设置Material Symbols后UIImageView不遵循NSLayoutConstraints的修复方案

我在代码中使用基础UIImageView，并从Material Symbols设置图片。设置Symbol后，UIImageView不再遵守NSLayoutConstraints，自行调整大小，导致无法实现完美圆角。

附上代码：

import UIKit

func Image(_ name: String, weight: UIImage.SymbolWeight, scale: UIImage.SymbolScale) -> UIImage {
    
    let configuration = UIImage.SymbolConfiguration(weight: weight)
        .applying(UIImage.SymbolConfiguration(scale: scale))
    return UIImage(named: name, in: nil, with: configuration)!
}


class ViewController: UIViewController {

    private lazy var imageView: UIImageView = {
    
        let view = UIImageView()
        self.view.addSubview(view)
        view.translatesAutoresizingMaskIntoConstraints = false
        
        let size: CGFloat = 64
       
        NSLayoutConstraint.activate([
        
            view.leftAnchor.constraint(equalTo: self.view.leftAnchor, constant: 8),
            view.topAnchor.constraint(greaterThanOrEqualTo: self.view.topAnchor, constant: 8),
            view.bottomAnchor.constraint(lessThanOrEqualTo: self.view.bottomAnchor, constant: -8),
            view.centerYAnchor.constraint(equalTo: self.view.centerYAnchor),
            view.widthAnchor.constraint(equalToConstant: size),
            view.heightAnchor.constraint(equalToConstant: size)
        ])
 
        view.layer.cornerRadius = size / 2
        
        view.contentMode = .scaleAspectFit
        return view
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        view.backgroundColor = .black
        imageView.backgroundColor = UIColor.white
        imageView.tintColor = .black
        imageView.image = Image("info", weight: .light, scale: .small)
        
    }
}

我想要实现完美的圆形效果，但目前无法做到：

核心问题是系统会为Symbol图片自动添加额外内边距，导致UIImageView的背景区域被压缩，圆角无法完全贴合。以下是几种可行的解决方式：

方法1：开启裁剪（最简单有效） #

在初始化imageView时，添加clipsToBounds = true，强制裁剪超出layer圆角范围的内容：

private lazy var imageView: UIImageView = {
    let view = UIImageView()
    self.view.addSubview(view)
    view.translatesAutoresizingMaskIntoConstraints = false
    
    let size: CGFloat = 64
   
    NSLayoutConstraint.activate([
        view.leftAnchor.constraint(equalTo: self.view.leftAnchor, constant: 8),
        view.topAnchor.constraint(greaterThanOrEqualTo: self.view.topAnchor, constant: 8),
        view.bottomAnchor.constraint(lessThanOrEqualTo: self.view.bottomAnchor, constant: -8),
        view.centerYAnchor.constraint(equalTo: self.view.centerYAnchor),
        view.widthAnchor.constraint(equalToConstant: size),
        view.heightAnchor.constraint(equalToConstant: size)
    ])

    view.layer.cornerRadius = size / 2
    // 添加这一行开启裁剪
    view.clipsToBounds = true
    view.contentMode = .scaleAspectFit
    return view
}()

方法2：关闭Symbol的自动内边距 #

创建Symbol图片时，通过配置取消系统自动添加的内边距：

func Image(_ name: String, weight: UIImage.SymbolWeight, scale: UIImage.SymbolScale) -> UIImage {
    // 用pointSize:0的配置，让系统不添加额外内边
    let configuration = UIImage.SymbolConfiguration(pointSize: 0, weight: weight, scale: scale)
    return UIImage(named: name, in: nil, with: configuration)!
}

方法3：调整Symbol渲染模式 #

将Symbol图片设置为原始渲染模式，配合tintColor使用，避免内边距影响：

override func viewDidLoad() {
    super.viewDidLoad()
    
    view.backgroundColor = .black
    imageView.backgroundColor = UIColor.white
    imageView.tintColor = .black
    // 添加渲染模式设置
    imageView.image = Image("info", weight: .light, scale: .small).withRenderingMode(.alwaysOriginal)
}

内容的提问来源于stack exchange，提问作者Vin