Convert UIImage to RGB values

uiimage2rgb.swift

    let inputCGImage = UIImage(contentsOfFile: "<filename>")!.CGImage
    let width = CGImageGetWidth(inputCGImage)
    let height = CGImageGetHeight(inputCGImage)

    let bytesPerPixel = 4
    let bytesPerRow = bytesPerPixel * width
    let bitsPerComponent = 8

    let pixels = UnsafeMutablePointer<UInt32>(calloc(height * width, sizeof(UInt32)))
    let colorSpace = CGColorSpaceCreateDeviceRGB()

    let context = CGBitmapContextCreate(pixels, width, height, bitsPerComponent, bytesPerRow, colorSpace, CGImageAlphaInfo.PremultipliedFirst.rawValue)

    CGContextDrawImage(context, CGRectMake(0, 0, CGFloat(width), CGFloat(height)), inputCGImage)

    let dataType = UnsafePointer<UInt8>(pixels)

    for j in 0 ..< height {
      for i in 0 ..< width {
        let offset = 4*((Int(width) * Int(j)) + Int(i))
        let alphaValue = dataType[offset] as UInt8
        let redColor = dataType[offset+1] as UInt8
        let greenColor = dataType[offset+2] as UInt8
        let blueColor = dataType[offset+3] as UInt8
      }
    }

    free(pixels)