Question

I have the following code in ViewDidLoad and it squashes my UIImage/ UIImageView. I want the image to fill the UIScrollView.

[super viewDidLoad];

_imageHolder = [[UIImageView alloc]initWithFrame:self.view.frame];
_scrollView = [[UIScrollView alloc]initWithFrame:self.view.frame]; 

[_scrollView setBackgroundColor:[UIColor purpleColor]];

// Tell the scroll view the size of the contents
self.scrollView.contentSize = self.view.frame.size;

self.scrollView.delegate = self;
self.scrollView.scrollEnabled = YES;

FfThumbnailData* thumbData = [self.arrayOfImages objectAtIndex:self.thisImageIndex];
UIImage* fullSizedImage = [[UIImage alloc]initWithContentsOfFile:thumbData.path];
[self.imageHolder setImage:fullSizedImage];
float x = fullSizedImage.size.width;
float y = fullSizedImage.size.height;
CGRect rect = CGRectMake(0, 0, x, y);
NSLog(@"Size of image: %@", NSStringFromCGRect(rect));
//
//[self.imageHolder setImage:[UIImage imageNamed:@"P1020486.png"]];

[self.scrollView addSubview:_imageHolder];
[self.view addSubview:self.scrollView];

_imageHolder.contentMode = UIViewContentModeScaleAspectFit;

I set the backgound of the UIScrollView to purple for clarity:

http://i1219.photobucket.com/albums/dd427/Dave_Chambers/IMG_0315.png

I should add that after I zoom in and then zoom out, the image IS correctly placed in the scrollview and not squashed.

Strangely, the commented line [self.imageHolder setImage:[UIImage imageNamed:@"P1020486.png"]]; correctly displays the dummy image P1020486.png.

Also, when I download my app data, the image looks right and is indeed the correct size of an iPad image – {1936, 2592} – the size reported by my NSLog line NSLog(@"Size of image: %@", NSStringFromCGRect(rect));

Further, before I needed a UIScrollView (for zooming the photo in the full size View Controller) I access the same image and display it via an animation from one View Controller to another with the following code and it displays correctly. Crucially thought, this second section of code lacks a UIScollview.

-(void)animateTransition:(int)buttonInPositon {
@try {

FfThumbnailData* thumbData = [self.images objectAtIndex:buttonInPositon];
UIImage* fullSizedImage = [[UIImage alloc]initWithContentsOfFile:thumbData.path];
fullSize = [[FullSizeViewController alloc]init];
fullSize.imageHolderGhost.contentMode = UIViewContentModeScaleAspectFit;
fullSize.arrayOfImages = self.images;
fullSize.imageToPresent = fullSizedImage;
fullSize.numberOfImages = self.images.count;
fullSize.thisImageIndex = buttonInPositon;
[fullSize.imageHolderGhost setImage:fullSizedImage];

float screenWidth = self.view.bounds.size.width;
float screenHeight = self.view.bounds.size.height;

NSLog(@"ButtonFrame: %@", NSStringFromCGRect(buttonFrame));
[fullSize.view setFrame:CGRectMake(buttonFrame.origin.x, buttonFrame.origin.y, buttonFrame.size.width, buttonFrame.size.height-44)];
NSLog(@"ButtonFrame: %@", NSStringFromCGRect(fullSize.view.frame));

[self.view addSubview:fullSize.view];

fullSize.view.backgroundColor = [UIColor clearColor];
[UIView animateWithDuration:0.9 delay:0 options:UIViewAnimationCurveEaseIn animations:^{

    [fullSize.view setFrame:CGRectMake(0, 0, screenWidth, screenHeight)];


} completion:^(BOOL finished){
    [[self navigationController] pushViewController:fullSize animated:NO];
    self.navigationController.navigationBarHidden = YES;
}];
}
@catch (NSException *exception) {
    NSLog(@"%@", exception);
}
}

For completeness, the code with the UIScrollView has the following method in one VC:

-(void)presentWithScrollview:(int)buttonInPositon {

FfThumbnailData* thumbData = [self.images objectAtIndex:buttonInPositon];
UIImage* fullSizedImage = [[UIImage alloc]initWithContentsOfFile:thumbData.path];

fullSize = [[FullSizeViewController alloc]init];

fullSize.arrayOfImages = self.images;
fullSize.imageToPresent = fullSizedImage;
fullSize.numberOfImages = self.images.count;
fullSize.thisImageIndex = buttonInPositon;

[[self navigationController] pushViewController:fullSize animated:NO];
    self.navigationController.navigationBarHidden = YES;
}

and in the destination VC the following methods may be relevant to my problem (ViewDidLoad pasted at the top of this question):

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];

    // Set up the minimum & maximum zoom scales
    CGRect scrollViewFrame = self.scrollView.frame;
    CGFloat scaleWidth = scrollViewFrame.size.width / self.scrollView.contentSize.width;
    CGFloat scaleHeight = scrollViewFrame.size.height / self.scrollView.contentSize.height;
    CGFloat minScale = MIN(scaleWidth, scaleHeight);
    //
self.scrollView.minimumZoomScale = minScale;
//Can set this bigger if needs be - match iPhoto
self.scrollView.maximumZoomScale = 2.0f;

[self centerScrollViewContents];
}

- (void)centerScrollViewContents {
CGSize boundsSize = self.scrollView.bounds.size;
//NSLog(@"boundsSize: %@", NSStringFromCGSize(boundsSize));
CGRect contentsFrame = self.imageHolder.frame;
//NSLog(@"contentsFrame: %@", NSStringFromCGRect(contentsFrame));

if (contentsFrame.size.width < boundsSize.width) {
    contentsFrame.origin.x = (boundsSize.width - contentsFrame.size.width) / 2.0f;
} else {
    contentsFrame.origin.x = 0.0f;
}

if (contentsFrame.size.height < boundsSize.height) {
    contentsFrame.origin.y = (boundsSize.height - contentsFrame.size.height) / 2.0f;
} else {
    contentsFrame.origin.y = 0.0f;
}

self.imageHolder.frame = contentsFrame;
}

#pragma mark - UIScrollViewDelegate

- (UIView*)viewForZoomingInScrollView:(UIScrollView *)scrollView {
// Return the view that we want to zoom
return self.imageHolder;
//return self.scrollViewBar;
}

- (void)scrollViewDidZoom:(UIScrollView *)scrollView {
// The scroll view has zoomed, so we need to re-center the contents
[self centerScrollViewContents];
    }

Any help on this would be great. Thanks

Answer 1

So, I found the solution myself. For some reason, as I wrote in my update to the question, any zooming in, followed by zooming out of the image fixed the image problem and presented it properly. I added these two lines to viewWillAppear, above [self centerScrollViewContents];

self.scrollView.zoomScale = 2.0;
self.scrollView.zoomScale = 1.0;

Problem solved