Hinzufügen einer Textebene mit weißem Hintergrund zum Bild mit gimp python-fu

Ich möchte einem Foto einen variablen Text (Dateiname) hinzufügen und den Hintergrund mit einer Farbe (weiß) füllen, damit der Text gut sichtbar ist.

Wie kann ich die bereits erstellte Textebene bequem zB Danube-Iron-Gates(c) TESTmit einem farbigen zB weißen Hintergrund füllen?

Ich verwende GIMP 2.10.2 (Windows10).

Der folgende Beispielcode führt bei zweimaliger Verwendung des Python-Plugins zum Ergebnisbild mit Text inklusive Rand, den ich hier angehängt habe. Der Code hat nur Entwicklungsstufe.

#!/usr/bin/env python

# --------------------------------------------
# Add file name box
# --------------------------------------------
# Change Log
# ============================================
# Version 0.0.1 Initial release.

import math
import os
import os.path
import sys

from array import array 
from gimpfu import *

#------------------------------
def format_pkz(sText):
    sConcatenatedText = sText + "(c) TEST"
    return sConcatenatedText

# -------------------------------------------------------------------------------------------
def add_filename_box(image, layer, use_filename, pkz1, placement):
    # set start of undo
    pdb.gimp_image_undo_group_start(image)

    # Save the current foreground color:
    pdb.gimp_context_push()

    # Set foreground and background color to default
    gimp.set_foreground(0,0,0)
    gimp.set_background(255, 255, 255)

    # use filename for pkz1
    if use_filename:
        filename = image.filename
        filename_w_ext = os.path.basename(filename)
        file_name, file_extension = os.path.splitext(filename_w_ext) 
        pkz1 = format_pkz(file_name)

        if placement == 0:      # top right
            xOffset = image.width - 630
            yOffset = 50
        elif placement == 1:    # down right
            xOffset = image.width - 630
            yOffset = image.height - 150
        elif placement == 2:    # down left
            xOffset = 50
            yOffset = image.height - 150        
        else:                   # top left
            xOffset = 50
            yOffset = 50
        # create layer with text and add it to the image: image, drawable, x, y, text, border, antialias, size, size_type, fontname
        pdb.gimp_text_fontname(image, None, xOffset, yOffset, pkz1 , 10, True, 64, PIXELS, "Verdana Bold")   

    else:                       # don't use file name
        xOffset = 50
        yOffset = 200
        # create layer with text and add it to the image: image, drawable, x, y, text, border, antialias, size, size_type, fontname
        pdb.gimp_text_fontname(image, None, xOffset, yOffset, pkz1 , 10, True, 64, PIXELS, "Verdana Bold")         

    # Restore the old foreground color:
    pdb.gimp_context_pop()
    # set end of undo
    pdb.gimp_image_undo_group_end(image)

# -----------------------------------------------------------------------------
# register the plug-in
# ----------------------------------------------------------------------------- 

register(
    "python_fu_add_filename_box",
    "My function test.",
    "My function test for developing cases.",
    "help-info.de",
    "help-info.de (c)",
    "2018-06-03",
    "<Image>/DEVELOP/Add filename box ...",
    "RGB*",
     [
            (PF_TOGGLE, "use_filename", "PKZ aus Dateinamen ableiten", 1),
            (PF_STRING, "pkz1", "User Input", "0000-0-00000"),            
            (PF_OPTION, "placement", "Placement", 3, ("top right", "down right", "down left", "top left")),         
     ],
     [],
     add_filename_box)

main()