question: public void repaintTripleBuffer ( Rectangle dirty ) { if ( tripleBuffered && tripleBufferGraphics != null ) { if ( dirty == null ) { dirty = new Rectangle ( tripleBuffer . getWidth ( ) , tripleBuffer . getHeight ( ) ) ; } mxUtils . clearRect ( tripleBufferGraphics , dirty , null ) ; tripleBufferGraphics . setClip ( dirty ) ; paintGraph ( tripleBufferGraphics , true ) ; tripleBufferGraphics . setClip ( null ) ; } }
target:  Clears and repaints the triple buffer at the given rectangle or repaints the complete buffer if no rectangle is specified.