allowsEdgeAntialiasing not working on iOS17

I have some UIImageView rotated (using the transform property) in an app and I have noticed that on iOS17 the edges are heavily aliased, this is something I addressed originally by setting allowsEdgeAntialiasing to true in the layer of those views and it has been working in other versions of iOS just fine.

This is how the view is set up

        self.imageView.contentMode = .scaleAspectFill
        self.imageView.clipsToBounds = true
        self.imageView.backgroundColor = theme.BackgroundColor
        self.imageView.layer.borderWidth = theme.BorderSize
        self.imageView.alpha = theme.Alpha
        self.imageView.layer.borderColor = theme.BorderColor.cgColor
        self.imageView.layer.allowsEdgeAntialiasing = true

I tried setting the antialiasing globally in the .info file, but the result is the same. Setting allowsEdgeAntialiasing to false in the view doesn’t change the render result.

iOS 16 screenshot:

iOS 17 screenshot:

Edit

Quick complete example showing the issue:

class EdgeAntialiasingVC: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let g = view.safeAreaLayoutGuide

        let imageViewA = UIImageView()
        let imageViewB = UIImageView()
        
        let viewA = UIView()
        let viewB = UIView()
        
        let labelA = UILabel()
        let labelB = UILabel()
        
        [imageViewA, imageViewB, viewA, viewB].forEach { v in
            v.backgroundColor = .red
            v.translatesAutoresizingMaskIntoConstraints = false
            view.addSubview(v)
            v.layer.transform = CATransform3DMakeRotation(-.pi * 0.05, 0.0, 0.0, 1.0)
            NSLayoutConstraint.activate([
                v.widthAnchor.constraint(equalToConstant: 20.0),
                v.heightAnchor.constraint(equalToConstant: 30.0),
            ])
        }
        for (v, s) in zip([labelA, labelB], ["UIImageView", "UIView"]) {
            v.translatesAutoresizingMaskIntoConstraints = false
            view.addSubview(v)
            v.font = .systemFont(ofSize: 14.0, weight: .light)
            v.text = s
        }
        
        NSLayoutConstraint.activate([
            
            labelA.topAnchor.constraint(equalTo: g.topAnchor, constant: 20.0),
            labelA.leadingAnchor.constraint(equalTo: g.leadingAnchor, constant: 20.0),
            
            imageViewA.topAnchor.constraint(equalTo: labelA.bottomAnchor, constant: 4.0),
            imageViewB.topAnchor.constraint(equalTo: labelA.bottomAnchor, constant: 4.0),
            imageViewA.leadingAnchor.constraint(equalTo: g.leadingAnchor, constant: 20.0),
            imageViewB.leadingAnchor.constraint(equalTo: imageViewA.trailingAnchor, constant: 20.0),
            
            labelB.topAnchor.constraint(equalTo: imageViewA.bottomAnchor, constant: 12.0),
            labelB.leadingAnchor.constraint(equalTo: g.leadingAnchor, constant: 20.0),

            viewA.topAnchor.constraint(equalTo: labelB.bottomAnchor, constant: 4.0),
            viewB.topAnchor.constraint(equalTo: labelB.bottomAnchor, constant: 4.0),
            viewA.leadingAnchor.constraint(equalTo: g.leadingAnchor, constant: 20.0),
            viewB.leadingAnchor.constraint(equalTo: viewA.trailingAnchor, constant: 20.0),

        ])
        
        imageViewB.layer.allowsEdgeAntialiasing = true
        viewB.layer.allowsEdgeAntialiasing = true

    }
    
}

Two UIImageViews, and two UIViews … right-side views have .layer.allowsEdgeAntialiasing = true:

on iOS 16 – UIImageView and UIView both antialias the edges:

on iOS 17 – only UIView antialiases the edges: