optimize_image.py

#!/usr/bin/env python3

# Copyright 2022 Megan Leet

# Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

import shutil
import subprocess
import sys
import tempfile
from collections.abc import Collection
from datetime import timedelta
from pathlib import Path
from time import perf_counter
from typing import Optional
from zipfile import ZipFile
import py7zr

from wand.exceptions import CorruptImageError, ImageError, WandRuntimeError, MissingDelegateError
from wand.image import Image  # Supports more formats than Pillow


class DidNotOptimizeException(Exception):
	pass

class OptimizationError(Exception):
	pass

def format_byte_size(b: int) -> str:
	if b > (1024 ** 3):
		return f'{b / (1024 ** 3):.3g} GiB'
	if b > (1024 ** 2):
		return f'{b / (1024 ** 2):.3g} MiB'
	if b > (1024):
		return f'{b / 1024:.3g} KiB'
	return f'{b} bytes'

def report(old_size: int, new_size: int) -> None:
	print(f'Old size = {format_byte_size(old_size)}, new size = {format_byte_size(new_size)}')
	print(f'Reduction: By {format_byte_size(old_size - new_size)}, to {new_size/old_size:.3%} of original')

def run_png_compression(path: Path, old_size: int, old_path: Optional[Path]=None, print_stuff: bool=True) -> int:
	time_started = perf_counter()

	#Since we are going to check the new size ourselves anyway, might as well suppress the messages
	temp_optipng_path = Path(tempfile.gettempdir(), path.stem + '.optipng.png')
	subprocess.check_call(['optipng', '-quiet', '-o7', '-fix', '-out', temp_optipng_path, path])
	optipng_size = temp_optipng_path.stat().st_size
	if not optipng_size:
		temp_optipng_path.unlink(missing_ok=True)
		if old_path: #if we were converting a different format, never mind the converted file we're creating
			path.unlink(missing_ok=True)
		raise OptimizationError('New size was zero somehow')
	#subprocess.check_call(['advpng', '-z4', path], stdout=subprocess.DEVNULL) #Not sure that one is worth doing actually

	new_path = temp_optipng_path
	new_size = optipng_size
	temp_pngcrush_path = Path(tempfile.gettempdir(), path.stem + '.pngcrush.png')
	try:
		subprocess.check_call(['pngcrush', '-fix', '-brute', temp_optipng_path, temp_pngcrush_path], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
		#This seems to fail a bit too often, so if that happens just stick with optipng
		pngcrush_size = temp_pngcrush_path.stat().st_size
	except FileNotFoundError:
		pngcrush_size = 0
	if not pngcrush_size:
		temp_pngcrush_path.unlink(missing_ok=True)
	else:
		temp_optipng_path.unlink(missing_ok=True)
		new_path = temp_pngcrush_path
		new_size = pngcrush_size

	if new_size >= old_size:
		temp_optipng_path.unlink(missing_ok=True)
		temp_pngcrush_path.unlink(missing_ok=True)
		if old_path:
			path.unlink(missing_ok=True)
		raise DidNotOptimizeException(f'Old size was {format_byte_size(old_size)} but new size is {format_byte_size(new_size)}')
	if print_stuff:
		print(f'Optimized {path} in {timedelta(seconds=perf_counter() - time_started)}')
		report(old_size, new_size)
	path.unlink()
	if old_path:
		old_path.unlink()
	shutil.move(new_path, path)
	return new_size

def optimize_cbz(path: Path) -> int:
	old_size = path.stat().st_size
	time_started = perf_counter()
	temp_dir = Path(tempfile.gettempdir(), path.name)
	temp_dir.mkdir()
	with ZipFile(path, 'r') as z:
		#Flatten all inner subdirectories, so we don't use extractall
		for info in z.infolist():
			basename = Path(info.filename).name
			if info.is_dir() or basename == 'Thumbs.db':
				continue
			data = z.read(info)
			temp_dir.joinpath(basename).write_bytes(data)
	files = set(temp_dir.iterdir())
	count = len(files)
	optimize_images(files, False)
	new_path = path.with_suffix('.cb7')
	with py7zr.SevenZipFile(new_path, 'w') as sevenzip:
		#Well that's just fucking annoying, writeall() writes the directory
		for f in files:
			sevenzip.write(f, f.name)
		#sevenzip.writeall(temp_dir)
	shutil.rmtree(temp_dir, ignore_errors=True)
	new_size = new_path.stat().st_size
	if new_size >= old_size:
		new_path.unlink(missing_ok=True)
		raise DidNotOptimizeException(f'Old size was {format_byte_size(old_size)} but new size is {format_byte_size(new_size)}')
	#Just want to _really_ make sure
	with py7zr.SevenZipFile(new_path, 'r') as sevenzip:
		new_count = len(sevenzip.files)
	if new_count != count:
		new_path.unlink(missing_ok=True)
		raise OptimizationError(f'Something has gone wrong! cbz had {count} images but cb7 has {new_count}')
	print(f'Optimized {path} to cb7 ({count} images) in {timedelta(seconds=perf_counter() - time_started)}')
	report(old_size, new_size)
	path.unlink(missing_ok=True)
	return new_size

def optimize_image(path: Path, print_stuff: bool=True) -> int:
	if path.is_dir():
		return optimize_images(set(path.iterdir()), print_stuff)
	if path.suffix == '.cbz':
		return optimize_cbz(path)

	old_size = path.stat().st_size
	with Image.ping(filename=path) as image:
		image_format = image.format
		if image_format in {'PSD', 'XCF', 'SVG', 'SVGZ', 'MVG', 'MSVG'}:
			raise OptimizationError(f'Not messing with {image_format} even if we could')
		if len(image.sequence) > 1:
			raise OptimizationError(f'Not messing around with animated or multiple images (format = {image_format}, length = {len(image.sequence)}, animated = {image.animation})')
	
	if image_format == 'JPEG':
		if path.suffix not in {'.jpg', '.jpeg'}:
			new_path = path.with_suffix('.jpg')
			if new_path.exists():
				raise FileExistsError(f'Actually a JPEG, but not going to clobber {new_path}')
			print(f'{path} is actually a JPEG, moving to {new_path}')
			shutil.move(path, new_path)
			path = new_path
		#--stdout does not send an image if it does not result in a smaller image
		time_started = perf_counter()
		jpegopt_proc = subprocess.run(['jpegoptim', '-q', '--stdout', path], check=True, stdout=subprocess.PIPE, stderr=subprocess.DEVNULL)
		new_image = jpegopt_proc.stdout
		if new_image:
			if print_stuff:
				print(f'Optimized {path} in {timedelta(seconds=perf_counter() - time_started)}')
				report(old_size, len(new_image))
			path.write_bytes(new_image)
			return len(new_image)
		raise DidNotOptimizeException('jpegoptim did not create a smaller image')
	if image_format == 'PNG':
		if path.suffix != '.png':
			new_path = path.with_suffix('.png')
			if new_path.exists():
				raise FileExistsError(f'Actually a PNG, but not going to clobber {new_path}')
			print(f'{path} is actually a PNG, moving to {new_path}')
			shutil.move(path, new_path)
			path = new_path
		return run_png_compression(path, old_size, print_stuff=print_stuff)

	with Image(filename=path) as image:
		with image.convert('png') as converted:
			print(f'{path} is {image_format}, converting to PNG')
			new_path = path.with_suffix('.png')
			if new_path.exists():
				raise FileExistsError(f'Not going to clobber {new_path}')
			converted.save(filename=new_path)
	return run_png_compression(new_path, old_size, path, print_stuff=print_stuff)

def _get_size(path: Path) -> int:
	return path.stat().st_size if path.is_file() else sum(_get_size(p) for p in path.iterdir())

def optimize_images(paths: Collection[Path], print_stuff: bool=True) -> int:
	time_started = perf_counter()
	total_old_size = 0
	total_new_size = 0
	count = 0
	for path in paths:
		old_size = _get_size(path)
		total_old_size += old_size
		count += 1
		try:
			new_size = optimize_image(path, print_stuff)
			if print_stuff:
				print('-' * 10)
			total_new_size += new_size
		except DidNotOptimizeException:
			total_new_size += old_size
		except (OptimizationError, FileExistsError, CorruptImageError, WandRuntimeError, ImageError, MissingDelegateError, subprocess.CalledProcessError) as ex:
			total_new_size += old_size			
			print(path, ex, file=sys.stderr)
			if print_stuff:
				print('-' * 10)
	if print_stuff and total_old_size != total_new_size:
		print(f'Optimized {count} images in {timedelta(seconds=perf_counter() - time_started)}')
		report(total_old_size, total_new_size)
		print('-' * 15)
	return total_new_size

def main() -> None:
	if len(sys.argv) == 2 and not Path(sys.argv[1]).is_dir():
		try:
			optimize_image(Path(sys.argv[1]))
		except DidNotOptimizeException:
			sys.exit(1)
		sys.exit(0)

	paths = [Path(arg) for arg in sys.argv[1:]]
	optimize_images(paths)
			
if __name__ == '__main__':
	main()