Swift Sprite Animation

SpriteAnimation.swift

//
//  SpriteAnimation.swift
//
//  Created by Antonio Junior on 5/10/16.
//  Copyright © 2016 Antonio Junior. All rights reserved.
//

import UIKit


/**
 SpritAnimation simplifies the use of images sequences with UIImageView
 */
public class SpriteAnimation: UIImageView {

    
    internal var loop = false
    internal var duration: TimeInterval = 1
    
    fileprivate var images = [UIImage]()
    
    /**
    You should pass the base image name with a replacement selector to load all sequences correctly
    e.g: to assets named as "myImage1", "myImage2" ... "myImage20" you should use the constructor like that:
 
        (CGRect, imageNamed: "myImage%", relaceSelector: "%", range: 0...20)
     */
    public init(frame: CGRect, imageNamed: String, replaceSelector: String, range: CountableClosedRange<Int>, numberOfDigits: Int = 1) {
        assert(numberOfDigits > 0, "Number of digits should be higher than zero")
        super.init(frame: frame)
        
        let images = SpriteAnimation.imageRange(imageNamed, replaceSelector: replaceSelector, range: range, numberOfDigits: numberOfDigits)
        
        contentMode = .scaleAspectFill
        animationImages = images
        animationDuration = duration
    }
    
    public static func imageRange(_ imageNamed: String, replaceSelector: String, range: CountableClosedRange<Int>, numberOfDigits: Int = 1) -> [UIImage] {
        let formatter = NumberFormatter()
        formatter.minimumIntegerDigits = numberOfDigits
        var images = [UIImage]()
        
        // create images
        for i in range {
            let number = formatter.string(from: NSNumber(integerLiteral: i)) ?? String(i)
            let name = imageNamed.replacingOccurrences(of: replaceSelector, with: number)
            if let image = UIImage(named: name) {
                images.append(image)
            }
        }
        return images
    }
    
    required public init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

}