code: public function brightness( $value, $region = null )
      {
          $resource = $this->getActiveResource();
  
          if ( $value < - 255 || $value > 255 )
          {
              throw new ezcBaseValueException( 'value', $value, 'int >= -255 && int <= 255' );
          }
          
          if( $region )
          {
              $this->region( "brightnessImg", $resource, $region, null, $value );
          }
          else
          {
              $this->brightnessImg( $resource, $value );
          }
      }
docs: /* (non-PHPdoc)
  @see extension/ezie/autoloads/eziezc/interfaces/eZIEEzcConversions#brightness($value)