nl_tokens: / * @see http : // www . w3 . org / TR / PNG - Chunks . html
pl_tokens: function paethPredictor ( left , up , upLeft ) { var p = left + up - upLeft , pLeft = Math . abs ( p - left ) , pUp = Math . <mask> ( p - up ) , pUpLeft = Math . abs ( p - upLeft ) ; return pLeft <= pUp && pLeft <= pUpLeft ? left : pUp <= pUpLeft ? up : upLeft ; }