question: public Bounds windowView ( Bounds rangeBounds ) { Bounds newBounds = new Bounds ( this . start - rangeBounds . start , this . end - rangeBounds . start ) ; if ( ( newBounds . start >= rangeBounds . size ( ) ) || ( newBounds . end <= 0 ) ) { return null ; } newBounds . start = Math . max ( newBounds . start , 0 ) ; newBounds . end = Math . min ( newBounds . end , rangeBounds . size ( ) ) ; return newBounds ; }
target:  Creates a new Bounds object representing this interval relative a rangeBounds interval. --i.e: this [4,9] ; this.windowView([2,7]) == [2,7]  When this Bounds object is out of the window, windowView returns null. 