图像上传后如何在codeigniter中旋转图像

Question

我想在编辑模式下旋转图像。意思是我可以在上传后旋转图像或获取图像路径并旋转该图像。

以下代码无效

        $image_id = $_GET['id'];

        $imagedata = $this->universaladmin_model->getSingleRecords('gallery',array('image_id'=>$image_id));

        $source_image = base_url(GALLERY_UPLOAD_DIRECTORY)."/". $imagedata['imagename'];


        $config['create_thumb'] = FALSE; //No thumbnail
        $config['source_image'] = $source_image; //full path for the source image
        $config['rotation_angle'] = '90';// 

        $this->load->library('image_lib',$config);

        //Rotate the image
        $this->image_lib->rotate();