View source for Swift: Convert between CGImage, CIImage and UIImage

===Swift: Convert CIImage to CGImage===
<pre class="brush:swift">
func convertCIImageToCGImage(inputImage: CIImage) -> CGImage! {
    let context = CIContext(options: nil)
    if context != nil {
        return context.createCGImage(inputImage, fromRect: inputImage.extent())
    }
    return nil
}
</pre>
===Swift: Convert CGImage to CIImage===
<pre class="brush:swift">
func convertCGImageToCIImage(inputImage: CGImage) -> CIImage! {
   var ciImage = CIImage(CGImage: inputImage)
    return ciImage
}
</pre>
===Swift: Convert CGImage or CIImage to UIImage===
<pre class="brush:swift">
UIImage(CGImage: cgImage)
UIImage(CIImage: ciImage)
</pre>
===Swift: Convert UIImage to CIImage===
<pre class="brush:swift">
//uiImage: UIImage
//Convert to CIImage
var ciImage = CIImage(image: uiImage)
</pre>
===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]]