iOS17中UIImageView的allowsEdgeAntialiasing属性失效问题

在App中使用transform属性旋转UIImageView后，发现iOS 17系统下这些视图的边缘出现严重锯齿。此前通过设置视图layer的allowsEdgeAntialiasing = true可以解决该问题，且在其他iOS版本中均正常生效。

视图设置代码 #

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

尝试在.info文件中全局设置抗锯齿，结果无变化；将allowsEdgeAntialiasing设为false也不会改变渲染结果。

系统版本效果对比 #

iOS 16 效果 #

iOS 17 效果 #

补充测试示例 #

以下是完整的测试代码，用于对比UIImageView和UIView在iOS 16/17下的抗锯齿表现：

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

    }
    
}

测试示例包含两个UIImageView和两个UIView，右侧视图均设置了layer.allowsEdgeAntialiasing = true，效果对比如下：

iOS 16 测试效果 #

iOS 17 测试效果 #

内容的提问来源于stack exchange，提问作者displayname