title: Android Camera2 API Showing Processed Preview Image
body: <p>New Camera 2 API is very different from old one.Showing the manipulated camera frames to user part of pipeline is confuses me. I know there is very good explanation on <a href="https://stackoverflow.com/questions/25462277/camera-preview-image-data-processing-with-android-l-and-camera2-api">Camera preview image data processing with Android L and Camera2 API</a> but showing frames is still not clear. My question is  what is the way of showing frames on screen which came from ImageReaders callback function after some processing while preserving efficiency and speed in Camera2 api pipeline?</p>
  
  <p>Example Flow :</p>
  
  <p>camera.add_target(imagereader.getsurface) -> on imagereaders callback do some processing -> (show that processed image on screen?)</p>
  
  <p>Workaround Idea : Sending bitmaps to imageview every time new frame processed.</p>