setting view boundaries - objective-c

Question

I have a scrollview with an image as a subview. I would like to set the boundaries of the scrollview to be the size of the image view, so that you wouldn't be able to see any of the background.
I don't want this happening anymore.
The weird part is, that after you zoom in or out on the image, then the boundaries seem to fix themselves, and you can no longer move the image out of the way and see the background.
This is what I have going for code:
-(UIView *) viewForZoomingInScrollView:(UIScrollView *)scrollView
{
// return which subview we want to zoom
return self.imageView;
}
-(void)viewDidLoad{
[super viewDidLoad];
[self sendLogMessage:#"Second View Controller Loaded"];
//sets the initial view to scale to fit the screen
self.imageView.frame = CGRectMake(0, 0, CGRectGetWidth(self.view.bounds), CGRectGetHeight(self.view.bounds));
//sets the content size to be the size our our whole frame
self.scrollView.contentSize = self.imageView.image.size;
//setes the scrollview's delegate to itself
self.scrollView.delegate = self;
//sets the maximum zoom to 2.0, meaning that the picture can only become a maximum of twice as big
[self.scrollView setMaximumZoomScale : 2.5];
//sets the minimum zoom to 1.0 so that the scrollview can never be smaller than the image (no matter how far in/out we're zoomed)
[self.scrollView setMinimumZoomScale : 1.0];
[imageView addSubview:button];
}
I thought that this line would solve my problem
//sets the content size to be the size our our whole frame
self.scrollView.contentSize = self.imageView.image.size;
But like I said, it only works after I zoom in or out.
EDIT: When I switch
self.scrollView.contentSize = self.imageView.image.size;
to
self.scrollView.frame = self.imageView.frame;
It works like I want it to (you can't see the background), except the toolbar on the top is covered by the image.

Answer 1

imageView.image.size isn't necessarily the frame of the imageView itself, try setting the
scrollview.frame = imageView.frame
and then
scrollView.contentSize = imageView.image.size
Then you won't see any border. If you want the image to be the maximum size to start with,
do
imageView.frame = image.size;
[imageView setImage:image];
scrollView.frame = self.view.frame; //or desired size
[scrollView addSubView:imageView];
[scrollView setContentSize:image.size]; //or imageView.frame.size

Answer 2

To fix this, I ended up declaring a new CGRect , setting its origin to my scrollView's origin, setting its size with the bounds of my view, and then assigning this CGRect back to my scrollview frame
CGRect scrollFrame;
scrollFrame.origin = self.scrollView.frame.origin;
scrollFrame.size = CGSizeMake(CGRectGetWidth(self.view.bounds), CGRectGetHeight(self.view.bounds));
self.scrollView.frame = scrollFrame;