iOS UILabel设置内边距

有时候我们希望可以设置UILabel的内边距，为了解决这个问题，设计MarginLabel如下，继承自UILabel：

class MarginLabel: UILabel {
    
    var contentInset: UIEdgeInsets = .zero
    
    override func textRect(forBounds bounds: CGRect, limitedToNumberOfLines numberOfLines: Int) -> CGRect {
        var rect: CGRect = super.textRect(forBounds: UIEdgeInsetsInsetRect(bounds, contentInset), limitedToNumberOfLines: numberOfLines)
        //根据edgeInsets，修改绘制文字的bounds
        rect.origin.x -= contentInset.left;
        rect.origin.y -= contentInset.top;
        rect.size.width += contentInset.left + contentInset.right;
        rect.size.height += contentInset.top + contentInset.bottom;
        return rect
    }
    
    override func drawText(in rect: CGRect) {
        super.drawText(in: UIEdgeInsetsInsetRect(rect, contentInset))
    }
}

实例化一个MarginLabel：

private lazy var marginLabel: MarginLabel = {
        MarginLabel().chain
            .text("测试UILabel内边距测试UILabel内边距测试UILabel内边距测试UILabel内边距测试UILabel内边距测试UILabel内边距")
            .backgroundColor(UIColor.gray)
            .textColor(UIColor.white)
            .numberOfLines(0)
            .build
}()

不设置内边距的时候：

AF6DA567-20B3-47FE-BE0C-406B144BDBD5.png

设置内边距：

marginLabel.contentInset = UIEdgeInsetsMake(10, 10, 10, 10)

效果：

CD59CDD8-EA90-4049-9210-B9534A9FDB4C.png