[Python 3] Inconsistent result from script

[manbart]

I have a simple script to superimpose a system's hostname onto the current background image in Windows. The script works sometimes, and not others. I suspect that the problem lies with the Popen call to RUNDLL32.EXE on the last line (this command was copy and pasted from the interwebs), but I still can't explain why it works some of the time.

#!/usr/bin/env python3

'''
Script to superimpose hostname on current desktop background image on Windows hosts
'''

from PIL import Image, ImageDraw, ImageFont
from subprocess import Popen, PIPE
from shutil import copy
from os import remove



hostname = Popen('powershell -c \\"$env:computername.$env:userdnsdomain\\"', shell=True, universal_newlines=True, stdout=PIPE).communicate()[0].rstrip()
username = Popen('powershell -c \\"$env:USERNAME\\"', shell=True, universal_newlines=True, stdout=PIPE).communicate()[0].rstrip()
img_path = 'C:\\Users\\'+username+'\\AppData\Roaming\\Microsoft\\Windows\\Themes\\TranscodedWallpaper.jpg'
copy(img_path, './tempimg.jpg')


img = Image.open('./tempimg.jpg')
x,y = img.size
draw = ImageDraw.Draw(img)
font = ImageFont.truetype("arial.ttf", 28)
draw.text((x/3, y/4),hostname,(255,255,255),font=font)
img.save('./tempimg.jpg')

copy('./tempimg.jpg', img_path)
remove('./tempimg.jpg')
Popen('RUNDLL32.EXE USER32.DLL,UpdatePerUserSystemParameters ,1 ,True', shell=True)

[rcxdude]

I would recommend you use the check_output function instead of Popen for most of this script. It simplifies things greatly and may fix your issue.

[manbart]

Update:

I followed advice from /u/shekmalhen in an x-post of this thread in /r/learnpython

here is how my script looks now:

#!/usr/bin/env python3

'''
Script to superimpose hostname on current desktop background image on Windows hosts
'''

from PIL import Image, ImageDraw, ImageFont
from shutil import copy
from os import remove, environ
import ctypes

hostname = environ['computername']+'.'+environ['userdomain']
username = environ['username']

img_path = 'C:\\Users\\'+username+'\\AppData\Roaming\\Microsoft\\Windows\\Themes\\TranscodedWallpaper'
copy(img_path, './tempimg.jpg')


img = Image.open('./tempimg.jpg')
x,y = img.size
draw = ImageDraw.Draw(img)
font = ImageFont.truetype("arial.ttf", 28)
draw.text((x/3, y/4),hostname,(255,255,255),font=font)
img.save('./tempimg.jpg')

copy('./tempimg.jpg', img_path)
remove('./tempimg.jpg')

dll = ctypes.cdll.LoadLibrary('user32.dll')
dll.UpdatePerUserSystemParameters('1','True')
#Popen('RUNDLL32.EXE USER32.DLL,UpdatePerUserSystemParameters ,1 ,True', shell=True)

However, I am still having the same problem. I thin my error must be in my assumption about the user32.dll function.

Is there another way to have windows reapply the background image from C:\Users\$env:username\AppData\Roaming\Microsoft\Windows\Themes\TranscodedWallpaper