限制任何UIView的UIPinchGestureRecognizer缩放_Objective-C_Swift_下载.zip

LimitPinchGestureZoom ===================== Limit UIPinchGestureRecognizer Zoom for any UIView The code sample shows two things (Objective-C and Swift 3): 1. Use multiple gestures together to create a responsive user experience with media content. 2. How to zoom using the UIPinchGestureRecognizer and limit the zoom extents as well as speed. I have used this code in my iPhone apps/games (i.e. [Bomb Dodge](https://itunes.apple.com/us/app/protect-the-bomb/id660318608?mt=8)) and recently revised it to make it easier to use as discussed on [Stack Overflow](http://stackoverflow.com/a/5449865/276626). Video ---- [](https://www.youtube.com/watch?v=J5l47tSGTv0) Code ---- Create a view, if you use UILabel or UIImageView, you must set userInteractionEnabled = YES - (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]; UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePanGesture:)]; panGesture.delegate = self; [blueView addGestureRecognizer:panGesture]; UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(handlePinchGesture:)]; pinchGesture.delegate = self; [blueView addGestureRecognizer:pinchGesture]; } Implement methods to respond to gesture messages. Pan gesture can use relative motion by reseting the translation back to (0,0). - (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 } The Pinch gesture is a little more complex. This sample code shows how to apply a scale factor. If you want to change font sizes, you'll need to use different code. (Creating too many UIFont objects can slow down responsiveness) - (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; } } Conform to the UIGestureRecognizerDelegate Protocol and make sure to set the delegate for each gesture you create. This method can have more complex logic, but I find that YES is enough for general photo collage type apps. - (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer { return YES; // Works for most use cases of pinch + zoom + pan } Resources ---- * [Gesture Video](https://www.youtube.com/watch?v=J5l47tSGTv0) * [Apple's Multi-touch Gestures](https://developer.apple.com/library/ios/documentation/EventHandling/Conceptual/EventHandlingiPhoneOS/GestureRecognizer_basics/GestureRecognizer_basics.html#//apple_ref/doc/uid/TP40009541-CH2-SW2) * [StackOverflow Simultaneous Gestures](http://stackoverflow.com/a/5449865/276626) * [Bomb Dodge with multitouch gestures](https://itunes.apple.com/us/app/protect-the-bomb/id660318608?mt=8)