UIImageView范围内放大，缩小，移动 -- 官方文档代码
我们都知道，使用UIImagePickerController选择完图片时，设置属性allowsEditing=YES;，那么选中的图片就会跳转到一个新的控制器，在这个控制器里可以在指定的范围内放大、缩小和移动，但是这个界面是CocoaTouch决定的
如果我们自己单独新建一个控制器要写这样的代码，直接用UIPinchGestureRecognizer来做还是有点麻烦的，所以本人在Google上搜了搜，得到如下的完美答案，官方推荐的写法：
@interface ImageViewController ()<UIScrollViewDelegate> @property (nonatomic, strong) UIScrollView *scrollView; @property (nonatomic, strong) UIImageView *imageView; @end @implementation ImageViewController - (instancetype)initWithImage:(UIImage *)image { if (self = [super init]) { _originalImage = image; } return self; } - (void)viewDidLoad { [super viewDidLoad]; [self toggleNavigationBar]; self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"完成" style:UIBarButtonItemStylePlain target:self action:@selector(doneWithRecognization)]; self.navigationItem.leftBarButtonItem = [[BarButtonItem alloc] initWithTitle:nil position:kBackPosition style:UIBarButtonItemStylePlain target:self action:@selector(dismissPresentVC)]; /* * As the Apple Documentation said, it is the easiest way to implement pinch-in and pinch-out on an UIImageView, see below links. * http://stackoverflow.com/questions/500027/how-to-zoom-in-out-an-uiimage-object-when-user-pinches-screen * https://developer.apple.com/library/content/documentation/WindowsViews/Conceptual/UIScrollView_pg/ZoomZoom/ZoomZoom.html * */ _scrollView = [[UIScrollView alloc] initWithFrame:self.view.frame]; _scrollView.minimumZoomScale = 1.0; _scrollView.maximumZoomScale = 6.0; _scrollView.contentSize = CGSizeMake(1280, 960); _scrollView.delegate = self; [self.view addSubview:_scrollView]; CGRect rect = [UIScreen mainScreen].bounds; UIImage *scaledImg = [self.originalImage aspectScaleToSize:rect.size]; UIImageView *imgView = [[UIImageView alloc] initWithImage:scaledImg]; CGFloat Y = (rect.size.height - scaledImg.size.height) / 2; imgView.frame = CGRectMake(0, Y, rect.size.width, rect.size.height); imgView.userInteractionEnabled = YES; [imgView addGestureRecognizer:[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(toggleNavigationBar)]]; [imgView setMultipleTouchEnabled:YES]; _imageView = imgView; [_scrollView addSubview:imgView]; } #pragma mark UIScrollViewDelegate - (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView { return self.imageView; } - (void)doneWithRecognization { if ([self.imageExhibitionDelegate respondsToSelector:@selector(imageViewExhibitionDidClickDone:)]) { [self.imageExhibitionDelegate imageViewExhibitionDidClickDone:self]; } } - (void)toggleNavigationBar { if (self.navigationController.navigationBar.hidden) { self.navigationController.navigationBar.hidden = NO; [[UIApplication sharedApplication] setStatusBarHidden:NO]; } else { self.navigationController.navigationBar.hidden = YES; [[UIApplication sharedApplication] setStatusBarHidden:YES]; } self.navigationController.navigationBar.alpha = 0.7; self.navigationController.navigationBar.barStyle = UIBarStyleBlackTranslucent; CGRect rect = [UIScreen mainScreen].bounds; self.view.frame = CGRectMake(0, 0, rect.size.width, rect.size.height + rect.origin.y); self.view.backgroundColor = [UIColor blackColor]; } - (void)dismissPresentVC { self.navigationController.navigationBar.alpha = 1.0; self.navigationController.navigationBar.barStyle = UIBarStyleDefault; [self.navigationController popViewControllerAnimated:YES]; } @end
此处原文链接
http://stackoverflow.com/questions/500027/how-to-zoom-in-out-an-uiimage-object-when-user-pinches-screen
https://developer.apple.com/library/content/documentation/WindowsViews/Conceptual/UIScrollView_pg/ZoomZoom/ZoomZoom.html
其中重点就是：
1.在当前控制器添加一个UIScrollView，设置参数如下，并且实现代理方法
viewForZoomingInScrollView:- (void)viewDidLoad { [super viewDidLoad]; self.scrollView.minimumZoomScale = 0.5; self.scrollView.maximumZoomScale = 6.0; self.scrollView.contentSize = self.imageView.frame.size; self.scrollView.delegate = self; }
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView { return self.imageView; }
