處理縮放手勢

// 處理縮放手勢
- (void) pinchView:(UIPinchGestureRecognizer *)pinchGestureRecognizer
{
    NSLog(@"---%ld",pinchGestureRecognizer.state);
    NSLog(@"=====%f",pinchGestureRecognizer.scale);
    UIView *view = pinchGestureRecognizer.view;
    
    if (pinchGestureRecognizer.state == UIGestureRecognizerStateBegan || pinchGestureRecognizer.state == UIGestureRecognizerStateChanged)
    {
        if (view.transform.a<_oldTransform.a/2||view.transform.a>_oldTransform.a*3) {
            return;
        }
        view.transform = CGAffineTransformScale(view.transform, pinchGestureRecognizer.scale, pinchGestureRecognizer.scale);
        pinchGestureRecognizer.scale = 1;
       
    }
    if (pinchGestureRecognizer.state ==UIGestureRecognizerStateEnded||pinchGestureRecognizer.state==UIGestureRecognizerStateCancelled||pinchGestureRecognizer.state== UIGestureRecognizerStateFailed)
    {
        
        if (view.transform.a < _oldTransform.a) {
            [UIView animateWithDuration:.3 animations:^{
                _imageView.transform = CGAffineTransformScale(_oldTransform, 1, 1 );
                
            }];
    
            
        }else if (view.transform.a>_oldTransform.a*2){
            [UIView animateWithDuration:.3 animations:^{
                 _imageView.transform = CGAffineTransformScale(_oldTransform, 2,2 );
            }];
        }

    }
}