Image is stretching while Pinch

Question

I'm getting images from remote server and displaying in UIImageView then doing pinch gesture to this imageview. But when i pinching image, i'm getting image stretching. It's loosing original resolution and quality.

mmageView=[[UIImageView alloc]initWithFrame:CGRectMake(50,50,150,150)];
 [self.view addSubview:mmageView];

 UIPinchGestureRecognizer *dbpinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(dbhandlePinch:)];
 [mmageView addGestureRecognizer:dbpinchGesture];

UIPinchGesture:

 -(void)dbhandlePinch:(UIPinchGestureRecognizer*)recognizer {

 if([recognizer state] == UIGestureRecognizerStateBegan) {
 // Reset the last scale, necessary if there are multiple objects with different scales
 LastScale = [recognizer scale];
 }

 if ([recognizer state] == UIGestureRecognizerStateBegan ||
 [recognizer state] == UIGestureRecognizerStateChanged) {

 CGFloat currentScale = [[[recognizer view].layer valueForKeyPath:@"transform.scale"] floatValue];

 // Constants to adjust the max/min values of zoom
 // const CGFloat kMaxScale = 2.0;
 const CGFloat kMinScale = 0.8;

 CGFloat newScale = 1 -  (LastScale - [recognizer scale]);
 // newScale = MIN(newScale, kMaxScale / currentScale);
 newScale = MAX(newScale, kMinScale / currentScale);
 CGAffineTransform transform = CGAffineTransformScale([[recognizer view] transform], newScale, newScale);
 [recognizer view].transform = transform;

 LastScale = [recognizer scale];  // Store the previous scale factor for the next pinch gesture call
 }

 }

That's probably expected, CGAffineTransformScale isn't going to preserve quality. — brandonscript, Apr 02 '14 at 04:43
imageView.contentMode = UIViewContentModeScaleAspectFit; Is it? — user3351727, Apr 02 '14 at 04:47
Should i use below code ? mmageView=[[UIImageView alloc]initWithFrame:CGRectMake(50,50,150,150)]; — user3351727, Apr 02 '14 at 04:49
mmageView=[[UIImageView alloc]initWithFrame:CGRectMake(50,50,150,150)]; mmageView.contentMode = UIViewContentModeScaleAspectFit; — Arun, Apr 02 '14 at 04:51
No. It's not working for me. I'm loosing original resolution of image — user3351727, Apr 02 '14 at 05:26
check my answer. if it is working for you please accept the answer. — Vineesh TP, Apr 02 '14 at 06:13
@Spynet: Does original image size cause problem? Because i used different CGRect in code — user3351727, Apr 02 '14 at 07:21

score 1 · Answer 1 · answered Apr 02 '14 at 04:54

1

For pinch zoom add your imageView in a scrollView and Import UIScrollViewDelegate

- (void)viewDidLoad
{
    [super viewDidLoad];

    //for pinch gesture
    _scrollView.minimumZoomScale = 0.5;
    _scrollView.maximumZoomScale = 6.0;
    _scrollView.contentSize = CGSizeMake(_imageView.frame.size.width, _imageView.frame.size.height);
    _scrollView.delegate = self;

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

answered Apr 02 '14 at 04:54

Vineesh TP

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Did you subview imageview on scrollview – Vineesh TP Apr 02 '14 at 06:37
did you Import ' ' ? – Vineesh TP Apr 02 '14 at 08:58
Check delegate connect with scrollView. – Vineesh TP Apr 02 '14 at 12:24

score 0 · Answer 2 · answered Apr 02 '14 at 06:17

0

UIScrollView makes supporting the pinch gestures for zooming easy. Better solution in Apple Documentation.

answered Apr 02 '14 at 06:17

iOS

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Image is stretching while Pinch

2 Answers2