public function addPostFilter(FilterInterface $filter, $priority = 0)
    {
        $this->post_transformation->add($filter, $priority);
        return $this;
    }
public function addPostFilter(FilterInterface $filter, $priority = 0)
    {
        $this->post_transformation->add($filter, $priority);
        return $this;
    }
public function addPostFilter ( FilterInterface $ filter , $ priority = 0 ) { $ this -> post_transformation -> add ( $ filter , $ priority ) ; return $ this ; }
add a post-processing filter to be always executed

This filter will ALWAYS be executed no matter whether the image has
actually been resized or not. Usefull e.g. for Strip or Monochrome filter.

@param FilterInterface $filter
@param int $priority
@return $this
add a post - processing filter to be always executed