: scale)
}
override func didRotate(recognizer: UIRotationGestureRecognizer) {
    if shouldSaveGestures(recognizer: recognizer) {
      saveChanges(operation: .rotate)
      return
    }
    activeView.transform = savedTransform.scaledBy(x: editedScale.x, y: editedScale.y).rotated(by: recognizer.rotation)
    editedRotation = recognizer.rotation
}
private func shouldSaveGestures(recognizer: UIGestureRecognizer) -> Bool {
    return recognizer.state == .ended || recognizer.state == .failed
}
private func saveChanges(operation: OperationType) {
    savedTransform = activeView.transform
    editedScale = TransformConstants.defaultScale
    editedRotation = TransformConstants.defaultRotation
}