question: public void checkTripleBuffer ( ) { mxRectangle bounds = graph . getGraphBounds ( ) ; int width = ( int ) ( bounds . getWidth ( ) + 2 ) ; int height = ( int ) ( bounds . getHeight ( ) + 2 ) ; if ( tripleBuffer != null ) { if ( tripleBuffer . getWidth ( ) != width || tripleBuffer . getHeight ( ) != height ) { destroyTripleBuffer ( ) ; } } if ( tripleBuffer == null ) { createTripleBuffer ( width , height ) ; } }
target:  Checks if the triple buffer exists and creates a new one if it does not. Also compares the size of the buffer with the size of the graph and drops the buffer if it has a different size.