Image inside Scrollview with gestures - ios

Question

I have a control I'm making that includes having an image inside a scrollview, and I applied many gestures to it especially for zooming (pinch). Problem is, I want the scrollView's content size to match image new size without affecting:
Image center current location
Size
I can scroll to see all of image boundaries, with no extra space.
If there was anything not clear, please let me know.

Answer 1

You should do like this:
Swift3:
import UIKit
class ViewController: UIViewController,UIScrollViewDelegate
{
#IBOutlet weak var ScrollView: UIScrollView!
#IBOutlet weak var ScrollImgView: UIImageView!
override func viewDidLoad()
{
super.viewDidLoad()
self.ScrollView.minimumZoomScale = 0.1
self.ScrollView.maximumZoomScale = 5.0
ScrollView.isUserInteractionEnabled = true
}
func viewForZooming(in scrollView: UIScrollView) -> UIView?
{
return self.ScrollImgView
}
func scrollViewDidZoom(_ scrollView: UIScrollView)
{
let imgViewSize:CGSize! = self.ScrollImgView.frame.size;
let imageSize:CGSize! = self.ScrollImgView.image?.size;
var realImgSize : CGSize;
if(imageSize.width / imageSize.height > imgViewSize.width / imgViewSize.height)
{
realImgSize = CGSize(width: imgViewSize.width,height: imgViewSize.width / imageSize.width * imageSize.height);
}
else
{
realImgSize = CGSize(width: imgViewSize.height / imageSize.height * imageSize.width, height: imgViewSize.height);
}
var fr:CGRect = CGRect.zero
fr.size = realImgSize;
self.ScrollImgView.frame = fr;
let scrSize:CGSize = scrollView.frame.size;
let offx:CGFloat = (scrSize.width > realImgSize.width ? (scrSize.width - realImgSize.width) / 2 : 0);
let offy:CGFloat = (scrSize.height > realImgSize.height ? (scrSize.height - realImgSize.height) / 2 : 0);
scrollView.contentInset = UIEdgeInsetsMake(offy, offx, offy, offx);
let scrollViewSize:CGSize = self.scrollViewVisibleSize();
var imageCenter:CGPoint = CGPoint(x: self.ScrollView.contentSize.width/2.0, y:
self.ScrollView.contentSize.height/2.0);
let scrollViewCenter:CGPoint = self.scrollViewCenter()
if (self.ScrollView.contentSize.width < scrollViewSize.width)
{
imageCenter.x = scrollViewCenter.x;
}
if (self.ScrollView.contentSize.height < scrollViewSize.height)
{
imageCenter.y = scrollViewCenter.y;
}
self.ScrollImgView.center = imageCenter;
}
func scrollViewCenter() -> CGPoint
{
let scrollViewSize:CGSize = self.scrollViewVisibleSize()
return CGPoint(x: scrollViewSize.width/2.0, y: scrollViewSize.height/2.0);
}
func scrollViewVisibleSize() -> CGSize
{
let contentInset:UIEdgeInsets = self.ScrollView.contentInset;
let scrollViewSize:CGSize = self.ScrollView.bounds.standardized.size;
let width:CGFloat = scrollViewSize.width - contentInset.left - contentInset.right;
let height:CGFloat = scrollViewSize.height - contentInset.top - contentInset.bottom;
return CGSize(width:width, height:height);
}
override func didReceiveMemoryWarning()
{
super.didReceiveMemoryWarning()
}
}