Thumb::__construct PHP Method

    public function __construct($source, $params = array())
    {
        $this->source = $this->result = is_a($source, 'Media') ? $source : new Media($source);
        $this->options = array_merge(static::$defaults, $this->params($params));
        $this->destination = $this->destination();
        // don't create the thumbnail if it's not necessary
        if ($this->isObsolete()) {
            return;
        }
        // don't create the thumbnail if it exists
        if (!$this->isThere()) {
            // try to create the thumb folder if it is not there yet
            dir::make(dirname($this->destination->root));
            // check for a valid image
            if (!$this->source->exists() || $this->source->type() != 'image') {
                throw new Error('The given image is invalid', static::ERROR_INVALID_IMAGE);
            }
            // check for a valid driver
            if (!array_key_exists($this->options['driver'], static::$drivers)) {
                throw new Error('Invalid thumbnail driver', static::ERROR_INVALID_DRIVER);
            }
            // create the thumbnail
            $this->create();
            // check if creating the thumbnail failed
            if (!file_exists($this->destination->root)) {
                return;
            }
        }
        // create the result object
        $this->result = new Media($this->destination->root, $this->destination->url);
    }