Swift code snippets

Swift Code snippts

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Swift:Example of fetching messages from Parse

https://gist.github.com/sandofsky/7134b1ff90d235901254

Swift: Scale down CGImage

func scaleDownCGImage(image: CGImage, scale: Float) -> CGImage!{
    var scaleDiv = UInt(1.0 / scale)
    let width = CGImageGetWidth(image) / scaleDiv
    let height = CGImageGetHeight(image) / scaleDiv
    let bitsPerComponent = CGImageGetBitsPerComponent(image)
    let bytesPerRow = CGImageGetBytesPerRow(image)
    let colorSpace = CGImageGetColorSpace(image)
    let bitmapInfo = CGImageGetBitmapInfo(image)
    let context = CGBitmapContextCreate(nil, width, height, bitsPerComponent, bytesPerRow, colorSpace, bitmapInfo)
    CGContextSetInterpolationQuality(context, kCGInterpolationMedium)
    let imgSize = CGSize(width: Int(width), height: Int(height))
    CGContextDrawImage(context, CGRect(origin: CGPointZero, size: imgSize), image)
    return CGBitmapContextCreateImage(context)
}

Swift: Convert between CGImage, CIImage and UIImage

Swift: Convert CIImage to CGImage

func convertCIImageToCGImage(inputImage: CIImage) -> CGImage! {
    let context = CIContext(options: nil)
    if context != nil {
        return context.createCGImage(inputImage, fromRect: inputImage.extent())
    }
    return nil
}

Swift: Convert CGImage to CIImage

func convertCGImageToCIImage(inputImage: CGImage) -> CIImage! {
   var ciImage = CIImage(CGImage: inputImage)
    return ciImage
}

Swift: Convert CGImage or CIImage to UIImage

UIImage(CGImage: cgImage)
UIImage(CIImage: ciImage)

Swift: Convert UIImage to CIImage

//uiImage: UIImage
//Convert to CIImage
var ciImage = CIImage(image: uiImage)

Swift: Convert UIImage to CGImage

To convert to CGImage, it requires 2 steps:

First convert to CIImage #Swift: Convert UIImage to CIImage.

Then convert to CGImage #Swift:_Convert_CIImage_to_CGImage

Swift Detect Volumn Button Press

Credit to http://stackoverflow.com/questions/28471481/swift-detect-volume-button-press

Detect volume button press, also hide volume HUD

import MediaPlayer //Only for hidding  Volume view
func listenVolumeButton(){

    let audioSession = AVAudioSession.sharedInstance()
    audioSession.setActive(true, error: nil)
    audioSession.addObserver(self, forKeyPath: "outputVolume", options: NSKeyValueObservingOptions.New, context: nil)
    //If you want to hide Volume HUD view
    var volumeView: MPVolumeView = MPVolumeView(frame: CGRectZero)
    view.addSubview(volumeView)
}

override func observeValueForKeyPath(keyPath: String, ofObject object: AnyObject,
    change: [NSObject : AnyObject], context: UnsafeMutablePointer<Void>) {
    if keyPath == "outputVolume"{
        print("got in here")
    }
}