Change/add labelInfo to "attach_metadata_obj"

Hi, i am using deepstream4.0.2
I am using gst-dsexample for custom changes in object detection.

In “attach_metadata_object” API, i can see details of “label_info”.
For addition of extra text , need to do -
g_strlcpy (label_info->result_label, “new text”, MAX_LABEL_SIZE);

Any other method to change/add the extra text information with label?
Also how can i change the label background color?

I tried to set “text_params.x_offset” etc but no result.