BFCommonKit/BFCommonKit/Classes/BFCategorys/BFUIButton+ext.swift

//
//  UIButton+ext.swift
//  PQSpeed
//
//  Created by ak on 2020/8/14.
//  Copyright © 2020 BytesFlow. All rights reserved.
//
/**
 UIButton图像文字同时存在时---图像相对于文字的位置

 - top:    图像在上
 - left:   图像在左
 - right:  图像在右
 - bottom: 图像在下
 */
public enum PQButtonImageEdgeInsetsStyle {
    case top, left, right, bottom
}

import Foundation
public extension UIButton {
    func imagePosition(at style: PQButtonImageEdgeInsetsStyle, space: CGFloat) {
        guard let imageV = imageView else { return }
        guard let titleL = titleLabel else { return }
        // 获取图像的宽和高
        let imageWidth = imageV.frame.size.width
        let imageHeight = imageV.frame.size.height
        // 获取文字的宽和高
        let labelWidth = titleL.frame.size.width
        let labelHeight = titleL.frame.size.height

        var imageEdgeInsets = UIEdgeInsets.zero
        var labelEdgeInsets = UIEdgeInsets.zero
        // UIButton同时有图像和文字的正常状态---左图像右文字，间距为0
        switch style {
        case .left:
            // 正常状态--只不过加了个间距
            imageEdgeInsets = UIEdgeInsets(top: 0, left: -space * 0.5, bottom: 0, right: space * 0.5)
            labelEdgeInsets = UIEdgeInsets(top: 0, left: space * 0.5, bottom: 0, right: -space * 0.5)
        case .right:
            // 切换位置--左文字右图像
            // 图像：UIEdgeInsets的left是相对于UIButton的左边移动了labelWidth + space * 0.5，right相对于label的左边移动了-labelWidth - space * 0.5
            imageEdgeInsets = UIEdgeInsets(top: 0, left: labelWidth + space * 0.5, bottom: 0, right: -labelWidth - space * 0.5)
            labelEdgeInsets = UIEdgeInsets(top: 0, left: -imageWidth - space * 0.5, bottom: 0, right: imageWidth + space * 0.5)
        case .top:
            // 切换位置--上图像下文字
            /** 图像的中心位置向右移动了labelWidth * 0.5，向上移动了-imageHeight * 0.5 - space * 0.5
              *文字的中心位置向左移动了imageWidth * 0.5，向下移动了labelHeight*0.5+space*0.5
             */
            imageEdgeInsets = UIEdgeInsets(top: -(imageHeight * 0.5 - space), left: labelWidth * 0.5, bottom: imageHeight * 0.5 - space, right: -labelWidth * 0.5)
            labelEdgeInsets = UIEdgeInsets(top: labelHeight * 0.5 + space * 2, left: -imageWidth * 0.5, bottom: -(labelHeight * 0.5 + space * 2), right: imageWidth * 0.5)
        case .bottom:
            // 切换位置--下图像上文字
            /** 图像的中心位置向右移动了labelWidth * 0.5，向下移动了imageHeight * 0.5 + space * 0.5
             *文字的中心位置向左移动了imageWidth * 0.5，向上移动了labelHeight*0.5+space*0.5
             */
            imageEdgeInsets = UIEdgeInsets(top: imageHeight * 0.5 + space * 0.5, left: labelWidth * 0.5, bottom: -imageHeight * 0.5 - space * 0.5, right: -labelWidth * 0.5)
            labelEdgeInsets = UIEdgeInsets(top: -labelHeight * 0.5 - space * 0.5, left: -imageWidth * 0.5, bottom: labelHeight * 0.5 + space * 0.5, right: imageWidth * 0.5)
        }
        titleEdgeInsets = labelEdgeInsets
        self.imageEdgeInsets = imageEdgeInsets
    }
}