121 lines
3.0 KiB
Python
121 lines
3.0 KiB
Python
"""Image encoding / decoding utilities for VLM."""
|
|
|
|
from __future__ import annotations
|
|
|
|
import base64
|
|
import io
|
|
from pathlib import Path
|
|
|
|
from PIL import Image
|
|
|
|
|
|
def read_image_bytes(image: str | bytes) -> bytes:
|
|
"""Read raw image bytes from a path or return bytes unchanged.
|
|
|
|
Args:
|
|
image: File path to an image, or raw image bytes.
|
|
|
|
Returns:
|
|
bytes: Raw image bytes.
|
|
|
|
Raises:
|
|
FileNotFoundError: If image is a path and the file does not exist.
|
|
"""
|
|
if isinstance(image, bytes):
|
|
return image
|
|
path = Path(image)
|
|
if not path.is_file():
|
|
raise FileNotFoundError(f"Image file not found: {image}")
|
|
return path.read_bytes()
|
|
|
|
|
|
def detect_mime(data: bytes) -> str:
|
|
"""Infer MIME type from image magic bytes.
|
|
|
|
Args:
|
|
data: Raw image bytes (at least 8 bytes for PNG check).
|
|
|
|
Returns:
|
|
str: 'image/png', 'image/jpeg', or 'image/png' as fallback.
|
|
"""
|
|
if data[:8] == b"\x89PNG\r\n\x1a\n":
|
|
return "image/png"
|
|
if data[:3] == b"\xff\xd8\xff":
|
|
return "image/jpeg"
|
|
return "image/png"
|
|
|
|
|
|
def detect_suffix(data: bytes) -> str:
|
|
"""Infer file suffix from image magic bytes.
|
|
|
|
Args:
|
|
data: Raw image bytes.
|
|
|
|
Returns:
|
|
str: '.png', '.jpg', or '.bin' as fallback.
|
|
"""
|
|
if data[:8] == b"\x89PNG\r\n\x1a\n":
|
|
return ".png"
|
|
if data[:3] == b"\xff\xd8\xff":
|
|
return ".jpg"
|
|
return ".bin"
|
|
|
|
|
|
def image_to_mime_and_bytes(image: str | bytes) -> tuple[str, bytes]:
|
|
"""Get MIME type and raw bytes; convert to PNG if format is not PNG/JPEG.
|
|
|
|
Args:
|
|
image: File path or raw image bytes.
|
|
|
|
Returns:
|
|
tuple[str, bytes]: (mime_type, raw_bytes). Unknown formats become PNG.
|
|
"""
|
|
raw = read_image_bytes(image)
|
|
mime = detect_mime(raw)
|
|
if mime in ("image/png", "image/jpeg"):
|
|
return mime, raw
|
|
img = Image.open(io.BytesIO(raw)).convert("RGBA")
|
|
buf = io.BytesIO()
|
|
img.save(buf, format="PNG")
|
|
return "image/png", buf.getvalue()
|
|
|
|
|
|
def image_to_base64(image: str | bytes) -> tuple[str, str]:
|
|
"""Encode image to MIME type and base64 string.
|
|
|
|
Args:
|
|
image: File path or raw image bytes.
|
|
|
|
Returns:
|
|
tuple[str, str]: (mime_type, base64_encoded_string).
|
|
"""
|
|
mime, raw = image_to_mime_and_bytes(image)
|
|
return mime, base64.b64encode(raw).decode("utf-8")
|
|
|
|
|
|
def image_to_data_url(image: str | bytes) -> str:
|
|
"""Build a data URL (data:mime;base64,...) for the image.
|
|
|
|
Args:
|
|
image: File path or raw image bytes.
|
|
|
|
Returns:
|
|
str: Data URL string.
|
|
"""
|
|
mime, b64 = image_to_base64(image)
|
|
return f"data:{mime};base64,{b64}"
|
|
|
|
|
|
def mask_secret(secret: str) -> str:
|
|
"""Mask a secret for logging (e.g. show first 6 and last 4 chars).
|
|
|
|
Args:
|
|
secret: Raw secret string.
|
|
|
|
Returns:
|
|
str: Masked string (e.g. 'abcdef...ghij' or all '*' if length <= 8).
|
|
"""
|
|
if len(secret) <= 8:
|
|
return "*" * len(secret)
|
|
return f"{secret[:6]}...{secret[-4:]}"
|