void recalcDimensions(){
  final int wOld=fWidth;
  final int hOld=fHeight;
  calcDimensions();
  if (wOld != fWidth || hOld != fHeight) {
    fComponent.invalidate();
  }
}

void recalcDimensions ( ) { final int wOld = fWidth ; final int hOld = fHeight ; calcDimensions ( ) ; if ( wOld != fWidth || hOld != fHeight ) { fComponent . invalidate ( ) ; } }
calculates the dimensions . if they ' ve changed , invalidates the component
