himawari-wallpaper.py

# Use latest himawari 8 photo as wallpaper
# for Windows user

from datetime import datetime, timezone, timedelta
import requests
import ctypes
from PIL import Image, ImageDraw, ImageFont
import cv2
import numpy as np

minutes_before = 30
resolution = 1500
max_retry = 10
slices = 4

base_path = r"PATH/TO/PROJECT/DIR"
font_path = r"PATH/TO/FONT.TTF"
earth_img_path = base_path + r"\latest-earth.jpg"
wallpaper_img_path = base_path + r"\wallpaper.jpg"

utc_now = datetime.now(timezone.utc)
formatted_time = utc_now - timedelta(
    minutes=minutes_before + utc_now.minute % 10,
    seconds=utc_now.second,
)


def download_earth_img():
    for i in range(slices):
        for j in range(slices):
            url = "https://himawari8.nict.go.jp/img/D531106/{}d/550/{:04d}/{:02d}/{:02d}/{}_{}_{}.png".format(
                slices,
                formatted_time.year,
                formatted_time.month,
                formatted_time.day,
                formatted_time.strftime("%H%M%S"),
                i,
                j,
            )
            retry_cnt = 1

            while True:
                try:
                    response = requests.get(url)
                    response.raise_for_status()
                    break
                except Exception as e:
                    if retry_cnt >= max_retry:
                        print(f"max retry exceeded: {e}")
                        break
                    print(f"retrying... {retry_cnt}")
                    retry_cnt += 1

            temp_img_path = base_path + "/temp_{}_{}.png".format(i, j)

            with open(temp_img_path, "wb") as f:
                f.write(response.content)

    imgs = []
    for j in range(slices):
        for i in range(slices):
            temp_img_path = base_path + "/temp_{}_{}.png".format(i, j)
            img = cv2.imread(temp_img_path)
            imgs.append(img)

    rows = []
    for i in range(0, slices * slices, slices):
        row = np.hstack(imgs[i:i + slices])
        rows.append(row)
    earth_img = np.vstack(rows)    
    earth_img = cv2.resize(earth_img, (resolution, resolution))

    cv2.imwrite(earth_img_path, earth_img)


def color_correct(img_path, new_img_path):
    img = cv2.imread(img_path)

    def levels(img, thres):
        inBlack  = np.array([0, 0, 0], dtype=np.float32)
        inWhite  = np.array([255, 255, 255], dtype=np.float32)
        inGamma  = np.array([thres, thres, thres], dtype=np.float32)
        outBlack = np.array([0, 0, 0], dtype=np.float32)
        outWhite = np.array([255, 255, 255], dtype=np.float32)
        
        img = np.clip( (img - inBlack) / (inWhite - inBlack), 0, 255 )                            
        img = ( img ** (1/inGamma) ) *  (outWhite - outBlack) + outBlack
        img = np.clip( img, 0, 255).astype(np.uint8)

        return img

    # increase levels to 1.30
    img = levels(img, 1.30)

    # increase saturation by 15%
    img = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)
    h, s, v = cv2.split(img)
    s = cv2.add(s, 0.15)
    img = cv2.merge((h, s, v))
    img = cv2.cvtColor(img, cv2.COLOR_HSV2BGR)

    # split color into R, G, B
    b, g, r = cv2.split(img)

    new_r = 0.2 * g + 0.8 * r
    new_g = 0.33 * r + 0.66 * g
    new_b = 0.2 * r + 0.8 * b

    new_img = cv2.merge((new_b, new_g, new_r))

    # new_img = cv2.convertScaleAbs(new_img, alpha=1.0, beta=0)
    new_img = levels(new_img, 1.40)

    cv2.imwrite(new_img_path, new_img)

def generate_wallpaper():
    wallpaper = Image.new("RGB", (3840, 2160), "black")
    earth_img = Image.open(earth_img_path)
    start_x = (wallpaper.width - earth_img.width) // 2
    start_y = (wallpaper.height - earth_img.height) // 2
    wallpaper.paste(earth_img, (start_x, start_y))

    draw = ImageDraw.Draw(wallpaper)
    text = f"Last Update: {formatted_time.astimezone().strftime("%Y-%m-%d %H:%M:%S")}"
    text_width = draw.textlength(
        text, font=ImageFont.truetype(font_path, 25)
    )
    draw.text(
        ((wallpaper.width - text_width) / 2, wallpaper.height - 200),
        text,
        fill=(100, 100, 100, 100),
        font=ImageFont.truetype(font_path, 25),
    )

    wallpaper.save(wallpaper_img_path)


if __name__ == '__main__':
    download_earth_img()
    color_correct(earth_img_path, earth_img_path)
    generate_wallpaper()
    ctypes.windll.user32.SystemParametersInfoW(20, 0, wallpaper_img_path, 0)