Button that contains image and title. Their relative position can be modified.

ImageTitleButton.swift

//
//  ImageTitleButton.swift
//  Coyote
//
//  Created by Samuel Beek on 01/05/2017.
//  Copyright © 2017 Samuel Beek. All rights reserved.
//

import UIKit

/// Button that contains image and title. Their relative position can be modified.
class ImageTitleButton: UIButton {

    override var intrinsicContentSize: CGSize {
        var result = super.intrinsicContentSize
        switch titlePosition {
        case .top:
            fallthrough
        case .bottom:
            result.height += spacing
        case .left:
            fallthrough
        case .right:
            result.width += spacing
        default:
            break
        }

        return result

    }

    /// Relative position of the title
    public var titlePosition: UIViewContentMode = .right {
        didSet {
            updateImageInset()
        }
    }

    /// Spacing between title and image
    var spacing: CGFloat = 0 {
        didSet {
            updateImageInset()
        }
    }

    /// Updates the insets based on the relative image/title position and the spacing
    private func updateImageInset() {
        if let title = currentTitle {
            positionLabelRespectToImage(title: title, position: titlePosition, spacing: spacing)
        }
    }

    override func setImage(_ image: UIImage?, for state: UIControlState) {
        super.setImage(image, for: state)
        updateImageInset()
    }

    override func setTitle(_ title: String?, for state: UIControlState) {
        super.setTitle(title, for: state)
        updateImageInset()
    }

    /// Sets the righ position of label and image
    ///
    /// - Parameters:
    ///   - title: title to be displayed
    ///   - position: relative position of title
    ///   - spacing: spacing between title and image
    private func positionLabelRespectToImage(title: String, position: UIViewContentMode, spacing: CGFloat) {
        let imageSize = imageRect(forContentRect: frame)
        let titleFont = titleLabel?.font
        let titleSize = title.size(attributes: [NSFontAttributeName: titleFont ?? UIFont.systemFont(ofSize: 10)])

        var titleEdgeInsets: UIEdgeInsets
        var imageEdgeInsets: UIEdgeInsets

        switch position {
        case .top:
            titleEdgeInsets = UIEdgeInsets(top: -(imageSize.height + titleSize.height + spacing), left: -(imageSize.width), bottom: 0, right: 0)
            imageEdgeInsets = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: -titleSize.width)
        case .bottom:
            titleEdgeInsets = UIEdgeInsets(top: (imageSize.height + titleSize.height + spacing), left: -(imageSize.width), bottom: 0, right: 0)
            imageEdgeInsets = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: -titleSize.width)
        case .left:
            titleEdgeInsets = UIEdgeInsets(top: 0, left: -(imageSize.width * 2), bottom: 0, right: 0)
            imageEdgeInsets = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: -(titleSize.width * 2 + spacing))
        case .right:
            titleEdgeInsets = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: -spacing)
            imageEdgeInsets = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
        default:
            titleEdgeInsets = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
            imageEdgeInsets = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
        }

        self.titleEdgeInsets = titleEdgeInsets
        self.imageEdgeInsets = imageEdgeInsets
        invalidateIntrinsicContentSize()
    }
}