Backgrounds: Introduce a script to generate small wallpapers

#!/usr/bin/env python3

import imghdr

import os

from PIL import Image

path = os.path.dirname(os.path.realpath(__file__))

resources = ["res_1080p/common/drawable-nodpi",

             "res_1080p/full/drawable-nodpi",

             "res_1440p/common/drawable-nodpi",

             "res_1440p/full/drawable-nodpi"]

def generate_smallvariants(resource):

    global path

    wallpapers_path = os.path.join(path, resource)

    clean(wallpapers_path)

    wallpapers = os.listdir(wallpapers_path)

    for wallpaper in wallpapers:

        # Test if the wallpaper is a valid jpeg file

        if imghdr.what(os.path.join(wallpapers_path, wallpaper)) != "jpeg":

            print(os.path.join(resource, wallpaper) + " is not a valid jpeg file")

            continue

        # Append _small.jpg to the wallpaper

        wallpaper_small = os.path.splitext(wallpaper)[0] + "_small.jpg"

        wallpaper_small_path = os.path.join(wallpapers_path, wallpaper_small)

        # Save the wallpaper with 1/4 size to wallpaper_small_path

        with Image.open(os.path.join(wallpapers_path, wallpaper)) as img:

            size = int(img.width / 4), int(img.height / 4)

            img_small = img.resize(size, Image.ANTIALIAS)

            img_small.save(wallpaper_small_path, "JPEG")

def clean(wallpapers_path):

    wallpapers = os.listdir(wallpapers_path)

    for wallpaper in wallpapers:

        # Get rid of existing small variants

        if wallpaper.endswith("_small.jpg"):

            os.remove(os.path.join(wallpapers_path, wallpaper))

for resource in resources:

    generate_smallvariants(resource)