CodeIgniter水印未添加

Question

我正在尝试在上传的图像上添加水印，但是即使-> watermark（）函数返回1，也不会添加水印。

我首先将图像添加到临时文件夹中，以防用户取消该过程，这就是我要对图像加水印的地方。

到目前为止，这是我的代码：

public function upload_temp_image($file_name)
    {
        $watermarkSrc = $this->upload_model->get_watermark_src();
        if (isset($_FILES[$file_name])) {
            if (empty($_FILES[$file_name]['name'])) {
                return null;
            }
        }
        $config['upload_path'] = './uploads/temp/';
        $config['allowed_types'] = 'gif|jpg|jpeg|png';
        $config['file_name'] = 'img_temp_' . generate_unique_id();
        $this->load->library('upload', $config);

        if ($this->upload->do_upload($file_name)) {
            $data = array('upload_data' => $this->upload->data());
            if (isset($data['upload_data']['full_path'])) {
                //watermark the image
                print_r($data['upload_data']['full_path']);
                 $imgConfig = array();
                 $imgConfig['image_library'] = 'GD2';
                 $imgConfig['source_image']  = $data['upload_data']['full_path'];
                 $imgConfig['wm_type']       = 'overlay';
                 $imgConfig['wm_overlay_path'] = 'https://hackteam.co/'.$watermarkSrc;
                 $this->load->library('image_lib', $imgConfig);
                 $this->image_lib->initialize($imgConfig);
                 $this->image_lib->watermark();


                return $data['upload_data']['full_path'];
            }
            return null;
        } else {
            return null;
        }
    }

我的路径错误吗？如何调试此功能？