UITabBarController

1. 设置透明背景

tabBar.backgroundImage = UIImage()

2. 阻止系统渲染 tabBar.image

UITabBarItem 初始化方法init(title:image:selectedImage:)中有说明

By default, the actual unselected and selected images are automatically created from the alpha values in the source images. To prevent system coloring, provide images with UIImage.RenderingMode.alwaysOriginal.

因此如果想要阻止系统渲染 tabBar 图片，需要使用UIImage(named: "ta bImageName")?.withRenderingMode(.alwaysOriginal)的方式设置图片

3. tintColor 与 barTintColor

tintColor 可设置 tabBar title 颜色，barTintColor 设置 tabBar 背景色，如果想要在设置 tintColor 时不影响 tabBar 的标题，可使用

tabBarItem.setTitleTextAttributes([NSAttributedString.Key.foregroundColor: UIColor.init(rgb: 0x26000000),NSAttributedString.Key.font: font], for: .normal)

tabBarItem.setTitleTextAttributes([NSAttributedString.Key.foregroundColor: UIColor.white : UIColor.init(rgb: 0xFF9064E4),NSAttributedString.Key.font: font], for: .selected)