Issue with UIPinchGestureRecognizer and UIImageView - iphone

Question

I am trying to pinch an image via UIPinchGestureRecognizer but , the problem is my code does not work properly and actually it could not zoom my image
-(void) pinching: (UIPinchGestureRecognizer *) sender {
CGAffineTransform myTransformation =
CGAffineTransformMakeScale(sender.scale, sender.scale);
sender.view.transform = myTransformation;
}
- (void)viewDidLoad
{
UIPinchGestureRecognizer *pinch =
[[UIPinchGestureRecognizer alloc]
initWithTarget:self
action:#selector(pinching:)];
pinch.delegate = self;
[imageBG addGestureRecognizer:pinch];
[imageBG setUserInteractionEnabled:YES];
[imageBG setMultipleTouchEnabled:YES];
}

Answer 1

Try using a UIScrollView.
To do this, create it
self.scrollView = [[UIScrollView alloc] initWithFrame:...];
self.scrollView.delegate = self;
self.scrollView.maximumZoomScale = 2.0; // adjust as you need
self.scrollView.minimumZoomScale = 0.5; // adjust as you need
[self.scrollView addSubview:self.imageView];
and add the delegate method:
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
return self.imageView;
}

Answer 2

just take one variable in .h file like bellow..
CGFloat lastScale;
and use this type of code...
in viewWillAppear: method just add it..
- (void)viewWillAppear:(BOOL)animated
{
UIPinchGestureRecognizer *pinchRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:#selector(scale:)];
[pinchRecognizer setDelegate:self];
[yourImageView addGestureRecognizer:pinchRecognizer];
}
-(void)scale:(id)sender {
if([(UIPinchGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded) {
lastScale = 1.0;
return;
}
CGFloat scale = 1.0 - (lastScale - [(UIPinchGestureRecognizer*)sender scale]);
CGAffineTransform currentTransform = [(UIPinchGestureRecognizer*)sender view].transform;
CGAffineTransform newTransform = CGAffineTransformScale(currentTransform, scale, scale);
[[(UIPinchGestureRecognizer*)sender view] setTransform:newTransform];
yourImageView.transform = newTransform
lastScale = [(UIPinchGestureRecognizer*)sender scale];
}
try this code also..

Answer 3

You need to add a scrollView to enable zooming. Add your imageView as a subView of the scroll view. Set the delegate for UIScrollViewDelegate to self. Implement the delegate methods.
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
//return the imageview here
return self.imageView;
}
Scale your imageview here:
- (CGRect)zoomRectForScrollView:(UIScrollView *)scrollView withScale:(float)scale withCenter:(CGPoint)center
You can refer this example from Apple .