UIButton subclass for having the image at different positions

DZPositionedImageButton.swift

//
//  DZPositionedImageButton.swift
//  Boppl
//
//  Created by Davide De Franceschi on 18/05/2015.
//  Copyright (c) 2015 Boppl. All rights reserved.
//

import UIKit

@IBDesignable
public class DZPositionedImageButton: UIButton {
	public enum ImagePosition: Int {
		case BottomLeft = 1, BottomCenter, BottomRight, CenterLeft, CenterRight = 6, TopLeft, TopCenter, TopRight
		
		public enum HorizontalPosition {
			case Left, Center, Right
		}
		public var horizontalPosition: HorizontalPosition {
			switch self {
			case .TopLeft, .CenterLeft, .BottomLeft: return .Left
			case .TopCenter, .BottomCenter: return .Center
			case .TopRight, .CenterRight, .BottomRight: return .Right
			}
		}
		
		public enum VerticalPosition {
			case Top, Center, Bottom
		}
		public var verticalPosition: VerticalPosition {
			switch self {
			case .TopLeft, .TopCenter, .TopRight: return .Top
			case .CenterLeft, .CenterRight: return .Center
			case .BottomLeft, .BottomCenter, .BottomRight: return .Bottom
			}
		}
	}
	public var imagePosition: ImagePosition = .CenterLeft {
		didSet { updateEdgeInsets() }
	}
	@IBInspectable public var imagePositionInteger: Int {
		get { return imagePosition.rawValue }
		set { imagePosition = ImagePosition(rawValue: newValue) ?? .CenterLeft }
	}
	
	@IBInspectable public var contentGap: CGSize = .zeroSize {
		didSet { updateEdgeInsets() }
	}
	
	private var _contentEdgeInsets: UIEdgeInsets = UIEdgeInsetsZero {
		didSet { updateEdgeInsets() }
	}
	override public var contentEdgeInsets: UIEdgeInsets {
		get { return super.contentEdgeInsets }
		set { _contentEdgeInsets = newValue }
	}
	
	private func updateEdgeInsets() {
		let initialEdgeInsets = contentEdgeInsets
		if let image = currentImage,
			label = titleLabel {
				let imageSize = image.size
				let labelSize = label.intrinsicContentSize()
				
				let horizontalMultiplier = { () -> CGFloat in
					switch self.imagePosition.horizontalPosition {
					case .Left:		return -0.5
					case .Center:	return +0.0
					case .Right:	return +0.5
					}
				}()
				let imageXOffset = +(labelSize.width * (horizontalMultiplier + 0.5) + contentGap.width * horizontalMultiplier)
				let labelXOffset = -(imageSize.width * (horizontalMultiplier + 0.5) + contentGap.width * horizontalMultiplier)
				
				let verticalMultiplier = { () -> CGFloat in
					switch self.imagePosition.verticalPosition {
					case .Top:		return -0.5
					case .Center:	return +0.0
					case .Bottom:	return +0.5
					}
				}()
				let imageYOffset = +(labelSize.height * verticalMultiplier + contentGap.height * verticalMultiplier)
				let labelYOffset = -(imageSize.height * verticalMultiplier + contentGap.height * verticalMultiplier)
				
				super.imageEdgeInsets = UIEdgeInsetsMake(imageYOffset, imageXOffset, -imageYOffset, -imageXOffset)
				super.titleEdgeInsets = UIEdgeInsetsMake(labelYOffset, labelXOffset, -labelYOffset, -labelXOffset)
				
				let contentWidthInset = { () -> CGFloat in
					switch self.imagePosition.horizontalPosition {
					case .Center: return min(imageSize.width, labelSize.width)
					default: return -self.contentGap.width
					}
				}()
				let contentHeightInset = { () -> CGFloat in
					switch self.imagePosition.verticalPosition {
					case .Center: return 0
					default: return -(min(imageSize.height, labelSize.height) + self.contentGap.height)
					}
				}()
				super.contentEdgeInsets = UIEdgeInsets(top: -contentHeightInset / 2, left: -contentWidthInset / 2, bottom: -contentHeightInset / 2, right: -contentWidthInset / 2) + _contentEdgeInsets
		}
	}
	
	required public init(coder aDecoder: NSCoder) {
		super.init(coder: aDecoder)
		_contentEdgeInsets = contentEdgeInsets
	}
}

public class DZLocalizedAttributedTitlePositionedImageButton: DZPositionedImageButton {
	override public func awakeFromNib() {
		super.awakeFromNib()
		
		if let nibAttributedNormalTitle = attributedTitleForState(.Normal) {
			setAttributedTitle(nibAttributedNormalTitle, forState: .Normal)
		}
	}
	override public func setAttributedTitle(title: NSAttributedString!, forState state: UIControlState) {
		super.setAttributedTitle(localizeAttributedStringByAttributesSections(title), forState: state)
		updateEdgeInsets()
	}
}