batch resize images

resize_images.py

#!/usr/bin/env python

import os
from PIL import Image, ExifTags 
from shutil import copyfile

orientation = 0x0112            # image exif info for Orientation 274
device = 0x010f                 # image exif info for Make 271

src_dir = 'todo'

thumbnail_config = {
    'max_size': 50 * 1024,      # 50 kB
    'min_wh': 400,              # 0 measn not to resize height or width
    'min_quality': 20,          # jpg quality
    'quality_fall': 5,          # quality will decrease per step
    'bytes_quality': 220 * 1024,    # every x byte get 1 quality decrease
    'debug': True,
    'output_dir': 'todo',
}

opt_config = {
    'max_size': 2 * 1024 * 1024,    # 2 MB
    'min_wh': 1560,             # 0 measn not to resize height or width
    'min_quality': 75,          # jpg quality
    'quality_fall': 3,          # quality will decrease per step
    'bytes_quality': 1024 * 1024,   # every x byte get 1 quality decrease
    'debug': True,
    'output_dir': 'todo',
}

# config = thumbnail_config
config = opt_config

def init_exif_keys():
    global orientation
    global device
    for key in ExifTags.TAGS.keys(): 
        if ExifTags.TAGS[key] == 'Orientation': 
            orientation = key
        elif ExifTags.TAGS[key] == 'Make': 
            device = key


def resize(src_path, output_path):
    
    max_size = config['max_size']
    min_wh = config['min_wh']
    min_quality = config['min_quality']
    quality_fall = config['quality_fall']
    bytes_quality = config['bytes_quality']
    debug = config['debug']
    
    if not os.path.exists(output_path):
        os.mkdir(output_path)
    files = list(os.listdir(src_path))
    print('⬇ resize and copy {} files from {} to {}'.format(len(files), src_path, output_path))
    for file in files:
        if debug:
            print('# process file', file)
        src_file = os.path.join(src_path, file)
        src_size = os.path.getsize(src_file)
        if os.path.isdir(src_file):
            continue
        if src_file.endswith('DS_Store'):
            os.remove(src_file)
            continue
        output_file = os.path.join(output_path, file)
        img = Image.open(src_file)
        img = process_exif(img)
        if (src_size > max_size):
            min_px = min(img.size)
            if min_px > min_wh:
                scale = min_px / float(min_wh)
                w, h = int(img.width / scale), int(img.height / scale)
                img = img.resize((w, h), Image.ANTIALIAS)
            quality = int(100 - src_size / bytes_quality)
            if quality < min_quality:
                quality = min_quality
            if debug:
                print('init quality is', quality)
            img.save(output_file, optimize=True, quality=quality)
            while os.path.getsize(output_file) > max_size and quality > min_quality:
                quality -= quality_fall
                if debug:
                    print('+ adjust quality to', quality)
                img.save(output_file, optimize=True, quality=quality)
            img.close()
        else:
            copyfile(src_file, output_file)
    return len(files)

def process_exif(image):
    if hasattr(image, '_getexif') and isinstance(image._getexif(), dict):
        exif = image._getexif()
        # if device in exif and exif[device] == 'Apple': # Canon XiaoMi Apple
        if orientation in exif:
            if exif[orientation] == 3: 
                image = image.rotate(180, expand=True) 
            elif exif[orientation] == 6: 
                image = image.rotate(270, expand=True) 
            elif exif[orientation] == 8: 
                image = image.rotate(90, expand=True) 
    return image

if __name__ == '__main__':

    init_exif_keys()

    cnt = 0
    output_dir = config['output_dir']

    for file in os.listdir(src_dir):
        src_path = os.path.join(src_dir, file)
        if os.path.isdir(src_path):
            output_path = os.path.join(output_dir, file)
            cnt += resize(src_path, output_path)

    print('cnt:', cnt)