# The resizeAndAddLogo.py program in this chapter works with PNG and JPEG files,
# but Pillow supports many more formats than just these two. Extend
# resizeAndAddLogo.py to process GIF and BMP images as well.
#
# Another small issue is that the program modifies PNG and JPEG files only if their
# file extensions are set in lowercase. For example, it will process zophie.png but
# not zophie.PNG. Change the code so that the file extension check is case insensitive.
#
# Finally, the logo added to the bottom-right corner is meant to be just a small mark,
# but if the image is about the same size as the logo itself, the result will look
# ugly. Modify resizeAndAddLogo.py so that the image must be at least
# twice the width and height of the logo image before the logo is pasted. Otherwise,
# it should skip adding the logo.

# The resizeAndAddLogo.py program in this chapter works with PNG and JPEG files,
# but Pillow supports many more formats than just these two. Extend
# resizeAndAddLogo.py to process GIF and BMP images as well.
#
# Another small issue is that the program modifies PNG and JPEG files only if their
# file extensions are set in lowercase. For example, it will process zophie.png but
# not zophie.PNG. Change the code so that the file extension check is case insensitive.
#
# Finally, the logo added to the bottom-right corner is meant to be just a small mark,
# but if the image is about the same size as the logo itself, the result will look
# ugly. Modify resizeAndAddLogo.py so that the image must be at least
# twice the width and height of the logo image before the logo is pasted. Otherwise,
# it should skip adding the logo.

import os
from PIL import Image

SQUARE_FIT_SIZE = 300
LOGO_FILENAME = '../catlogo.png'
EXTENSIONS = ['.png', '.jpg', '.gif', '.bmp']
FOLDER = '../'

logoIm = Image.open(LOGO_FILENAME)
logoWidth, logoHeight = logoIm.size

os.makedirs(os.path.join(FOLDER, 'withLogo'), exist_ok=True)
# Loop over all files in the working directory.
for filename in os.listdir(FOLDER):
    if not filename.endswith(tuple(EXTENSIONS)) or filename == LOGO_FILENAME:
        continue  # skip non-image files and the logo file itself

    im = Image.open(os.path.join(FOLDER, filename))
    width, height = im.size

    # Check if image needs to be resized.
    if width > SQUARE_FIT_SIZE and height > SQUARE_FIT_SIZE:
        # Calculate the new width and height to resize to.
        if width > height:
            height = int((SQUARE_FIT_SIZE / width) * height)
            width = SQUARE_FIT_SIZE
        else:
            width = int((SQUARE_FIT_SIZE / height) * width)
            height = SQUARE_FIT_SIZE

        # Resize the image.
        print('Resizing %s...' % filename)
        im = im.resize((width, height))

    # Add the logo.
    print('Adding logo to %s...\n' % filename)
    im.paste(logoIm, (width - logoWidth, height - logoHeight), logoIm)

    # Save changes.
    im.save(os.path.join(os.path.join(FOLDER, 'withLogo'), filename))

Update P1_remixResizeAndAddLogo added new extensions and process files from FOLDER