两指缩放功能不仅可以用UIPinchGestureRecognizer手势来实现，还能用UIScorllView来实现，UIScrollView可以轻松的实现最大与最小缩放值，以及滚动的效果。代码如下：
#import "ViewController.h"
@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIScrollView *scrollView;
@property (strong, nonatomic) UIImageView *imageView;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
_scrollView.minimumZoomScale = 1.0; // 最小缩放值
_scrollView.maximumZoomScale = 10.0; // 最大缩放值
[_scrollView setZoomScale:_scrollView.minimumZoomScale]; // 初始时候的缩放值
_scrollView.delegate = self;
_imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"image"]];
_imageView.frame = self.view.frame;
[_scrollView addSubview:_imageView];
}
#pragma mark - 返回需要缩放的控件
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
return _imageView;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
@end
关键点就是调用viewForZoomingInScrollView:代理方法，这里返回了需要缩放的控件。
