UIPinchGestureRecognizer 和 UIPanGestureRecognizer 可以合并吗？

Question

我正在努力弄清楚是否可以创建一个将 UIPinchGestureRecognizer 与 UIPanGestureRecognizer 结合起来的单个组合手势识别器。

我使用平移进行视图平移，使用捏合进行视图缩放。我正在进行增量矩阵串联，以导出应用于视图的最终转换矩阵。这个矩阵既有尺度又有平移。使用单独的手势识别器会导致抖动/缩放。不是我想要的。因此，我想在一个手势中处理一次缩放和平移的串联。有人可以阐明如何做到这一点吗？

Answer 1

2014 年 6 月 14 日：使用 ARC 更新了 iOS 7+ 的示例代码。

UIGestureRecognizer 可以一起工作，您只需要确保不会破坏当前视图的变换矩阵。使用 CGAffineTransformScale 方法和相关方法将变换作为输入，而不是从头开始创建它（除非您自己维护当前的旋转、缩放或平移。

下载 Xcode 项目

• Github 上的示例 UIPinchGesture 项目。

注意：对于应用了平移/捏合/旋转手势的 IB 中的 UIView，iOS 7 的行为很奇怪。iOS 8 修复了这个问题，但我的解决方法是在代码中添加所有视图，如此代码示例

1. 将它们添加到视图中并符合 UIGestureRecognizerDelegate 协议

   @interfaceViewController() ;
   
   @结尾
   
   @实现ViewController
   
   - (void)viewDidLoad
   {
       [超级viewDidLoad];
   
       UIView *blueView = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 150, 150)];
       blueView.backgroundColor = [UIColor 蓝色];
       [self.view addSubview:blueView];
       [self addMovementGesturesToView:blueView];
   
       // UIImageView 和 UILabel 默认没有 userInteractionEnabled！
       UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"BombDodge.png"]]; // Xcode 项目中的任意图像
       imageView.center = CGPointMake(100, 250);
       [图像视图大小适合];
       [self.view addSubview:imageView];
       [自我addMovementGesturesToView:imageView];
   
       // 注意：更改字体大小比缩放字体更清晰！
       UILabel *label = [[UILabel alloc] init];
       label.text = @"你好手势！";
       label.font = [UIFont systemFontOfSize:30];
       label.textColor = [UIColor blackColor];
       [标签大小适合]；
       标签.center = CGPointMake(100, 400);
       [self.view addSubview:标签];
       [自我addMovementGesturesToView:标签];
   }
   
   - (void)addMovementGesturesToView:(UIView *)view {
       view.userInteractionEnabled = YES; // 启用用户交互
   
       UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePanGesture:)];
       panGesture.delegate = self；
       [查看addGestureRecognizer:panGesture];
   
       UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(handlePinchGesture:)];
       inchGesture.delegate = self；
       [查看addGestureRecognizer:pinchGesture];
   }
   

2. 实现手势方法

   - (void)handlePanGesture:(UIPanGestureRecognizer *)panGesture {
       CGPoint 翻译 = [panGesture TranslationInView:panGesture.view.superview];
   
       if (UIGestureRecognizerStateBegan == panGesture.state ||UIGestureRecognizerStateChanged == panGesture.state) {
           panGesture.view.center = CGPointMake(panGesture.view.center.x + 翻译.x,
                                                panGesture.view.center.y + 翻译.y);
           // 重置翻译，这样我们就可以获得翻译增量（即翻译的变化）
           [panGesture setTranslation:CGPointZero inView:self.view];
       }
       // 不需要任何结束/失败/取消状态的逻辑
   }
   
   - (void)handlePinchGesture:(UIPinchGestureRecognizer *)pinchGesture {
   
       if (UIGestureRecognizerStateBegan ==捏Gesture.state ||
           UIGestureRecognizerStateChanged ==捏Gesture.state) {
   
           // 使用 x 或 y 比例，它们对于典型缩放应该是相同的（非倾斜）
           float currentScale = [[pinchGesture.view.layer valueForKeyPath:@"transform.scale.x"] floatValue];
   
           // 调整缩放最大/最小值的变量
           浮动最小比例 = 1.0;
           浮动最大比例 = 2.0;
           浮动缩放速度= .5；
   
           浮动 deltaScale =inchGesture.scale;
   
           // 您需要将缩放平移到 0（原点），以便您
           // 可以乘以速度系数，然后转换回 1 左右的“zoomSpace”
           deltaScale = ((deltaScale - 1) * 缩放速度) + 1;
   
           // 限制最小/最大尺寸（即 maxScale = 2，当前比例 = 2, 2/2 = 1.0）
           // deltaScale 为 ~0.99（递减）或 ~1.01（递增）
           // deltaScale 为 1.0 将保持缩放大小
           deltaScale = MIN(deltaScale, maxScale / currentScale);
           deltaScale = MAX(deltaScale, minScale / currentScale);
   
           CGAffineTransform ZoomTransform = CGAffineTransformScale(pinchGesture.view.transform, deltaScale, deltaScale);
           inchGesture.view.transform = ZoomTransform;
   
           // 比例增量重置为 1
           // 注意：不是0，否则我们不会看到尺寸：0 * width = 0
           inchGesture.scale = 1;
       }
   }
   
   - (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
       返回是； // 适用于大多数捏合 + 缩放 + 平移的用例
   }
   

资源

• Xcode 手势示例项目
• Apple 手势指南< /a>

Answer 2

如果有人对使用 Metal 进行渲染的 Swift 实现感兴趣，我有一个项目这里。

Answer 3

斯威夫特

非常感谢保罗！这是他的 Swift 版本：

import UIKit

class ViewController: UIViewController, UIGestureRecognizerDelegate {

    var editorView: EditorView!

    override func viewDidLoad() {
        super.viewDidLoad()

        let blueView = UIView(frame: .init(x: 100, y: 100, width: 300, height: 300))
        view.addSubview(blueView)
        blueView.backgroundColor = .blue
        addMovementGesturesToView(blueView)
    }

    func addMovementGesturesToView(_ view: UIView) {
        view.isUserInteractionEnabled = true

        let panGesture = UIPanGestureRecognizer(target: self, action: #selector(handlePanGesture(_:)))
        panGesture.delegate = self
        view.addGestureRecognizer(panGesture)

        let pinchGesture = UIPinchGestureRecognizer(target: self, action: #selector(handlePinchGesture(_:)))
        pinchGesture.delegate = self
        view.addGestureRecognizer(pinchGesture)
    }

    @objc private func handlePanGesture(_ panGesture: UIPanGestureRecognizer) {
        guard let panView = panGesture.view else { return }

        let translation = panGesture.translation(in: panView.superview)

        if panGesture.state == .began || panGesture.state == .changed {
            panGesture.view?.center = CGPoint(x: panView.center.x + translation.x, y: panView.center.y + translation.y)

            // Reset translation, so we can get translation delta's (i.e. change in translation)
            panGesture.setTranslation(.zero, in: self.view)
        }
        // Don't need any logic for ended/failed/canceled states
    }

    @objc private func handlePinchGesture(_ pinchGesture: UIPinchGestureRecognizer) {
        guard let pinchView = pinchGesture.view else { return }

        if pinchGesture.state == .began || pinchGesture.state == .changed {
            let currentScale = scale(for: pinchView.transform)

            // Variables to adjust the max/min values of zoom
            let minScale: CGFloat = 0.2
            let maxScale: CGFloat = 3
            let zoomSpeed: CGFloat = 0.8

            var deltaScale = pinchGesture.scale

            // You need to translate the zoom to 0 (origin) so that you
            // can multiply a speed factor and then translate back to "zoomSpace" around 1
            deltaScale = ((deltaScale - 1) * zoomSpeed) + 1

            // Limit to min/max size (i.e maxScale = 2, current scale = 2, 2/2 = 1.0)
            //  A deltaScale is ~0.99 for decreasing or ~1.01 for increasing
            //  A deltaScale of 1.0 will maintain the zoom size
            deltaScale = min(deltaScale, maxScale / currentScale)
            deltaScale = max(deltaScale, minScale / currentScale)

            let zoomTransform = pinchView.transform.scaledBy(x: deltaScale, y: deltaScale)
            pinchView.transform = zoomTransform

            // Reset to 1 for scale delta's
            //  Note: not 0, or we won't see a size: 0 * width = 0
            pinchGesture.scale = 1
        }
    }

    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
        return true
    }

    private func scale(for transform: CGAffineTransform) -> CGFloat {
        return sqrt(CGFloat(transform.a * transform.a + transform.c * transform.c))
    }
}

演示（在模拟器上）：