UIImage from UIImagePickerController resize + fix orientation

UIImageExt.swift

import UIKit

extension UIImage {

  // Based on http://stackoverflow.com/a/1262395/449607
  // Optimized for JPEG output
  func imageResized(longEdge : CGFloat) -> UIImage {
    func radians (degrees : Double) -> CGFloat {
      return CGFloat(degrees * M_PI/180)
    }
    
    let ratio = longEdge/max(self.size.height, self.size.width)
    let targetHeight = self.size.height * ratio
    let targetWidth = self.size.width * ratio
    
    // We need to calculate the proper transformation to make the image upright.
    // We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
    var transform = CGAffineTransformIdentity
    
    switch (self.imageOrientation) {
    case UIImageOrientation.Down, UIImageOrientation.DownMirrored:
      transform = CGAffineTransformTranslate(transform, targetWidth, targetHeight)
      transform = CGAffineTransformRotate(transform, CGFloat(M_PI))
      break;
    case UIImageOrientation.Left,UIImageOrientation.LeftMirrored:
      transform = CGAffineTransformTranslate(transform, targetWidth, 0);
      transform = CGAffineTransformRotate(transform, CGFloat(M_PI_2))
      break;
    case UIImageOrientation.Right, UIImageOrientation.RightMirrored:
      transform = CGAffineTransformTranslate(transform, 0, targetHeight);
      transform = CGAffineTransformRotate(transform, CGFloat(-M_PI_2))
      break;
    case UIImageOrientation.Up, UIImageOrientation.UpMirrored:
      break;
    }
    
    switch (self.imageOrientation) {
    case UIImageOrientation.UpMirrored, UIImageOrientation.DownMirrored:
      transform = CGAffineTransformTranslate(transform, targetWidth, 0);
      transform = CGAffineTransformScale(transform, -1, 1);
      break;
      
    case UIImageOrientation.LeftMirrored, UIImageOrientation.RightMirrored:
      transform = CGAffineTransformTranslate(transform, targetHeight, 0);
      transform = CGAffineTransformScale(transform, -1, 1);
      break;
    case UIImageOrientation.Up, UIImageOrientation.Down, UIImageOrientation.Left, UIImageOrientation.Right:
      break;
    }
    
    let ctx = CGBitmapContextCreate(
      nil, UInt(targetWidth), UInt(targetHeight),
      8, UInt(targetWidth)*4,
      CGColorSpaceCreateDeviceRGB(),
      CGBitmapInfo(rawValue: CGImageAlphaInfo.NoneSkipFirst.rawValue|CGBitmapInfo.ByteOrder32Little.rawValue)
    )
    CGContextConcatCTM(ctx, transform)
    CGContextSetBlendMode(ctx, kCGBlendModeCopy)
    CGContextSetInterpolationQuality(ctx, kCGInterpolationMedium)
    
    switch (self.imageOrientation) {
    case UIImageOrientation.Left, UIImageOrientation.LeftMirrored, UIImageOrientation.Right, UIImageOrientation.RightMirrored:
       CGContextDrawImage(ctx, CGRectMake(0,0,targetHeight,targetWidth), self.CGImage)
    default:
      CGContextDrawImage(ctx, CGRectMake(0,0,targetWidth,targetHeight), self.CGImage);
    }
    let result = CGBitmapContextCreateImage(ctx)
    return UIImage(CGImage: result)!
  }
}