cropToSquare.swift

    func cropToSquare(image: UIImage) -> UIImage? {
        
        if let cgImg = image.cgImage {
            let contextSize: CGSize = image.size
            var posX: CGFloat = 0
            var posY: CGFloat = 0
            var length: CGFloat = 0
            
            if contextSize.width > contextSize.height {
                posX = (contextSize.width - contextSize.height) / 2
                posY = 0
                length = contextSize.height
            } else {
                posX = 0
                posY = ((contextSize.height - contextSize.width) / 2)
                length = contextSize.width
            }
            
            let rect = CGRect(x: posX, y: posY, width: length, height: length)
            
            // Create bitmap image from context using the rect
            guard let imageRef: CGImage = cgImg.cropping(to: rect) else {
                return nil
            }
            
            // Create a new image based on the imageRef and rotate back to the original orientation
            let image = UIImage(cgImage: imageRef, scale: image.scale, orientation: image.imageOrientation)
            
            return image
            
        } else {
            // convert failure
            return nil
        }
        
    }