////  RootViewController.m//  ScrollView////  Copyright (c) 2014年 Y.X. All rights reserved.//#import "RootViewController.h"@interface RootViewController ()<UIScrollViewDelegate>{    BOOL tapped;}@property (nonatomic, strong) UIScrollView           *scrollView;@property (nonatomic, strong) UIImageView            *imageView;@property (strong, nonatomic) UITapGestureRecognizer *tapGesture;@end@implementation RootViewController- (void)viewDidLoad{    [super viewDidLoad];    self.view.backgroundColor = [UIColor blackColor];        // scrollView    {        _scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 200, 200)];        [self.view addSubview:_scrollView];                _scrollView.center              = self.view.center;        _scrollView.delegate            = self;        _scrollView.layer.borderWidth   = 2.f;        _scrollView.layer.borderColor   = [UIColor redColor].CGColor;        _scrollView.layer.masksToBounds = NO;                // 不显示滚动的条        _scrollView.showsHorizontalScrollIndicator = NO;        _scrollView.showsVerticalScrollIndicator   = NO;        _scrollView.bouncesZoom      = YES;        _scrollView.minimumZoomScale = 1.f;        _scrollView.maximumZoomScale = 10.f;        _scrollView.contentMode      = UIViewContentModeScaleAspectFit;    }        // 图片    _imageView       = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 200, 200)];    _imageView.image = [UIImage imageNamed:@"back"];    _imageView.contentMode = UIViewContentModeScaleAspectFit;    [_scrollView addSubview:_imageView];        // 手势    _tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self                                                          action:@selector(tapRecognized:)];    [_scrollView addGestureRecognizer:_tapGesture];}- (void)tapRecognized:(id)sender{    if (!tapped)    {        CGPoint tapPoint = [self.tapGesture locationOfTouch:0                                                     inView:self.tapGesture.view];        CGRect zoomRect = [self zoomRectForScrollView:self.scrollView                                            withScale:6.0f                                           withCenter:tapPoint];        [self.scrollView zoomToRect:zoomRect animated:YES];        tapped = YES;    }    else    {        [self.scrollView setZoomScale:1.0f animated:YES];        tapped = NO;    }}- (CGRect)zoomRectForScrollView:(UIScrollView *)scrollView                      withScale:(float)scale                     withCenter:(CGPoint)center{    CGRect zoomRect;    zoomRect.size.height = scrollView.frame.size.height / scale;    zoomRect.size.width  = scrollView.frame.size.width / scale;    zoomRect.origin.x    = center.x - (zoomRect.size.width / 2.0);    zoomRect.origin.y    = center.y - (zoomRect.size.height / 2.0);    return zoomRect;}#pragma mark - UIScrollView代理方法- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{    return self.imageView;}@end