Extract preview image from Barotrauma .sub files

extract_preview.py

#!/usr/bin/env python3
import gzip, base64, xml.etree.ElementTree as ElementTree

# USAGE:
#	cd steamapps/common/Barotrauma
#	python3 extract_preview.py LocalMods/Foo/Foo.sub preview.png

# TESTED WITH SUBS GENERATED BY:
# - v0.17.12.0

def extract_preview(sub):
	"""Take a Barotrauma .sub file as input and return the binary blob of its preview image"""
	with gzip.open(sub, 'r') as f:
		tree = ElementTree.parse(f)
	root = tree.getroot()
	im_encoded = root.attrib['previewimage']
	return base64.b64decode(im_encoded)


def main(i, o):
	with open(i, 'rb') as f_in,\
	     open(o, 'wb') as f_out:
		im = extract_preview(f_in)
		f_out.write(im)

if __name__ == '__main__':
	import sys
	main(*sys.argv[1:])