Question

我正在努力想弄清楚是否有可能创建一个将UIPinchGestureRecognizer与UIPanGestureRecognizer相结合的单一组合手势识别器。

我正在使用平移进行视图转换和捏合视图缩放。我正在进行增量矩阵连接，以导出应用于视图的结果最终变换矩阵。该矩阵具有缩放和平移。使用单独的手势识别器会导致抖动运动/缩放。不是我想要的。因此，我想在一个手势内处理一次缩放和翻译。有人可以说明如何做到这一点？

Answer 1

6/14/14：使用ARC更新了iOS 7+的示例代码。

UIGestureRecognizers可以协同工作，您只需要确保不要删除当前视图的变换矩阵。使用CGAffineTransformScale方法和将变换作为输入的相关方法，而不是从头开始创建（除非您自己维护当前的旋转，缩放或平移。

下载Xcode项目

Sample UIPinchGesture project on Github。

注意：iOS 7中的UIView在应用了Pan / Pinch / Rotate手势时表现得很奇怪。 iOS 8修复了它，但我的解决方法是在代码中添加所有视图，如此代码示例。

演示视频

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

@interface ViewController () <UIGestureRecognizerDelegate>

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    UIView *blueView = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 150, 150)];
    blueView.backgroundColor = [UIColor blueColor];
    [self.view addSubview:blueView];
    [self addMovementGesturesToView:blueView];

    // UIImageView's and UILabel's don't have userInteractionEnabled by default!
    UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"BombDodge.png"]]; // Any image in Xcode project
    imageView.center = CGPointMake(100, 250);
    [imageView sizeToFit];
    [self.view addSubview:imageView];
    [self addMovementGesturesToView:imageView];

    // Note: Changing the font size would be crisper than zooming a font!
    UILabel *label = [[UILabel alloc] init];
    label.text = @"Hello Gestures!";
    label.font = [UIFont systemFontOfSize:30];
    label.textColor = [UIColor blackColor];
    [label sizeToFit];
    label.center = CGPointMake(100, 400);
    [self.view addSubview:label];
    [self addMovementGesturesToView:label];
}

- (void)addMovementGesturesToView:(UIView *)view {
    view.userInteractionEnabled = YES;  // Enable user interaction

    UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePanGesture:)];
    panGesture.delegate = self;
    [view addGestureRecognizer:panGesture];

    UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(handlePinchGesture:)];
    pinchGesture.delegate = self;
    [view addGestureRecognizer:pinchGesture];
}

实施手势方法

- (void)handlePanGesture:(UIPanGestureRecognizer *)panGesture {
    CGPoint translation = [panGesture translationInView:panGesture.view.superview];

    if (UIGestureRecognizerStateBegan == panGesture.state ||UIGestureRecognizerStateChanged == panGesture.state) {
        panGesture.view.center = CGPointMake(panGesture.view.center.x + translation.x,
                                             panGesture.view.center.y + translation.y);
        // Reset translation, so we can get translation delta's (i.e. change in translation)
        [panGesture setTranslation:CGPointZero inView:self.view];
    }
    // Don't need any logic for ended/failed/canceled states
}

- (void)handlePinchGesture:(UIPinchGestureRecognizer *)pinchGesture {

    if (UIGestureRecognizerStateBegan == pinchGesture.state ||
        UIGestureRecognizerStateChanged == pinchGesture.state) {

        // Use the x or y scale, they should be the same for typical zooming (non-skewing)
        float currentScale = [[pinchGesture.view.layer valueForKeyPath:@"transform.scale.x"] floatValue];

        // Variables to adjust the max/min values of zoom
        float minScale = 1.0;
        float maxScale = 2.0;
        float zoomSpeed = .5;

        float 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);

        CGAffineTransform zoomTransform = CGAffineTransformScale(pinchGesture.view.transform, deltaScale, deltaScale);
        pinchGesture.view.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;
    }
}

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
    return YES; // Works for most use cases of pinch + zoom + pan
}

资源

Answer 2

如果有人对使用Metal进行渲染的Swift实现感兴趣，我有一个可用的项目here。

Answer 3

迅速

非常感谢Paul ！！！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))
    }
}

UIPinchGestureRecognizer和UIPanGestureRecognizer可以合并吗？

3 个答案:

下载Xcode项目

演示视频

资源

迅速

演示（在模拟器上）：