sclass ChessOCR_Pipeline {
  transient BufferedImage inputImage;
  new SeenAndQueue<Rect> possibleBoardPositions;
  new ChessOCR_BoardsFound boardsFound;
  ChessPieceRecognizer pieceRecognizer;
  transient ReliableSingleThread rstProcessPositions = new(r processPositions);
  
  *() {
    possibleBoardPositions.onAddedToQueue(rstProcessPositions);
  }
  
  void addPossiblePosition(Rect r) {
    possibleBoardPositions.add(r);
  }
  
  // internal
  
  void processPositions() {
    Rect r;
    while not null (r = possibleBoardPositions.popQueue()) {
      ping();
      ChessOCR_RecognizedBoard board = pieceRecognizer.recognizeBoard(clipBufferedImage(inputImage, r));
      boardsFound.add(board);
    }
  }
  
  void cleanMeUp {
    cleanUp(rstProcessPositions);
  }
}