code: public function colorspace( $space, $region = null )
      {
          $resource = $this->getActiveResource();
  
          if ( $region )
          {
              $newResource = $this->region( null, $resource, $region, $space );
          }
          else
          {
              parent::colorspace( $space );
              return;
          }
  
          $this->setActiveResource( $newResource );
      }
docs: /* (non-PHPdoc)
  @see lib/ezc/ImageConversion/src/handlers/ezcImageGdHandler#colorspace($space)