UIImage+Crop.swift

import UIKit

extension UIImage {
    func fixedOrientation() -> UIImage? {
        guard imageOrientation != UIImage.Orientation.up else {
            return self
        }

        guard let cgImage = self.cgImage else {
            return nil
        }

        guard let colorSpace = cgImage.colorSpace,
             let ctx = CGContext(data: nil,
                                 width: Int(size.width),
                                 height: Int(size.height),
                                 bitsPerComponent: cgImage.bitsPerComponent,
                                 bytesPerRow: 0,
                                 space: colorSpace,
                                 bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue) else {
            return nil
        }

        var transform: CGAffineTransform = CGAffineTransform.identity

        switch imageOrientation {
        case .down, .downMirrored:
            transform = transform.translatedBy(x: size.width, y: size.height)
            transform = transform.rotated(by: CGFloat.pi)
        case .left, .leftMirrored:
            transform = transform.translatedBy(x: size.width, y: 0)
            transform = transform.rotated(by: CGFloat.pi / 2.0)
        case .right, .rightMirrored:
            transform = transform.translatedBy(x: 0, y: size.height)
            transform = transform.rotated(by: CGFloat.pi / -2.0)
        case .up, .upMirrored:
            break
        }

        switch imageOrientation {
        case .upMirrored, .downMirrored:
            transform = transform.translatedBy(x: size.width, y: 0)
            transform = transform.scaledBy(x: -1, y: 1)
        case .leftMirrored, .rightMirrored:
            transform = transform.translatedBy(x: size.height, y: 0)
            transform = transform.scaledBy(x: -1, y: 1)
        case .up, .down, .left, .right:
            break
        }

        ctx.concatenate(transform)

        switch imageOrientation {
        case .left, .leftMirrored, .right, .rightMirrored:
            ctx.draw(self.cgImage!, in: CGRect(x: 0, y: 0, width: size.height, height: size.width))
        default:
            ctx.draw(self.cgImage!, in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
        }

        guard let newCGImage = ctx.makeImage() else { return nil }
        return UIImage.init(cgImage: newCGImage, scale: 1, orientation: .up)
    }

    func crop(to size: CGSize) -> UIImage? {
        guard let image = fixedOrientation() else { return nil }
        guard let cgImage = image.cgImage else { return nil }

        let contextImage = UIImage(cgImage: cgImage)
        let contextSize = contextImage.size

        var positionX: CGFloat = 0.0
        var positionY: CGFloat = 0.0
        let cropAspect: CGFloat = size.width / size.height

        var cropWidth: CGFloat = size.width
        var cropHeight: CGFloat = size.height

        if size.width > size.height { // Landscape
            cropWidth = contextSize.width
            cropHeight = contextSize.width / cropAspect
            positionY = (contextSize.height - cropHeight) / 2
        } else if size.width < size.height { // Portrait
            cropHeight = contextSize.height
            cropWidth = contextSize.height * cropAspect
            positionX = (contextSize.width - cropWidth) / 2
        } else { // Square
            if contextSize.width >= contextSize.height { // Square on landscape (or square)
                cropHeight = contextSize.height
                cropWidth = contextSize.height * cropAspect
                positionX = (contextSize.width - cropWidth) / 2
            } else { // Square on portrait
                cropWidth = contextSize.width
                cropHeight = contextSize.width / cropAspect
                positionY = (contextSize.height - cropHeight) / 2
            }
        }

        let rect = CGRect(x: positionX, y: positionY, width: cropWidth, height: cropHeight)

        // Create bitmap image from context using the rect
        let imageRef = contextImage.cgImage!.cropping(to: rect)!

        // Create a new image based on the imageRef and rotate back to the original orientation
        let cropped = UIImage(cgImage: imageRef, scale: image.scale, orientation: image.imageOrientation)

        cropped.draw(in: CGRect(x: 0, y: 0, width: size.width, height: size.height))

        return cropped
    }
}