Lineで画像を見るときのような、ピンチイン後に画像の表示領域を指で動かせるような画面を作っているのですが、どうすればいいか分からず困っています。ScrollViewをベースにピンチイン・アウトは作ったのですが、ピンチイン後に画像の表示領域が動かせません。どのようにすればピンチイン後に画像の表示領域を動かすことができるでしょうか？どなたか分かる方がいれば教えていただきたいです。すみませんが、よろしくお願いします。

---追記---

UIPanGestureRecognizerを使うことでピンチイン後に画像の表示領域を動かすことができたのですが、画像を動かした後にピンチアウトすると、全てのViewの位置がずれてしまいます。
例えばピンチインしたいImageViewが画面の真ん中にあったとして、ピンチイン後にUIPanGestureRecognizerでその拡大されたImageViewを動かした後ピンチアウトすると、ImageViewが画面の真ん中に戻るのではなく、画面の右上だったり左下だったりします。
どうすれば元の位置にピンチアウト後画像を戻すことができるでしょうか？下記にコードを記します。すみませんが、よろしくお願いします。

ViewContoller.h

@interface ViewController : UIViewController<UIScrollViewDelegate>

@property (weak, nonatomic) IBOutlet UIImageView *imageButtonView;
@property (weak, nonatomic) IBOutlet UIImageView *cancelButton;

@end

ViewController.m

@implementation ViewController {
    UIPinchGestureRecognizer *pinchGestureRecognizer;
    UIPanGestureRecognizer *panGestureRecognizer;
}

bool isImageMax = false;

- (void)viewDidLoad {
    [super viewDidLoad];

    _imageButtonView.tag = 100;
    _imageButtonView.userInteractionEnabled = YES;
    _imageButtonView.multipleTouchEnabled = YES;
    _imageButtonView.image = [UIImage imageNamed:@"coupon.png"];

    _cancelButton.tag = 200;
    _cancelButton.userInteractionEnabled = YES;
    _cancelButton.hidden = YES;

    pinchGestureRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget: self action: @selector(pinchGesture:)];
    panGestureRecognizer = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(viewDragged:)];
}

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [[event allTouches] anyObject];

    if (touch.view.tag == _imageButtonView.tag) {
        self.view.backgroundColor = [UIColor blackColor];
        _imageButtonView.userInteractionEnabled = NO;

        [self imageMoveAndScale:1.0 scaleTo:2.0 moveFrom:_imageButtonView.layer.position moveTo:CGPointMake(self.view.center.x, self.view.center.y) duration:0.5];

    } else if (touch.view.tag == _cancelButton.tag) {

        [self imageMoveAndScale:2.0 scaleTo:1.0 moveFrom:CGPointMake(self.view.center.x, self.view.center.y) moveTo:_imageButtonView.layer.position duration:0];
    }
}

- (void)imageMoveAndScale:(float)scaleFrom scaleTo:(float)scaleTo moveFrom:(CGPoint)moveFrom moveTo:(CGPoint)moveTo duration:(float)duration {
    CABasicAnimation *scaleAnimation = [CABasicAnimation animationWithKeyPath:@"transform.scale"];
    scaleAnimation.fromValue = [NSNumber numberWithFloat:scaleFrom];
    scaleAnimation.toValue = [NSNumber numberWithFloat:scaleTo];

    CABasicAnimation *moveAnimation = [CABasicAnimation animationWithKeyPath:@"position"];
    moveAnimation.duration = duration;
    moveAnimation.repeatCount = 1;
    moveAnimation.fromValue = [NSValue valueWithCGPoint:moveFrom];
    moveAnimation.toValue = [NSValue valueWithCGPoint:moveTo];

    CAAnimationGroup *group = [CAAnimationGroup animation];
    group.duration = duration;
    group.repeatCount = 1;
    group.delegate = self;
    group.removedOnCompletion = NO;
    group.fillMode = kCAFillModeForwards;
    group.animations = [NSArray arrayWithObjects:scaleAnimation, moveAnimation, nil];
    [_imageButtonView.layer addAnimation:group forKey:@"move-scale-layer"];
}

- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
    return _imageButtonView;
}


- (CGFloat)distanceWithPointA:(CGPoint)pointA pointB:(CGPoint)pointB
{
    CGFloat dx = fabs( pointB.x - pointA.x );
    CGFloat dy = fabs( pointB.y - pointA.y );
    return sqrt(dx * dx + dy * dy);
}

- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag {
    if (isImageMax) {
        self.view.backgroundColor = [UIColor whiteColor];
        _cancelButton.hidden = YES;
        _imageButtonView.userInteractionEnabled = YES;
        isImageMax = false;

        [self.view removeGestureRecognizer:pinchGestureRecognizer];
        [self.view removeGestureRecognizer:panGestureRecognizer];

    } else {
        _cancelButton.hidden = NO;
        isImageMax = true;

        [self.view addGestureRecognizer: pinchGestureRecognizer];
    }
}

- (void)pinchGesture: (UIPinchGestureRecognizer *)gesture {
    if (gesture.scale > 1) {

        if (gesture.state == UIGestureRecognizerStateBegan) {
            CGFloat length = 300.0;

            [UIView animateWithDuration: 0.5 delay: 0.0 usingSpringWithDamping: 0.4 initialSpringVelocity: 0.8 options: UIViewAnimationOptionCurveEaseIn animations: ^{
                CGRect viewRect = _imageButtonView.frame;
                _imageButtonView.frame = CGRectMake(viewRect.origin.x + (viewRect.size.width - length) / 2.0, viewRect.origin.y + (viewRect.size.height - length) / 2.0, length, length);
            } completion: NULL];

            [self.view addGestureRecognizer:panGestureRecognizer];
            _cancelButton.hidden = YES;
        }

    } else {
        CGFloat length = 160.0;

        [UIView animateWithDuration: 0.5 delay: 0.0 usingSpringWithDamping: 0.4 initialSpringVelocity: 0.8 options: UIViewAnimationOptionCurveEaseIn animations: ^{
            CGRect viewRect = _imageButtonView.frame;
            _imageButtonView.frame = CGRectMake(viewRect.origin.x + (viewRect.size.width - length) / 2.0, viewRect.origin.y + (viewRect.size.height - length) / 2.0, length, length);
        } completion: NULL];

        [self.view removeGestureRecognizer:panGestureRecognizer];
        _cancelButton.hidden = NO;
    }
}

- (void)viewDragged:(UIPanGestureRecognizer *)recognizer
{
    UIGestureRecognizerState state = [recognizer state];

    if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged) {
        CGPoint translation = [recognizer translationInView:recognizer.view];
        [recognizer.view setTransform:CGAffineTransformTranslate(recognizer.view.transform, translation.x, translation.y)];
        [recognizer setTranslation:CGPointZero inView:recognizer.view];
    }
}

@end