CODEWITHSUNDEEP
swiftuiscrollviewuiimage
Kieran
Kieran

Reputation: 87

making an image the full size of a scrollview

I have set an image as a background in my scrollView so i can zoom in a pan around it, however, when the image is completely zoomed out it creates white borders to the left and right of the image which i can only assume is the scrollView margins.

Any way to get rid of these so the image fills the screen?

EDIT: here is a picture to show what i mean, the white bars along the sides of the grey background are the edges of the scrollview, i want the grey background to fill the screen completely apart from the iAd bar. https://i.sstatic.net/qX0Kk.png

Many thanks!

// 1
        let image = UIImage(named: "Photo1")!
        imageView = UIImageView(image: image)
        imageView.frame = CGRect(origin: CGPointMake(0, 0), size:image.size)
        
        // 2
        scrollView.addSubview(imageView)
        scrollView.contentSize = image.size
        
        // 3
        var doubleTapRecognizer = UITapGestureRecognizer(target: self, action: "scrollViewDoubleTapped:")
        doubleTapRecognizer.numberOfTapsRequired = 2
        doubleTapRecognizer.numberOfTouchesRequired = 1
        scrollView.addGestureRecognizer(doubleTapRecognizer)
        
        // 4
        let scrollViewFrame = scrollView.frame
        let scaleWidth = scrollViewFrame.size.width / scrollView.contentSize.width
        let scaleHeight = scrollViewFrame.size.height / scrollView.contentSize.height
        let minScale = min(scaleWidth, scaleHeight);
        scrollView.minimumZoomScale = minScale;
        
        // 5
        scrollView.maximumZoomScale = 1.0
        scrollView.zoomScale = minScale;
        
        // 6
        centerScrollViewContents()    }
    
    func centerScrollViewContents() {
        let boundsSize = scrollView.bounds.size
        var contentsFrame = imageView.frame
        
        if contentsFrame.size.width < boundsSize.width {
            contentsFrame.origin.x = (boundsSize.width - contentsFrame.size.width) / 2.0
        } else {
            contentsFrame.origin.x = 0.0
        }
        
        if contentsFrame.size.height < boundsSize.height {
            contentsFrame.origin.y = (boundsSize.height - contentsFrame.size.height) / 2.0
        } else {
            contentsFrame.origin.y = 0.0
        }
        
        imageView.frame = contentsFrame
        
    }
    
    func scrollViewDoubleTapped(recognizer: UITapGestureRecognizer) {
        // 1
        let pointInView = recognizer.locationInView(imageView)
        
        // 2
        var newZoomScale = scrollView.zoomScale * 1.5
        newZoomScale = min(newZoomScale, scrollView.maximumZoomScale)
        
        // 3
        let scrollViewSize = scrollView.bounds.size
        let w = scrollViewSize.width / newZoomScale
        let h = scrollViewSize.height / newZoomScale
        let x = pointInView.x - (w / 2.0)
        let y = pointInView.y - (h / 2.0)
        
        let rectToZoomTo = CGRectMake(x, y, w, h);
        
        // 4
        scrollView.zoomToRect(rectToZoomTo, animated: true)
    }
    
    func viewForZoomingInScrollView(scrollView: UIScrollView) -> UIView? {
        return imageView
    }
    
    func scrollViewDidZoom(scrollView: UIScrollView) {
        centerScrollViewContents()
    }

Upvotes: 0

Views: 845

Answers (1)

Chris Conover
Chris Conover

Reputation: 9039

You are setting the min zoomscale to be the min of width and height scales. This is generally desired, as it allows you to see the entire image (AspectFit). It sounds like you want AspectFill though, to do that, you would need to use the max of width and height scales.

let minScale = max(scaleWidth, scaleHeight);

Upvotes: 2

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