Recursively compress pictures

compress-photos.py

#!/usr/bin/env python3

"""
Compresses all photos in a directory recursively.
Outputs a new directory tree instead of replacing original photos.
Tools 'djpeg', 'moz-cjpeg', and 'exiftool' must be installed.
"""

import sys
import argparse
import subprocess
import os
import shutil
import time
from os.path import join as pjoin

IS_TTY = sys.stderr.isatty()
START_TIME = time.time()
JUNK_FILES = {'.DS_Store', 'Thumbs.db'}


def main():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('-i', '--input', required=True,
        help='path to input file/directory')  # noqa: E128
    parser.add_argument('-o', '--output', required=True,
        help='path to output file/directory')  # noqa: E128

    parser.add_argument('--dry-run', action='store_true', default=False)
    parser.add_argument('--overwrite', action='store_true', default=False)
    parser.add_argument('--copy-factor', type=float, default=1.05,
        help='copy original if compressed size is within this factor of original')  # noqa: E128, E501

    parser.add_argument('--no-exif',
        action='store_false', dest='copy_exif', default=True,  # noqa: E128
        help='do not copy EXIF metadata')  # noqa: E128, E501
    parser.add_argument('--rexec', default='pamscale',
        help='resize program to use')  # noqa: E128
    parser.add_argument('--cexec', default='moz-cjpeg',
        help='compression program to use')  # noqa: E128

    parser.add_argument('--quality', type=int, default=70,
        help='compression quality')  # noqa: E128
    parser.add_argument('--resize-factor', type=float)
    parser.add_argument('--resize-filter', default='lanczos')

    args = parser.parse_args()

    stats = {'nCompressed': 0, 'nCopied': 0, 'nIgnored': 0, 'nNonImg': 0,
        'oldSize': 0.0, 'newSize': 0.0}  # noqa: E128
    compressRecursive(args.input, args.output, args, stats)
    printStats(stats)


# [compress files]=============================================================

def compressRecursive(ipath, opath, args, stats):
    if os.path.isdir(ipath):
        if args.dry_run:
            print('$ mkdir ' + opath)
        else:
            os.makedirs(opath, exist_ok=True)
        for fname in os.listdir(ipath):
            if fname not in JUNK_FILES:
                compressRecursive(pjoin(ipath, fname), pjoin(opath, fname),
                    args, stats)  # noqa: E128
    else:
        compressFile(ipath, opath, args, stats)


def chainRun(argsSeq, fpath, dryRun):
    if dryRun:
        parts = [' '.join(args) for args in argsSeq]
        cmd = ' '.join(['$', ' | '.join(parts), '>', fpath])
        print(cmd)
    else:
        stdin = None
        with open(fpath, 'wb') as fp:
            for i, args in enumerate(argsSeq):
                isFinal = (i + 1) == len(argsSeq)
                stdout = fp if isFinal else subprocess.PIPE
                proc = subprocess.Popen(args, stdin=stdin, stdout=stdout)
                # print('opened:', args, stdin, stdout)
                if stdin is not None:
                    # allow the previous process to receive a SIGPIPE
                    # if the current process exits
                    stdin.close()
                stdin = proc.stdout
                if isFinal:
                    proc.communicate()


def compressFile(ipath, opath, args, stats):
    _, ext = os.path.splitext(ipath)
    exists = os.path.exists(opath)
    is_jpg = ext.lower() in ('.jpg', '.jpeg')
    if exists and not (args.overwrite and is_jpg):
        stats['nIgnored'] += 1
        return
    if (not exists) and (not is_jpg):
        stats['nNonImg'] += 1
        if args.dry_run:
            print('cp {} {}'.format(repr(ipath), repr(opath)))
        else:
            shutil.copyfile(ipath, opath)
        return

    # compress
    argsSeq = []
    argsSeq.append(['djpeg', ipath])
    if args.resize_factor:
        argsSeq.append([args.rexec, str(args.resize_factor),
            '-filter=' + args.resize_filter])  # noqa: E128
    argsSeq.append([args.cexec, '-quality', str(args.quality)])
    chainRun(argsSeq, opath, args.dry_run)
    stats['nCompressed'] += 1

    # update sizes and copy if not enough compression
    copied = False
    if not args.dry_run:
        oldSize = os.stat(ipath).st_size
        newSize = os.stat(opath).st_size
        stats['oldSize'] += oldSize
        if oldSize <= newSize * args.copy_factor:
            shutil.copyfile(ipath, opath)
            copied = True
            stats['nCompressed'] -= 1
            stats['nCopied'] += 1
            stats['newSize'] += oldSize
        else:
            stats['newSize'] += newSize

    # copy EXIF metadata
    if not copied and args.copy_exif:
        exifArgs = ['exiftool', '-quiet', '-quiet',
            '-overwrite_original', '-TagsFromFile', ipath,  # noqa: E128
            '-Orientation#', '-DateTimeOriginal', opath]  # noqa: E128
        if args.dry_run:
            print('$ ' + ' '.join(exifArgs))
        else:
            subprocess.run(exifArgs, check=True)

    if not args.dry_run:
        printStats(stats, progressMode=True)


# [print status]===============================================================

def hsizeStr(x):
    if x >= 1e9:
        return '{:>6.2f} GB'.format(x / 1e9)
    elif x >= 1e6:
        return '{:>6.2f} MB'.format(x / 1e6)
    elif x >= 1e3:
        return '{:>6.2f} KB'.format(x / 1e3)
    else:
        return '{:>6} B'.format(x)


def timeStr(x):
    h = int(x // 3600)
    x -= h * 3600
    m = int(x // 60)
    x -= m * 60
    s = int(x)
    x -= s
    parts = []
    if h > 0:
        parts.append(str(h))
    parts.append('{:02}'.format(m))
    parts.append('{:02}'.format(s))
    return ':'.join(parts)


def printStats(stats, progressMode=False):
    if progressMode and not IS_TTY:
        return
    parts = [timeStr(time.time() - START_TIME)]
    parts.append('compressed {}'.format(stats['nCompressed']))
    if stats['nCopied'] > 0:
        parts.append('copied {}'.format(stats['nCopied']))
    if stats['nIgnored'] > 0:
        parts.append('ignored {}'.format(stats['nIgnored']))
    if stats['nNonImg'] > 0:
        parts.append('{} non-images'.format(stats['nNonImg']))
    parts.append('old size: ' + hsizeStr(stats['oldSize']))
    parts.append('new size: ' + hsizeStr(stats['newSize']))
    if progressMode:
        print(', '.join(parts), file=sys.stderr, end='\r', flush=True)
    else:
        print(', '.join(parts))


# [main]=======================================================================

if __name__ == '__main__':
    main()