pi features docs

image_handler.py

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+"""Status image functions — loading, alpha compositing, and WS transmission."""
+
+import json
+import logging
+from pathlib import Path
+
+from PIL import Image
+
+log = logging.getLogger(__name__)
+
+IMG_DIR = Path(__file__).parent / "assets" / "img"
+STATUS_IMG_SIZE = 120
+MONOCHROME_THRESHOLD = 120
+
+
+def load_status_image(path: Path) -> bytes:
+    """Load a PNG, convert to 1-bit 120x120 monochrome bitmap (MSB-first, black=1).
+
+    Transparent pixels are composited onto white so they don't render as black.
+    """
+    img = Image.open(path)
+
+    # Composite transparent pixels onto white background
+    if img.mode in ("RGBA", "LA", "PA"):
+        bg = Image.new("RGBA", img.size, (255, 255, 255, 255))
+        bg.paste(img, mask=img.split()[-1])
+        img = bg
+
+    img = img.convert("L")
+
+    # Resize to fit within 120x120, preserving aspect ratio
+    img.thumbnail((STATUS_IMG_SIZE, STATUS_IMG_SIZE), Image.LANCZOS)
+
+    # Paste centered onto white canvas
+    canvas = Image.new("L", (STATUS_IMG_SIZE, STATUS_IMG_SIZE), 255)
+    x_off = (STATUS_IMG_SIZE - img.width) // 2
+    y_off = (STATUS_IMG_SIZE - img.height) // 2
+    canvas.paste(img, (x_off, y_off))
+
+    # Threshold to 1-bit: black (< 128) -> 1, white -> 0
+    bw = canvas.point(lambda p: 1 if p < MONOCHROME_THRESHOLD else 0, "1")
+    raw = bw.tobytes()
+    log.info("Status image loaded: %s -> %d bytes", path.name, len(raw))
+    return raw
+
+
+async def send_status_image(ws, img_bytes: bytes):
+    """Send a status image over the WebSocket (text header + binary payload)."""
+    header = json.dumps({"type": "status_image", "width": STATUS_IMG_SIZE, "height": STATUS_IMG_SIZE})
+    await ws.send(header)
+    await ws.send(img_bytes)
+    log.info("Sent status image (%d bytes)", len(img_bytes))