quangtqag

let image = UIImage(named: "images.jpeg")!

UIGraphicsBeginImageContextWithOptions(image.size, false, 1.0)
var context = UIGraphicsGetCurrentContext()

//move and invert canvas by scaling
CGContextTranslateCTM(context, 0, image.size.height)
CGContextScaleCTM(context, 1, -1)

image.drawInRect(CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height))

quangtqag

func grayScale() -> UIImage {
    let width = self.size.width
    let height = self.size.height
    let imageRect:CGRect = CGRectMake(0, 0, width, height)
    let colorSpace = CGColorSpaceCreateDeviceGray()
    
    let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.None.rawValue)
    let context = CGBitmapContextCreate(nil, Int(width), Int(height), 8, 0, colorSpace, bitmapInfo.rawValue)
    
    CGContextDrawImage(context, imageRect, self.CGImage)

quangtqag

class ViewController: UIViewController {

  override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    
    // Force view follow specific orientation
    let value = UIInterfaceOrientation.LandscapeRight.rawValue
    UIDevice.currentDevice().setValue(value, forKey: "orientation")
  }

quangtqag

func cgImageFromSampleBuffer(sampleBuffer: CMSampleBuffer) -> CGImage {
    
    let pixelBuffer : CVPixelBufferRef = CMSampleBufferGetImageBuffer(sampleBuffer)!
    let ciImage = CIImage(CVPixelBuffer: pixelBuffer)
    let context: CIContext = CIContext(options: nil)
    let rect = CGRectMake(0, 0, CGFloat(CVPixelBufferGetWidth(pixelBuffer)), CGFloat(CVPixelBufferGetHeight(pixelBuffer)))
    let cgImage = context.createCGImage(ciImage, fromRect: rect)
    
    return cgImage
  }

quangtqag

func ciImageFromSampleBuffer(sampleBuffer: CMSampleBuffer) -> CIImage {
    let pixelBuffer : CVPixelBufferRef = CMSampleBufferGetImageBuffer(sampleBuffer)!
    let attachments : CFDictionaryRef = CMCopyDictionaryOfAttachments(kCFAllocatorDefault, pixelBuffer, CMAttachmentMode( kCMAttachmentMode_ShouldPropagate))!
    let ciImage = CIImage(CVPixelBuffer: pixelBuffer, options: attachments as? [String : AnyObject])
    return ciImage
  }

quangtqag

class AWSS3Util: NSObject {

  class func uploadFileAtURL(fileURL: NSURL,
    fileName: String,
    progessCallBack: AWSNetworkingUploadProgressBlock?,
    responseCallBack: (error: NSError?) -> Void ) {
    
      let uploadRequest = AWSS3TransferManagerUploadRequest()
      uploadRequest.body = fileURL
      uploadRequest.key = fileName

quangtqag

//http://blog.apoorvmote.com/uitapgesturerecognizer-to-switch-between-two-uiviews-in-ios-swift/

var isPurpleViewShowing = false
  @IBOutlet weak var greenView: UIView!
  @IBOutlet weak var purpleView: UIView!
  
  override func viewDidLoad() {
    super.viewDidLoad()
  }

quangtqag

extension UIView {
  func removeAllConstraints() {
    var superview = self.superview
    while superview != nil {
      for c in superview!.constraints {
        if c.firstItem as? UIView == self || c.secondItem as? UIView == self {
          superview!.removeConstraint(c)
        }
      }
      superview = superview!.superview

quangtqag

  var block: dispatch_block_t?
  
  override func viewDidLoad() {
    super.viewDidLoad()    
  }
  
  override func viewDidAppear(animated: Bool) {
    block = dispatch_block_create(DISPATCH_BLOCK_INHERIT_QOS_CLASS) {
      print("I executed")
    }

quangtqag

// iOS 9 or Above
// Reference: https://www.raywenderlich.com/125718/coding-auto-layout
//
avatarView.translatesAutoresizingMaskIntoConstraints = false
avatarView.topAnchor.constraintEqualToAnchor(topLayoutGuide.bottomAnchor).active = true
avatarView.leadingAnchor.constraintEqualToAnchor(view.layoutMarginsGuide.leadingAnchor).active = true
chapterLabel.centerXAnchor.constraintEqualToAnchor(view.centerXAnchor).active = true
avatarView.bottomAnchor.constraintEqualToAnchor(chapterLabel.topAnchor,constant: -10).active = true
chapterLabel.setContentHuggingPriority(UILayoutPriorityRequired, forAxis: .Vertical)
chapterLabel.setContentCompressionResistancePriority(UILayoutPriorityRequired, forAxis: .Vertical)