Divide image in array of images with swift

Question

I\'m trying to divide an image to create 16 out of it (in a matrix). I\'m using swift 2.1. Here\'s the code:

let cellSize = Int(originalImage.size.height) /          


        

Answer 1

you can split your image im two parts vertically and horizontally and sub split the result as needed:

extension UIImage {
    var topHalf: UIImage? {
        guard let cgImage = cgImage, let image = cgImage.cropping(to: CGRect(origin: .zero, size: CGSize(width: size.width, height: size.height/2))) else { return nil }
        return UIImage(cgImage: image, scale: scale, orientation: imageOrientation)
    }
    var bottomHalf: UIImage? {
        guard let cgImage = cgImage, let image = cgImage.cropping(to: CGRect(origin: CGPoint(x: 0,  y: CGFloat(Int(size.height)-Int(size.height/2))), size: CGSize(width: size.width, height: CGFloat(Int(size.height) - Int(size.height/2))))) else { return nil }
        return UIImage(cgImage: image, scale: scale, orientation: imageOrientation)
    }
    var leftHalf: UIImage? {
        guard let cgImage = cgImage, let image = cgImage.cropping(to: CGRect(origin: .zero, size: CGSize(width: size.width/2, height: size.height))) else { return nil }
        return UIImage(cgImage: image, scale: scale, orientation: imageOrientation)
    }
    var rightHalf: UIImage? {
        guard let cgImage = cgImage, let image = cgImage.cropping(to: CGRect(origin: CGPoint(x: CGFloat(Int(size.width)-Int((size.width/2))), y: 0), size: CGSize(width: CGFloat(Int(size.width)-Int((size.width/2))), height: size.height)))
            else { return nil }
        return UIImage(cgImage: image, scale: scale, orientation: imageOrientation)
    }
    var splitedInFourParts: [UIImage] {
        guard case let topHalf = topHalf,
              case let bottomHalf = bottomHalf,
            let topLeft = topHalf?.leftHalf,
            let topRight = topHalf?.rightHalf,
            let bottomLeft = bottomHalf?.leftHalf,
            let bottomRight = bottomHalf?.rightHalf else{ return [] }
        return [topLeft, topRight, bottomLeft, bottomRight]
    }
    var splitedInSixteenParts: [UIImage] {
        var array = splitedInFourParts.flatMap({$0.splitedInFourParts})
        // if you need it in reading order you need to swap some image positions
        swap(&array[2], &array[4])
        swap(&array[3], &array[5])
        swap(&array[10], &array[12])
        swap(&array[11], &array[13])
        return array
    }
}

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Splitting the image by columns and rows:

extension UIImage {
    func matrix(_ rows: Int, _ columns: Int) -> [UIImage] {
        let y = (size.height / CGFloat(rows)).rounded()
        let x = (size.width / CGFloat(columns)).rounded()
        var images: [UIImage] = []
        images.reserveCapacity(rows * columns)
        guard let cgImage = cgImage else { return [] }
        (0..

---

let myPicture = UIImage(data: try! Data(contentsOf: URL(string:"https://i.stack.imgur.com/Xs4RX.jpg")!))!

let images = myPicture.matrix(4, 4)

images.count   // 16