space-ios/iOSClient/Library/PhotoEditor/UIImage+Crop.swift

//
//  UIImage+Crop.swift
//  CropViewController
//
//  Created by Guilherme Moura on 2/26/16.
//  Copyright © 2016 Reefactor, Inc. All rights reserved.
// Credit https://github.com/sprint84/PhotoCropEditor

import UIKit

extension UIImage {
    func rotatedImageWithTransform(_ rotation: CGAffineTransform, croppedToRect rect: CGRect) -> UIImage {
        let rotatedImage = rotatedImageWithTransform(rotation)
        
        let scale = rotatedImage.scale
        let cropRect = rect.applying(CGAffineTransform(scaleX: scale, y: scale))
        
        let croppedImage = rotatedImage.cgImage?.cropping(to: cropRect)
        let image = UIImage(cgImage: croppedImage!, scale: self.scale, orientation: rotatedImage.imageOrientation)
        return image
    }
    
    fileprivate func rotatedImageWithTransform(_ transform: CGAffineTransform) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(size, true, scale)
        let context = UIGraphicsGetCurrentContext()
        context?.translateBy(x: size.width / 2.0, y: size.height / 2.0)
        context?.concatenate(transform)
        context?.translateBy(x: size.width / -2.0, y: size.height / -2.0)
        draw(in: CGRect(x: 0.0, y: 0.0, width: size.width, height: size.height))
        let rotatedImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return rotatedImage!
    }
}