From Newsgroup: alt.privacy
Hi all,
here is a Python3 implementation of my file2png program,
available here:
https://github.com/706f6c6c7578/file2png
Hope you find it useful, when for example uploading such
images to platforms like X, which does not compress .png
images, as I have tested!
import argparse
import math
import os
import struct
from PIL import Image
import sys
def encode_file(input_stream, output_stream):
data = input_stream.read()
file_size = len(data)
pixel_count = (file_size + 8) // 3
dimension = math.ceil(math.sqrt(pixel_count))
img = Image.new('RGBA', (dimension, dimension), (0, 0, 0, 255))
pixels = img.load()
size_buf = struct.pack('<Q', file_size)
x, y = 0, 0
for i in range(0, 8, 3):
r = size_buf[i]
g = size_buf[i+1] if i+1 < 8 else 0
b = size_buf[i+2] if i+2 < 8 else 0
pixels[x, y] = (r, g, b, 255)
x += 1
if x >= dimension:
x = 0
y += 1
for i in range(0, len(data), 3):
r = data[i]
g = data[i+1] if i+1 < len(data) else 0
b = data[i+2] if i+2 < len(data) else 0
pixels[x, y] = (r, g, b, 255)
x += 1
if x >= dimension:
x = 0
y += 1
img.save(output_stream, format='PNG')
def decode_file(input_stream, output_stream):
img = Image.open(input_stream)
pixels = img.load()
width, height = img.size
size_buf = bytearray(8)
pixel_index = 0
for i in range(0, 8, 3):
x = pixel_index % width
y = pixel_index // width
r, g, b, _ = pixels[x, y]
size_buf[i] = r
if i+1 < 8:
size_buf[i+1] = g
if i+2 < 8:
size_buf[i+2] = b
pixel_index += 1
file_size = struct.unpack('<Q', size_buf)[0]
data = bytearray(file_size)
data_index = 0
start_pixel = (8 + 2) // 3
for y in range(start_pixel // width, height):
start_x = 0 if y != start_pixel // width else start_pixel % width
for x in range(start_x, width):
if data_index >= file_size:
break
r, g, b, _ = pixels[x, y]
data[data_index] = r
if data_index + 1 < file_size:
data[data_index+1] = g
if data_index + 2 < file_size:
data[data_index+2] = b
data_index += 3
output_stream.write(data[:file_size])
def main():
parser = argparse.ArgumentParser(description="file2png - Convert any file to PNG and back")
parser.add_argument("-d", action="store_true", help="decode PNG to file")
parser.add_argument("input", nargs="?", default="-", help="Input file (default: stdin)")
parser.add_argument("output", nargs="?", default="-", help="Output file (default: stdout)")
args = parser.parse_args()
input_stream = sys.stdin.buffer if args.input == "-" else open(args.input, "rb")
output_stream = sys.stdout.buffer if args.output == "-" else open(args.output, "wb")
try:
if args.d:
decode_file(input_stream, output_stream)
else:
encode_file(input_stream, output_stream)
except Exception as e:
print(f"Error: {e}", file=sys.stderr)
sys.exit(1)
finally:
if input_stream is not sys.stdin.buffer:
input_stream.close()
if output_stream is not sys.stdout.buffer:
output_stream.close()
if __name__ == "__main__":
main()
--
Regards
Stefan
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