How can I zoom an image inside a scroll view using objective c methods? Page control is also used here for paging the scroll view.

I have a pagecontrol using which I am managing a scroll view. Different pages in the scroll view contains imageviews. I want to zoom the images in that. Please help to find a solution. Following is my code.

              pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(0, self.navigationController.navigationBar.frame.size.height, self.view.bounds.size.width,self.view.bounds.size.height/3)];
                [self.view addSubview:pageControl];
                scrollView =[[UIScrollView alloc] initWithFrame:CGRectMake(0, self.navigationController.navigationBar.frame.size.height, self.view.bounds.size.width,self.view.bounds.size.height/3)];
                scrollView.contentSize = CGSizeMake(scrollView.frame.size.width * floorIdArray.count, scrollView.frame.size.height);
                for( int i=0;i<floorIdArray.count; i++) {
                    NSString *floorid = [[NSString alloc] initWithFormat:@"%@",[floorIdArray objectAtIndex:i]];
                    NSString *imagePath = @"http:/
                    imagePath = [imagePath stringByAppendingString:floorid];
                    CGRect frame;
                    frame.origin.x = scrollView.frame.size.width * i;
                    frame.origin.y = 0;
                    frame.size = scrollView.frame.size;
                    UIImageView* imgView = [[UIImageView alloc] init];
                    [imgView sd_setImageWithURL:[NSURL URLWithString:imagePath]
                                            placeholderImage:[UIImage imageNamed:@"imgmap.png"]];
                    imgView.frame = frame;
                    [scrollView addSubview:imgView];
                    UIPinchGestureRecognizer *pinchRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchDetected:)];
                    pinchRecognizer.delegate=self;
                    [scrollView addGestureRecognizer:pinchRecognizer];
                }
                pageControl.currentPage = 0;
                pageControl.numberOfPages = floorIdArray.count;
             
              
                [self.view addSubview:scrollView];