UIScrollView缩放

- (void)viewDidLoad{

    UIScrollView *sv2 = [[UIScrollView
alloc]initWithFrame:self.view.bounds];
    sv2.delegate =
self;

    sv2.minimumZoomScale =
1;

    sv2.maximumZoomScale =
10;

    float scale =
self.view.frame.size.height/self.view.frame.size.width;
   
NSLog(@"%f",scale);
   
UIImageView *iv1 = [[UIImageView
alloc]initWithFrame:CGRectMake(0,
0,
2960/8,
3208/8)];

    iv1.image = [UIImage
imageNamed:@"tool_subwayLine.gif"];
    [sv2
addSubview:iv1];

    UITapGestureRecognizer *tap = [[UITapGestureRecognizer
alloc]initWithTarget:self
action:@selector(tap:)];

    tap.numberOfTapsRequired =
2;

    [sv2 addGestureRecognizer:tap];
    sv2.zoomScale=3;

    //[sv2 setContentSize:CGSizeMake(320*4, 347*4)];
    [self.view
addSubview:sv2];
}

- (void)tap:(UITapGestureRecognizer *)tap {

    UIScrollView *sv = (UIScrollView *)tap.view;

    
   
if (sv.zoomScale >=
4){
        sv.zoomScale =
1;
    }else sv.zoomScale=4;
}
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{
   
return [scrollView.subviews
firstObject];
}