helpers.py

from os import listdir
from os.path import isfile, join


def get_image_names(base, folder, word=None):
    """
    Return a list of image names from a directory
    named folder at base/folder by default only
    if name contains the folder name.        
    """
    word = word or folder
    contents = listdir(join(base, folder))
    image_files = [f for f in contents
                   if is_img_ext(f)
                   and word in f]
    return image_files


def is_img_ext(file_name):
    """
    Return True if file_name ends with
    one of the valid_ext extensions.
    """
    ext = file_name.split('.')[-1]
    valid_ext = ('jpg',
                 'png',
                 'jpeg',
                 'gif',
                 'tif',
                 'tga',
                 #'svg',
                 )
    return ext.lower() in valid_ext

def remove_transparency(im, bg_colour=(255, 255, 255)):
    from PIL import Image
    # Only process if image has transparency (http://stackoverflow.com/a/1963146)
    if im.mode in ('RGBA', 'LA') or (im.mode == 'P' and 'transparency' in im.info):

        # Need to convert to RGBA if LA format due to a bug in PIL (http://stackoverflow.com/a/1963146)
        alpha = im.convert('RGBA').split()[-1]

        # Create a new background image of our matt color.
        # Must be RGBA because paste requires both images have the same format
        # (http://stackoverflow.com/a/8720632  and  http://stackoverflow.com/a/9459208)
        bg = Image.new("RGBA", im.size, bg_colour + (255,))
        bg.paste(im, mask=alpha)
        return bg

    else:
        return im

make_gifs.py

#! /usr/bin/python3

from os import listdir
from os.path import isfile, join

from PIL import Image, GifImagePlugin

from helpers import get_image_names, remove_transparency

YEAR = "2021"
base_path = "/home/villares/GitHub/sketch-a-day/"
year_path = join(base_path,YEAR)
folders = listdir(year_path)


images = []
for folder in sorted(folders):
    folder_path = join(year_path, folder)
    f_images = get_image_names(year_path, folder)
    if f_images:
        img_path = join(folder_path, f_images[0])
        images.append(Image.open(img_path))
        
thumb_size = (800, 400)
n = None # degub with 5
thumbs = []
for img in images[:n]:

    if img.format == 'GIF' and img.is_animated:
        p = img.getpalette()
        img.seek(img.n_frames // 2)
        if not img.getpalette():
                im.putpalette(p)
        img = img.convert('RGBA')
        print('gif')
        
    img.thumbnail(thumb_size, Image.BICUBIC)
    img = remove_transparency(img)
    
    bg = Image.new('RGB', thumb_size, (0, 0, 0))
    print(img.size)
    iw, bw = img.size[0], bg.size[0]
    if  iw < bw:
        x = (bw - iw) // 2
    else:
        x = 0
    ih, bh = img.size[1], bg.size[1]
    if  ih < bh:
        y = (bh - ih) // 2
    else:
        y = 0     
    bg.paste(img, (x, y))
    thumbs.append(bg)

thumbs[0].save('export{}.gif'.format(YEAR),
               save_all=True, append_images=thumbs,
               optimize=True,
               duration=500,
               loop=0)