question: public void add ( mxRectangle rect ) { if ( rect != null ) { double minX = Math . min ( x , rect . x ) ; double minY = Math . min ( y , rect . y ) ; double maxX = Math . max ( x + width , rect . x + rect . width ) ; double maxY = Math . max ( y + height , rect . y + rect . height ) ; x = minX ; y = minY ; width = maxX - minX ; height = maxY - minY ; } }
target:  Adds the given rectangle to this rectangle.