A script to crop a bunch of photo to match a given ratio. Requires imagemagick installed (convert) and pip install Pillow

ratio_gallery.py

import os
import sys
import subprocess
from PIL import Image

ROTATE = True
CREATE_PAIRS = True

try:
    folder = sys.argv[1]
    ratio_x = float(sys.argv[2])
    ratio_y = float(sys.argv[3])
except:
    print('Args: folder x y (ratio)')
    exit()

def call(command):
    print('  ', command)
    subprocess.call(command, shell=True)

call('mkdir -p {}/pngs'.format(folder))
call('mkdir -p {}/cropped'.format(folder))

filenames = []

for filename in os.listdir(folder):

    print(filename)
    filename_without_extension = u'.'.join(filename.split('.')[:-1])
    if not filename_without_extension:
        continue
    filenames.append(filename_without_extension)

    if os.path.exists('{}/cropped/{}.png'.format(folder, filename_without_extension)):
        print('  Already cropped, skipped')
        continue

    call('convert "{}/{}" "{}/pngs/{}.png"'.format(
        folder, filename,
        folder, filename_without_extension,
    ))

    path = '{}/pngs/{}.png'.format(folder, filename_without_extension)
    with Image.open(path) as image:
        x, y = image.size

        if (ROTATE
            and ((ratio_x > ratio_y and x < y)
                 or (ratio_x < ratio_y and x > y))):
            print('  Rotated 90deg')
            call('convert "{}" -rotate 90 "{}"'.format(path, path))
            tmp = x
            x = y
            y = tmp

        if x < y:
            # ratio_x : ratio_y <-> x : ?
            new_x = x
            new_y = new_x * (ratio_y / ratio_x)
            margin_x = 0
            margin_y = (y - new_y) / 2
        else:
            # ratio_x : ratio_y <-> ? : y
            new_y = y
            new_x = new_y * (ratio_x / ratio_y)
            margin_x = (new_x - x) / 2
            margin_y = 0
        print('  Size: ', x, y)
        print('  New size: ', new_x, new_y)
        print('  Margin: ', margin_x, margin_y)

        new_path = path.replace('/pngs/', '/cropped/')
        crop_command = 'convert "{}" -crop {}x{}+{}+{} "{}"'.format(
            path,
            int(new_x), int(new_y),
            int(margin_x), int(margin_y),
            new_path
        )
        print('  ', crop_command)
        call(crop_command)

if CREATE_PAIRS:
    print('Create pairs')
    call('mkdir -p {}/pairs'.format(folder))
    loner = None
    if len(filenames) % 2 > 0:
        loner = filenames[-1]
        filenames = filenames[:-1]
    for image1, image2 in zip(
            filenames[:int(len(filenames)/2)],
            filenames[int(len(filenames)/2):],
    ):
        with Image.open('{}/cropped/{}.png'.format(folder, image1)) as image:
            x1, y1 = image.size
        with Image.open('{}/cropped/{}.png'.format(folder, image2)) as image:
            x2, y2 = image.size
        if x1 > x2:
            call('convert \( {}/cropped/{}.png -resize {}x \) {}/cropped/{}.png +append {}/pairs/{}{}.png'.format(
                folder, image1, x2,
                folder, image2,
                folder, image1, image2,
            ))
        else:
            call('convert {}/cropped/{}.png \( {}/cropped/{}.png -resize {}x \) +append {}/pairs/{}{}.png'.format(
                folder, image1,
                folder, image2, x1,
                folder, image1, image2,
            ))
    if loner:
        print((loner,))
        call('cp {}/cropped/{}.png {}/pairs/{}.png'.format(
            folder, loner,
            folder, loner,
        ))