Zebra_Image::_flip PHP Method

    private function _flip($orientation)
    {
        // if image resource was successfully created
        if ($this->_create_from_source()) {
            // prepare the target image
            $target_identifier = $this->_prepare_image($this->source_width, $this->source_height, -1);
            // flip according to $orientation
            switch ($orientation) {
                case 'horizontal':
                    imagecopyresampled($target_identifier, $this->source_identifier, 0, 0, $this->source_width - 1, 0, $this->source_width, $this->source_height, -$this->source_width, $this->source_height);
                    break;
                case 'vertical':
                    imagecopyresampled($target_identifier, $this->source_identifier, 0, 0, 0, $this->source_height - 1, $this->source_width, $this->source_height, $this->source_width, -$this->source_height);
                    break;
                case 'both':
                    imagecopyresampled($target_identifier, $this->source_identifier, 0, 0, $this->source_width - 1, $this->source_height - 1, $this->source_width, $this->source_height, -$this->source_width, -$this->source_height);
                    break;
            }
            // write image
            return $this->_write_image($target_identifier);
        }
        // if script gets this far, return false
        // note that we do not set the error level as it has been already set
        // by the _create_from_source() method earlier
        return false;
    }