code: public void floodFill(int xx, int yy, IntPredicate target, int replacement)
      {
          floodFill(xx, yy, 0, 0, width, height, target, replacement);
      }
docs: Fills area starting at xx,yy. Pixels fullfilling target are replaced with
  replacement color.
  @param xx
  @param yy
  @param target
  @param replacement