Display any emoji on your WLED Matrix

wled_emoji.py

#!/usr/bin/env python3
"""Render an emoji on a WLED matrix via JSON API."""

import argparse
import sys
from pathlib import Path

import requests
from PIL import Image, ImageDraw, ImageFont

EMOJI_FONT_PATHS = [
    "/usr/share/fonts/noto/NotoColorEmoji.ttf",
    "/usr/share/fonts/google-noto/NotoColorEmoji.ttf",
    "/usr/share/fonts/truetype/noto/NotoColorEmoji.ttf",
    "/usr/share/fonts/noto-emoji/NotoColorEmoji.ttf",
    "/usr/share/fonts/TTF/NotoColorEmoji.ttf",
    "/System/Library/Fonts/Apple Color Emoji.ttc",
]


def find_font() -> str | None:
    for path in EMOJI_FONT_PATHS:
        if Path(path).exists():
            return path
    return None


def render_emoji(emoji: str, size: int, debug: bool = False) -> Image.Image:
    """Render an emoji to a sized RGBA image."""
    font_path = find_font()
    if font_path is None:
        print("No emoji font found.", file=sys.stderr)
        sys.exit(1)

    font = ImageFont.truetype(font_path, 109)

    # Large canvas to guarantee the emoji fits
    canvas_size = 512
    img = Image.new("RGBA", (canvas_size, canvas_size), (0, 0, 0, 0))
    draw = ImageDraw.Draw(img)
    draw.text((100, 100), emoji, font=font, embedded_color=True)

    if debug:
        debug_dir = Path("debug_emoji")
        debug_dir.mkdir(exist_ok=True)
        img.save(debug_dir / "raw.png")
        print(f"Raw canvas bbox: {img.getbbox()}", file=sys.stderr)

    bbox = img.getbbox()
    if not bbox:
        print(f"Rendering produced empty image for '{emoji}'.", file=sys.stderr)
        sys.exit(1)

    img = img.crop(bbox)

    # Pad to square to preserve aspect ratio
    w, h = img.size
    side = max(w, h)
    square = Image.new("RGBA", (side, side), (0, 0, 0, 0))
    square.paste(img, ((side - w) // 2, (side - h) // 2))
    img = square.resize((size, size), Image.LANCZOS)

    if debug:
        img.save(debug_dir / "final.png")
        print(f"Final image saved to {debug_dir / 'final.png'}", file=sys.stderr)

    return img


def image_to_wled_payload(img: Image.Image, brightness: int = 128) -> dict:
    """Convert an RGBA image to a WLED JSON API payload."""
    img = img.convert("RGBA")
    pixels = list(img.get_flattened_data())

    segment_data = []
    for r, g, b, a in pixels:
        if a < 32:
            segment_data.append("000000")
        else:
            segment_data.append(f"{r:02x}{g:02x}{b:02x}")

    return {
        "on": True,
        "bri": brightness,
        "seg": {"i": segment_data},
    }


def send_to_wled(host: str, payload: dict) -> None:
    """Send pixel data to WLED via JSON API."""
    url = f"http://{host}/json/state"
    resp = requests.post(url, json=payload, timeout=5)
    resp.raise_for_status()
    print(f"Sent to {host} — status: {resp.status_code}")


def main() -> None:
    parser = argparse.ArgumentParser(description="Display an emoji on a WLED matrix")
    parser.add_argument("host", help="WLED device IP or hostname")
    parser.add_argument("emoji", help="Emoji character to display")
    parser.add_argument(
        "-b", "--brightness", type=int, default=128, help="Brightness 0-255"
    )
    parser.add_argument(
        "-s", "--size", type=int, default=16, help="Matrix size NxN (default: 16)"
    )
    parser.add_argument(
        "--debug", action="store_true", help="Save debug images to debug_emoji/"
    )
    args = parser.parse_args()

    img = render_emoji(args.emoji, args.size, args.debug)
    payload = image_to_wled_payload(img, args.brightness)
    send_to_wled(args.host, payload)


if __name__ == "__main__":
    main()