process4leaflet.py

import os
import shutil
from PIL import Image
from collections import defaultdict

input_folder = "minimap_data"
input_dir = f"./stitched_{input_folder}"
output_dir = "./stitched4leaflet"
tile_size = 256
output_size = 512
MAX_Z = 8
MIN_Z = 0
os.makedirs(output_dir, exist_ok=True)

# Maximum tile coordinates
max_x = 0   # x in range
max_y = 0   # y in range

for file in os.listdir(input_dir):
    base = file.rsplit(".", 1)[0]   # remove extension
    _, x, y = base.split("_")
    max_x = max(max_x, int(x))
    max_y = max(max_y, int(y))

# First step is to create the leaflet folder structure and then move the most zoomed in tiles into the highest Z
# Second step is to create zoomed out leaflet folder structures and tiles
for x in range(0, max_x + 1, 1):
    for y in range(0, max_y + 1, 1):
        tile_name = f"tile_{x}_{y}.webp"
        tile_path = os.path.join(input_dir, tile_name)

        if os.path.exists(tile_path):
            os.makedirs(f"{output_dir}/{MAX_Z-1}/{x}", exist_ok=True)
            shutil.copy2(tile_path, f"{output_dir}/{MAX_Z-1}/{x}/{y}.webp")

# Skip the first Z due to it being max zoomed and that's already created as the base
for z in range(MAX_Z-1, MIN_Z, -1):
    groups = defaultdict(list)

    for x in os.listdir(f"{output_dir}/{z}"):
        for yfile in os.listdir(f"{output_dir}/{z}/{x}"):
            y = int(yfile.replace(".webp",""))
            nx, ny = int(x)//2, y//2
            groups[(nx,ny)].append(f"{output_dir}/{z}/{x}/{yfile}")

    for (nx,ny), files in groups.items():
        os.makedirs(f"{output_dir}/{z-1}/{nx}", exist_ok=True)
        canvas = Image.new("RGBA",(output_size,output_size),(0,0,0,0))

        for f in files:
            img = Image.open(f).convert("RGBA")
            px = int(f.split("/")[-2]) % 2
            py = int(f.split("/")[-1].replace(".webp","")) % 2
            canvas.paste(img,(px*tile_size,py*tile_size))

        canvas.resize((tile_size,tile_size),Image.BILINEAR)\
            .save(f"{output_dir}/{z-1}/{nx}/{ny}.webp", "WEBP", quality=82, method=6)
        print(f"Processed: {output_dir}/{z-1}/{nx}/{ny}.webp")

print("Batch processing complete.")