支持上下左右图片文字布局的 button，支持 xib

Button.swift

import UIKit

@IBDesignable
class Button: UIButton {
    enum TextPosition: Int {
        case top
        case left
        case bottom
        case right
    }
    
    @IBInspectable private var position: Int {
        set {
            textPosition = TextPosition(rawValue: newValue) ?? .right
        }
        
        get {
            return textPosition.rawValue
        }
    }
    
    var textPosition: TextPosition = .right
    @IBInspectable var spacing: CGFloat = 0
    
    // in case frame pixel
    func scaleFloor(_ value: CGFloat) -> CGFloat {
        return floor(value * UIScreen.main.scale) / UIScreen.main.scale
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        
        if currentImage == nil {
            return
        }
        
        if currentTitle == nil {
            return
        }
        
        guard let titleLabel = titleLabel, let imageView = imageView else {
            return
        }
        
        let textIntrinsicSize = titleLabel.intrinsicContentSize
        let imageIntrinsicSize = imageView.intrinsicContentSize
        
        switch textPosition {
        case .top:
            let textWidth = textIntrinsicSize.width
            let textHeight = textIntrinsicSize.height
            let imageWidth = imageIntrinsicSize.width
            let imageHeight = imageIntrinsicSize.height
            let totalHeight = textHeight + spacing + imageHeight
            
            titleLabel.bounds.size = textIntrinsicSize
            titleLabel.frame.origin.x = scaleFloor((bounds.width - textWidth)/2)
            titleLabel.frame.origin.y = scaleFloor((bounds.height - totalHeight)/2)
            
            imageView.bounds.size = imageIntrinsicSize
            imageView.frame.origin.x = scaleFloor((bounds.width - imageWidth)/2)
            imageView.frame.origin.y = scaleFloor(titleLabel.frame.maxY) + spacing
        case .bottom:
            let textWidth = textIntrinsicSize.width
            let textHeight = textIntrinsicSize.height
            let imageWidth = imageIntrinsicSize.width
            let imageHeight = imageIntrinsicSize.height
            let totalHeight = imageHeight + spacing + textHeight
            
            imageView.bounds.size = imageIntrinsicSize
            imageView.frame.origin.x = scaleFloor((bounds.width - imageWidth)/2)
            imageView.frame.origin.y = scaleFloor((bounds.height - totalHeight)/2)
            
            titleLabel.bounds.size = textIntrinsicSize
            titleLabel.frame.origin.x = scaleFloor((bounds.width - textWidth)/2)
            titleLabel.frame.origin.y = scaleFloor(imageView.frame.maxY) + spacing
        case .left:
            let imageWidth = imageIntrinsicSize.width
            let imageHeight = imageIntrinsicSize.height
            let textWidth = textIntrinsicSize.width
            let textHeight = textIntrinsicSize.height
            let totalWidth = textWidth + spacing + imageWidth

            titleLabel.bounds.size = textIntrinsicSize
            titleLabel.frame.origin.y = scaleFloor((bounds.height - textHeight)/2)
            titleLabel.frame.origin.x = scaleFloor((bounds.width - totalWidth)/2)
            
            imageView.bounds.size = imageIntrinsicSize
            imageView.frame.origin.y = scaleFloor((bounds.height - imageHeight)/2)
            imageView.frame.origin.x = scaleFloor(titleLabel.frame.maxX) + spacing
        case .right:
            let imageWidth = imageIntrinsicSize.width
            let imageHeight = imageIntrinsicSize.height
            let textWidth = textIntrinsicSize.width
            let textHeight = textIntrinsicSize.height
            let totalWidth = imageWidth + spacing + textWidth
            
            imageView.bounds.size = imageIntrinsicSize
            imageView.frame.origin.y = scaleFloor((bounds.height - imageHeight)/2)
            imageView.frame.origin.x = scaleFloor((bounds.width - totalWidth)/2)
            
            titleLabel.bounds.size = textIntrinsicSize
            titleLabel.frame.origin.y = scaleFloor((bounds.height - textHeight)/2)
            titleLabel.frame.origin.x = scaleFloor(imageView.frame.maxX) + spacing
        }
    }
    
    override var intrinsicContentSize: CGSize {
        if currentImage == nil {
            return super.intrinsicContentSize
        }
        
        if currentTitle == nil {
            return super.intrinsicContentSize
        }
        
        guard let titleLabel = titleLabel, let imageView = imageView else {
            return super.intrinsicContentSize
        }
        
        let textSize = titleLabel.intrinsicContentSize
        let imageSize = imageView.intrinsicContentSize
        switch textPosition {
        case .top, .bottom:
            let width = contentEdgeInsets.left + max(textSize.width, imageSize.width) + contentEdgeInsets.right
            let height = contentEdgeInsets.top + textSize.height + spacing + imageSize.height + contentEdgeInsets.bottom
            return CGSize(width: width, height: height)
        case .left, .right:
            let height = contentEdgeInsets.top + max(textSize.height, imageSize.height) + contentEdgeInsets.bottom
            let width = contentEdgeInsets.left + textSize.width + spacing + imageSize.width + contentEdgeInsets.right
            return CGSize(width: width, height: height)
        }
    }
}