Glitches GIFs for https://steamcommunity.com/sharedfiles/filedetails/?id=1627692828

gif_glitcher.py

"""
Steam Long Workshop / Guide GIF Glitcher
========================================
https://github.com/notderw/
========================================

THIS SCRIPT IS EXPERIMENTAL!
If you have any issues, please leave a comment detailing any errors you are having.
If this script does not work on your GIF, try using the HEX editor method detailed
in the guide below.

Original Guide: https://steamcommunity.com/sharedfiles/filedetails/?id=1627692828

This script replaces the hex editor step in the above guide.

Requirements: Python 3.6+ (?) (Tested on 3.7.0)

TLDR steps:
1. Split your gif into 160px wide sections
2. Add 100px of extra space to the bottom of each
3. Run this script on each, Ex: 'python gif_glitcher.py <source image>'
4. Upload to Steam (see guide for specific instructions)
"""

import os, sys
import struct
import re

if len(sys.argv) < 2:
    print(f'Usage: {sys.argv[0]} <source image>')
    sys.exit(1)

infile = sys.argv[1]
outfile = os.path.splitext(infile)[0] + "_glitched.gif"

with open(infile, "rb") as infile:
    b = infile.read()

    # Get the 4 resolution bytes
    res = b[6:10]

    # Get the actual resolution pixels
    h, w = divmod(struct.unpack("<I", res)[0], 256)
    h //= 256

    print(f'Image size: {w}x{h} ({w}x{h - 100} after resize)')
    print(f'Found {len(re.findall(b[6:10], b))} resolution instances')

    # Create glitched resolution bytes
    new_res = struct.pack('<I', ((h - 100) * 256) * 256 + w)

    # Replace normal resolution bytes with glitched ones
    glitched = re.sub(b[6:10], new_res, b)

    with open(outfile, 'wb') as of:
        of.write(glitched)
        print(f'Wrote file {outfile}')